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 work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples. The results showed that the catalyst with the highest molecular weight of polyethylene glycol had the highest AgNP content. Catalyst mass, NaBH₄ concentration, and type of catalyst were shown to have a significant influence on the conversion and rate constant. The material with the highest silver nanoparticle content was identified as the optimal catalyst for the reduction of both pollutants. The measured rate constants for the reduction of methylene blue (MB) and 4-nitrophenol (4-NP) were 164 × 10⁻⁴ s⁻¹ and 25 × 10⁻⁴ s⁻¹, respectively. The reduction of MB and 4-NP in the binary system showed high selectivity for MB dye, with rate constants of 64 × 10⁻⁴ s⁻¹ and 9 × 10⁻⁴ s⁻¹ for MB and 4-NP, respectively. The reuse of the best catalyst via MB dye reduction for four cycles showed good results without loss of performance.

Water pollution by organic dyes poses serious environmental and health challenges, demanding efficient and selective remediation methods. In this study, we engineered tailored organo-clay nanocomposites by modifying montmorillonite with hexadecyltrimethylammonium bromide (HTAB) and intercalating polyethylene glycol (PEG) chains of two distinct molecular weights (PEG200 and PEG4000). Comprehensive characterization techniques (XRD, FTIR, SEM, zeta potential, and TGA) confirmed the successful modification of the composites. Notably, PEG4000 promoted significant interlayer expansion, as evidenced by the shift of the (00l) reflection corresponding to the basal spacing d, indicating an increase in basal spacing. This expansion contributed to the formation of a well-ordered porous framework with uniformly distributed pores. In contrast, PEG200 produced smaller pores with a more uniform distribution but induced less pronounced interlayer expansion. Adsorption tests demonstrated rapid kinetics, achieving equilibrium in under 15 min, and impressive capacities: 420 mg/g of methylene blue (MB) adsorbed on PEG200/MMT@HTAB, and 385 mg/g of Congo red (CR) on PEG4000/MMT@HTAB. The crucial role of PEG chain length in adsorption selectivity was assessed, showing that shorter PEG chains favored methylene blue adsorption by producing narrower pores and faster kinetics, while longer PEG chains enhanced CR uptake via a stable, interconnected pore network that facilitates diffusion of larger dye molecules. Thermodynamic and Dubinin–Radushkevich analyses confirmed that the adsorption was spontaneous, exothermic, and predominantly driven by physical adsorption mechanisms involving weak van der Waals and dipole interactions. These findings highlight the potential of PEG-modified montmorillonite nanocomposites as cost-effective, efficient, and tunable adsorbents for rapid and selective removal of organic dyes in wastewater treatment.

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.