Chemically modified clay for adsorption of contaminants: trends, advantages and limitations - a concise review

The removal of contaminants has employed the practical and effective utilisation of clay and modified clay minerals as adsorbents amongst the most appealing treatment technologies and detoxification. A vital class of contaminants including dyes, pharmaceuticals, heavy metals and persistent organic pollutants are considered for the study. The interaction mechanisms targeting adsorption techniques between the contaminants as adsorbate and the clay minerals depend on the structural and morphological layout of the modified clay. The significant factors peculiar for enhancing adsorptive properties of clays and their adsorption capacities, and useful modification procedures for better contaminants−modified clay interactions are highlighted. The advantages, limitations and adsorption capacities of modified clay prepared using popular organic modifiers (surfactants, amine, organic acids and organosilane) and inorganic modifiers (metal/metal oxide, pillaring agents and mineral acids) for adsorption of the selected contaminants are reviewed. The prospects for an improved adsorption of contaminants onto the various modified clays are discussed.