ORIGINAL RESEARCH article
Front. Mater.
Sec. Environmental Degradation of Materials
Experimental Study on Chemical Compatibility of Polymer Amended Bentonite Subjected to Inorganic Salt Solutions
Provisionally accepted
- Nanjing Vocational lnstitute of Transport Technology, Nanjing, China
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Abstract: This study aims to improve the chemical stability and engineering performance of bentonite slurry used in slurry trench cutoff walls, which often suffers from reduced swelling and permeability when exposed to saline environments. To address this, five superabsorbent polymers-polyanionic cellulose (PAC), hydroxypropyl methylcellulose (HPMC), carboxymethyl starch sodium (CMS), xanthan gum (XG), and sodium polyacrylamide (Na-PAM), were evaluated as additives to enhance unamended bentonite (CB). Key performance indicators including swell index, Marsh viscosity, filtrate loss, and hydraulic conductivity were systematically measured in CaCl₂ solutions (0-100 mM). Results show that XG-amended bentonite (XB) significantly outperforms CB, achieving higher swell index (24.2 vs. 15.9 mL/2 g) and liquid limit (403% vs. 267%), while maintaining low filtrate loss and acceptable viscosity under saline conditions. Hydraulic conductivity tests indicate a 75.3% reduction in permeability for XB filter cakes compared to CB. Additionally, polymer performance varies with cation type, with Pb²⁺ causing more severe degradation than Ca²⁺ due to pH effects. The study demonstrates that polymer amendments, particularly XG, can effectively enhance bentonite performance in saline environments, providing practical guidance for the design and construction of durable slurry trench cutoff walls.
Keywords: Chemical compatibility, hydraulic conductivity, Polymer-amended bentonite, slurrytrench walls, Xanthan gum
Received: 23 Nov 2025; Accepted: 02 Feb 2026.
Copyright: © 2026 Shen, Zhang and Qi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Nian Qi
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