Selective adsorption of toxic heavy metal ions using guanine-functionalized mesoporous silica [SBA-16-g] from aqueous solution

Abstract The removal of toxic metal ions e.g. Pb 2+ , Hg 2+ and Cd 2+ from aqueous solution were explored using guanine functionalized SBA-16 [SBA-16-G]. Nitrogen sorption isotherm, HRXRD, FESEM, HRTEM, EDA-X analysis were performed to investigate the changes in the surface morphology and chemical characteristics of [SBA-16-G] before and after the adsorption of toxic metal ions. Owing to the presence of large number of active functional groups of –NH, –C O on the surface, this adsorbent demonstrated proficient toxic metal ions removal capacities (maximum adsorption capacity, q m a x : 289.9 mg g −1 for Pb 2+ at 303 K, 259.9 mg g −1 for Hg 2+ at 308 K and 228.8 mg g −1 for Cd 2+ at 313 K, respectively) from aqueous medium. The isotherm study dictated that the adsorption data better comply to Langmuir isotherms with R L value