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Goryan, Alexander S.
Alternative names
Publications (4 of 4) Show all publications
Goryan, A. S. (2012). Nuclear magnetic resonance studies on bentonite in complex mixed systems (ed.). (Licentiate dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Nuclear magnetic resonance studies on bentonite in complex mixed systems
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In this work 23Na MAS NMR was validated as a successful quantitative method for studies of exchanging sodium in bentonites useful, in particular, for studies of ion-exchange kinetics. Na-enriched bentonites equilibrated in a re-circulated process water at iron-oxide pelletizing plants may acquire properties of Ca-bentonites after already 20 minutes of the equilibration time, since >50 % of sodium ions will be exchanged by calcium ions during first minutes of bentonite placed in contact with the process water. It was shown that all sodium activated bentonites used in this study exchange >50% of sodium in Na+/Ca2+ and ca 20 % of sodium in binary Na+/Mg2+ systems with the same bentonite/solution ratio and same concentrations of these ions in aqueous solutions as in the process water at a pelletizing plant. In total, approximately 50 % of the exchangeable sodium in original bentonites was exchanged after equilibrating of bentonites in the process water already after 20 minutes. Experimental Na+/Ca2+ exchange curves for ‘model’ Ca2+(aq) solutions and for process water are very similar as Ca2+ is the dominant constituent in the process water. Since bivalent ions (Ca2+ and Mg2+) that present in the process water readily replace Na+ ions, Na-bentonite transforms into Ca- or Mg- bentonite, which have worse rheological, swelling and, therefore, binding properties. This ion-exchange process can influence the binder performance in the pelletizing process. Taking into account that fluorapatite is one of the components present in a blend of minerals processed, possible interactions between orthophosphate (the principal anionic component of apatites) and bentonites in aqueous suspensions are considered. It was found that sorption of orthophosphate on Ca-montmorillonite follows a different pattern from sorption of orthophosphate on aluminum oxides and kaolinite. While there is a small amount of sorption below pH 7, which may involve inner-sphere complexation and precipitation of AlPO4 to Al-OH edge sites on the montmorillonite crystals, most sorption of orthophosphate occurs at higher pH. Both macroscopic sorption measurements and solid-state 31P MAS NMR suggest that above pH 7 there is precipitation of proton depleted calcium phosphate phases. Based on both 31P chemical shifts and 31P chemical shift anisotropies it was concluded that the principal precipitated phased are most likely ‘brushite-like’ phases. Very short spin-lattice T2(31P) relaxation times (≤100 μs) for the orthophosphate/bentonite systems can possibly be explained by the presence of paramagnetic Fe in bentonites. Since there are insufficient concentrations of soluble Fe species in the supernatant solution that may give rise to the observed effects, it is likely that orthophosphate is precipitated as thin layers on the surfaces of montmorillonite crystals, where phosphorus may interact with Fe atoms present in the crystal lattice. PO4-tetrahedra in sorbed species can be also distorted giving rise to a larger 31P CSA than for pure ‘apatite-like phases’. 29Si MAS and 1H-29Si CP/MAS NMR experiments on bentonite samples also performed in this work provide information about impurities of quartz in bentonites, a level of substitution of aluminum by iron atoms in the structure of montmorillonite and about the degree of hydration of montmorillonite. 29Si NMR experiments on bentonite incubated with waterglass in aqueous suspensions at concentrations of sodium silicates as in the process water demonstrated that one can follow the process of polymerization of waterglass in solutions and also detect sodium silicates polymerized on surfaces of bentonites already after 1 hour of incubation. Polymerized waterglass sorbed on bentonite surfaces may also alter rheological, swelling and, therefore, binding properties of sodium-activated bentonites used in pelletization of iron-oxide ores.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2012. p. 80
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
bentonite, montmorillonite, 23Na, 31P, 29Si NMR, interaction, ion exchange, sorption., Chemistry - Physical chemistry, Kemi - Fysikalisk kemi
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-18463 (URN)8bb7b5fb-ab4d-42ea-babd-786df607aa03 (Local ID)978-91-7439-511-2 (ISBN)8bb7b5fb-ab4d-42ea-babd-786df607aa03 (Archive number)8bb7b5fb-ab4d-42ea-babd-786df607aa03 (OAI)
