Clay-based materials for enhanced water treatment: adsorption mechanisms, challenges, and future directions

Abstract

AbstractWater treatment is of paramount importance to ensure the availability of clean and safe drinking water. In recent years, clay-based materials have gained significant attention as promising adsorbents for water treatment applications. This review provides a comprehensive analysis of different clay types and their surface adsorption properties for water treatment. This review begins by introducing the diverse types of clays commonly used in water treatment, including kaolin, montmorillonite, bentonite, and others. Each clay type is examined in terms of its unique mineral composition, surface properties, and structural characteristics. Subsequently, the adsorption mechanisms of clay surfaces are explored, shedding light on the intricate interactions between contaminants and the active sites on clay surfaces. The factors influencing the adsorption process, such as pH, temperature, contact time, and initial concentration of contaminants, are discussed in detail. Furthermore, the review highlights the adsorption capacity and efficiency of different clay types for the removal of various contaminants from water. These contaminants encompass heavy metals, organic pollutants, dyes, and emerging contaminants. The role of surface modification techniques, such as cation exchange, functionalization, and composite formation, in enhancing the adsorption performance of clays is also elucidated. Moreover, the review addresses the challenges and limitations associated with clay-based adsorbents, including issues related to regeneration, disposal, and cost-effectiveness. Strategies for overcoming these challenges and potential future directions in the field of clay-based water treatment are presented.