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  • 51.
    Barai, Manas
    et al.
    Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore, West Bengal, India.
    Mandal, Manas Kumar
    Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore, West Bengal, India.
    Karak, Atanu
    Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore, West Bengal, India.
    Bordes, Romain
    Chemistry and Chemical Engineering, Applied Surface Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
    Patra, Anuttam
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Dalai, Sudipta
    Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore, West Bengal, India.
    Panda, Amiya Kumar
    Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore, West Bengal, India.
    Interfacial and Aggregation Behavior of Dicarboxylic Amino Acid-Based Surfactants in Combination with a Cationic Surfactant2019In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, no 47, p. 15306-15314Article in journal (Refereed)
    Abstract [en]

    The interfacial and micellization behavior of three dicarboxylic amino acid-based anionic surfactants, abbreviated as AAS (N-dodecyl derivative of -aminomalonate, -aspartate, and -glutamate) in combination with hexadecyltrimethylammonium bromide (HTAB) were investigated by surface tension, conductance, UV–vis absorption/emission spectroscopy, dynamic light scattering (DLS), and viscosity studies. Critical micelle concentration (CMC) values of the surfactant mixtures are significantly lower than the predicted values, indicating associative interaction between the components. Surface excess, limiting molecular area, surface pressure at the CMC, and Gibbs free energy indicate spontaneity of the micellization processes compared to the pure components. CMC values were also determined from the sigmoidal variation in the plot of micellar polarity and pyrene UV–vis absorption/emission intensities with surfactant concentration. The aggregation number, determined by static fluorescence quenching method, increases with decreasing mole fraction of the AAS (αAAS), where the micelles are mainly dominated by the HTAB molecules. The size of the micelle increases with decreasing αAAS, leading to the formation of larger and complex aggregates, as also supported by the viscosity studies. Micelles comprising 20–40 mol % AAS are highly viscous, in consonance with their sizes. Some of the mixed surfactant systems show unusual viscosity (shear thickening and increased viscosity with increasing temperature). Such mixed surfactant systems are considered to have potential in gel-based drug delivery and nanoparticle synthesis.

  • 52. Baxter, Douglas
    et al.
    Rodushkin, Ilya
    ALS Scandinavia AB.
    Engström, Emma
    ALS Scandinavia AB.
    Isotope abundance ratio measurements by inductively coupled plasma-sector field mass spectrometry2012In: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 27, no 8, p. 1355-1381Article in journal (Refereed)
    Abstract [en]

    This tutorial reviews fundamental aspects of isotope abundance ratio measurement by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). After a synopsis of the scope of isotope abundance ratio measurement and a summary introduction to the factors affecting precision and accuracy, attention is turned to noise sources. Detailed theory behind Poisson or counting statistics and plasma flicker noise components is given, since much of the observed imprecision can be attributed to these sources. Using single collector instruments, ion beams from different isotopes are sampled in rapid sequence, and so ratioing of the signals will be subject to fluctuations derived from intensity variations, i.e., flicker noise. It is demonstrated that flicker noise can, under specified circumstances, become the limiting factor for the attainable precision. Furthermore, the practice of partitioning dwell times, ostensibly to optimize precision based on isotopic abundances and assumed Poisson statistics, is shown to be flawed and actually requires accounting for flicker noise. In addition to random uncertainty, various offset factors may contribute to systematic error in measured isotope abundance ratios. Two of these, namely mass scale shift and spectral interferences are ameliorated using ICP-SFMS. The former is eliminated when operating under conditions providing flat-topped peaks, such that the minor drift in mass calibration typical of the technique becomes inconsequential and the intensity remains the same. Isotope abundance ratio measurements are subject to three further important offset factors. First is abundance sensitivity, which quantifies the extent of peak tailing to neighboring masses and can present a considerable source of offset. Second is mass bias, resulting from the fact that all sector field devices exhibit increasing sensitivity with ion mass, and various empirical methods used to correct for this effect are compared and contrasted. Third is detector dead time, which affects mass spectrometers equipped with ion counting systems. Although a well-understood phenomenon, all current methods for determining the dead time on the basis of experimentally measured isotope abundance ratios are likely to yield biased estimates. Finally, the capabilities of ICP-SFMS for the determination of isotope abundance ratios are placed in perspective by making a brief comparison with other techniques.

  • 53.
    Beattie, D.A.
    et al.
    Ian Wark Research Institute, University of South Australia.
    Lidström-Larsson, Margareta
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    In situ total internal reflection Raman spectroscopy of surfactant adsorption at a mineral surface2006In: Vibrational Spectroscopy, ISSN 0924-2031, E-ISSN 1873-3697, Vol. 41, no 2, p. 198-204Article in journal (Refereed)
    Abstract [en]

    We present the first attempt to characterise surfactant adsorption from solution onto a particle film using total internal reflection Raman spectroscopy. Three surfactant collectors of interest to the mineral processing industry were studied in their adsorption onto sphalerite: heptyl xanthate, 2-mercaptobenzothiazole (MBT), and O,O-dibutyldithiophosphate (DTP). All three surfactants adsorbed to the surface of the sphalerite. Adsorption of heptyl xanthate was monitored as a function of time and increasing concentration. The spectrum of heptyl xanthate indicated the presence of a small amount of dixanthogen on the surface of the sphalerite. MBT adsorption studies were complicated due to the fluorescence of the adsorbed layer. However, peaks due to the adsorbed MBT were observed on top of the fluorescent background, allowing the identification of the adsorbed species to be confirmed as the oxidised dimer species. Spectra obtained from MBT and DTP co-adsorption studies did not display the strong adsorbate layer fluorescence, indicating that the fluorescence spectrum of the adsorbed MBT is most likely affected by ring-ring interactions.

  • 54.
    Becker-Baldus, Johanna
    et al.
    University of Warwick.
    Uldry, A-C
    Webber, A.L.
    Wong, Alan
    University of Warwick.
    Smith, Merk E.
    University of Warwick.
    Joyce, S.A.
    Yeats, J.R.
    Pickard, C.J.
    Dupree, Ray
    University of Warwick.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Probing NH-O hydrogen bonding by solid-state NMR: using 15N-17O dipolar and J-couplings2009Conference paper (Refereed)
  • 55.
    Berezovsky, Vladimir
    et al.
    Department of Applied Mathematics and High-performance ComputingM.V.Lomonosov Northern (Arctic) Federal University, Arkhangelsk.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Computational study of the CO adsorption and diffusion in zeolites: validating the Reed–Ehrlich model2018In: Adsorption, ISSN 0929-5607, E-ISSN 1572-8757, Vol. 24, no 4, p. 403-413Article in journal (Refereed)
    Abstract [en]

    Molecular simulations have been employed to explore at the microscopic scale the adsorption of CO in zeolites (MFI, CHA and DDR). On the basis of classical force fields, grand canonical Monte Carlo simulations are performed to predict the adsorption properties (isotherms) of these types of zeolites up to high pressure. Subsequent careful analysis yields details the microscopic mechanism in play, along the whole adsorption process, together with a considering of the arrangements of CO in MFI at high pressure. This work also summarizes an approach which uses single component diffusion data in prediction of multicomponent diffusion.

  • 56.
    Bertilsson, Olle
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Study of leaching behavior of tin in Zinc-clinker and Mixed Oxide2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the increasing usage of Sn in different electronics, such as solders and in touchscreens, together with Boliden Rönnskärs increased intake of electronic waste as a secondaryraw material, a Zn-containing product called Zn-clinker has increasing amounts of Sn. TheZn-clinker is shipped to Boliden Zn-smelter in Odda, where the Zn-clinker is mixed in withcalcine (roasted concentrate) and leached in several steps. Since Zn-clinker is a product froma halogen removal in a clinker-furnace, the feed material (Mixed Oxide), for this furnace, wasalso investigated since there are plans to replace clinkering with soda-washing in the future.Most of the Sn ends up in the leaching residue which then is deposited in the mountaincaverns close by the Boliden Odda smelter. Boliden is studying the possibility to recoverPb/Ag and Sn content from the leaching residue and create a valuable by-product. Bystudying how the leaching of Sn behaves, together with a characterization of the materials, thefollowing question should be answered: “During which sulphuric acid leaching conditions, ofZn-clinker and Mixed Oxide, is the leaching of Sn minimized?”

