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Acid–base membranes have been prepared by mixing a 1-vinyl-1,2,4-triazole polymer (PVT) with phenol-2,4-disulfonic acid (PDSA) in the presence of products of intermolecular crosslinking of polyvinyl alcohol and oxalic acid. The composition and structure of the membranes have been studied by elemental analysis and IR and NMR spectroscopy techniques. The membranes are thermally stable up to 245°C. Their electrical conductivity increases from 6.23 mS cm−1 (PVT–PDSA 80 : 20 wt % membrane) to 59.8 mS cm−1 (PVT–PDSA 10 : 90 wt %) with increasing temperature and phenol-2,4-disulfonic acid content at a temperature of 80°C and a humidity of 75%. The activation energy of the membranes ranges from 19.5 to 38.2 kJ/mol, respectively. The water uptake of membranes, which determines, among other things, the electrical conductivity, depends on the PVT content: the water uptake decreases from 200 to 50% with an increase in its amount in the membrane composition from 9.1 to 81.30 mol %, leading to a decrease in electrical conductivity along with a decrease in the proportion of PDSA.

The results of a study of the adsorption of zinc(II) and chromium(III) ions by zeolites modified by HCl are presented. According to the data of elemental analysis and electron spectroscopy, the zeolites contain at least 75% heulandite in their composition. The removal of aluminum ions from the tetrahedral framework of the sorbent formed by AlO4 and SiO4 occurs upon modifying the zeolites by HCl. This leads to the destruction of the main component, heulandite, and compaction of the silicate layer. The time of establishment of adsorption equilibrium in the zeolite–aqueous solution system is 90 min. The isotherms of adsorption of zinc(II) ions are obtained in a temperature range 298–318 K at pH 5.6–5.8. It is shown that the adsorption of zinc(II) ions increases with growing temperature. The isotherms of adsorption of chromium(III) ions are obtained in a temperature range 298–318 K at pH 7.6–7.9. It is found that the adsorption of chromium(III) ions decreases with increasing temperature. The differential heats of adsorption are calculated based on the isosteres of adsorption. The increase in the adsorption of chromium(III) ions is accompanied by a decrease in the differential heat of adsorption from 36.9 to 26.8 kJ/mol. This may be associated with the nonuniformity of the surface of the adsorbent, due to what the metal ions are adsorbed on less active regions of the surface as far as the growth in the saturation of more active sites. The change in the differential heat of adsorption of zinc(II) ions with the growth in the degree of filling of the surface has a nonmonotone character. In the region of low degrees of filling of the surface, the differential heat of adsorption decreases, and then increases, which is probably determined by polymolecular adsorption presuming the presence of an adsorbate–adsorbate interaction. The efficiency of treatment of industrial wastewaters of the electroplating industry in the case of the use of the modified zeolites is over 97%.

Binary copolymers possessing thermal stability up to 290°C and suitable for the formation of ion-exchange membranes have been obtained by free radical copolymerization of sodium p-styrene sulfonate and 1-vinylimidazole with subsequent conversion to the H-form. The composition and structure of the copolymers are confirmed by elemental analysis and IR and NMR spectroscopy. Multicomponent membranes based on the copolymers of sodium p-styrene sulfonate and 1-vinylimidazole have been obtained using poly(vinyl alcohol) crosslinked by oxalic acid as a film-forming agent. It is shown by scanning electron microscopy that the surface and cut of the membranes have a uniform structure. The specific electric conductivity of the membranes with different concentrations of styrene sulfonic acid (20 to 80 mol % in the copolymer) increases with an increase in the fraction of styrene sulfonic acid and is 29.5 to 52.0 mS cm−1 at 80°C. The activation energy of proton transport of the membranes is 12.5 to 15.5 kJ mol−1. The water uptake of the membranes decreases with the increase in the concentration of the basic (imidazole) component in them, which may be associated with the increase in the density of ionic crosslinking due to the acid–base interaction of the sulfo groups and pyridine nitrogen atoms of the imidazole cycle. The formation of acid–base pairs results in the formation of continuous proton transport channels in addition to the sulfonic acid channels, which is confirmed by the high values of specific electric conductivity even in the case of a decrease in the concentration of sulfostyrene in the composition of the membrane. Increasing the concentration of 1‑vinylimidazole in the composition of the copolymer from 20 to 80 mol % leads to an increase in the relative elongation at break from 3 to 6%, an increase in the tensile strength at break from 4 to 7 MPa, a decrease in the Young modulus of the membranes from 127 to 102 MPa, and a decrease in the water uptake from 45 to 15.

