Adsorption Properties and Mechanism of Cd2+ in Water by Zr-containing Silica Residue Purification

摘要

Zirconium (Zr)-containing silica residue purification (ZSR-P) discharged from industrial production of ZrOCl2 was used as an adsorbent, and CdCl2 solution was used as the simulated wastewater containing cadmium ions (Cd²⁺). The properties and mechanisms of ZSR-P absorbing Cd²⁺ were studied. The results showed that ZSR-P had a good effect on the adsorption and removal of Cd²⁺ in water. The adsorption time, initial concentration of Cd²⁺, and pH of the solution had a significant effect on the adsorption behavior, whilst the pH value had the greatest effect amongst them. Under optimal conditions, the amount of Cd²⁺ adsorbed by ZSR-P was 43.1 mg/g. The isothermal adsorption conformed to the Langmuir adsorption model, and the adsorption kinetics conformed to the secondary adsorption rate model. In ZSR-P-Cd, Cd²⁺ was uniformly distributed on the surface of SiO2 particles and in the pores formed by the accumulation of particles. Adsorption of Cd²⁺ by ZSR-P was achieved through the reaction between Si-OH on the surface of SiO2 and Cd²⁺ hydroxyl compounds.