    The leaching results for Zn-clinker showed that 8-10% Sn will leach out, despite changingtemperature, redox potential, time and pH. A characterization of the material with SEM-EDSand XRD-analysis was also conducted to see if Sn could be identified in any phases in thematerials. The studies provided enough evidence that Zn2SnO4 could be concluded to be themain phase in the leaching residue for Zn-clinker, a form that would not leach underconditions presented in this project. However, 8-10% of the Sn will come together with Feand when Fe leach out, so does Sn.

    The leaching results for Mixed Oxide pointed towards that different phases from them foundin Zn-clinker was present. Sn losses varied between 10-20% but raised to 47% whentemperature was changed to 80 °C during leaching. The SEM-EDS analysis showed that theidentified Sn-phases contained more Sn than in Zn-clinker and together with the leachingresults, a conclusion that Sn would mainly be found as SnO2 or SnO in the Mixed Oxide, butthere is still uncertainty about the distributions of these forms.

    Unfortunately half of the As leached out during the soda-washing for Mixed Oxide, creating aleachate with Cl, F and As that need to be taken care of. This could be challenging andpresenting a costly side-project for the route different from the Zn-clinker route used today.Another observation was that PbCO3 formed during the soda-washing, a phase that willconsume more sulphuric acid during leaching.

  • 57.
    Bhaskar, Raju G.
    et al.
    Luleå tekniska universitet.
    Subrahmanyam, T.V
    Luleå tekniska universitet.
    Sun, Z.
    Luleå tekniska universitet.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Shear-flocculation of quartz1991In: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 32, no 3-4, p. 283-294Article in journal (Refereed)
    Abstract [en]

    The present work deals with the shear-flocculation of quartz in aqueous solutions of dodecylamine chloride. The variables studied include pH, concentration of the amine, size of the coarse particles, stirring speed and time. The zeta potentials were correlated with flocculation behaviour. It was observed that particle hydrophobicity and pH were most important since the dodecylamine chloride-solution reactions are pH-and concentration-dependent.

  • 58.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Institute of Physics, Kazan Federal University, Russia.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    High CO2 absorption capacity by chemisorption at cations and anions in choline-based ionic liquids2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 46, p. 31216-31226Article in journal (Refereed)
    Abstract [en]

    The effect of CO2 absorption on the aromaticity and hydrogen bonding in ionic liquids is investigated. Five different ionic liquids with choline based cations and aprotic N-heterocyclic anions were synthesized. Purity and structures of the synthesized ionic liquids were characterized by 1H and 13C NMR spectroscopy. CO2 capture performance was studied at 20 °C and 40 °C under three different pressures (1, 3, 6 bar). The IL [N1,1,6,2OH][4-Triz] showed the highest CO2 capture capacity (28.6 wt%, 1.57 mol of CO2 per mol of the IL, 6.48 mol of CO2 per kg of the ionic liquid) at 20 °C and 1 bar. The high CO2 capture capacity of the [N1,1,6,2OH][4-Triz] IL is due to the formation of carbonic acid (–OCO2H) together with carbamate by participation of the –OH group of the [N1,1,6,2OH]+ cation in the CO2 capture process. The structure of the adduct formed by CO2 reaction with the IL [N1,1,6,2OH][4-Triz] was probed by using IR, 13C NMR and 1H–13C HMBC NMR experiments utilizing 13C labeled CO2 gas. 1H and 13C PFG NMR studies were performed before and after CO2 absorption to explore the effect of cation–anion structures on the microscopic ion dynamics in ILs. The ionic mobility was significantly increased after CO2 reaction due to lowering of aromaticity in the case of ILs with aromatic N-heterocyclic anions.

  • 59.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Insights into the Effect of CO2 Absorption on the Ionic Mobility of Ionic Liquids2016In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 18, no 41, p. 28617-28625Article in journal (Refereed)
    Abstract [en]

    We investigate a comparative effect of CO2 absorption on the ionic mobility of two choline based ionic liquids comprising two different anions such as threonine and imidazole. The synthesized ionic liquids were characterized using 1H and 13C NMR and other spectroscopic techniques. By keeping a common cation and changing the anion from threonine to imidazole both the viscosity and density reduced drastically. We found that [N1,1,6,2OH][Imi] exhibits the highest CO2 capture capacity at 20 °C of 5.27 mol of CO2 per kg of ionic liquid (1.27 mol of CO2 per mol of ionic liquid, 23.26 wt% of CO2) whereas [N1,1,6,2OH][Threo] exhibits 3.6 mol of CO2 per kg of ionic liquid (1.05 mol of CO2 per mol of ionic liquid, 15.87 wt% of CO2). The activation energy for diffusion is calculated using the Vogel-Fulcher-Tamman (VFT) equation in the form of diffusivity. It was found that the activation energy for the diffusion of [N1,1,6,2OH][Threo] is ∼10 times higher than that of [N1,1,6,2OH][Imi]. 1H diffusion NMR data revealed that the diffusivity of [N1,1,6,2OH][Imi] is increased after CO2 absorption whereas a decrease in diffusivity was observed in the case of [N1,1,6,2OH][Threo]. This anomalous behavior of [N1,1,6,2OH][Imi] was further explained by using DFT calculations.

  • 60.
    Bhattacharyya, Shubhankar
    et al.
    Synthetic Chemistry Division, Defense R and D Establishment.
    Hatua, Kaushik
    Department of Chemistry, Bengal Engineering and Science University.
    Computational insight of the mechanism of Algar-Flynn-Oyamada (AFO) reaction2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 36, p. 18702-18709Article in journal (Refereed)
    Abstract [en]

    The present DFT investigation supports a previous conclusion of Dean et al. that hydroxylation occurs without epoxide intermediate at room temperature due to a strong electrostatic interaction of peroxide ions with π electrons of CC bonds of chalcone, and 3-hydroxyflavone has been found to be the major product. The calculated activation energy difference (ΔG#) of initial enolization followed by hydroxylation or simultaneous cyclization and hydroxylation has been found to be negligible (∼4 kcal mol-1). On the other hand, epoxide formation requires significant activation energy, which is supposed to occur at high temperatures. In addition, if epoxide is formed, the ring opens by an attack of phenolic oxygen, occurring preferentially at α position via a five-member transition state due to a low activation barrier height (19.82 kcal mol-1 in the gas phase and 19.55 kcal mol-1 in ethanol) compared to that of a six-member transition state (44.41 kcal mol-1 at B3LYP in the gas phase and 38.55 kcal mol -1 in ethanol). It is also observed that the solvation study does not affect the main conclusion of the paper. These findings also support the previous observation of Dean et al. Predicted ΔG# in different DFT functionals are consistent, although the total energy is significantly different

  • 61.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Kaushik, Hatua
    Department of Chemistry, IIEST, Shibpur.
    Theoretical investigation of banert cascade reaction2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 4, article id 171075Article in journal (Refereed)
    Abstract [en]

    Computational inside of Banert cascade reaction for triazole formation is studied with B3LYP/6-31G(d,p) level of theory. The reaction proceeds mainly by SN2 initial chloride displacement rather than SN2 -type attack. Furthermore, according to the rate of reaction calculation, SN2 displacement is much faster than SN2 displacement in the order of 8. The [3,3]-sigmatropic rearrangement for the conversion of propargyl azide into triazafulvene has been proved as the rate-determining step having highest activation energy parameter. Solvent effect on total course of reaction has been found negligible. Furthermore, effects of different density functional theory functionals and functional groups on activation energies of [3,3]-sigmatropic rearrangement of propargyl azide were also studied. BHHLYP, ωB97XD, M062X and BMK calculated ∆G are consistent with B3LYP.

