Dynamic adsorption characteristics of orthophosphate using iron-loaded coconut shell-activated carbon

Abstract

The excessive presence of orthophosphate in water often leads to eutrophication, which is detrimental to aquatic ecosystem. Also, coconut shell is a sustainable source of activated carbon for adsorption applications. Hence, the present work was aimed at evaluating iron-loaded coconut shell activated carbon for the removal of orthophosphate from water. The resulting activated carbon exhibits a specific surface of 722 m2 g−1 for a superior adsorption of orthophosphate. In batch mode, the activated carbon shows a greater capacity of 315 mg g−1, while in dynamic mode, it recorded a 12 mg g−1 capacity in a 10 cm bed height with 10 mg/L orthophosphate concentration at flow rate of 3 mL min−1. At fixed flow rate, the breakthrough time was found to be directly proportional with bed height and inversely proportional with inlet concentration. The Thomas model was suitable to describe the breakthrough curve and dynamic behaviour. Excellent orthophosphate adsorbent can be produced from coconut shell as an alternative to commercial metal oxide adsorbents.