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  • 1.
    Bekin, Seda
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Sarmad, Shokat
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Keçeli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdağ, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Synthesis, characterization and bending behavior of electroresponsive sodium alginate / poly (acrylic acid) interpenetrating network films in an electric stimulus2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 202, p. 878-892Article in journal (Refereed)
  • 2.
    Bekin, Seda
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Sarmad, Shokat
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Yenici, Gökcen
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University, Avcilar.
    Keceli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdag, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Dielectric, thermal, and swelling properties of calcium ion crosslinked sodium alginate film2014In: Polymer Engineering and Science, ISSN 0032-3888, E-ISSN 1548-2634, Vol. 54, no 6, p. 1372-1382Article in journal (Refereed)
  • 3.
    Gürdağ, Gülten
    et al.
    Faculty of Engineering, Department of Chemical Engineering, Istanbul University.
    Sarmad, Shokat
    Faculty of Engineering, Department of Chemical Engineering, Istanbul University.
    Cellulose Graft Copolymers: Synthesis, Properties, and Applications2013In: Polysaccharide based Graft Copolymers / [ed] Susheel Kalia and M.W. Sabaa, Berlin: Springer, 2013, p. 15-57Chapter in book (Refereed)
    Abstract [en]

    Grafting of vinyl monomers onto cellulose is an important tool for the modification of cellulose. Depending on the monomer grafted onto cellulose, it gains new properties. The grafting can be performed in heterogeneous or homogeneous medium. In the grafting performed in heterogeneous medium, the reaction is carried out in aqueous medium using a suitable initiator. As initiator, the radiation or chemical initiators such as ceric ammonium nitrate (CAN), various persulfates, azobisisobutyronitrile (AIBN), and Fenton reagent (Fe(II)–H2O2) are mostly used. In case of CAN initiator, the grafting should be performed in acidic medium in order to prevent its hydrolysis. In the homogeneous grafting reactions, either a water-soluble cellulose derivative is used in the grafting or cellulose is dissolved in a suitable solvent, and then the grafting is performed. Higher number of grafts per cellulose chain is obtained in homogeneous grafting than those in heterogeneous medium

  • 4.
    Ma, Chunyan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sarmad, Shokat
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Development of Low-Cost Deep Eutectic Solvents for CO2 Capture2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 3320-3325Article in journal (Refereed)
    Abstract [en]

    CO2 capture plays an important role to mitigate CO2 emissions. Deep eutectic solvents (DESs) as promising absorbents for CO2 separation have raised lots of attention. As a new class of ionic liquids (ILs), DESs maintain most of the favorite properties of ILs but avoid their economic and environmental problems. However, the viscosity of the synthesized DESs is relatively high, resulting in slow mass transfer rate (or slow sorption kinetics) and then may lead to a large equipment-size. The CO2 solubility in the DESs still needs to be improved. In our work, 35 DESs were prepared and screened in terms of their CO2 solubility and viscosity. Among them, 15 DESs with high CO2 solubility and low viscosity compared to the conventional ILs were chosen as the promising candidates. In addition, the effect of water as a co-solvent for the glycerol-based DES with relatively high viscosity was investigated, and two other DESs that demonstrated relatively high sorption capacity and low viscosity were chosen for functionalization to further improve their CO2 sorption capacity. The results showed that the viscosity decreased drastically from 716 to 20 mPa·s, while the CO2 solubility increased from 0.26 to 0.33 mol/kg DES by the addition of a small amount of water into the glycerol-based DES (BTMA/GLY (1:2)). The further increase of the amount of H2O decreased the CO2 solubility due to the low CO2 solubility in H2O. In addition, after functionalization of TPAC/ EA(1:4), the CO2 solubility increased from 1.4 to 3.2 mol/kg DES, which showed a better performance compared with the common ILs.

  • 5.
    Sarmad, Shokat
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University, Umeå, Sweden.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Carbon Dioxide Capture with Ionic Liquids and Deep Eutectic Solvents: A New Generation of Sorbents2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 2, p. 324-352Article, review/survey (Refereed)
    Abstract [en]

    High cost and high energy penalty for carbon dioxide (CO2) uptake from flue gases are important obstacles in large-scale industrial applications, and developing efficient technology for CO2 capture from technic and economic points is crucial. Ionic liquids (ILs) show the potential for CO2 separation due to their inherent advantages and have been proposed as alternatives in order to overcome the drawbacks of conventional sorbents. Chemical modification of ILs to improve their performance in CO2 absorption has received more attention. Deep eutectic solvents (DESs) as a new generation of ILs are considered as more economical alternatives to cope with the deficiencies of high cost and high viscosity of conventional ILs. This review discusses the potential of the functionalized ILs and DESs as CO2 sorbents. Incorporation of CO2-philic functional groups like amine in cation and/or anion moiety of ILs can be promoted their absorption capacity. In general, the functionalization of anion part of ILs is more effective than cation part. DESs represent favourable solvent properties and are capable of capturing CO2, but the research work is scarce and undeveloped compared to the studies conducted on ILs. It is possible to develop novel DESs with promising absorption capacity. However, more investigation needs to be carried out on the mechanism of CO2 sorption of DESs to clarify how these novel sorbents can be adjusted and fine-tuned to best tailored as optimized media for CO2 capture.

