Fabrication of metal ions cross-linked alginate assisted biocomposite beads for selective phosphate removal

The present work focus to enhance the properties of commercial clay (bentonite) and synthetic clay (hydrotalcite) by encapsulating with alginate (Alg) biopolymer. To increase the sorption capacity (SC) and stability of these biocomposites, metal ions were utilized as cross-linking agents to obtain usable form of biocomposite beads. The metal anchored Alg supported biocomposite beads were synthesized using bentonite (Bent) and hydrotalcite (HT) followed by cross-linked with multivalence metal ions like Zr⁴⁺, Ce³⁺, La³⁺, Ca²⁺ and Mg²⁺ ions. Alg encapsulated biocomposite beads were utilized for phosphate removal in batch mode. Numerous phosphate adsorption parameters viz., contact time, co-ions, pH, temperature and initial phosphate concentration were optimized. The developed biocomposite beads were characterized by FTIR, TEM, SEM and EDAX analysis. The obtained data was explained with various isotherm models and thermodynamics parameters. The feasible mechanism of phosphate removal by the biocomposite beads was proposed. The suitability of biocomposite beads at field situations was analyzed with industrial water.