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Sorption of Noble Metals on Silica Gel Chemically Modified with N-(5-Mercapto-1,3,4-Thiadiazol-2-yl)-N'-Propylurea Groups

“…The presence of thiol groups in the grafted MTS molecule predetermines its sorption activity towards noble metals in many respects, similar to the behaviour of silica gels with grafted mercaptopropyl groups (SH-C) (Losev et al 2003(Losev et al , 2004Trokhimchuk et al 2004). In fact, quantitative sorption of Pd(II), Ag(I) and Au(I, III) occurred on the MTS sorbent over a wide range of solution acidity in a similar manner to the SH-C sorbent (Table 1).…”

“…Indeed, the presence of thiol groups in the MTS sorbent also allows the occurrence of oxidation-reduction processes on its surface during the sorption of some metal ions from solutions [Cu(II), Au(III), Pt(IV) and others]. For example, the sorption of Au(III) onto SH-C is accompanied by its reduction to Au(I) (Losev et al 2004;Okabayashi et al 2002) according to the equation:…”

Application of Silica Chemically Modified by Sulfur-Containing Groups to the Separation and Determination of Platinum and Rhenium in Catalysts Based on Aluminum Oxide

“…Procedure for determining platinum and rhenium in catalyst. Weighed portions (0.5000 g) of catalyst samples were dissolved in 6 M HCl in a quartz autoclave in the presence of manganese dioxide according to the procedure described in [10]. The autoclave content was transferred to a 100-mL volumetric flask and diluted up to the mark with distilled water.…”

“…The developed procedures enable the sequential isolation of platinum(IV) and rhenium(VII) from one sample of a solution, using one type of adsorbent, and the determination of them directly on the adsorbent surface with good precision and reproducibility. The use of TDTS decreases more than twofold the detec-tion limit of platinum and expanded twice the analytical range compared to the silica-based adsorbent chemically modified by N-allyl-N'-propylthiourea (ATMS) [10]. The use of DTCS and TDCS adsorbents makes it possible to lower fourfold the detection limits of rhenium in comparison with ATMS at a comparable analytical range.…”

“…Procedures for the sequential isolation and adsorption-luminescence determination of platinum and adsorption-photometric determination of rhenium in an aluminum-platinum-rhenium catalyst, using silica chemically modified by N-allyl-N'-propylthiourea, were developed [10].…”