  • 6.
    Sarmad, Shokat
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Xie, Yujiao
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Screening of Deep Eutectic Solvents (DESs) as green CO2 sorbents: from solubility to viscosity2017In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 41, no 1, p. 290-301Article in journal (Refereed)
    Abstract [en]

    Deep eutectic solvents (DESs) as ionic liquid (IL) analogues show great potential for CO2 capture. They exhibit favorable solvent properties and are considered to be economical alternatives to conventional ILs. In this study, we prepare 35 DESs and screen them in terms of their CO2 solubility and viscosity, both crucial factors to be considered when designing efficient CO2 sorbents. The influence of salt and HBD type and structure, as well their molar ratio on the CO2 solubility and viscosity of the DESs is investigated. The viscosity and CO2 solubility of the DESs are compared with those of other DESs and conventional ILs. 15 DESs, which exhibit comparable CO2 absorption capacity to choline chloride-urea DESs, glycerol DESs and fluorinated ILs, are chosen as the promising ones. The viscosities of the selected DESs are below 200 mPa s and are lower than those of choline chloride-based DESs. Since the viscosity of the DESs is relatively high, on a par with those of conventional ILs, the effect of water as a co-solvent is investigated in order to decrease the viscosity. The addition of water to the glycerol-based DESs improves the kinetics of absorption by decreasing the viscosity, thus increasing the CO2 absorption capacity. Dry or aqueous DESs that demonstrate a high sorption capacity and low viscosity are chosen for additional analysis and characterization, and further functionalization will be carried out in the future to improve their sorption capacityy

  • 7.
    Sarmad, Shokat
    et al.
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Yenici, Gökçen
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Gürkan, Koray
    Department of Electrical and Electronics Engineering, Faculty of Engineering, Istanbul University.
    Keçeli, Gönül
    Department of Chemistry, Faculty of Engineering, Istanbul University.
    Gürdağ, Gülten
    Department of Chemical Engineering, Faculty of Engineering, Istanbul University.
    Electric field responsive chitosan–poly(N,N-dimethyl acrylamide) semi-IPN gel films and their dielectric, thermal and swelling characterization2013In: Smart materials and structures (Print), ISSN 0964-1726, E-ISSN 1361-665X, Vol. 22, no 5, article id 055010Article in journal (Refereed)
    Abstract [en]

    The electroresponsive, dielectric and swelling behavior of semi-interpenetrated polymer network (semi-IPN) gel films prepared from chitosan (CS) and N,N-dimethyl acrylamide (DA) were investigated and compared with those CS film. CS–DA semi-IPN films were also characterized by Fourier transform infrared, x-ray diffraction and differential scanning calorimetry measurements. The electrosensitivity of CS–DA films to an electric field was investigated by determining their bending at 8 V in (0.05 M/0.1 M/0.15 M) NaCl solution. Equilibrium swelling values of CS–DA films both in distilled water and buffer solution with pH = 2.2 decreased with poly-DA (PDA) content of the films. While the maximum decomposition of CS film took place at about 296 °C, the presence of PDA in CS–DA semi-IPN films reduced the thermal stability, and their maximum decomposition temperature shifted from 261 to 240 °C with the increase in PDA content. In addition, the PDA network led to a decrease in the dielectric constant (ε'), dielectric loss (ε'') and conductance (σ) of CS–DA semi-IPN films in the frequency range between 12 Hz and 100 kHz. The values of electric modulus and impedance, and Cole–Cole plots confirmed that the conductance values of CS–DA films are lower than that of CS film. The PDA network also led CS–DA films to respond more slowly to electric field. The increase in NaCl concentration in the bending medium increased the response rate of CS–DA films to an electric field. The final bending angle of all CS–DA films was 90°, and it was not dependent on either NaCl concentration or PDA content of the films.

