Sorption of cobalt on modified silica gel materials

Abstract

R. HANZELALLDECO, SK-919 31 Jaslovsk( Bohunice Silica gel materials were chemically modified with imidazole. The degree of functionalisation of the covalently attached molecule was calculated from C, H, N analysis and ranged between 0.270 and 0.552 mmol/g, depending on the reflux time and silica gel matrix used. Experimental sorption capacity for cobalt ranged from 0.038 to 0.228 mmol/g.Synthesised hexagonal mesoporous silica matrix MCM -41 with uniform pore diameter < 400 nm was used too. Change of pore diameters of silica gel support to larger pores has a positive influence on access of cobalt ion to sorption centres and increases sorption capacity of sorbents.The sorption of cobalt under various conditions (pH, contact time of phases) with constant liquid-solid ratio (V/m = 50 mL/g) was studied. The distribution coefficients ranged between 200 and 50 000 mL/g according to the silica gel matrix used. The influence of presence of other heavy or toxic metals and the influence of sodium and potassium on sorption of Co (II) from aqueous solutions was investigated. Influence of different metals on cobalt sorption decreases in the order Hg > Cu > Cd > Zn, Fe > Mn > A1, Cr.

Preparation, Characterization and Voltammetric Aspects of a Silsesquioxane Organofunctionalized With Imidazole Groups and Subsequent Reaction With Silver and Potassium Hexacyanoferrate (III)

“…Therefore silsesquioxanes are potential candidates for organofunctionalization with imidazole groups. When compared with silica gel, the advantage of using silsesquioxanes modified by covalent attachment of organofunctional groups regards their easy preparation, high sorption capacity and fast adsorption kinetics, in addition to their good chemical stability (Rajec & Hanzel, 2003;Silveira, 2012). Within this context, particularly our interest in the silsesquioxane chemistry is to prepare multifunctional nanostructured materials that can be used as electrochemical sensors.…”