  • 62.
    Bhattacharyya, Shubhankar
    et al.
    Synthetic Chemistry Division, Defence R and D Establishment.
    Pathak, Uma
    Synthetic Chemistry Division, Defence R and D Establishment.
    A single-reagent-driven multistep one-pot preparation of thiazolines and 1,3-thiazines from aldoximes, nitriles, and carboxylic acids2015In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 47, no 22, p. 3553-3560, article id ss-2015-n0248-opArticle in journal (Refereed)
    Abstract [en]

    N-(ω-Bromoalkyl)dichlorothiophosphoramidates have been designed as a new class of reagent for the single-reagent-driven multistep preparation of 2-substituted thiazolines and 1,3-thiazines from ald-oximes, nitriles, or carboxylic acids. A wide range of substrates both aromatic as well as aliphatic were investigated and found suitable for the developed protocol

  • 63.
    Bhattacharyya, Shubhankar
    et al.
    Synthetic Chemistry Division, Defence R and D Establishment.
    Pathak, Uma
    Synthetic Chemistry Division, Defence R and D Establishment.
    Mathur, Sweta
    Synthetic Chemistry Division, Defence R and D Establishment.
    Vishnoi, Subodh
    Synthetic Chemistry Division, Defence R and D Establishment.
    Jain, Rajeev
    School of Studies in Chemistry, Jiwaji University.
    Selective N-alkylation of primary amines with R-NH2·HBr and alkyl bromides using a competitive deprotonation/protonation strategy2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 35, p. 18229-18233Article in journal (Refereed)
    Abstract [en]

    Monoalkylation of primary amines using amine hydrobromides and alkyl bromides has been carried out. Under controlled reaction conditions the reactant primary amine was selectively deprotonated and made available for reaction, while the newly generated secondary amine remained protonated, and did not participate in alkylation further. Reaction was carried out under mild reaction conditions and was applicable to a wide range of primary amines and alkyl bromides.

  • 64.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ether Functionalized Choline Tethered Amino Acid Ionic Liquids for Enhanced CO2 Capture2016In: A C S Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 4, no 10, p. 5441-5449Article in journal (Refereed)
    Abstract [en]

    Amino acid ionic liquids (ILs) are the most interesting and effective for CO2 capture due to their low toxicity, biodegradability and fast reactivity towards CO2. Ionic nature of amino acid ILs can raise an environmental issue if the cation counterpart becomes toxic to the aquatic ecosystems and can become potential atmospheric pollutant. In this regard, choline based ILs are known to be promising scaffolds for the development of less toxic amino acid ILs. However, the existing choline amino acid ILs are highly viscous limiting their applicability as solvents. Ether functionalized choline based amino acid ILs with novel series of less toxic green ILs were explored with reduced viscosity and high CO2 capture capacity. A simple, economic, clean and environmentally benign method was utilized for the synthesis of novel choline based amino acid ILs using a commercially available and economical starting material 2-(dimethylamino)ethanol (deanol, a human dietary food supplement). Reported ILs have low viscosity with high CO2 capture capacity (1.62 mol of CO2 /mol of IL, 4.31 mol of CO2/kg of IL, 19.02 wt.% of CO2). Mechanism of [N1,1,6,2O4][Lys]+CO2 reaction and adduct structure was proposed by means of DFT and NMR.

  • 65.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Functionalized Choline Based Amino Acid Ionic Liquids: Scope Of Bio-ILs2016Conference paper (Refereed)
  • 66.
    Bhattacharyya, Shubhankar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Thermal stability of choline based amino acid ionic liquids2018In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 266, p. 597-602Article in journal (Refereed)
    Abstract [en]

    Thermal stability of different choline based amino acid ionic liquids were studied. Both short term as well as long term thermal studies were carried out. Long term thermal studies of all ILs were carried out by isothermal TGA and short term thermal studies were measured by temperature ramped TGA. Isothermal TGA were studied at two different temperatures 100 °C and 150 °C for 500 min. Whereas, short term thermal stability represents as T2%, T5% and T10% which are the temperature at which 2%, 5% and 10% mass loss of ILs were observed. The effect of alkyl side chain on the cation, etherification of the cation as well structural variation of anion on the thermal stability of choline based ILs were investigated. It was observed that thermal characteristics of ILs towards temperature ramped TGA were different compared to isothermal TGA.

  • 67.
    Billes, Ferenc
    et al.
    Department of Physical Chemistry, Budapest University of Technology and Economics, Budapest.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Molecular geometry and vibrational spectroscopy of potassium O,O-diethyldithiophosphate2006In: Vibrational Spectroscopy, ISSN 0924-2031, E-ISSN 1873-3697, Vol. 40, no 1, p. 89-97Article in journal (Refereed)
    Abstract [en]

    The aim of this work was to build a good theoretical and experimental basis for the further study of changes in structure and spectra of the O,O-diethyldithiophosphate anion upon its adsorption on the surfaces of transition metal sulfides.Infrared and Raman spectra of potassium O,O-diethyldithiophosphate were recorded. High level quantum chemical calculations were carried out to optimize the molecular geometry of both the potassium salt and its anion. Vibrational force constants were calculated from the second derivative of the molecular energy function with respect to the Cartesian coordinates of the atoms. With the aid of the optimized geometry and the calculated vibrational force constants a normal coordinate analysis was carried out to characterize the molecular vibrational modes and to assign the vibrational frequencies.

  • 68.
    Billes, Ferenc
    et al.
    Budapest University of Technology and Economics.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mikosch, Hans
    Vienna University of Technology.
    A combined DFT and vibrational spectroscopy study of the nickel and zinc O,O-diethyldithiophosphate complexes2010In: Vibrational Spectroscopy, ISSN 0924-2031, E-ISSN 1873-3697, Vol. 53, no 2, p. 296-306Article in journal (Refereed)
    Abstract [en]

    Based on our earlier results on the theoretical and experimental study of potassium O,O-diethyldithiophosphate, the normal modes of nickel and zinc O,O-diethyldithiophoshate complexes were elucidated. Infrared and Raman spectra of these compounds were recorded. Quantum chemical calculations resulted in optimized structures, electric charge distributions, vibrational force constants, and fundamental frequencies. Normal coordinate analysis was applied to characterize the vibrational modes. Based on the results of these calculations vibrational spectra were simulated. The largest spectral differences between the two complexes appeared in vibrational modes encompassing the central part of the formula unit viz. PS2MS2P, where M is the metal atom. Namely, this central part of the Ni complex has D2h symmetry, while that of the Zn one has D2d symmetry.

  • 69.
    Billes, Ferenc
    et al.
    Department of Physical Chemistry, Budapest University of Technology and Economics, Budapest.
    Mohammed-Ziegler, Ildikó
    Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
    Mikosch, Hans
    Institute for Solid State Chemistry and Electrochemistry, Vienna University of Technology.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Vibrational spectroscopic and conformational analysis of pinosylvin2002In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 106, no 26, p. 6232-6241Article in journal (Refereed)
    Abstract [en]

    Infrared and Raman spectra of pinosylvin were recorded and the vibrational frequencies with the corresponding infrared intensities were compared with the results of ab initio calculations utilizing the DFT method with the Becke3P86 functional and the 6-31G(d) basis set. Normal coordinate analysis was carried out. The effect of the conformation of the OH groups on the distribution of net charges, molecular energy and vibrational fundamentals were analyzed. One of the OH-cis-OH-trans conformers has the lowest energy. The conformation has a strong effect on the aforementioned properties, e.g., the cis-to-trans transition generates electron repulsion toward the vinylidene group between the two benzene rings. The changes in the different properties are in good accordance with each other. For comparison, the vibrational spectra were also recorded and calculated for the parent compound, trans-stilbene.

