Organosilicon ion‐exchange and complexing adsorbents

Abstract

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.

Carbofunctional sulfur‐containing organosilicon compounds

“…Poly[bis‐ N , N ‐(silsesquioxanylalkyl)‐ S , S ‐dioxathiocarbamide was additionally found to be effective for adsorption of vanadium(V) and rare earth elements . The polymer adsorbed vanadium in the range pH = 2–9, where the transformation of vanadium cation form (VO 2 + ) occurred to become vanadium anion form (VO 3 − ) …”

“…[67] The polymer adsorbed vanadium in the range pH = 2-9, where the transformation of vanadium cation form (VO 2 + ) occurred to become vanadium anion form (VO 3 − ). [68] The ampholytic properties of the polymer were predetermined by the zwitterionic structure of its S,Sdioxothiocarbamide fragment. All the rare earth elements SCHEME 25 The reaction with cyclohexane of bis-N,N′-(trialkylsilylalkyl)-S,S-dioxathiocarbamides SCHEME 27 The reduced of elemental tellurium SCHEME 26 The reaction of bis-N,N′-(3-triethylsilylpropyl)-S,Sdioxathiocarbamide and bi-propylsulfide and bromobenzene SCHEME 28 The reaction of bis-(N,N′-triethylsilylmethyl)-S,Sdioxathiocarbamide (neutral medium) SCHEME 29 The reaction of bis-(N,N′-triethylsilylmethyl)-S,Sdioxathiocarbamide (acid medium) SCHEME 32 The side-reaction of oxidative decomposition of S-C bond SCHEME 31 The reaction of the same "dioxide" with ammonia SCHEME 30 Reactions of poly[bis-N,N-(silsesquioxanylalkyl)-S,S-dioxathiocarbamide] with ammonia or with methylamine (from lanthanum to lutetium) were adsorbed by the polymer at pH = 5-6.…”

Gold Recovery from its Flotation Concentrate using Acidic Thiourea Leaching and Organosilicon Polymer

“…Fraction of monomer in the PSTM-3C is represented by following formula as given in Eq. (2) [14]. Organosilicon polymer used in this study was synthesized at the Irkutsk Institute of Chemistry, Siberian branch, Russian Academy of Sciences [14].…”

“…polymer (PSTM-3C) The application of the organosilicon polymer as an ionexchange sorbent PSTM-3C for the recovery of gold from the pregnant solution has also been described in this paper. The PSTM-3C polymer was synthesized by immobilization of N, N'-bis(3triethoxysilylpropyl)thiocarbamide on the surface of silica [16]. The sorption property of the sorbent was studied as a function of acid concentration, adsorption time and temperature.…”

Organosilicon ion-exchange and complexing adsorbents

“…The thus obtained polymers are efficient ion exchangers and complexing agents being the subjects of several reviews. 8,9,60,61 Particularly, the products of copolycondensation of teraethoxysilane with 3-chloro-and 3-aminopropyl(triethoxy)silanes and their derivatives were prepared and studied, along with chemically modified silica gel, as adsorbents for copper, zinc, cobalt and nickel. 26 Adsorbent 21 containing the N(CH 2 CO 2 Na) 2 group was prepared by the reaction of sodium iminodiacetate with the product of copolycondensation of teraethoxysilane with 3-chloropropyl(triethoxy)silanes in DMSO in the presence of sodium iodide (Scheme 11).…”