One-Pot Synthesis of ZnO-Activated Eggshell@kaolinite: Sorbents for Phosphate Capture in Water

The availability of colossal amounts of phosphate in water bodies has led to serious environmental challenges all over the world. In this study, a new adsorbent was synthesized using treated kaolinite clay, pulverized eggshells, and ZnCl₂. Surface characterizationof these adsorbents showed the availability of functional moieties, morphological variations, pore sizes, particle sizes, etc. Adsorption of phosphate occurs via multiple mechanisms, comprising ligand exchange, complexation, hydrogen bonding, and electrostatic interaction, among others. The effect of pH, showed that maximum adsorption of 93.3 % was achieved at pH 3.0. It was also shown that these cost-effective adsorbents could be regenerated in six cycles, hence increasing their applicability.