M 57 Mercury sorption on a thiocarbamoyl derivative of chitosan [Text] / K. C. Gavilan, A. V. Pestov, H. M. Garcia, Yu. G. Yatluk, J. Roussy, E. Guibal // Journal of Hazardous Materials. - 2009. - Vol. 165, № 1-5. - P415-426 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The grafting of thiourea on chitosan backbone allows synthesizing a thiocarbamoyl derivative that was very efficient for mercury sorption in acidic solutions. Though the sorption capacity is not increased compared to raw chitosan in near neutral solutions, this modification allowed maintaining high sorption capacity (close to 2.3 mmol Hg g-1) at pH 2. Mercury sorption in acidic solutions is not affected by the presence of competitor metals (such as Zn(II), Pb(II), Cu(II), Cd(II), Ni(II)) or the presence of nitrate anions (even at concentration as high as 0.8 M)). The presence of chloride or sulfate anions (0.8 M) decreased Hg(II) sorption capacity to 1 mmol Hg g-1. Kinetics are controlled by a combination of pseudo second-order reaction rate and resistance to intraparticle diffusion. Mercury desorption reached about 75% using thiourea (in HCl solution) \\\\Expert2\\nbo\\Journal of Hazardous Materials\\2009, v.165.p.415.pdf |
N 10 N-(2-(2-Pyridyl)ethyl)chitosan (PEC) for Pd(II) and Pt(IV) sorption from HCl solutions [] / L. A. Santos Sorena, M. Ruiz, A. V. Pestov, A. M. Sastre, Yu. G. Yatluk, E. Guibal // Cellulose. - 2010. - 6 December. - Online first : рис., табл. Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: Chitosan was modified by grafting 2-pyridyl-ethyl moieties on the biopolymer backbone for the synthesis of a Platinum Group Metal (PGM) sorbent. The sorbent was tested for Pd(II) and Pt(IV) sorption from HCl solutions. Stable for HCl concentrations below 0.5 M, the sorbent reached sorption capacities as high as 3.2 and 2.6 mmol metal g1 for Pd(II) and Pt(IV), respectively. Metal sorption mainly proceeds by electrostatic attraction in acidic solutions, though a contribution of complexation mechanism cannot be totally rejected. The resistance to intraparticle diffusion is the main controlling mechanism for uptake kinetics. While agitation speed has a limited effect on kinetics, metal concentration and sorbent dosage have a greater effect on the kinetic profiles. The intraparticle diffusivity varies between 3 10?11 and 4.5 1010 m2 min1. Thiourea (combined with HCl solution) is used for Pd(II) and Pt(IV) desorption. The resin could be desorbed and recycled for a minimum of five cycles maintaining high efficiencies of sorption and desorption |
T 45 Thiocarbamoyl chitosan as a novel sorbent with high sorption capacity and selectivity for the ions of gold(III), platinum(IV), and palladium [Electronic resource] / A. V. Pestov, S. Yu. Bratskaya, A. Slobodyuk, V. A. Avramenko, Yu. G. Yatluk // Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya). - 2010. - Vol. 59, № 7. - P1303-1306 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CHITOSAN -- THIOCARBAMOYL CHITOSAN -- IONS OF GOLD(III) Аннотация: Thiocarbamoyl chitosan (TCC) was synthesized by grafting thiourea on chitosan backbone in eutectic composition of ammonium thiocyanate—thiourea. Insoluble products with the amno group functionalization degree of 0.3–1.1 can be prepared by varying the conditions of polymer-analogous (synthesis in a gel) transformation. Structure of the synthesized chitosan derivatives was characterized by elemental analysis, diffuse reflectance infrared spectroscopy, and the solid state 13C NMR. Study of sorption properties of TCC shows high sorption capacity and selectivity for the ions of gold(III), platinum(IV), and palladium(II) as evidenced by results obtained at pH 2 in the presence of 100–1000-fold excess of iron(III), copper(II), zinc(II), and nickel(II). Sorption capacity of TCC for all ions increases with the increase in the degree of substitution and changes in the series: AuIII > PdII > PtIV \\\\Expert2\\nbo\\Russian Chemical Bulletin\\2010, 59 (7), 1303-1306.pdf |
N 10 N-(2-(2-Pyridyl)ethyl)chitosan (PEC) for Pd(II) and Pt(IV) sorption from HCl solutions [Text] / L. A. Santos Sorena, M. Ruiz, A. V. Pestov, A. M. Sastre, Yu. G. Yatluk, E. Guibal // Cellulose. - 2011. - Vol. 18, № 2. - P309-325. - Bibliogr. : p. 324-325 (32 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: Chitosan was modified by grafting 2-pyridyl-ethyl moieties on the biopolymer backbone for the synthesis of a Platinum Group Metal (PGM) sorbent. The sorbent was tested for Pd(II) and Pt(IV) sorption from HCl solutions. Stable for HCl concentrations below 0.5 M, the sorbent reached sorption capacities as high as 3.2 and 2.6 mmol metal g?1 for Pd(II) and Pt(IV), respectively. Metal sorption mainly proceeds by electrostatic attraction in acidic solutions, though a contribution of complexation mechanism cannot be totally rejected. The resistance to intraparticle diffusion is the main controlling mechanism for uptake kinetics. While agitation speed has a limited effect on kinetics, metal concentration and sorbent dosage have a greater effect on the kinetic profiles. The intraparticle diffusivity varies between 3 ? 10?11 and 4.5 ? 10?10 m2 min?1. Thiourea (combined with HCl solution) is used for Pd(II) and Pt(IV) desorption. The resin could be desorbed and recycled for a minimum of five cycles maintaining high efficiencies of sorption and desorption \\\\Expert2\\nbo\\Cellulose\\2011, v.18, p. 309.pdf |
