Removal of Fluoride from Water by Metal Ions (Al³⁺, La³⁺and ZrO²⁺) Loaded Natural Zeolite

Abstract

Abstract In this study, the ion exchange of metal ions (Al3+, La3+ and ZrO2+) on modified zeolites was carried out using batch method. Fluoride removal from water using Al3+‐, La3+‐ and ZrO2+‐ exchanged zeolite was subsequently investigated to evaluate the fluoride sorption characteristics of the sorbents. Natural zeolite samples (<45 µm) were pre‐conditioned with HNO3 solution (ZEO‐1), NaNO3 solution (ZEO‐2), and deionized water (ZEO‐3) before loading Al3+, La3+, and ZrO2+ on zeolite. ZEO‐1 type zeolite had a higher capacity than ZEO‐2 and ZEO‐3 type zeolites. Metal exchange capacities are 0.233, 0.089, 0.090 mmol/g for ZrO2+‐, La3+‐, and Al3+‐ exchanged zeolite (ZEO‐1), respectively. Equilibrium isotherms fitted well to Langmuir and Freundlich models. Percent removal of fluoride from aqueous solution containing 2.5 mg F/L was 94% using metal loaded zeolite (ZEO‐1 type) at an adsorbent concentration of 6.00 g/L.