Self-assembled monolayers on mesoporous support (SAMMS) technology for contaminant removal and stabilization

摘要

A study of mercury-adsorption kinetics showed that at all pH values (3, t, 7 and 9), the adsorption by thiol-SAMMS occurred very rapidly ((approximately) 82 to 95% of total mercury adsorption occurred within the first 5 min). The adsorption equilibrium in all cases was attained with (approximately)4 h. At fixed solid:solution ratio, the mercury-loading density on thiol-SAMMS increased with decreasing iodide concentrations. The highest mercury loading of (approximately)270 mg/g of thiol-SAMMS was observed at an iodide concentration of (approximately)90 mmoL/L. Calculated free energy of adsorption value showed that Hg(sup 2+) ion has high affinity for thiol-groups. This strong adsorption affinity is typical of soft-cation/soft-base interaction. Very high distribution coefficient values indicated that thiol-SAMMS adsorbs mercury from KI-K(sub 2)SO(sub 4) solutions with very high specificity.