The escalating global water crisis necessitates the development of efficient, sustainable, and cost-effective remediation technologies. This review highlights bentonite–sawdust-derived carbon composites as a promising class of adsorbents for the removal of diverse water pollutants. The synthesis strategies, physicochemical properties, key interfacial adsorption mechanisms, and adsorption performance toward different pollutant categories are systematically discussed. These hybrid materials exhibit synergistically enhanced properties, including increased surface area, optimized porosity, abundant functional groups, tunable surface charge, and improved structural stability, often outperforming the individual components. Their effectiveness has been demonstrated for both heavy metals (e.g., Cd and Pb) and organic contaminants (e.g., dyes and pharmaceuticals), governed by a combination of ion exchange, electrostatic attraction, π–π interactions, and pore-filling mechanisms. Current challenges related to large-scale production, long-term stability, and regeneration are critically evaluated, and future research directions for the sustainable application of these composites in advanced water treatment systems are outlined.

Zeolite-based composite nanomaterials represent a versatile and mechanistically rich platform for the removal of organic micropollutants (OMPs)—including pharmaceuticals, endocrine-disrupting compounds, pesticides, and per- and polyfluoroalkyl substances (PFAS)—from contaminated water systems. Although pristine zeolite frameworks provide well-defined microporous architectures, tunable Si/Al ratios, and ion-exchange capacity, their intrinsic hydrophilicity restricts interaction diversity and limits performance toward the structurally heterogeneous OMPs prevalent in real aquatic environments. Composite integration with carbonaceous nanophases, functional polymers and surfactants, and catalytically active metal oxide nanoparticles substantially extends this interaction repertoire, yielding multifunctional materials whose adsorption performance exceeds that of the individual components. Drawing on a systematic survey of peer-reviewed literature published between 2016 and 2026, this review develops a mechanism-oriented, structure–property–performance framework examining five dominant adsorption mechanisms—electrostatic attraction, π–π stacking, hydrogen bonding, hydrophobic partitioning, and micropore confinement—in relation to composite nanoarchitecture, surface chemistry, and structural parameters. The modulating influence of realistic water matrix conditions on adsorption efficiency is critically assessed, alongside challenges of regeneration, long-term stability, metal leaching, and the persistent gap between laboratory-scale synthesis and scalable deployment. Priority research directions are identified, including standardized performance evaluation under environmentally representative conditions and rational design of hierarchical multifunctional nanocomposites from earth-abundant and waste-derived precursors.

The aim of this study was to evaluate the textural changes produced by metal-chloride-assisted carbonization of wood sawdust in a bentonite matrix and to compare FeCl3-, NiCl2-, and CoCl2-containing formulations under the same thermal regime. Composites were prepared from 2 g of bentonite and 1 g of sawdust with the corresponding metal chloride, dried at 80 °C for 24 h, and carbonized at 550 °C for 1 h under argon. Nitrogen physisorption at 77.35 K was used to determine BET specific surface area and BJH pore parameters for raw bentonite and three carbonized composites: B-Co (0.75 g CoCl2), B-Fe (0.50 g FeCl3), and B-Ni (0.50 g NiCl2). The BET surface area increased from 45.836 m² g⁻¹ for raw bentonite to 223.915, 248.350, and 233.406 m² g⁻¹ for B-Co, B-Fe, and B-Ni, respectively, corresponding to 4.89-, 5.42-, and 5.09-fold increases. At the same time, BJH adsorption pore volume decreased from 0.012 cm³ g⁻¹ to 0.007–0.008 cm³ g⁻¹, and the characteristic BJH pore radius decreased from 2.152 nm to 1.626–1.955 nm. These results indicate that the additional nitrogen-accessible surface is not explained by an increase in BJH mesopore volume and is consistent with the development of finer porosity and carbon–clay interfacial surface. Among the tested formulations, B-Fe exhibited the highest BET area. Thus, FeCl3-assisted carbonization provides the strongest basis for subsequent structural characterization and adsorption testing, although graphitic ordering and sorption capacity require independent verification.