The adsorption kinetics of nickel(II) and copper(II) ions by alumosilicates modified with N,N'-bis (3-triethoxysilylpropyl) thiocarbamide (BTM-3) and HCl is studied using the kinetic pseudo-first and pseudo-second order models. It is shown that when aluminosilicates are modified the time for equilibrium establishment is reduced by factors of 1.33 for adsorption of copper(II) ions and 2 for nickel(II) ions. The rate and energy of adsorption increase. It is established that the kinetics of the adsorption of the studied ions is best described by a pseudo-second order model. At the same time, the values of the correlation coefficients are 0.997–0.998. The maximum value of the adsorption rate constant of 33.7 × 10–5 g/(mmol min) corresponds to nickel(II) ions for aluminosilicates modified with HCl. The initial adsorption rate is 8.70 × 10–3 mmol/(g min). The maximum value of the adsorption rate constant value of 2.91 × 10–5 g/(mmol min) for aluminosilicates modified with BTM-3 corresponds to Cu(II) ions.

Copolymers of ethylene glycol vinyl glycidyl ether (VGE) and vinyl chloride (VC) have been obtained via radical copolymerization of VGE with VC at 70°C in the presence of the initiator azobisisobutyronitrile. By the sol–gel synthesis involving VGE–VC copolymers and carbofunctional organosilicon precursors, such as N,N'-bis(3-triethoxysilylpropyl)thiocarbamide (BTM) and 2-([triethoxysilylpropyl]amino)pyridine (TEAP), hybrid organic–inorganic membranes possessing proton conductivity after doping with orthophosphoric acid have been fabricated. The proton conductivity of the membranes in the temperature range of 30–80°C is characterized by the values of 3.52–4.88 × 10−3 S cm−1 for VGE–VC/ BTM/H3PO4 and 1.19–2.89 × 10−3 S cm−1 for VGE–VC/TEAP/H3PO4.

Radical copolymerization of divinyl sulfide and 4-vinylpyridine was used to synthesize 3D copolymers having in their structure “pyridine” nitrogen atoms and sulfide sulfur. It was found that the copolymers have high sorption capacities reaching for Au(III), Ag(I), Pt(IV) and Pd(II) values of 1200, 340, 1040, and 520 mg g−1, respectively. The results obtained indicate that divinyl sulfide is promising as a cross-linking monomer in syntheses of ion-exchange resins.

A new composite adsorbent was obtained by hydrolytic polycondensation of N,N'-bis(3-triethoxysilyl propyl)thiocarbamide in the presence of poly-2-methyl-5-vinylpyridine. The sorption activity of the composite toward platinum(IV) ions was studied in hydrochloric acid solutions. The maximum extraction efficiency of Pt (IV) and the maximum values of sorptive capacity (218 mg g–1) and coefficient of interphase distribution (7090 cm3 g–1) of the studied adsorbent in 1 М solution of HCl were found at 338 K. The Langmuir, Freundlich, and Dubinin–Radushkevich models were used to describe adsorption nature.

The adsorption of platinum(IV) in hydrochloric acid solutions of a composite based on N,N-bis(3-triethoxysilylpropyl)thiourea and 4-vinylpyridine‒2-hydroxyethylmethacrylate copolymer is studied. The value of the static adsorption capacity of the composite for platinum(IV) is found to be 215 mg/g. To describe the nature of the adsorption, Langmuir, Freundlich, and Dubinin–Radushkevich models are used. The adsorption kinetics is estimated using Boyd–Adamson models of pseudo-first and pseudo-second order and the Elovich equation.

