Functionalized hectorite clay mineral for Ag(Ⅰ) ions extraction from wastewater and preparation of silver nanoparticles supported clay

摘要

A novel clay mineral-based adsorbent for Ag(Ⅰ) ions extraction was obtained by modifying hectorite with 2-(3-(2-aminoethylthio)propylthio)ethanamine (AEPE-hectorite). The modified hectorite was used to recover Ag(Ⅰ) ions from wastewater for further preparation of silver nanoparticles supported hectorite. The parameters affecting silver ions extraction by AEPE-hectorite were investigated. The adsorbent could extract Ag(Ⅰ) ions from solution in a wide pH range (1-8) and high extraction efficiencies were achieved in the solution pH ranged from 4 to 9. AEPE-hectorite showed a good selectivity toward Ag(Ⅰ) ions over Co(Ⅱ), Ni(Ⅱ) and Cd(Ⅱ) ions and the solution ionic strength had no significant effect on extraction efficiency. The adsorption of Ag(Ⅰ) ions onto AEPE-hectorite followed the Freundlich isotherm model with maximum adsorption capacity observed in the experiment of 49.5 mg g~(-1). The adsorbent was successfully used to recover silver ions from a wastewater containing high concentration of silver and silver nanoparticles supported hectorite was obtained after reducing with NaBH_4. These results show an alternative in the preparation of silver nanoparticles supported clay.