Natural Mineral Sorbents as Green Materials for the Remediation of Oil-Contaminated Waters
Belgibayeva D. Aikenova N. Abilova G. Biktasova A. Lepesbayeva G. Nazarov S.
February 2026Multidisciplinary Digital Publishing Institute (MDPI)
Processes
2026#14Issue 3
This study experimentally demonstrates that a bentonite–vermiculite composite (1:2 mass ratio) is the most effective formulation for the treatment of crude oil–contaminated wastewater. The sorbents were characterized using XRD, SEM/EDS, ζ-potential, DLS, and TGA/DSC to evaluate their structural, surface, and adsorption-related properties. Kinetic analysis showed that the adsorption process followed the pseudo-second-order (PSO) model (R2 = 0.96–0.99), suggesting that surface interactions and intraparticle diffusion within the layered composite governed the overall adsorption rate. Thermodynamic analysis revealed negative Gibbs free energy values (ΔG < 0) and a moderately positive enthalpy change (ΔH ≈ 26 kJ·mol−1), confirming that adsorption is spontaneous and endothermic, with contributions from physical interactions, ion exchange, and hydrophobic effects. After adsorption, the ζ-potential shifted toward less negative values, indicating partial surface charge neutralization by hydrocarbon species. TGA/DSC data further confirmed strong oil retention and preserved structural stability of the sorbents, while the DSC-derived enthalpy increased from 2.0 kJ·g−1 to 141.6 kJ·g−1 after hydrocarbon uptake, indicating pronounced energetic effects associated with sorbate incorporation. Techno-economic evaluation under industrially relevant conditions (Q = 120,000 L·h−1; C0 = 392 mg·L−1) showed effective oil removal to residual concentrations below regulatory discharge limits at a low treatment cost.
adsorption , bentonite clay , green technologies , vermiculite , wastewater
Text of the article Перейти на текст статьи
Departament of Chemistry, Institute of Natural Sciences, L.N. Gumilyov, Eurasian National University, Astana, 010000, Kazakhstan
Department of Oil and Gas Business, Laboratory of Chemistry and Ecology, Technical Faculty, K. Zhubanov, Aktobe Regional University, Aktobe, 030000, Kazakhstan
Department of Chemistry and Oil and Gas Technology, Bukhara State University, Bukhara, 200100, Uzbekistan
Departament of Chemistry
Department of Oil and Gas Business
Department of Chemistry and Oil and Gas Technology
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026