Journal Published Online: 06 December 2021
Volume 50, Issue 6

The Test Research on the Adsorption of Heavy Metal Ions by Ultra-Low Permeability Polymer-Bentonite with Chemical Resistance Stability

CODEN: JTEVAB

Abstract

It is often difficult for the modification of impermeable bentonite to meet the requirements of low permeability, high chemical resistance, and strong adsorption performance. Based on the low permeability and high chemical resistance of the modified bentonite with sodium polyacrylate (SPB), the adsorption characteristics of the modified bentonite on copper were further compared and analyzed. A series of batch adsorption experiments were performed considering the effects of contact time, pH, temperature, and adsorbate concentration. The morphological changes and microstructure of raw bentonite and SPB at different cupric ion (Cu2+) concentrations were studied through scanning electron microscopy. The pore structure was analyzed with mercury intrusion porosimetry. Kinetic, Langmuir, and Freundlich models were applied to analyze the adsorption mechanism. The results indicated that the SPB not only improves the impermeability and chemical resistance of bentonite but also significantly improves the adsorption of heavy metals. The saturated adsorption capacity of Cu2+ is increased by 116.08 %. The modification mechanism of SPB is that the mineral particles of bentonite were coated by a negatively charged and hydrophilic group (carboxyl group, -COO-). The protective effect of the polymer on the bentonite is the main reason for its chemical resistance, and the solid bonding of the polymer closes the pores of the material, thus reducing the hydraulic performance. Based on the above, it can be concluded that SPB has the characteristics of lower permeability, stronger chemical corrosion resistance, and greater heavy metal adsorption capacity, which makes it an ideal anti-seepage material for landfill.

Author Information

Cai, Xiaoqing
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
Chen, Ying
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
Liao, Rao-ping
College of Architecture and Civil Engineering, Wenzhou University, Wenzhou, China
Wu, Ze-xiang
College of Architecture and Civil Engineering, Wenzhou University, Wenzhou, China
Yu, Chuang
College of Architecture and Civil Engineering, Wenzhou University, Wenzhou, China
Shi, Tiantian
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
Wu, Yinxia
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China
Jiang, Jifang
College of Architecture and Civil Engineering, Wenzhou University, Wenzhou, China
Pages: 12
Price: $25.00
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Stock #: JTE20210414
ISSN: 0090-3973
DOI: 10.1520/JTE20210414