Adsorption of phosphate from aqueous solution onto iron-coated waste mussel shell: physicochemical characteristics, kinetic, and isotherm studies

Abstract

High amounts of phosphate (PO43–) discharged in receiving water can lead to eutrophication, which endangers life below water and human health. This study elucidates the removal of PO43– from synthetic solution by iron-coated waste mussel shell (ICWMS). The PO4 3– adsorption by ICWMS was determined at different process parameters, such as initial PO43– concentration (7 mg L−1), solution volume (0.2 L), adsorbent dosage (4, 8, 12, 16, and 20 g), and contact time. The highest efficiency of PO43− removal can reach 96.9% with an adsorption capacity of 0.30 mg g−1 could be obtained after a contact time of 48 h for the use of 20 g of ICWMS. Batch experimental data can be well described by the pseudo-second-order kinetic model (R2 = 0.999) and Freundlich isotherm model (R2 = 0.996), suggesting that chemisorption and multilayer adsorption occurred. The efficiency of PO43– removal from aqueous solution by ICWMS was verified to contribute to applying a new low-cost adsorbent obtained from waste mussel shell in the field of wastewater treatment.