Improvement in adsorption of Hg2+ from aqueous media using sodium-type fine zeolite grains

Abstract

To increase the adsorption capability of Hg2+ from aqueous media, we prepared sodium-type fine zeolite grains with various particle sizes (denoted as ZE1, ZE2 and ZE3). The particle sizes of ZE1, ZE2 and ZE3 were 16.363 ± 0.365, 1.454 ± 0.357 and 0.607 ± 0.377 μm, respectively. Moreover, the CEC, specific surface area and pore volume were in the order ZE1 (42 mmol/g and 23.5 m2/g) < ZE2 (72 mmol/g and 67.1 m2/g) < ZE3 (135 mmol/g and 176.6 m2/g). Subsequently, the Hg2+ adsorption capability was investigated. The performance of tested agents on Hg2+ adsorbed was in the order ZE1 (5.0 mg/g) < ZE2 (9.4 mg/g) < ZE3 (20.2 mg/g). It was concluded that fine crystalline zeolite was important in enhancing the adsorption capability of Hg2+. In addition, the mechanism of adsorption of Hg2+ on the ZE samples was evaluated. Our results suggested that Hg2+ was exchanged with sodium ions in the interlayers of ZE samples with correlation coefficients of 0.966–0.979. Our findings revealed that these ZE samples constitute potential agents for the adsorption of Hg2+ from aqueous media. HIGHLIGHTS The intensity of mercury (Hg) onto ZE3 increased after adsorption.; Hg2+ was exchanged with Na+ in the interlayers of ZE3.; Hg2+ was selectively adsorbed by ZE3 in a binary solution system.;

Keywords

• adsorption
• hydrothermal activation
• mercury ion
• zeolite