  • 70.
    Björn, Erik
    et al.
    Department of Chemistry, Analytical Chemistry, Umeå University.
    Baxter, Douglas
    Fresh, Wolfgang
    Department of Chemistry, Analytical Chemistry, Umeå University.
    Calibration errors due to variations in peak characteristics in the measurement of transient signals by inductively coupled plasma-scanning mass spectrometry2002In: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 17, no 12, p. 1582-1588Article in journal (Refereed)
    Abstract [en]

    The impact of variations in peak characteristics on the fidelity of transient signal measurement by inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) was investigated. Specifically, the question as to whether the multi-element capabilities or the accuracy in determined analyte amounts were deteriorated compared to what has been reported previously when not considering peak variations was addressed. The peak characteristics considered were the time of the signal maximum (tpeak), the standard deviation of the assumed Gaussian input function generated by the sample introduction system (σG), and the time constant for signal decay (τ). Investigations of simulated exponentially-modified Gaussian peaks revealed that, for variations of peak characteristics within reasonable ranges, measurement noise and variations in tpeak, σG and τ all contributed to calibration uncertainty. Electrothermal vaporisation (ETV) and flow injection (FI) systems were used to experimentally generate transient signals of varying peak characteristics. Removing data points from the raw signals simulated the monitoring of up to 100 mass-to-charge ratios, allowing calibration data and analyte amounts to be determined from the processed signals. To obtain calibration graph slopes with relative standard deviations below 1% for the ETV-ICP-QMS system, it was found necessary to acquire 7-24 data points per peak for 50-5 ms dwell times. On this basis, the maximum number of mass-to-charge ratios that could be monitored in a typical ETV-ICP-QMS analysis was 4-10 using dwell times of 50-5 ms. With the FI-ICP-QMS system, variations in the peak characteristics between calibration standards and samples meant that, to obtain less than 3% error in determined analyte amounts, at least 7 or 10 points per peak were required for external and internal standardisation, respectively. It was found that variations in peak characteristics contributed more than measurement noise to the error in determined analyte amounts. In recent studies it has been reported that 3-4 data points per peak are sufficient to accurately monitor a transient if peak variations are not considered, which, for typical ETV signals, would allow the monitoring of 20 mass-to-charge ratios during a single measurement cycle. Thus the results obtained here show that the multi-element capability of ICP-QMS when monitoring transient signals can be severely compromised by such variations

  • 71.
    Blochin, Dimri S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Aganova, Oksana V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Yulmetov, Aidar R.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Gizatulin, Bulat L.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Afonin, Sergii
    Karlsruhe Institute of Technology.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of heptapeptide Glu-Ile-Leu-Asn-His-Met-Lys, a fragment of the HIV enhancer prostatic acid phosphatase, in aqueous and SDS micelle solutions2013In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1033, p. 59-66Article in journal (Refereed)
    Abstract [en]

    Prostatic acid phosphatase (PAP) is a protein abundantly present in human seminal fluid. PAP plays important role in fertilization. Its 39-amino-acid fragment, PAP(248-286), is effective in enhancing infectivity of HIV virus. In this work, we determined the spatial structure in aqueous solution of a heptapeptide within the PAP fragment, containing amino acid residues 266-272 (Glu-Ile-Leu-Asn-His-Met-Lys). We also report the structure of the complex formed by this heptapeptide with sodium dodecyl sulfate micelles, a model of a biological membrane, as determined by 1H NMR spectroscopy and 2D NMR (TOCSY, HSQC-HECADE, NOESY) spectroscopy. Complex formation was confirmed by chemical shift alterations in the 1H NMR spectra of the heptapeptide, as well as by the signs and values of NOE effects. We also present a comparison of the spatial structure of Glu-Ile-Leu-Asn-His-Met-Lys in water and in complex with sodium dodecyl sulfate

  • 72.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Fayzullina, Adeliya R.
    Chemistry Institute, Kazan Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University, Chemistry Institute, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of fibrinopeptide B in water solution with DPC micelles by NMR spectroscopy2015In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1102, p. 91-94Article in journal (Refereed)
    Abstract [en]

    Fibrinopeptide B (GluFib) is one of the factors of thrombosis. Normal blood protein soluble, fibrinogen (fibrinopeptide A and fibrinopeptide B), is transformed into the insoluble, fibrin, which in the form of filaments adheres to the vessel wall at the site of injury, forming a grid. However, the spatial structure of this peptide has not been established till now. In this article, GluFib peptide is investigated together with dodecylphosphocholine (DPC) micelles which were used for mimicking the environment of peptide in blood vessels. The spatial structure was obtained by applying 1D and 2D 1H-1H NMR spectroscopy (TOCSY, NOESY). It was shown that the fibrinopeptide B does not have a secondary structure but we can distinguish the fragment Gly 9 – Arg 14 with a good convergence (the backbone RMSD for the Gly9 – Arg14 is 0.18 ± 0.08 Å).

  • 73.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Afonin, Sergei
    Karlsruhe Institute of Technology.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial Structures of PAP(262–270) and PAP(274–284), Two Selected Fragments of PAP(248–286), an Enhancer of HIV Infectivity2015In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 46, no 7, p. 757-769Article in journal (Refereed)
    Abstract [en]

    Prostatic acid phosphatase (PAP) assembles into amyloid fibrils that facilitate infection by HIV. Its peptide fragments PAP(248–286) and PAP(85–120) also enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. The secondary structure of monomeric PAP(248–286) in a biomembrane-mimicking environment can be separated into an N-terminal unordered region, an α-helical central domain, and an α/310-helical C-terminal section (Nanga et al., J. Am. Chem. Soc., 131:17972–17979, 2009). In this work, we used two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy techniques to study spatial structures of isolated central [PAP(262–270)] and C-terminal [PAP(274–284)] fragments of PAP(248–286) in SDS micelle solutions. NMR studies revealed the formation of complexes of both peptides with SDS micelles, with attraction to the micelle membranes occurring mainly through nonpolar and uncharged residues of the peptides. We demonstrate that, when interacting with SDS micelles, PAP(262–270) and PAP(274–284) form α-helical and 310-helical secondary structures, respectively, similar to that found previously for the 39-residue PAP(248–286).

  • 74.
    Blokhin, Dimitry S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Karataeva, Farida Kh.
    Alexander Butlerov Institute of Chemistry, Kazan Federal University.
    Klochkov, Vladimir V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of oligopeptide PAP(248-261), the N-terminal fragment of the HIV enhancer prostatic acid phosphatase peptide PAP(248-286), in aqueous and SDS micelle solutions2014In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1070, p. 38-42Article in journal (Refereed)
    Abstract [en]

    Prostatic acid phosphatase (PAP) is an enzyme that facilitates infection of cells by HIV. Its peptide fragment PAP(248-286) forms amyloid fibrils known as SEVI, which enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. The secondary structure of PAP(248-286) in aqueous and SDS solutions can be divided into an N-terminal disordered region, an -helical central part and an /310-helical C-terminal region (R.P.R. Nanga et al., JACS, 2009, 131, 17972). In this work, we used NMR spectroscopy to study the spatial structure of the isolated N-terminal fragment of PAP(248-286), PAP(248-261) (GIHKQKEKSRLQGG), in aqueous and SDS micelle solutions. Formation of a PAP(248-261)-SDS complex was confirmed by chemical shift alterations in the 1H NMR spectra of the peptide, as well as by the signs and values of Nuclear Overhauser Effect (NOE). In addition, the PAP(248-261) peptide does not form any specified secondary structure in either aqueous or SDS solutions.

