Comparative activation of Darbaza bentonite for heavy metal removal from industrial wastewaters: Structural characterization and kinetic insights
Kadirbayeva A.A. Ishanova M.N. Minakouski A.
January 2026Elsevier B.V.
Desalination and Water Treatment
2026#325
This study investigates the adsorption performance of bentonite from the Darbaza deposit (southern Kazakhstan) activated by three methods—acid, salt, and soda treatments—for the removal of heavy metals from real industrial wastewaters. Bentonite has been extensively studied worldwide, but no previous work has evaluated Darbaza bentonite using multiple activation approaches on real multi-metal effluents. Comprehensive characterization (SEM–EDS, FTIR, XRF, DTA, XRD) confirmed the preservation of the montmorillonitic structure after activation. Batch experiments were conducted using real wastewaters from Sozak, Kentau, and Kazphosphate facilities containing Zn²⁺, Pb²⁺, Cd²⁺, Cu²⁺, and Fe³ ⁺. NaCl- and Na₂CO₃-activated samples achieved Zn²⁺ removal up to 97.7 % (q = 5.036 mg·g⁻¹), Pb²⁺ up to 65 % (q = 0.074 mg·g⁻¹), and Cd²⁺ up to 81 % (q = 0.182 mg·g⁻¹), compared to 30–40 % for raw bentonite. Adsorption kinetics followed a pseudo-second-order model (R² > 0.99), indicating high sorption capacity and rapid adsorption kinetics driven by chemisorption. These results demonstrate that simple activation substantially enhances the performance of Darbaza bentonite, offering a cost-effective local material for industrial wastewater treatment in Central Asia.
Acid , Activated Darbaza bentonite , Adsorption kinetics , And salt activation , Chemisorption mechanism , Heavy metal adsorption , Industrial wastewater treatment , Soda
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Higher School of Chemical Engineering and Biotechnology, M. Auezov South Kazakhstan University, Shymkent, Kazakhstan
Department of Science, Belarusian State Technological University, Minsk, Belarus
Higher School of Chemical Engineering and Biotechnology
Department of Science
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Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026