Data on the synthesis and sorption properties of natural calcium aluminosilicates modified by poly-1-vinyl imidazole (PVIm) and poly-4-vinyl pyridine (PVP) are presented. The fullest recovery of nickel (II) ions from low-concentration solutions is observed for PVP-modified aluminosilicates. Adsorption of nickel (II) ions by PVIm-modified aluminosilicates is best described by the Freundlich adsorption model. In the case of PVP-modified aluminosilicates, the Langmuir model is more adequate. The free adsorption energy values indicate that the interaction between nickel (II) ions and modified aluminosilicates is of a chemical nature.

Antibacterial properties of modified alumosilicates are investigated. It is established the improvement of antimicrobial properties and an increase of the degree of water disinfection to 89–97% in the case of modified sorbents. For all water samples taken in surface water bodies the most efficient results in the decrease of the total microbial number were shown by allumosilicates modified by HCl. Their practical use makes it possible to reduce the total microbial number to the standards of drinking water (50 CFU/cm3).

According to X-ray phase analysis, modification of natural aluminosilicates with hydrogen chloride is accompanied by the destruction of the main component—calcium heulandite—the content of which decreases from 64.3 to 42.9%. An increase in temperature during the modification process contributes to the packing of the cristobalite structure, which positively affects the adsorption properties of the materials. In the process of activation of aluminosilicates by hydrogen chloride, their texture characteristics change: the specific surface (from 33 to 75 m2/g) and the specific pore volume (from 0.015 to 0.036 cm3/g) increase more than double. The average pore size is reduced from 1.8 to 1.6 nm. The result of such changes is an increase in the adsorption capacity. Adsorption of nickel(II) and copper(II) ions on modified aluminosilicates is most adequately described by the Langmuir adsorption model.

Proton-conducting membranes have been obtained by sol–gel synthesis involving tetraethyl orthosilicate and sulfonated suspension copolymers of styrene with allyl glycidyl ether. The membranes are gels consisting of a polymer matrix, in which silica particles are uniformly distributed. The synthesized membranes are characterized by the proton conductivity of up to 4.21 × 10–2 S/cm at 343 K and 75% humidity, an ion exchange capacity of 3.5 meq/g, a proton-transfer activation energy of 25.2 ± 2.6 kJ/mol, thermal stability of up to 130°C, and mechanical strength (tensile modulus of elasticity, 322 MPa).

Composite materials are synthesized using the sol–gel method involving tetraethoxysilane and vinyl acetate/1-vinylimidazole and vinyl acetate/4-vinylpyridine copolymers, and their sorption capacity with respect to platinum(IV) ions is studied. The composites exhibit the highest sorption activity at 338 K in 1 M HCl solution (sorption capacity with respect to Pt(IV) varies from 180 to 249 mg g–1). The interaction between platinum(IV) and the surface of the sorption material is a result of the chemisorption process. The Langmuir, Freundlich, and Dubinin–Radushkevich models are used to describe the nature of adsorption.

Immobilization of N,N'-bis(3-triethoxysilylpropyl)thiocarbamide on the surface of natural alumosilicates from Eastern Transbaikal has been carried out. Adsorption isotherms of Ni(II), Cu(II), and Zn(II) ions on modified adsorbents have been plotted. The experimental data have been treated using the Langmuir, Freundlich, BET, and Dubinin–Radushkevich models. The constants of these equations have been determined. It has been shown that adsorption on alumosilicates modified with N,N'-bis(3-triethoxysilylpropyl)thiocarbamide is described in the best way by the Freundlich and Langmuir adsorption models. The Dubinin–Radushkevich model has been employed for the calculation of free energy of adsorption. For all the specimens under study, the free energy of adsorption indicates the presence of an ion-exchange mechanism, while the adsorption of heavy-metal ions has a chemical nature.

The adsorption of platinum(IV) solutions by a composite based on silicon dioxide and copolymer of 4-vinylpyridine and 2-hydroxyethylmetacrylate in hydrochloric acid solutions has been studied. The maximum efficiency of extraction of platinum(IV) ions has been detected in a solution of HCl with a concentration of 1 mol L–1 at a temperature of 338 K (sorption capacity equal to 188 mg g–1). The interaction of platinum (IV) with the surface of the composite is a result of chemisorption. The models of Langmuir, Freundlich, and Dubinin–Radushkevich have been used to describe the nature of adsorption. Adsorption kinetics was assessed using the models of Boyd–Adamson, pseudofirst and pseudosecond orders, and Elovich.

