Harnessing the potential of zeolites for effective fluoride removal from wastewater: a review.

Fluoride contamination in water poses significant health risks, including dental fluorosis, kidney failure, and reduced cognitive function in children. This comprehensive review examines the potential of zeolites for effective fluoride removal from wastewater. Zeolites, crystalline aluminosilicates with unique structural properties, have garnered attention due to their high adsorption capacity, low cost, and environmental compatibility. We discuss various zeolite types (natural, synthetic, and modified) and explore surface modification techniques, including chemical, composite, physical, and biological methods, to enhance fluoride adsorption capacity. Key factors influencing fluoride adsorption, such as pH, temperature, initial concentration, adsorbent dosage, and competing ions, are analyzed. The review elucidates adsorption mechanisms, including electrostatic interactions, ion exchange, Lewis acid-base interactions, and ligand exchange. Adsorption kinetics and isotherms are examined to understand process dynamics and equilibrium behavior. We compare conventional and novel zeolite synthesis methods, highlighting solvent-free approaches for sustainable production. Regeneration potential is assessed, considering environmental impact, cost, and efficiency. While zeolite-based adsorbents show promising results in laboratory settings, we emphasize the need for pilot-scale and full-scale implementations, particularly in treating real industrial wastewater. Future research directions are proposed to develop efficient, cost-effective, and environmentally friendly zeolite-based technologies for fluoride removal.