Synthesis of thiol functionalized organo-ceramic adsorbent by sol-gel technology

A new high performance adsorbent (SOL-AD) is synthesized by the sol-gel pro cessing technique for the purpose of treatment of cadmium and mercury ions contaminated aqueous streams. In order to synthesize this adsorbent, the fu nctional precursor (3-merceptopropyltrimethoxysilane) and the cross-linking agent (tetraethoxysilane) are hydrolyzed and cocondensed in an acidic wate r and ethanol mixture followed by gelation in a basic solution. This organo -ceramic adsorbent has high uptake capacities for cadmium and mercury ions. Especially. SOL-AD-IV synthesized at the optimal conditions has uptake cap acities of 222 and 1284 mg/g of cadmium and mercury ions, respectively. The se uptake capacities are considerably higher than those of covalently funct ionalized ceramic adsorbents and other functionalized polymeric resins. In addition, the beneficial properties of ceramic adsorbents, such as strong m echanical, thermal, and chemical stabilities are maintained. This paper dis cusses the effects of sol-gel processing parameters on the properties of SO L-AD adsorbents and the adsorption/desorption of cadmium and mercury ions o n the SOL-AD-IV adsorbent. (C) 2001 Elsevier Science B.V. All rights reserv ed.