4-Vinylpyridine–2-hydroxyethylmethacrylate copolymers have been synthesized by radical copolymerization. The composition and properties of the copolymers have been studied; the reactivity constants of the comonomers have been calculated. Sol–gel synthesis involving the resulting copolymers and tetraethoxysilane has yielded hybrid membranes comprising a polymer matrix with uniformly distributed hydrated silica particles and exhibiting a proton conductivity of up to 1.85 × 10−2 S/cm, an ion-exchange capacity of 2.1 meq/g, a heat resistance of 412°С, a tensile strength of 55.5 MPa, an elongation at break of 15%, and a proton-conductivity activation energy of 12 ± 2 kJ/mol.

The adsorption capacity of studied aluminosilicate samples was found to depend significantly on the sizes of grains of adsorbents. The equations for calculating the statistical exchange capacity of aluminosilicate of different fractions in relation to ions of heavy metals Ni(II), Cu(II), Zn(II), Fe(III), and Cr(III) were derived. The effective coefficients of diffusion in the adsorbent grain and in the film of solution were found. It was determined that external diffusion kinetics served as a limiting step of adsorption. The rate of the process was determined as varying from 0.16 × 10–6 to 2.8 × 10–6 mol/m2 s.

The kinetics of the adsorption of zinc(II) ions by natural zeolites was studied using pseudo-first and pseudo-second-order kinetic models. The objects of study were zeolites mined in East Transbaikalia. The X-ray phase analysis and IR spectroscopy data confirmed that natural zeolite-containing rock samples have the following composition: calcium heulandite Ca[Al2Si7O18]⋅6H2O and impurity rocks, namely, sanidine KAlSi3O8 and cristobalite SiO2. The dependence of the adsorption value on zeolite grain size was studied. It was shown that the adsorption value increases 3.8 times and reaches 0.075 mol/g as the grain size decreases from 5 to 0.1 mm. The kinetic study of zinc(II) ions adsorption was performed at pH 5.0–5.4 in the temperature range of 298–318 K. In a zeolite–zinc sulfate aqueous solution system, the adsorption equilibrium time was 120 min. It was shown that the zinc(II) ions adsorption rate decreases under the temperature increase. It was established that the kinetics of zinc(II) ions adsorption is best described by a pseudo-second-order model, the correlation coefficient values varying in the range of 0.998–0.999. The highest adsorption rate constant value of 0.446 g/(mmol⋅mm) corresponds to the temperature of 298 K. It was shown that zeolites demonstrate the highest adsorption value towards heavy metal ions at the temperature of wastewater. The proof-of-principle studies were performed to establish the feasibility of the recovery of copper(II), nickel(II), and zinc(II) ions from wastewater produced by galvanic manufacture using the studied minerals. The treatment process was performed under the conditions determined as optimal for model solutions. The efficiency of heavy metal ions removal was 85–89%.

The proton-conducting hybrid organic-inorganic composites based on tetraethoxysilane and sulfonated styrene (St) and allyl glycidyl ether (AGE) copolymers, which are characterized by high exchange capacity and specific conductivity, are formed by sol-gel synthesis. The results of a quantum-chemical calculations of the geometry of the structure of an organic-inorganic composite (for a model consisting of 78 atoms) allow us to associate an increase in the proton conductivity of hybrid membranes, compared with the initial copolymer, with the generation of crystallization water and free sulfuric acid during the formation of the composite.

In this paper, the research results on the adsorption process of final treatment of wastewater from electroplating production using a model filter with a nominal capacity of 0.3 m3/h are presented. Natural zeolite of the Trans-Baikal deposit heulandite was used as a charge. The processes of sorption and selective desorption of heavy metal ions were studied. Based on the results, the natural zeolites regeneration scheme was developed; the scheme provides the multiple reuse regenerated adsorbents in the processes of final treatment of wastewater from electroplating production, and eluates produced by regeneration can be reused in the manufacture as components for electrolytes used for electroplated coating deposition.

