Study of Hg2+ Sorption from Water Solutions by Mesoporous Silica with Thiourea Functional Groups

Abstract

The mesoporous silicas with thiourea functional group ?Si(CH2)3NHC(S)NHC2H5 were synthesized using sol-gel and template methods (with cetylpyridinium chloride as template). It has been found that the sorption properties of these mesoporous silicas are influenced both by the functional group content and the character of the sorbent’s porous structure. At low density of ligand groups all of them are accessible for Hg2+ sorption with formation, as a rule, of the simplest complexes (1:1 composition). The rising density of functional groups in the surface layer of sorbents results in the reduction of their accessibility and complicates the complex formation process. This, causes reducetion of static sorption capacity of such materials (from 357 to 46 mg/g). It was shown that mesoporous materials with thiourea groups synthesized by template method and possessing highly ordered structures have superior kinetic characteristics compared to xerogels with the same functional groups is stable.