  • 8.
    Sarmad, Shokat
    et al.
    Physical Chemistry Department, Faculty of Chemistry, University of Tabriz.
    Zafarani-Moattar, Mohammed Taghi
    Physical Chemistry Department, Faculty of Chemistry, University of Tabriz.
    Measurement and correlation of phase equilibria for poly(ethylene glycol) methacrylate + alcohol systems at 298.15 K2005In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 50, no 1, p. 283-287Article in journal (Refereed)
    Abstract [en]

    The activities of methanol, ethanol, 2-propanol, and 1-butanol in poly(ethylene glycol) methacrylate (Mn = 360) solutions have been measured by the isopiestic method at 298.15 K. Sodium iodide and calcium chloride were used as the isopiestic standards for the calculation of activities. The original equation of Flory−Huggins and the modified Flory−Huggins equation with concentration-dependent interaction parameters have been used for the correlation of the experimental solvent activity data. The strength of interaction between different alcohols and the polymer was discussed on the basis of the obtained Flory−Huggins interaction parameters. The reliability of the two local-composition models, NRTL and NRF, were also assessed by fitting the experimental activity data to these models. All of these models satisfactorily present the obtained experimental activity data

  • 9.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, University of Tabriz.
    Sadeghi, Rahmat
    Physical Chemistry Department, University of Tabriz.
    Sarmad, Shokat
    Physical Chemistry Department, University of Tabriz.
    Measurement and modeling of densities and sound velocities of the systems poly(propylene glycol) + methanol, +ethanol, +1-propanol, +2-propanol and +1-butanol at T = 298.15 K2006In: Journal of Chemical Thermodynamics, ISSN 0021-9614, E-ISSN 1096-3626, Vol. 38, no 3, p. 257-263Article in journal (Refereed)
    Abstract [en]

    Experiments have been performed at T = 298.15 K to measure the density and sound velocity of the systems {poly(propylene glycol) + methanol, +ethanol, +1-propanol, 2-propanol and +1-butanol} over the whole range of composition. From these measurements, values of the excess molar volume (Vmex)">(Vmex) and excess molar isentropic compression, Ks,mex">Ks,mex , equal to -(∂Vmex/∂p)s">-(∂Vmex/∂p)s were calculated. The excess molar volume for all of these systems were found to be negative and decreases in magnitude as size of alcohol increases, except for 2-propanol solutions for which the magnitude of the excess volume is higher than that of 1-butanol solutions. Expressions for VmexandKs,mex">VmexandKs,mex of polymer solutions were obtained for the model of Flory–Huggins and the polymer non-random two liquid (NRTL) model. These expressions were used to fit the experimental VmexandKs,mex">VmexandKs,mex data of the investigated systems.

  • 10.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Sarmad, Shokat
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Apparent molar volumes, apparent isentropic compressibilities, and viscosity B-coefficients of 1-ethyl-3-  methylimidazolium bromide in aqueous di-potassium hydrogen phosphate and potassium di-hydrogen phosphate solutions at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K2012In: Journal of Chemical Thermodynamics, ISSN 0021-9614, E-ISSN 1096-3626, Vol. 54, p. 192-203Article in journal (Refereed)
    Abstract [en]

    Apparent molar volumes Vϕ, apparent isentropic compressibilities κϕ, and viscosity B-coefficients for 1-ethyl-3-methylimidazolium bromide (EmimBr) in aqueous di-potassium hydrogen phosphate (K2HPO4) solutions with salt weight fractions (ws = 0.00, 0.10, 0.15, and 0.20) and potassium di-hydrogen phosphate (KH2PO4) solutions with salt weight fractions (ws = 0.00, 0.04, 0.07, and 0.10) have been determined from solution density, sound velocity and viscosity measurements at temperatures over the range (298.15 to 318.15) K as function of concentration of 1-ethyl-3-methylimidazolium bromide (EmimBr). In the investigated temperature range, the relation: Vϕ0=a0+a1T+a2T2, has been used to describe the temperature dependence of the standard partial molar volumes Vϕ0. These results have, in conjunction with the results obtained in pure water, been used to deduce the standard volumes of transfer ΔVϕ0 and viscosity B-coefficients of transfer for 1-ethyl-3-methylimidazolium bromide from water to aqueous K2HPO4 and KH2PO4 solutions for rationalizing various interactions in the ternary solutions. The structure making or breaking ability of 1-ethyl-3-methylimidazolium bromide has been discussed in terms of the sign of ∂2Vϕ0∂T2. An increase in the transfer volume of 1-ethyl-3-methylimidazolium bromide with increasing phosphate salts concentration has been explained by Friedman–Krishnan co-sphere model. The activation parameters of viscous flow for the ternary solutions investigated were also determined and discussed by the application of transition state theory.