We have investigated the adsorption of platinum(IV) ions by sorbents based on sol—gel synthesis products with the participation of vinylglycidyl ether ethyleneglycol copolymers with vinylchloride and organisilicon monomers: N,N′-bis(3-triethoxysilylpropyl)thiocarbamide and 2-([triethoxysilylpropyl] amino)pyridine. We have shown that the interaction of platinum(IV) with the composite surface is a result of both physical adsorption and chemical adsorption. We have used the Langmuir, Freundlich, and Dubinin—Radushkevitch models to describe the nature of adsorption. Boyd—Adams, pseudo-first and pseudo-second-degree, and Elovitch models were used to evaluate adsorption kinetics

A method of synthesis of cationic polyelectrolites is suggested based on N,N-dimethyl-N,N-bis(β-chloroallyl)ammonium chloride prepared from organochlorine wastes from epichlorohydrin production and acrylamide. Flocculating ability of the copolymer was studied.

The sorption isotherms of copper(II) ions on natural calcium heulandite at a pH of 1.7 and temperature of 298–318 K have been obtained. The exchange sorption capacity with respect to Cu(II) ions at 298 K was 0.47 mg-eqv/g. The equilibrium constants of the ion exchange and thermodynamic functions including Gibbs energy and entropy and enthalpy of sorption have been calculated. The possibility of using calcium heulandite for purification of the wastewaters of the electroplating industry from ions of heavy metals has been assessed.

Membranes exhibiting proton conductivity have been prepared by sol-gel synthesis using tetraethoxysilane and heteroaromatic sulfonic acid derivatives (2-phenyl-5-benzimidazolesulfonic acid and 3-pyridinesulphonic acid) in the presence of phosphoric acid and polyvinyl butyral. The membranes are gels composed of a polyvinyl butyral polymer matrix with uniformly distributed particles of silica containing molecules of heteroaromatic sulfonic acid derivatives mechanically incorporated in its network structure. The membranes synthesized from 2-phenyl-5-benzimidazolesulfonic acid or 3-pyridinesulphonic acid exhibit a conductivity of 0.1 × 10−2 or 0.55 × 10−2 S/cm at 353 K, an ion-exchange capacity of 2.70 or 1.84 mequiv/g, and a proton-transfer activation energy of 24.93 or 21.73 kJ/mol, respectively; at a relative water content of 50%, the tensile strength is 4 or 6 MPa and the elastic modulus is 128 or 191 MPa, respectively.

Regularities of the sorption of heavy metal ions on the natural zeolite (calcium heulandite) have been investigated. Relationships of the sorption of heavy metal ions as a function of the fraction size of test zeolites were obtained. The sorption values in static conditions for nickel, copper and zinc ions amounted to 5.9, 4.8 and 2.7 mg/g, respectively, making it possible to use zeolites as sorbents in the treatment of wastewater from electroplating facilities. The degree of wastewater purification in a filter with calcium heulandite medium amounted to ∼ 90%.

Sibunite, a carbon sorbent, has been modified with organosilicon monomers containing aminoguanidine, thiocarbamide, malonodiamide, and ammonium dithiocarbamate moieties. The high adsorption activity of the synthesized materials in hydrochloric acid solutions with respect to platinum(IV) ions results from the formation of ion-coordinated platinum(IV) complexes with the chemically active moieties of modifying compounds.

The composition of a natural specimen of zeolite-containing rock of a Transbaikal field including Ca[Al2Si7O18] · 6H2O calcium heulandite and KAlSi3O8 potash fieldspar impurity is confirmed with X-ray phase analysis and infrared spectroscopy. The time necessary for attaining adsorption equilibrium in a zeolite-aqueous nickel sulfate solution system is estimated. The limiting adsorption at different temperatures is found from the Langmuir equation. Thermodynamic and kinetic characteristics of the adsorption of nickel (II) cation on natural minerals are calculated.

By the sol-gel synthesis involving copolymers of ethylene glycol vinyl glycidyl ether and vinyl chloride (VGE–VC) and carbofunctional organosilicon precursor 2-([triethoxysilylpropyl]amino)pyridine (TEAP), hybrid organic–inorganic membranes possessing proton conductivity after doping with orthophosphoric acid have been fabricated. The proton conductivity of the membranes VC/TEAP/H3PO4 in the temperature range of 30-80 °C is characterized by the values of 1.19-2.89 mS cm−1.

