Fluoride removal from aqueous solution by pumice: case study on Kuhbonan water

Abstract

The fluoride removal from synthetic water by pumice was studied at batch experiments in this study. The effect of pH, contact time, fluoride concentration and adsorbent dose on the fluoride sequestration was investigated. The optimum conditions were studied on Kuhbonan water as a case study. The results showed that with increasing of the absorbent amount; contact time and pH improve the efficiency of fluoride removal. The maximum fluoride uptake was obtained in pH and contact time 7.0 and 180 min, respectively. Also, with increasing initial concentration of fluoride in water, the efficiency of fluoride removal decreased. The obtained results in this study were matched with freundlich isotherm and pseudo second order kinetic. The maximum adsorption capacity (Q_m) and constant rate were found 0.31 (mg/g) and 0.21 (mg/g.min), respectively. This study also showed that in the optimum conditions, the fluoride removal efficiency from Kuhbonan water by 2.8 mg/L fluoride was 74.64%. Eventually, pumice is recommended as a suitable and low cost absorbent to fluoride removal from aqueous solutions.

Key words: Adsorption, Freundlich isotherm, Langmuir isotherm, Kuhbonan water.