Fluoride removal from water by zirconium (IV) doped chitosan bio-composite

Abstract

Water containing fluoride above 1.5 mg/L leads to health and environmental harms that creates skeletal and dental fluorosis. Adsorption technique prominently removes fluoride from water and its competence is reliant on development of recyclable, environmentally benign adsorbents. Many reported sorbents for defluoridation below stringent level 1.5 mg/L, displayed low to moderate adsorption capacity at varied concentrations and pH. Besides, viable defluoridation techniques are usually unsuccessful in developing countries. In this novel, cheap and efficient porous chelating resin, chitosan doped 20% zirconium (IV) with control morphologies were synthesized for delfuoridation. This bio-composite was at par with commercial alumina to mitigate water fluoride limit up to 1 to 1.5 mg/L. Effect of parameters namely pH, adsorbent dose, contact time and initial fluoride concentration were studied in batch scale. Kinetic data showed a rapid adsorption, indicated practicable operations in packed column. Findings encourage blending with other polymers as an effective option for defluoridation on a large scale.

Key words: Fluorosis, chitosan, zirconium, bio-composite, defluoridation, water.