Process in which composites are formed in sol-gel systems based on 3-aminopropyltriethoxysilane and vinyl derivatives of nitrogen-containing heterocyclic compounds was studied. These products are highly dispersed and thermally stable interpenetrating polymers insoluble in water and organic solvents. Their composition and structure were examined.

The formation of hybrid composites in sol-gel systems based on organosilicon monomers and acrylic acids was studied. The composition, properties, structure, and morphology of the products were examined.

The products of sol-gel synthesis involving tetraethoxysilane and the nitrogenous polybases poly(4-vinylpyridine), poly(2-methyl-5-vinylpyridine), poly(N-vinylimidazole), poly(N-vinylpyrazole), and poly(S-vinyl-2-mercaptobenzimidazole) are reported. The composition and properties of polyelectrolytes synthesized in alkali and neutral media are examined. Promising materials for fabrication of proton-conducting membranes are suggested.

Homopolymers of 4-vinylpyridine and 2-methyl-5-vinylpyridine and copolymers of 2-methyl-5-vinylpyridine with vinyl chloride and vinyl acetate were prepared by radical copolymerization. Organo-inorganic composites were prepared by hydrolytic polycondensation of the copolymers obtained and tetraethoxysilane. From solutions of the (co)polymers and composites, films were prepared by casting, and their protonic conductivity was determined.

The radical copolymerization of vinyl chloride with 2-methyl-5-vinylpyridine and 1-vinyl-4,5,6,7-tetrahydroindole is accompanied by dehydrochlorination. In the vinyl chloride-2-methyl-5-vinylpyridine system, the evolved hydrogen chloride interacts with a pyridine hydrogen atom to give charged units of a heterocycle. In the vinyl chloride-1-vinyl-4,5,6,7-tetrahydroindole system, the hydrogen chloride being formed initiates the cationic dimerization of a nitrogen-containing monomer. The synthesized copolymers based on vinyl chloride surpass the commercial poly(vinyl chloride) in terms of thermal stability and solubility in organic solvents.

Formation of nanocomposites in the sol-gel systems RSiX3 [R = CH3 (I), C6H5 (II), X = Cl; R = ClCH2 (III), X = OC2H5]-polyvinylazole [(-CH2-C(Y)H-)n, Y = pyrazolyl, imidazolyl, 4-pyridinyl, 2-methyl-5-pyridinyl], and also I-1-vinyl-4,5,6,7,-tetrahydroindole using was studied. The composition and structure of the resulting nanocomposites were analyzed.

The products of base hydrolysis of tetraethoxysilane in the presence of polymeric nitrogen bases poly-1-vinylpyrazole, poly-1-vinylimidazole, poly-4-vinylpyridine, and poly-2-methyl-5-vinylpyridine were isolated. The conditions of their formation, chemical composition, structural characteristics, and sorption properties with respect to noble metals (Ag, Au, Pt, and Pd) were studied. These products are highly dispersed thermally stable interpenetrating copolymers poorly soluble in water and organic solvents. Their composition and properties are governed by the kind of the polymeric nitrogen base.

Hybrid organoinorganic composites insoluble in water and organic solvents were prepared by the hydrolysis of tetraethoxysilane in the presence of poly-1-vinylpyrazole, poly-1-vinylimidazole, and poly-4-vinylpyridine. The composition of the composites was determined by the nature of the polymeric nitrogen base and hydrolysis conditions. The composites synthesized showed high sorption activity in the extraction of the [PdCl4]2−, [PtCl6]2−, and [AuCl4]− ions from hydrochloric acid solutions.

Reactions of organosilicon thiocarbamide dioxides {[R3Si(CH2)3NH]2CSO2, R = Et (I), O1.5 (II)} with methylamine and ammonia were studied. The reaction of compound I with ammonia involves, along with the substitution of the NHC(SO2)NH fragment by a guanidine residue, Si-C bond cleavage to form an oligomer comprising [O(Et)Si(CH2)3NH]2C=NH and [O1.5Si(CH2)3NH]2C=NH elementary units. The reactions of compound II with methylamine and ammonia resulted in the synthesis of organosilicon polymers containing guanidine groups. These polymers exhibit a high sorption capacity toward Ag(I).