  • 75.
    Blokhin, D.S.
    et al.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Efimov, S.V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Klochkov, A.V.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Yulmetov, A.R.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Aganov, A.G.
    Institute of Physics, Kazan (Volga Region) Federal University.
    Klochkov, V.V:
    Institute of Physics, Kazan (Volga Region) Federal University.
    Spatial structure of the decapeptide Val-Ile-Lys-Lys-Ser-Thr-Ala-Leu-Leu-Gly in water and in a complex with sodium dodecyl sulfate micelles2011In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 41, no 2-4, p. 267-282Article in journal (Refereed)
    Abstract [en]

    We have studied the spatial structure of the decapeptide Val-Ile-Lys-Lys-Ser-Thr-Ala-Leu-Leu-Gly in aqueous solution and in a complex with sodium dodecyl sulfate (SDS) micelles by 1H nuclear magnetic resonance (NMR) spectroscopy and two-dimensional (2-D) NMR spectroscopy (total correlation spectroscopy and nuclear Overhauser effect spectroscopy (NOESY)). The approach used to determine the decapeptide spatial structure was based on analysis of the 1H–13C residual dipolar couplings in the molecules partially aligned in lyotropic liquid crystalline media. Analysis of the interproton distances obtained from the 2-D NOESY NMR spectrum was used to reveal the spatial structure of the decapeptide in a complex with SDS micelles. Complex formation was confirmed by analysis of 1H chemical shifts in the NMR spectrum of the decapeptide and analysis of the signs and values of NOEs in a solution with SDS micelles.

  • 76.
    Bo, Qi-Bing
    et al.
    Institute of Chemistry and Chemical Engineering, University of Jinan.
    Sun, Zhong-Xi
    Institute of Chemistry and Chemical Engineering, University of Jinan.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    A new family of 3D 3d-4f heterometallic frameworks comprising 1D inorganic lanthanide ladders and organic Cu-bipyridine chains2008In: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 10, no 2, p. 232-238Article in journal (Refereed)
    Abstract [en]

    A new family of the 3D heterometallic coordination polymers [{Ln2(SO4)2(H2O)2(pydc)2Cu2 (bpy)2·2(H2O)}]n (Ln = Sm ( 1), Eu ( 2), Gd ( 3), Tb ( 4) and Dy ( 5); pydc = 2,6-pyridine-dicarboxylate anion; bpy= 4,4-bipyridine) have successfully been synthesized under solvothermal conditions (H2O/ethanol). All the coordination polymers obtained were characterized by elemental analysis, FT-IR analysis, differential thermal analysis/thermogravimetry (DTA/TG), fluorescent spectra and single crystal X-ray diffraction analysis. The most intriguing structural feature is that all the compounds exhibit 3D frameworks with 1D inorganic lanthanide ladders and organic CuI-bipyridine chains, which represent two types of 3d/4f coordination polymers (form I: Ln = Sm and Eu; form II: Ln = Gd, Tb and Dy) as the result of a so-called gadolinium break effect. Additionally, compounds 2 and 4 showed the characteristic emission spectra of the EuIII and TbIII ions, respectively, and appeared to have good fluorescence properties, while 1, 3 and 5 emitted fluorescence resembling CuI complexes. To our knowledge, the investigation of the

  • 77.
    Bradley, Jonathan P.
    et al.
    Department of Physics, Warwick University, Coventry.
    Velaga, Sitaram
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Brown, Steven P.
    Department of Physics, Warwick University, Coventry.
    Probing intermolecular crystal packing in gamma-indomethacin by high-resolution 1H solid-state NMR spectroscopy2011In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 11, no 8, p. 3463-3471Article in journal (Refereed)
    Abstract [en]

    An NMR crystallography approach that combines experimental solid-state magic-angle-spinning (MAS) NMR with calculation is applied to the gamma polymorph of the pharmaceutical molecule, indomethacin. First-principles calculations (GIPAW) for the full crystal structure and an isolated molecule show changes in the (1)H chemical shift for specific aliphatic and aromatic protons of over -1 ppm that are due to intermolecular CH-pi interactions. For the OH proton, (1)H double-quantum (DQ) CRAMPS (combined rotation and multiple-pulse spectroscopy) spectra reveal intermolecular H-H proximities to the OH proton of the carboxylic acid dimer as well as to specific aromatic CH protons. The enhanced resolution in (1)H DQ-(13)C spectra, recorded at 850 MHz, enables separate (1)H DQ build-up curves (as a function of the DQ recoupling time) to be extracted for the aromatic CH protons. Supported by eight-spin density-matrix simulations, it is shown how the relative maximum intensities and rates of build-up provide quantitative insight into intramolecular and intermolecular H-H proximities that characterize the crystal packing

  • 78.
    Bredyuk, O. A.
    et al.
    Russian Adademy of Sciences.
    Gerasimenko, A. V.
    Russian Adademy of Sciences.
    Lutsenko, I. A.
    Russian Adademy of Sciences.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Forsling, Willis
    Structural organization of cadmium(II) and copper(II) dithiocarbamate complexes with dialkyl-substituted and cyclic ligands: Synthesis, single-crystal X-ray diffraction, EPR, and CP/MAS13C, 15N, and 113Cd NMR2005In: Russian Journal of Inorganic Chemistry, ISSN 0036-0236, E-ISSN 1531-8613, Vol. 50, no 11, p. 1710-1726Article in journal (Refereed)
    Abstract [en]

    A comparative study of polynuclear thallium complexes with dialkyldithiocarbamates [Tl2{S2CNR2} 2]n (R = CH3, i-C3H7, C4H9, and i-C4H9; R2 = (CH2)6) was performed by solid-state 13C and 15N CP/MAS NMR spectroscopy. The dithiocarbamate groups were found to be structurally equivalent in the complexes studied. An increase in the positive inductive effect of alkyl substituents at the N atom increased 15N chemical shifts as a result of a combination of positive inductive effect of the alkyl substituents and the mesomeric effect of =NC(S)S-groups. The first representative of thallium(I) complexes with a cyclic dithiocarbamate ligand [Tl2{S2CN(CH2) 6}2]n was obtained. Its molecular structure was determined from X-ray diffraction data. The β-form of the isotope-substituted complex [63/65CuTl2{S 2CN(CH2)6}4] was obtained and examined by EPR spectroscopy. The EPR spectra were modeled at the second order of the perturbation theory. The spin density at the thallium atoms was calculated and its distribution over the AOs of thallium was determined.

  • 79.
    Bredyuk, O.A.
    et al.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Loseva, Olga V.
    Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences.
    Ivanov, Alexander V.
    Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences .
    Gowda, Vasantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. University of Oulu.
    Antzutkin, Oleg N.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Warwick University, Coventry.
    Three-Dimensional Polymeric Thallium(I) Morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2]n and Its Capability of Binding Gold(III) from Solutions: Chemisorption Synthesis of a Heteronuclear Gold(III)–Thallium(III) Complex of the Ionic Type, ([Au{S2CN(CH2)4O}2][TlCl4])n, the Role of Secondary Interactions Tl…O, Tl…S, and Au…S in the Supramolecular Self-Organization, 13C MAS NMR, and Thermal Behavior2017In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 43, no 10, p. 638-651Article in journal (Refereed)
    Abstract [en]

