Removal and recovery of nitrate from water by ZnCl₂ activated carbon from coconut coir pith, an agricultural solid waste

Abstract

Nitrate removal from aqueous solution was investigated using ZnCl₂activated carbon developed from coir pith. Influence of contact time, adsorbent dose, nitrate concentration, pH and temperature were investigated. Two theoretical adsorption isotherms namely Langmuir and Freundlich were used to describe the experimental results. The Langmuir adsorption capacity (<i style="">Q</i>_o) was found to be 10.3 mg nitrate per g of the adsorbent. Adsorption followed second order kinetics. Adsorption was maximum in the pH range 3-10. pH effect and desorption studies showed that ion exchange mechanism might be involved in the adsorption process. Effects of foreign ions such as chloride, sulphate, phosphate and perchlorate on the removal of nitrate have also been investigated. Removal of nitrate from ground water was also tested. Results show that ZnCl₂ activated coir pith carbon is effective for the removal of nitrate from water.