  • 11.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Sarmad, Shokat
    Effect of tri-potassium phosphate on volumetric, acoustic, and transport behaviour of aqueous solutions of 1-ethyl-3-methylimidazolium bromide at T = (298.15 to 318.15) K2010In: Journal of Chemical Thermodynamics, ISSN 0021-9614, E-ISSN 1096-3626, Vol. 42, no 10, p. 1213-1221Article in journal (Refereed)
    Abstract [en]

    Density, sound velocity, and viscosity of 1-ethyl-3-methylimidazolium bromide, [Emim][Br], in aqueous solutions of tri-potassium phosphate with salt weight fractions (ws = 0.00, 0.10, 0.15, and 0.20) have been measured as a function of concentration of [Emim][Br] at atmospheric pressure and T = (298.15, 303.15, 308.15, 313.15, and 318.15) K. The apparent molar volume, isentropic compressibility, apparent isentropic compressibility, and relative viscosity values have been evaluated from the experimental data. The partial molar volume and isentropic compressibility at infinite dilution, and viscosity B-coefficient obtained from these data have been used to calculate the corresponding transfer parameters for the studied IL from water to the aqueous tri-potassium phosphate solutions. Also, an empirical equation was satisfactorily used to correlate the experimental viscosity data.

  • 12.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Sarmad, Shokat
    Physical Chemistry Department, University of Tabriz.
    Osmotic and activity coefficient of 1-ethyl-3-methylimidazolium bromide in aqueous solutions of potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and tripotassium phosphate at T = 298.15 K2010In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 55, no 11, p. 5182-5190Article in journal (Refereed)
    Abstract [en]

    Vapor−liquid equilibrium data (water activity, vapor pressure, osmotic coefficient, and activity coefficient) of the mixed electrolyte aqueous solution, 1-ethyl-3-methylimidazolium bromide, [Emim][Br], + tripotassium phosphate, [Emim][Br], + dipotassium hydrogen phosphate, [Emim][Br], + potassium dihydrogen phosphate, and their corresponding binary aqueous solutions have been measured by the isopiestic method at temperature 298.15 K. The osmotic coefficients for binary aqueous solutions were correlated to the Pitzer and modified Pitzer models. From these data, the corresponding mean molal activity coefficients, γ±, have been calculated. The activity coefficients of mixed electrolytes were calculated by Scatchard’s neutral-electrolyte method. The activity results were also satisfactorily fitted to the semiempirical equation.

  • 13.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Sarmad, Shokat
    Physical Chemistry Department, University of Tabriz.
    Osmotic and activity coefficient of 1-ethyl-3-methylimidazolium chloride in aqueous solutions of tri-potassium phosphate, potassium carbonate, and potassium chloride at T=298.15 K2011In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 35, no 3, p. 331-341Article in journal (Refereed)
    Abstract [en]

    Vapour–liquid equilibrium data (water activity, vapour pressure, osmotic coefficient, and activity coefficient) of the mixed electrolyte aqueous solutions, 1-ethyl-3-methylimidazolium chloride, (EmimCl) + tri-potassium phosphate, EmimCl + potassium carbonate, EmimCl + potassium chloride and their corresponding binary aqueous solutions have been measured by the isopiestic method at a temperature of 298.15 K. The osmotic coefficients for binary aqueous solutions were correlated to the Pitzer, modified Pitzer and TCPC models. The osmotic coefficient of mixed electrolyte with common anion was correlated to the Pitzer model. From these data, the corresponding mean activity coefficients, γ±">γ± , have been calculated. The activity coefficients of mixed electrolytes were calculated by Scatchard’s neutral electrolyte method. A modified Pitzer model has been used to predict the osmotic and activity coefficients of mixed electrolyte solution with common anion.

  • 14.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, University of Tabriz.
    Sarmad, Shokat
    Physical Chemistry Department, University of Tabriz.
    Volumetric and Ultrasonic Studies of the Poly(ethylene glycol) Methacrylate 360 + Alcohol Systems at 298.15 K2006In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 51, no 3, p. 968-971Article in journal (Refereed)
    Abstract [en]

    Speed of sound and density of poly(ethylene glycol) methacrylate 360 (PEGMA) + methanol, + ethanol, + 2-propanol, and + 1-butanol systems have been measured experimentally over the whole range of composition at T = 298.15 K and atmospheric pressure. From these experimental data, the excess molar volumes, isentropic compressibility, and changes in speed of sound and isentropic compressibility have been determined for each composition. The results have been interpreted in light of polymer−solvent interactions and packing effects. Also, the excess molar volumes and the changes of the speed of sound and the isentropic compressibility were fitted to two different variable-degree polynomial equations.

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