    Crystalline polymeric thallium(I) morpholinedithiocarbamate [Tl2{S2CN(CH2)4O}2]n (I) and the heteronuclear ion–polymeric gold(III)–thalium(III) complex ([Au{S2CN(CH2)4O}2][TlCl4])n (II) are preparatively isolated and characterized by X-ray diffraction analysis and 13C MAS NMR spectroscopy. According to the X-ray diffraction data, the main structural units of compounds I and II (CIF files CCDC 1548079 and 1548080) are presented by the binuclear centrosymmetric molecule [Tl2{S2CN(CH2)4O}2], noncentrosymmetric complex cation [Au{S2CN(CH2)4O{2]+, and isomeric complex anions [TlCl4]. The formation of the three-dimensional polymeric structure (coordination number of Tl is 7), which is not characteristic of thallium(I) dithiocarbamates, is a consequence of the participation of the secondary Tl…O and Tl…S bonds of two types in the supramolecular self-organization of compound I. Nonequivalent secondary interactions of the first type join the binuclear molecules [Tl2{S2CN(CH2)4O}2] into polymer layers, which, in turn, form the three-dimensional polymeric framework due to the secondary bonds Tl…S. The revealed ability of freshly precipitated compound I to the chemisorption of gold(III) from solutions (2 M HCl) makes it possible to obtain heteronuclear supramolecular complex II as an individual form of binding. In the structure of the latter, the pairs of stronger secondary Au…S bonds join the gold(III) cations into dimers [Au2{S2CN(CH2)4O}4]2+ of the angular structure, the structural ordering of which is achieved in the cationcationic polymeric chain ([Au2{S2CN(CH2)4O}4]2+)n of the helical type involving the pairs of less strong Au…S bonds between the adjacent binuclear units. The distorted tetrahedral anions [TlCl4] are localized between the polymeric chains. The study of the thermal behavior of compounds I and II by simultaneous thermal analysis makes it possible to establish the character of thermal transformations of the substances and to identify Tl2S (I), TlCl, and elemental gold (II) as thermolysis products

  • 80.
    Butakov, Anatoly
    et al.
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Institute of Physics, Kazan Federal University, Kazan, Russian Federation.
    Gimatdinov, Roustam
    Medical and Biological Physics, Kazan Medical University, Kazan, Russian Federation.
    Chernov, Vladimir
    Radiophysics and Electronics, Chelyabinsk State University, Chelyabinsk, Russian Federation.
    Peculiarities of NMR relaxation in micellar gels of Pluronic F-1272019In: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351, Vol. 40, no 3, p. 403-407Article in journal (Refereed)
    Abstract [en]

    Based on the 1H relaxation of transverse nuclear magnetization of triblock-copolymer Pluronic F-127 in D2O, we proposed a model of the associated pluronic structure in which the polyethylene oxide of molecules in neighboring micelles are intertwined in regions of overlapping micellar coronas, while the polypropylene oxide cores of the micelles play a role of nodes in the 3D network. 

  • 81.
    Carabante, Ivan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Kumpiene, Jurate
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Adsorption of As (V) on iron oxide nanoparticle films studied by in situ ATR-FTIR spectroscopy2009In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 346, no 1-3, p. 106-113Article in journal (Refereed)
    Abstract [en]

    Stabilization of arsenic contaminated soils by iron oxides has been proposed as a remediation technique to prevent leaching of arsenate into the environment. Fundamental studies are needed to establish under which conditions the complexes formed are stable. In the present work, a powerful technique, viz. ATR-FTIR spectroscopy, is adapted to studies of adsorption of arsenate species on iron oxides. This technique facilitates acquisition of both quantitative and qualitative in situ adsorption data.In the present work, about 800 nm thick films of 6-lineferrihydrite were deposited on ZnSe ATR crystals. Arsenate adsorption on the ferrihydrite film was studied at pD values ranging from 4 to 12 and at an arsenate concentration of 0.03 mM in D2O solution. The amount of adsorbed arsenate decreased with increasing pD as a result of the more negatively charged iron oxide surface at higher pD values. The adsorption and desorption kinetics were also studied. Arsenate showed a higher adsorption rate within the first 70 minutes and a much lower adsorption rate from 70 up to 300 minutes. The low adsorption rate at longer reaction times was partly due to a low desorption rate of already adsorbed carbonate species adsorbed at the surface. The desorption of carbonate species was evidenced by the appearance of negative absorption bands. The desorption of adsorbed arsenate complexes was examined by flushing with D2O at pD 4 and 8.5 and it was found that the complexes were very stable at pD 4 suggesting formation of mostly inner-sphere complexes whereas a fraction of the complexes at pD 8.5 were less stable than at pD 4, possibly due to the formation of outer-sphere complexes.In summary, the ATR technique was shown to provide in situ information about the adsorption rate, desorption rate and the speciation of the complexes formed within a single experiment, which is very difficult to obtain using other techniques.

  • 82.
    Carabante, Ivan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Kumpiene, Jurate
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    A powerful method for studying the adsorption of As(V) on iron oxides in situ2008In: Arsenic in the environment - Arsenic from nature to humans: Book of Abstracts, 2008Conference paper (Other academic)
  • 83.
    Carlsson, Ludvig
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Undersökning av suspenderade ämnen i en avloppsvattenrening vid ett massa- och pappersbruk2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 84.
    Casellas, D.
    et al.
    Universitat Politècnica de Catalunya.
    Cumbrera, F. L.
    Universidad de Extremadura.
    Sánchez-Bajo, F.
    Universidad de Extremadura.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Llanes, L.
    Universitat Politècnica de Catalunya.
    Anglada, M.
    Universidad de Extremadura.
    On the transformation toughening of Y-ZrO2 ceramics with mixed Y-TZP/PSZ microstructures2001In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 21, no 6, p. 765-777Article in journal (Refereed)
    Abstract [en]

    Heat treatment of Y-TZP at high temperatures produces materials with a mixed Y-TZP/PSZ phase assemblage, which exhibit a unique combination of high mechanical strength and fracture toughness, uncommon in zirconia ceramics. The microstructure and crack growth resistance of the Y-TZP/PSZ materials developed by treating at 1650°C in air a fine-grained Y-TZP was studied. XRD as well as Raman spectroscopy results indicate that the obtained microstructure allow the retention of large tetragonal grains (up to ˜4 μm), resulting in both phase transformability enhancement and pronounced R-curve behavior. The large transformation zone, discerned from accurate measurements with Raman microprobe spectroscopy, sustains the above assessment and points out tetragonal to monoclinic phase transformation as the main toughening mechanism in the investigated Y-TZP/PSZ microstructures. This was confirmed by satisfactory agreement between the transformation toughening estimated from numerical analysis and the crack shielding experimentally determined from the R-curve measurements.

  • 85.
    Chanturiya, Valentine
    et al.
    Institute of Problems of Complex Development of Mineral Resources.
    Makarov, Victor
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Makarov, Dimitriy
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    Vasil'eva, Tatyana
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    Trofimenko, Tatyana
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    Kuznetsov, Victor
    Kola Science Centre, Russian Academy of Sciences, Apatity.
    The effect of crystallochemical peculiarities of nickel sulphide minerals on flotation of copper-nickel ore2004In: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 74, no 1-4, p. 289-301Article in journal (Refereed)
    Abstract [en]

    Flotation kinetics of pentlandite and violarite contained in copper-nickel ores and the effect of crystallochemical peculiarities of the minerals on their flotation features are studied. Studies of the effect of pentlandite crystallochemical features on its flotation properties have shown that the easiest to float is nickel-enriched pentladite, cobalt-enriched one being somewhat worse the worst being iron-enriched one. Pentlandite was found to be much better recovery to flotation concentrates than violarite. So, the process of violaritization of the surface of pentlandite grains, which may occur during the flotation, will negatively affect its characteristics.