N 10 N-(2-(2-Pyridyl)ethyl)chitosan (PEC) for Pd(II) and Pt(IV) sorption from HCl solutions / L. A. Santos Sorena, M. Ruiz, A. V. Pestov, A. M. Sastre, Yu. G. Yatluk, E. Guibal // Cellulose. - 2011. - Vol. 18, № 2. - С. 309-325 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CHITOSAN – PYRIDYL GROUPS -- PALLADIUM -- PLATINUM Аннотация: Chitosan was modified by grafting 2-pyridyl-ethyl moieties on the biopolymer backbone for the synthesis of a Platinum Group Metal (PGM) sorbent. The sorbent was tested for Pd(II) and Pt(IV) sorption from HCl solutions. Stable for HCl concentrations below 0.5 M, the sorbent reached sorption capacities as high as 3.2 and 2.6 mmol metal g?1 for Pd(II) and Pt(IV), respectively. Metal sorption mainly proceeds by electrostatic attraction in acidic solutions, though a contribution of complexation mechanism cannot be totally rejected. The resistance to intraparticle diffusion is the main controlling mechanism for uptake kinetics. While agitation speed has a limited effect on kinetics, metal concentration and sorbent dosage have a greater effect on the kinetic profiles. The intraparticle diffusivity varies between 3 ? 10?11 and 4.5 10?10 m2 min?1. Thiourea (combined with HCl solution) is used for Pd(II) and Pt(IV) desorption. The resin could be desorbed and recycled for a minimum of five cycles maintaining high efficiencies of sorption and desorption. ?? |
E 27 Effect of polarity of solvent on silanization of halloysite nanoclay using (3-glycidyloxy propyl) trimethoxy silane / A. M. Abu el-Soad, A. V. Pestov, N. A. Martemyanov [et al.] // Journal of inorganic and organometallic polymers and materials. - 2021. - № 31. - P2569–2578 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The grafting of silane groups on clay surfaces has been recently investigated in order to fabricate versatile compounds with new potential applications in materials science and ecological engineering. This work explored the influence of variety of solvents with variable polarity on the silanization of halloysite nanoclay (HNT) surface by (3-Glycidyloxy propyl) trimethoxy silane. To this purpose, the functionalization of HNT by 3-Glycidyloxypropyltrimethoxysilane (GOPTMS) has been conducted in Ethanol (polar protic solvent), Tetrahydrofuran (THF) and Acetonitrile (polar aprotic solvents), and Hexane, 1,4-Dioxane and Toluene (non polar solvents). The silane grafted materials were characterized by using several techniques, including Fourier Transform Infrared Spectroscopy (FT-IR), elemental analysis, Scanning Electron Microscopy (SEM), Thermogravimetry (TGA), X-ray Diffraction Analysis (XRD) and Nitrogen adsorption/desorption isotherms. The largest silane loading has been detected for the hybrid nanomaterials prepared in Hexane as a dispersing medium. |
Grafting of (3-chloropropyl)-trimethoxy silane on halloysite nanotubes surface / A. M. Abu El-Soad, G. Lazzara, A. V. Pestov [et al.] // Applied sciences. - 2021. - Vol. 11, № 12. - Ст. 5534 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): GRAFTING -- HALLOYSITE NANOTUBES -- CPTMS Аннотация: Modified halloysite nanotubes (HNTs-Cl) were synthesized by a coupling reaction with (3-chloropropyl) trimethoxysilane (CPTMS). The incorporation of chloro-silane onto HNTs surface creates HNTs-Cl, which has great chemical activity and is considered a good candidate as an active site that reacts with other active molecules in order to create new materials with great applications in chemical engineering and nanotechnology. The value of this work lies in the fact that improving the degree of grafting of chloro-silane onto the HNT’s surface has been accomplished by incorporation of HNTs with CPTMS under different experimental conditions. Many parameters, such as the dispersing media, the molar ratio of HNTs/CPTMS/H2O, refluxing time, and the type of catalyst were studied. The greatest degree of grafting was accomplished by using toluene as a medium for the grafting process, with a molar ratio of HNTs/CPTMS/H2O of 1:1:3, and a refluxing time of 4 h. The addition of 7.169 mmol of triethylamine (Et3N) and 25.97 mmol of ammonium hydroxide (NH4OH) led to an increase in the degree of grafting of CPTMS onto the HNT’s surface. |