Removal of Cd from solution and in-situ remediation of Cd-contaminated soil by a mercapto-modified cellulose/bentonite intercalated nanocomposite

Xi Li; Guisen Zhang; Yi Jin; Xue Gu; Guotuan Xie; Yongtao Li; Hong Liang; Bing Wang

doi:10.1016/j.envres.2024.118303

Removal of Cd from solution and in-situ remediation of Cd-contaminated soil by a mercapto-modified cellulose/bentonite intercalated nanocomposite

Environ Res. 2024 Feb 1;251(Pt 2):118303. doi: 10.1016/j.envres.2024.118303. Online ahead of print.

Authors

Xi Li¹, Guisen Zhang², Yi Jin², Xue Gu², Guotuan Xie², Yongtao Li³, Hong Liang³, Bing Wang³

Affiliations

¹ School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, PR China; Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Chengdu, Sichuan 610500, PR China. Electronic address: lixi@swpu.edu.cn.
² School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, PR China.
³ School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, PR China; Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Chengdu, Sichuan 610500, PR China.

PMID: 38295978
DOI: 10.1016/j.envres.2024.118303

Abstract

A novel intercalated nanocomposite of mercapto-modified cellulose/bentonite (LCS-BE-SH) was synthesized by high-speed shearing method in one step at room temperature, and was applied to remove Cd from solution and remediate Cd-contaminated soil. Results revealed that cellulose long-chain molecules have intercalated into bentonite nanolayers and interlayer spacing was increased to 1.411 nm, and grafting -SH groups improved adsorption selectivity, which enabled LCS-BE-SH to have distinct capability of Cd adsorption (q_max = 147.21 mg/g). Kinetic and thermodynamics showed that Cd adsorption onto LCS-BE-SH was well fitted by pseudo-second-order and Langmuir adsorption isotherm. Characterizations of the adsorbents revealed that synergistic effect of complexation (e.g., CdS, CdO) and precipitation (e.g., Cd(OH)₂, CdCO₃) mechanism played a major role in Cd removal. In soil remediation, application of LCS-BE-SH was most effective (67.31 %) in Cd immobilization compared to the control (8.85 %), which reduced exchangeable Cd from 37.03 % to 11.44 %. Meanwhile, soil pH, soil organic matter, available phosphorus, and enzyme activities (catalase, urease, and dehydrogenase) were improved LCS-BE-SH treatment. The main immobilization mechanism in soil included complexation (e.g., CdS, CdO) and precipitation (e.g., Cd(OH)₂, Cd-Fe-hydroxide). Overall, this work applied a promising approach for Cd removal in aqueous and Cd remediation in soil by using an effective eco-friendly LCS-BE-SH nanocomposites.

Keywords: Adsorption process; Cd immobilization; Cd removal; Nanocomposites; Soil remediation.