The reaction of triethoxysilylpropylamine (AGM-9) with dicyanodiamide was studied. The condensation of AGM-9 with dicyanodiamide occurs in the presence of a catalytic amount of CuCl2 at 125–145°C within 5–24 h; it involves both the amino group of AGM-9 and ethoxy substituents at the Si atoms, with an unusual exchange of a Si-O bond for a Si-N bond. The final reaction product is 1-N-(3-triethoxysilylpropyl)-2-N-[3-aminopropylsilyl(diethoxy)]biguanidine. Its hydrolytic polycondensation yields an organosilicon polymer, a polycondensate of AGM-9 with 1-N-(3-triethoxysilylpropyl)biguanidine, which is a highly efficient sorbent for Ag(I) (static sorption capacity 544 mg g−1).

Long and systematic investigations of the present authors in the creation of organosilicon adsorbents, ion-exchange and complexing agents are summarized. A wide series of such adsorption materials were synthesized by hydrolytic polycondensation and oxidizing hydrolytic polycondensation of organosilicon monomers of general formula X3SiQY and X3SiQZQSiX3, where X = Cl, AlkO; Q = alkylene C1–C3, phenylene; Y and Z = carbofunctional ionic and complexing groups. In this way, it was possible to obtain polyorganylsilsesquioxanes with carbofunctional groups such as Y = SH, SO3H, S(CH2)2NH2, SCH2COOH, NHC(O)CH3, NHC(S)CH3, NHC(NH)NH2, NHC(NH)NHC(NH)NH2, Z=S, SS, S(CH2)2S, NHC(O)NH, NHC(S)NH, NHSSNH, NHS(O)NH, NHS(O2)NH, NHC(SO2)NH, NHC(NH)NH, NHC(S)S− · NH3+, etc., which turned out to be very effective ion-exchange and complexing adsorbents. These adsorbents have a crosslinked silsesquioxane structure. The three-dimensional structure of the polyorganylsilsesquioxane skeleton of these adsorbents provides for their high thermal and chemical stability. They are stable up to 230–270°C and do not lose their adsorption activity in 10–18 mol/l H2SO4 at 100°C and in boiling concentrated HCl. The ion-exchange and complexing properties of organosilicon adsorbents were studied on 50 elements of the Periodical system. Effective adsorbents toward noble metals, rare, rare-earth and toxic elements have been found. The practical application of organosilicon adsorbents is described. Copyright © 2006 John Wiley & Sons, Ltd.

Organosilicon guanidine derivatives RNHC(=NH)NHCH2CH2CH2Si(OC2H5)3- n (OH)n [R = H, n = 1; R = (CH2)3Si(OC2H5)3, n = 0] were synthesized by condensation of guanidinium carbonate with (3-aminopropyl)triethoxysilane. The products were brought into ether interchange with thiethanolamine and hydrolytic polycondensation.

This study is devoted to the development and investigation of composite membrane materials for fuel cells. Proton conductive membranes consisting of silica and various low- and high-molecular organic compounds have been prepared by the sol-gel method. The synthesized membranes are characterized by proton conductivity (up to 10-2 S/cm), ion-exchange capacity (1.84-3.5 meq/g), thermal stability (260 – 400 °C), and tensile modulus (128 - 322 MPa).

Condensation of 3-triethoxysilylpropylamine with malonic amide was studied. The condensation products, dicarboxylic acid diamides (malonic and phthalic), were used for peretherification with triethanolamine and thus new representatives of silatran series compounds were prepared: N,N'-bis(3-triethoxysilyl)malonic diamide and -phthalic diamide. By hydrolytic polycondensation of N,N'-bis(3-triethoxysilyl)malonic diamide we synthesized an organosilicon polymer with silsesquioxane structure, which we studied as a sorbent of platinum group metals rhodium, palladium and platinum. Peculiar features of sorption activity of the polymer and speculative mechanism of metal sorption are discussed.