Use of Powdered Cockle Shell as a Bio‐Sorbent Material for Phosphate Removal from Water

In this study, powdered cockle shell was used as a bio‐sorbent material for the removal of phosphates in water. The SEM–EDX, XRD, and FT‐IR analyses showed that calcium carbonate (CaCO 3 ) exists in aragonite state in powdered cockle shell. The influences of pH, initial phosphate concentrations and contact time were conducted in a series of batch sorption experiments. Among the various factors studied, the pH was turned out to be a key variable for phosphate removal. Based on the experimental results for pH, it was found that the phosphate is chemically sorbed onto aragonite surface. At lower phosphate concentration, roughly 88% of sorption efficiency was accomplished by powdered cockle shell. The Pseudo‐second‐order kinetic and the Langmuir isotherm model were fitted well to the sorption experimental data of phosphate because of their higher correlation coefficients ( R 2 ).