This review explores the removal of textile dyes from wastewater using advanced polymer/clay composites. It provides an in-depth analysis of the chemical and physical properties of these composites, emphasizing how the combination of polymers and clays creates a synergistic effect that significantly improves the efficiency of dye removal. The structural versatility of the composites, derived from the interaction between the layered clay sheets and the flexible polymer matrices, is detailed, showcasing their enhanced adsorption capacity and catalytic properties for wastewater treatment. The review outlines the key functional groups present in both polymers and clays, which are crucial for binding and degrading a wide range of dyes, including acidic, basic, and reactive dyes. The role of specific interactions, such as hydrogen bonding, ion exchange, and electrostatic attractions between the dye molecules and the composite surface, is highlighted. Moreover, the selection criteria for different types of clays such as montmorillonite, kaolinite, and bentonite and their modifications are examined to demonstrate how structural and surface modifications can further improve their performance in composite materials. Various synthesis methods for creating polymer/clay composites, including in situ polymerization, solution intercalation, and melt blending, are discussed. These fabrication techniques are evaluated for their ability to control particle dispersion, optimize interfacial bonding, and enhance the mechanical and chemical stability of the composites. Furthermore, the review introduces advanced characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), to help researchers assess the morphological, structural, and thermal properties of the composites, aligning these features with their potential application in dye removal. Additionally, the review delves into the primary mechanisms involved in the dye removal process, such as adsorption, photocatalytic degradation, and catalytic reduction. It also provides an overview of the kinetic and thermodynamic models commonly used to describe the adsorption processes in polymer/clay composites. The environmental and operational factors influencing the efficiency of dye removal, such as pH, temperature, and composite dosage, are analyzed in detail, offering practical insights for optimizing performance under various wastewater conditions. In conclusion, this review not only highlights the promising potential of polymer/clay composites for textile dye removal but also identifies current challenges and future research directions. It underscores the importance of developing eco-friendly, cost-effective, and scalable solutions to address the growing concerns related to water pollution and sustainability in wastewater management.

This review provides information on the latest advances in inorganic materials with antimicrobial properties based on a metallic species immobilized on the clay mineral montmorillonite realized between the years 2015 and 2023. This class has shown many promising results compared to certain organic agents. Montmorillonite in natural and/or modified forms is a good platform for the storage and release of metallic species, and several researchers have worked on this mineral owing to its cation exchange capacity, low cost, biocompatibility, and local availability. The preparation methods and the properties such as the antibacterial, antifungal, and toxicological activities of this mineral are discussed. The main characteristics of this antibacterial class for the elimination of pathogenic bacteria were examined and the known weak points of its antimicrobial application are discussed, leading to suggestions for further research.

In this work, zeolite LTA (Linde Type A) was synthesised from natural clay as a novel adsorbent for copper and lead ions removal from water effluents. The applied process allowed the reuse of kaolin, as natural clay, for the production of zeolite LTA through a stepwise process, which involved the formation of metakaolin. The results of characterisation showed the formation of crystalline cubic crystals of zeolite with a mean dimension of 2–3 microns, indicating the successful nucleation and development of the LTA zeolite phase. Batch adsorption studies were carried out to study the removal ability of zeolite LTA by testing Cu²⁺ and Pb²⁺ ions. Effects of contact time, pH, and adsorbent dosage were investigated. At pH > 5, the removal efficiency for both metals exceeded 95%. As the zeolite dosage increases from 2 to 10 g/L, the removal effectiveness for both metals markedly enhances (>95% at 10 g/L for lead ions and >90% at 10 g/L for copper ions). The adsorbent showed a higher adsorption capacity in removing lead compared to copper (Q_m = 81.5 mg/g for Pb²⁺ and 67.5 mg/g for Cu²⁺). The adsorption process was well described by the pseudo-second-order kinetic model, while the Langmuir isotherm adequately depicted the equilibrium behavior. Notably, the kinetics revealed distinct contributions from chemisorption and physisorption, with the AOAS model effectively quantifying their respective roles in metal ion removal. The findings revealed that prepared zeolite LTA acts as an efficient adsorbent to remove heavy metals.

In this work, LTA-type zeolite synthesized from kaolin was successfully modified via ion exchange with Zn²⁺ and Cu²⁺ ions followed by thermal treatment at 550 °C and 650 °C, leading to the formation of ZnO–CuO/zeolite composites (ZA550ZnCu and ZA650ZnCu). The structural and physicochemical properties of the catalysts were investigated using XRD, SEM, EDS, XPS, TEM, and zeta-potential analysis, confirming the successful incorporation of metal oxides while preserving the zeolitic framework, particularly at moderate calcination temperature. The catalytic performance of the prepared materials was evaluated in the heterogeneous catalytic ozonation of methylene blue (MB) in aqueous solution. The results demonstrated a strong synergistic effect between adsorption on the zeolite surface and ozone activation by ZnO and CuO species, leading to the generation of reactive oxygen species (•OH, O₂^•−) responsible for rapid methylene blue degradation. Among the tested catalysts, ZA550ZnCu exhibited superior activity compared to ZA650ZnCu, attributed to better dispersion of active phases and higher structural stability. Operational parameters, including pH, catalyst dosage, and initial MB concentration, significantly influenced the decolorization efficiency. Alkaline conditions (pH 11) strongly enhanced MB removal due to increased hydroxyl radical formation. Kinetic analysis showed that the degradation process follows a pseudo-first-order model, with higher rate constants in the presence of the catalyst. The electronic structure and local reactivity of methylene blue were investigated through DFT calculations and used to support the identification of potentially reactive sites and to propose plausible initial oxidation steps. The most reactive sites were identified as the dimethylamino nitrogen atoms, the central sulfur and nitrogen centers, and certain carbon atoms of the conjugated framework using frontier molecular orbital analysis, global reactivity descriptors, Hirshfeld charges, condensed Fukui functions, and the dual descriptor. These results are consistent with an initial N-demethylation, oxidative attack on the heterocyclic chromophore, C–N and C–S bond cleavage, hydroxylation, and aromatic-ring opening followed by mineralization. The study highlights the effectiveness of natural-source zeolite-based bimetallic catalysts as promising and sustainable materials for wastewater treatment via catalytic ozonation.