Note
Godkänd; 2012; 20121011 (alegor); LICENTIATSEMINARIUM Ämne: Gränsytors kemi/Chemistry of Interfaces Examinator: Professor Oleg N. Antzutkin, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Professor emeritus Willis Forsling, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Onsdag den 5 december 2012 kl 13.00 Plats: C305, Luleå tekniska universitetAvailable from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Ivanov, A., Korneeva, E., Bukvetskii, B., Goryan, A. S., Antzutkin, O. & Forsling, W. (2008). Structural organization of mercury(II) and copper(II) dithiocarbamates from EPR and 13C and 15N MAS NMR spectra and X-ray diffraction analysis (ed.). Paper presented at . Russian journal of coordination chemistry, 34(1), 59-69
Open this publication in new window or tab >>Structural organization of mercury(II) and copper(II) dithiocarbamates from EPR and 13C and 15N MAS NMR spectra and X-ray diffraction analysis
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2008 (English)In: Russian journal of coordination chemistry, ISSN 1070-3284, E-ISSN 1608-3318, Vol. 34, no 1, p. 59-69Article in journal (Refereed) Published
Abstract [en]

The structures and spectroscopic properties of mononuclear and binuclear mercury(II) and copper(II) complexes with four dithiocarbamate ligands R 2NC(S)S- (R = CH3, C2H5, or iso-C3H7; R2 = (CH2)6) were studied by solid-state 13C and 15N CP/MAS NMR and EPR spectroscopy. Mercury(II) N,N-cyclohexamethylenedithiocarbamate [Hg 2{S2CN(CH2)6}4] was obtained and characterized in detail by X-ray diffraction analysis at 299 K. The binuclear molecule of the complex is centrosymmetric; the central tricyclic fragment [Hg2S4C2] is in the chair conformation. In the 13C and 15N NMR spectra, the signals were assigned to the dithiocarbamate ligands with different structural functions: bidentate chelating and combined (both chelating and bridging) ones. The differences between the isotropic 15N chemical shifts for the dialkyldithiocarbamate ligands were interpreted in terms of combination of the mesomeric effect of the =NC(S)S-groups and the inductive effect of the alkyl substituents. According to the EPR data, copper(II) in magnetically diluted systems is mainly found in heterobinuclear molecules [CuHg(S2CNR 2)4] and the geometry of the chromophores [CuS 5] approximates to a tetragonal pyramid.

National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-8368 (URN)10.1007/s11173-008-1010-3 (DOI)2-s2.0-38849161384 (Scopus ID)6e116be0-73a0-11dd-a60f-000ea68e967b (Local ID)6e116be0-73a0-11dd-a60f-000ea68e967b (Archive number)6e116be0-73a0-11dd-a60f-000ea68e967b (OAI)
Note
Validerad; 2008; 20080826 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Goryan, A. & Antzutkin, O. (2007). Solid state NMR studies on bentonites (ed.). Paper presented at Swedish NMR meeting : 04/09/2007 - 05/09/2007. Paper presented at Swedish NMR meeting : 04/09/2007 - 05/09/2007.
Open this publication in new window or tab >>Solid state NMR studies on bentonites
2007 (English)Conference paper, Oral presentation only (Other academic)
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-29883 (URN)38080650-aa5e-11dc-9057-000ea68e967b (Local ID)38080650-aa5e-11dc-9057-000ea68e967b (Archive number)38080650-aa5e-11dc-9057-000ea68e967b (OAI)
Conference
Swedish NMR meeting : 04/09/2007 - 05/09/2007
Note
Godkänd; 2007; 20071214 (olan)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Goryan, A. & Antzutkin, O. (2007). Solid state NMR studies on bentonites (ed.). Paper presented at Alpine Conference on Solid-State NMR: A European Conference on Solid State Nuclear Magnetic resonance. New Concepts and Applications : 09/09/2007 - 13/09/2007. Paper presented at Alpine Conference on Solid-State NMR: A European Conference on Solid State Nuclear Magnetic resonance. New Concepts and Applications : 09/09/2007 - 13/09/2007.
Open this publication in new window or tab >>Solid state NMR studies on bentonites
2007 (English)Conference paper, Oral presentation only (Other academic)
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-27358 (URN)0c835900-aa5c-11dc-9057-000ea68e967b (Local ID)0c835900-aa5c-11dc-9057-000ea68e967b (Archive number)0c835900-aa5c-11dc-9057-000ea68e967b (OAI)
Conference
Alpine Conference on Solid-State NMR: A European Conference on Solid State Nuclear Magnetic resonance. New Concepts and Applications : 09/09/2007 - 13/09/2007
Note
Godkänd; 2007; Bibliografisk uppgift: Sider: P5; 20071214 (olan)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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