Super-stable mineralization of Cu, Cd, Zn and Pb by CaAl-layered double hydroxide: Performance, mechanism, and large-scale application in agriculture soil remediation

Zewen Sun; Yiping Wang; Tian Liu; Xianggui Kong; Tianzun Pan; Fazhi Zhang; Xiaodong Lei; Xue Duan

doi:10.1016/j.jhazmat.2023.130723

Super-stable mineralization of Cu, Cd, Zn and Pb by CaAl-layered double hydroxide: Performance, mechanism, and large-scale application in agriculture soil remediation

J Hazard Mater. 2023 Apr 5:447:130723. doi: 10.1016/j.jhazmat.2023.130723. Epub 2023 Jan 3.

Authors

Zewen Sun¹, Yiping Wang², Tian Liu¹, Xianggui Kong¹, Tianzun Pan³, Fazhi Zhang¹, Xiaodong Lei⁴, Xue Duan¹

Affiliations

¹ State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
² State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: wangyiping@buct.edu.cn.
³ Horqin Left Middle Banner Agricultural Technology Extension Center, Tongliao, 028199, PR China.
⁴ State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: leixd@mail.buct.edu.cn.

PMID: 36640507
DOI: 10.1016/j.jhazmat.2023.130723

Abstract

The synthesized CaAl-layered double hydroxide (CaAl-LDH) shows excellent performance in potentially toxic metals (PTMs) removal, and the removal capacity of CaAl-LDH toward Cu²⁺, Zn²⁺ and Pb²⁺ in aqueous solution is 502.4, 315.2 and 600.0 mg/g respectively. Cu²⁺ and Zn²⁺ are removed through isomorphic substitution of laminate Ca and dissolution-reprecipitation, leading to the formation of CuAl-LDH and ZnAl-LDH mineralization products. Pb²⁺ is removed by the complexation and precipitation to form Pb₃(CO₃)₂(OH)₂. The application of CaAl-LDH in laboratory-scale soil remediation shows that target PTMs are gradually mineralized into relatively stable oxidizable and residual state, and the immobilization efficiency of available Cu, Zn, Cd and Pb reaches 84.62 %, 98.66 %, 96.81 % and 70.27 % respectively. In addition, practical application in farmland results in the significant reduction of available Cu, Zn, Cd and Pb with the immobilization efficiency of 30.15 %, 67.30 % and 57.80 % and 38.71 % respectively. Owing to the super-stable mineralization effect of CaAl-LDH, the content of PTMs in the roots, stems and grains of cultivated buckwheat also decreases obviously, and the growth and yield of buckwheat are not adversely affected but improved. The above prove that the super-stable mineralization based on CaAl-LDH is a promising scheme for the remediation of PTMs contaminated agriculture soil.

Keywords: Large-scale application; Layered double hydroxide; Potentially toxic metals contamination; Soil remediation; Super-stable mineralization.