Study on Capture Performance on PbCl₂ and CdCl₂ using Kaolin Modified by Sodium Ions

Abstract

Different concentrations solutions of NaOH and NaCl were used to modify raw kaolin for improving its heavy metal capture performance. The best modified kaolin was formed by 0.19375 g NaOH modifying 10 g kaolin based on the evaluating index of capture efficiency with 4 % and 47 % increase for PbCl 2 and CdCl 2 . This modified method can obtain a new adsorbent which has good capture effect on both PbCl 2 and CdCl 2 at the same time. Based on the evaluating index of the ratios of Pb/Al and Cd/Al, the best modified adsorbents on PbCl 2 and CdCl 2 were 10 g kaolin modified by 0.775 g NaOH and 10 g kaolin modified by 0.5675 g NaCl. The FTIR spectroscopy and specific surface areas of modified kaolin were measured. The adsorption products of modified kaolin were characterized by SEM, XRD. Leaching toxicity of adsorption products of modified kaolin was carried out and the modification mechanism was described.