Dual functional sites strategies toward enhanced heavy metal remediation: Interlayer expanded Mg-Al layered double hydroxide by intercalation with L-cysteine

Danyang Wang; Eveliina Repo; Fangshu He; Xiaowei Zhang; Hongrui Xiang; Weichun Yang; Xiaobo Min; Feiping Zhao

doi:10.1016/j.jhazmat.2022.129693

Dual functional sites strategies toward enhanced heavy metal remediation: Interlayer expanded Mg-Al layered double hydroxide by intercalation with L-cysteine

J Hazard Mater. 2022 Oct 5:439:129693. doi: 10.1016/j.jhazmat.2022.129693. Epub 2022 Jul 28.

Authors

Danyang Wang¹, Eveliina Repo², Fangshu He¹, Xiaowei Zhang³, Hongrui Xiang¹, Weichun Yang¹, Xiaobo Min¹, Feiping Zhao⁴

Affiliations

¹ School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Institute of Environmental Engineering, Central South University, Changsha 410083, Hunan, China.
² Department of Separation Science, School of Engineering Science, Lappeenranta-Lahti University of Technology LUT, Yliopistonkatu 34, FI-53850, Finland.
³ School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China.
⁴ School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Institute of Environmental Engineering, Central South University, Changsha 410083, Hunan, China. Electronic address: feiping.zhao@csu.edu.cn.

PMID: 36104925
DOI: 10.1016/j.jhazmat.2022.129693

Abstract

The discharge of toxic heavy metals poses a serious threat to human health and environment. The existing water purification systems are lack of promising materials for rapid, efficient, and cost-efficient remediation of numerous toxic heavy metals. Herein, we report on the development of L-cysteine (Cys) intercalated Mg-Al layered double hydroxide (MgAl-LDH/Cys) with a loose lamellar porous architecture as an efficient and economically viable adsorbent for Pb(II) and Cd(II) removal. The intercalation with Cys creates dual functionality, i.e., the interlayer expansion accelerates the diffusion of heavy metals, while Cys acts as additional capture sites for heavy metals. Therefore, remarkable high maximum sorption capacities of 279.58 and 135.68 mg g^-1 for Pb(II) and Cd(II) were obtained for MgAl-LDH/Cys compared to those for pristine MgAl-LDH (30.15 and 36.77 mg g^-1). MgAl-LDH/Cys exhibits also much faster sorption kinetics in comparison with MgAl-LDH. Such enhancements are attributed to the intercalation of the chelating agent Cys in the MgAl-LDH interlayer channels. Moreover, it is proposed that the adsorption mechanisms involve the isomorphous replacement of Mg sites by Cd(II) forming CdAl-LDH, the precipitation of PbS and CdS, and the chelation of sulfhydryl, carboxyl and amine groups toward Cd(II). Altogether, its facile and environmentally friendly fabrication, ultrahigh sorption efficiencies, and rapid kinetics demonstrate that MgAl-LDH/Cys has potential for practical applications in heavy metal remediation.

Keywords: Adsorption; Heavy metal; Intercalation modification; L-cysteine; Layered double hydroxides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cadmium
Cysteine*
Humans
Hydroxides
Metals, Heavy*

Substances

Hydroxides
Metals, Heavy
Cadmium
hydroxide ion
Cysteine