  • 86.
    Dinesha,
    et al.
    Department of Chemistry, Vivekananda College, Puttur, India.
    Viveka, S.
    Department of Chemistry, Mangalagangotri, Mangalore University, Konaje, India.
    Gowda, Vasantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering. NMR Research Group, Faculty of Science, University of Oulu, Oulu, Finland.
    Nagaraja, G.K
    Department of Chemistry, Mangalagangotri, Mangalore University, Konaje, India.
    Review: An experimental (synthesis, NMR and crystallography) and theoretical study of three biologically active diazoles2018In: Concept, property and application of micro/nanostructured materials / [ed] Li,J. & Du, S., Nova Science Publishers, Inc., 2018, p. 213-232Chapter in book (Refereed)
    Abstract [en]

    The current chapter overview to explain the synthesis of three important class of diazoles namely, pyrazoles, hydroxypyrazolines, and imidazoles followed by elucidation of structure by single-crystal X-ray crystallography, liquid state 1H and density functional theory (DFT) calculations. Our principal interest is focused on the relationship between molecular and/or crystal structure of the synthesized compounds and their efficacy as pharmaceutical drug molecules. Furthermore, they play a significant role as crucial synthetic intermediates. The synthesized molecules were tested for their biological activities like anticancer, antimicrobial, anti-inflammatory, analgesic and antioxidant agents. Strong intermolecular interactions mediated by hydrogen bonding C-H·O or p-p stacking has been observed in X-ray structures most of the molecules. DFT calculations of the NMR chemical shifts for the unambiguous structural assignments of the molecules were performed. Overall, a multidimensional approach has been used for rational design, synthesis and structural characterization of these biologically important molecules. The main goal of this chapter is to review our recent progress in this field. 

  • 87.
    Dobryden, Illia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Almqvist, Nils
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Weber, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Yang, Xiaofang
    Scanning probe microscopy study of magnetite particle force interactions in a solution2011Conference paper (Other academic)
  • 88.
    Dobryden, Illia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Yang, Xiaofang
    Almqvist, Nils
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Weber, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    An atomic force microscopy study of the interaction between magnetite particles: the effect of Ca2 + ions and pH2013In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 233, p. 116-122Article in journal (Refereed)
    Abstract [en]

    Force interactions between a microsize (m-s) magnetite probe and thin layers of synthesized magnetite particles as well as microsize (m-s) magnetite particles from magnetite concentrate were investigated using atomic force microscopy (AFM). Of special interest was the influence of Ca2 + ions and pH on the interaction between the probe and the two different magnetite particle surfaces. The probe and the magnetite surfaces were immersed in aqueous Ca2 + solutions (100, 10, and 1 mM) at various pH values (4, 6, and 10). The colloidal probe technique and a self-made computer program for automatic evaluation of adhesion forces were used. The analysis revealed an increase in adhesion force with increased calcium concentration at pH 6 for both the systems investigated. However, the adhesion behavior between the probe and the m-s and n-s magnetite particle surfaces is different at pH 10. The possible appearance of calcium carbonate precipitated onto the magnetite surfaces as well as the possible influence of already adsorbed silicate on magnetite particles from the concentrate is discussed. In addition to Ca, Cl and Na atoms, added to the working solutions, and the Fe and O detected signals, the SEM-EDS analysis also detected Si atoms on the surface of the m-s particles.

  • 89.
    Dobryden, Illia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Yang, Xiaofang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Almqvist, Nils
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Weber, Hans
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Interaction forces between surface modified magnetite particles in aqueous solution2011Conference paper (Other academic)
  • 90.
    Drouet, Benoit
    Luleå tekniska universitet.
    A spectroscopic study of mechanically activated sulphide minerals2002Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sulphide minerals are a major source of non-ferrous metals such as lead, zinc or copper. Ores are processed to be selectively separated which can be achieved by flotation. Yet, the system is complex on the industrial level since a lot of different minerals are present in the ore and interact with each other, giving rise to activation or depression reactions. This has a notable effect on the flotation efficiency. In this study, the interactions between galena and sphalerite, which are the most common lead and zinc sulphide minerals respectively, were investigated along the wet and dry fine grinding process in an agate mortar. Both minerals were mixed and ground in different proportions and different pH conditions. Their physical properties after grinding were studied by particle size analysis, surface measurement and X-ray diffraction. The use of scanning electron microscopy enabled also to image their surface state. Oxidation reaction products were identified by diffuse reflectance infrared spectroscopy, Raman microscopy and X-ray photoelectron spectroscopy.

  • 91.
    Du, Qing
    Luleå tekniska universitet.
    Surface complexation in natural particle suspensions1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is a summary of our studies on (i) the proton and copper adsorption at aqueous illite surfaces, (ii) the proton and copper complexation of humic substances (fulvic acid FA and humic acid HA), (iii) the interaction between illite and fulvic acid, and (iv) the copper complexation behaviors in illite-FA bi-complexant systems. These particular studies were designed to help us develop a framework for modelling heavy metal complexation/adsorption mechanisms at natural particle surfaces. Our data were mainly generated from potentiometric titration, batch adsorption and FI-IR experiments; the model calculations and simulations were accomplished using computer programs FITEQL and SOLGASWATER. To account for the complexation behavior in illite/water suspensions, we analyzed the experimental data using the constant capacitance surface complexation model. Our analysis showed that (i) the proton reactions in the supernatants of illite suspensions can be represented by those of Al(H20)6 3+ and Si(OH)4 in water solutions, (ii) the acid-base properties of illite surfaces can be illustrated using only deprotonation reactions, which suggests that the surface acidic behavior of illite is similar to that of amorphous SiO2, and (iii) the uptake of copper in illite suspensions can be interpreted by the surface adsorption of different Cu(II) aqueous species, followed by the formation of copper precipitates, which were found to be hydroxide precipitates in carbonate-free illite suspensions and hydroxylcarbonate precipitates in carbonate-containing illite suspensions. To account for the complexation properties of humic substances, we used a nonelectrostatic, discrete site distribution model. Model analysis showed that (i) the acid-base properties of FA and HA can be modelled as those of a mixture of three monoprotic acids (R1H, R2H and R3H), (ii) the complexation of copper can be explained by assuming that copper binds mainly with the strongest and weakest acid sites (R1H and R3H) to form monodentate complexes, and (iii) FA has a stronger acid strength, but a weaker copperbinding potential, than HA. As to the adsorption of FA by illite, we found that it decreases with increases in pH values and its pH adsorption edge resembles those of SiO2-FA and montmorillonite-FA systems. The adsorption mechanism might be explained by assuming that the functional groups of FA react with the water molecules held by electrostatic forces near the illite surfaces to form H-bonds. In FA-illite bi-complexant systems, the complexation of Cu2+ ions can be effectively simulated by taking it to be a combination of individual bindings by the illite surfaces and the FA functional groups. This suggests that in natural water systems, fulvic acid can inhibit the retention of heavy metals at solid surfaces by forming soluble complexes with metal ions.

  • 92.
    Du, Qing
    et al.
    Luleå tekniska universitet.
    Sun, Zhongxi
    Luleå tekniska universitet.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hongxiao, Tang
    Research Center for Eco-Environmental Sciences, Academia Sinica.
    Acid-base properties of aqueous illite surfaces1997In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 187, no 1, p. 221-231Article in journal (Refereed)
    Abstract [en]

    In this paper, the acid-base properties of illite/water suspensions are examined using the constant capacitance surface complexation model. On the basis of results of potentiometric titrations and solubility experiments, we conclude that the proton reactions in the supernatants of illite suspensions can be successfully represented by proton reactions of Al(H2O)63+and Si(OH)4in water solutions. For illustrating the acidic characteristics of aqueous illite surfaces, two surface protonation models are proposed: (1) one site-one pKamodel, ≡SOH ≡SO-+ H+, pKaint= 4.12-4.23; (2) two sites-two pKas model, ≡SIOH ≡SIO-+ H+, pKintaI= 4.17-4.44, and ≡SIIOH ≡SIIO-+ H+, [dipKintaII= 6.35-7.74. Evaluation of these two models indicates that both of them can give good descriptions of the experimental data of systems with different illite concentrations and ionic strengths and that the one site-one pKamodel can be considered as a simplification of the two sites-two pKas model. Since both models assume only deprotonation reactions at the illite surfaces, they suggest that the surface behavior of the illite is similar to that of amorphous SiO2. Model assumptions, experimental procedures, and evaluative criteria are detailed in the paper.

  • 93.
    Du, Qing
    et al.
    Luleå tekniska universitet.
    Sun, Zhongxi
    Luleå tekniska universitet.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Tang, Hongxiao
    Research Center for Eco-Environmental Sciences, Academia Sinica.
    Adsorption of copper at aqueous illite surfaces1997In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 187, no 1, p. 232-242Article in journal (Refereed)
    Abstract [en]

    In this paper, we conducted potentiometric titrations, batch adsorption experiments and FT-IR analysis to study the uptake of copper in illite/water suspensions and then applied the constant capacitance surface complexation model to interpret the reaction mechanism at the aqueous illite surfaces. Our research shows that the copper adsorption at these surfaces is strongly dependent on pH and that the adsorption causes a deprotonation of surface groups. We propose that the uptake of copper in the carbonate-free illite suspensions can be explained by the formation of mononuclear surface complexes, ≡SOCu+and ≡SOCuOH, and a multinuclear surface complex, ≡SOCu2(OH)2+, followed by the formation of a bulk precipitate, Cu(OH)2(s), or a surface precipitate, ≡SOCu2(OH)3(sp). For the illite suspensions containing carbonates, we propose that the copper-illite interaction can be depicted by the formation of mononuclear surface complexes, ≡SOCu+and ≡SOCuOH, followed by the formation of a copper hydroxylcarbonate precipitate, Cu2(OH)2CO3(s), rather than a copper hydroxide precipitate. The existence of Cu2(OH)2CO3(s) in the carbonate-containing illite suspensions was identified by FT-IR analysis

  • 94.
    Du, Qing
    et al.
    Luleå tekniska universitet.
    Sun, Zhongxi
    Luleå tekniska universitet.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Tang, Hongxiao
    SKLEAC, Research Center for Eco–Environmental Sciences, Academia Sinica.
    Complexations in illite-fulvic acid-Cu2+ systems1999In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 33, no 3, p. 693-706Article in journal (Refereed)
    Abstract [en]

    As part of an extended project to illustrate how heavy metals are complexed by natural aquatic particles, we conducted various experiments to study the adsorption of fulvic acid (FA) at aqueous illite surfaces and the complexation of heavy metal copper(II) in illite-FA bi-complexant systems. By analyzing batch adsorption and potentiometric titration data, we found that (i) the adsorption of FA by illite decreases with increases in pH values and its pH adsorption edge resembles those of SiO2-FA and montmorillonite-FA systems described by other researchers, (ii) it is possible to effectively simulate the complexation of Cu2+ ions in illite-FA bi-complexant systems by taking it to be an additive complexation of two mono-complexant systems (FA-Cu2+ and illite-Cu2+) and (iii) FA can inhibit the retention of heavy metals at solid surfaces by forming soluble complexes with metal ions. The above results and conclusions are supported by FT-IR analysis of various illite-FA-Cu2+ systems

  • 95.
    Du, Quing
    Luleå tekniska universitet.
    Surface complexation in illit/water suspentions1996Licentiate thesis, comprehensive summary (Other academic)
  • 96.
    Dudenko, D.V.
    et al.
    Cardiff University.
    Williams, P.A.
    Cardiff University.
    Hughes, C.E.
    Cardiff University.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Velaga, Sitaram
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Brown, S.P.
    University of Warwick.
    Harris, K.D.M.
    Cardiff University.
    Exploiting the synergy of powder x-ray diffraction and solid-state NMR spectroscopy in structure determination of organic molecular solids2013In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 23, p. 12258-12265Article in journal (Refereed)
    Abstract [en]

    We report a strategy for structure determination of organic materials in which complete solid-state nuclear magnetic resonance (NMR) spectral data is utilized within the context of structure determination from powder X-ray diffraction (XRD) data. Following determination of the crystal structure from powder XRD data, first-principles density functional theory-based techniques within the GIPAW approach are exploited to calculate the solid-state NMR data for the structure, followed by careful scrutiny of the agreement with experimental solid-state NMR data. The successful application of this approach is demonstrated by structure determination of the 1:1 cocrystal of indomethacin and nicotinamide. The 1H and 13C chemical shifts calculated for the crystal structure determined from the powder XRD data are in excellent agreement with those measured experimentally, notably including the two-dimensional correlation of 1H and 13C chemical shifts for directly bonded 13C-1H moieties. The key feature of this combined approach is that the quality of the structure determined is assessed both against experimental powder XRD data and against experimental solid-state NMR data, thus providing a very robust validation of the veracity of the structure

  • 97.
    Dvoyashkin, Dvoyashkin
    et al.
    aculty of Oil and Gas, Almetyevsk State Oil Institute.
    Filippov, Andrei
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Diffusivity of crude oils contained in macroporous medium: 1H NMR study2018In: Mendeleev communications (Print), ISSN 0959-9436, E-ISSN 1364-551X, Vol. 2, p. 222-224Article in journal (Refereed)
    Abstract [en]

    Diffusivity of crude oils confined in pores of sand decreased with raising the fraction of oil at ordinary temperatures. This behaviour is suggested to be caused by adsorption of the high-molecular fractions of oils at the solid–liquid interface.

  • 98.
    Dyer, Chris D.
    et al.
    University of Southampton.
    Hendra, Patrick J.
    University of Southampton.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    The Raman spectroscopy of cement minerals under 1064 nm excitation1993In: Spectrochimica Acta. Part A, Molecular Spectroscopy, ISSN 0584-8539, Vol. 49, no 5-6, p. 715-722Article in journal (Refereed)
    Abstract [en]

    The prospects for near-IR-excited Raman scattering from cement minerals are discussed, and a very unusual result concerning the intensity of the spectra is presented.

  • 99.
    Dyer, Chris
    et al.
    University of Southampton.
    Hendra, Patrick J.
    University of Southampton.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Surface hydration of aqueous γ-Al2O3 studied by Fourier transform Raman and infrared spectroscopy-I.: Initial results1993In: Spectrochimica Acta. Part A, Molecular Spectroscopy, ISSN 0584-8539, Vol. 49, no 5-6, p. 691-705Article in journal (Refereed)
    Abstract [en]

    The hydration of γ-Al2O3 has been studied by Fourier transform (FT) Raman and infrared (IR) spectroscopy, and by X-ray diffraction (XRD). The initial findings are presented, along with a discussion of the possible causes for the major spectral changes that occur after hydration. The aims of the study and ongoing research are described.

  • 100.
    Emmerik, Tristan J. Van
    et al.
    La Trobe University.
    Sandström, Dan
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Angove, Michael J.
    La Trobe University.
    Johnson, Bruce B.
    La Trobe University.
    31P solid-state nuclear magnetic resonance study of the sorption of phosphate onto gibbsite and kaolinite2007In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, no 6, p. 3205-3213Article in journal (Refereed)
    Abstract [en]

    Sorption of phosphate onto gibbsite (Υ-Al(OH)3) and kaolinite has been studied by both macroscopic and 31P solid-state NMR measurements. Together these measurements indicate that phosphate is sorbed by a combination of surface complexation and surface precipitation with the relative amounts of these phases depending on pH and phosphate concentration. At low pH and high phosphate concentrations sorption is dominated by the presence of both amorphous and crystalline precipitate phases. The similarity between the single-pulse and CP/MAS NMR spectra suggests that the precipitate phases form a thin layer on the surface of the particles in close contact with protons from surface hydroxyl groups or coordinated water molecules. While the crystalline phase is only evident on samples below pH 7, amorphous AlPO4 was found at all pH and phosphate concentrations studied. As pH was increased the fraction of phosphate sorbed as an inner-sphere complex increased, becoming the dominant surface species by pH 8. Comparison of sorption and NMR results suggests that the inner-sphere complexes form by monodentate coordinat

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