European Journal of Biomedical and Pharmaceutical Sciences

ADSORPTION ISOTHERM AND KINETICS OF REMOVAL OF FLUORIDES FROM WATER AND WASTEWATER BY ADSORPTION TECHNIQUE USING LOW COST ADSORBENT LIKE RED MUD.

*Dr. P. P. Vishwakarma

ABSTRACT

Fluoride contamination in drinking water due to natural and anthropogenic activities has been recognized as one of the major problems worldwide imposing a serious threat to human health. In the present study, Red Mud was used as an adsorbent for fluoride removal from aqueous solutions. Adsorption experiments were carried out by using batch adsorption contact method. The effects of different parameters affecting efficiency of fluoride removal such as adsorbent dose, contact time, initial fluoride concentration, and pH were investigated and optimized. The optimum adsorbent dose, contact time, initial fluoride concentration and pH values were 25 gm/L, 180 min, 10 mg/L, and 6.7, respectively. Langmuir and Freundlich isotherm models were applied to describe the equilibrium data. Compared to Langmuir isotherm (R² = 0.890), the Freundlich isotherm (R² = 0.990) model was better fitted to describe the adsorption characteristics of fluoride on adsorbent. The Langmuir maximum adsorption capacity was 1.67 mg/g. The pseudo second order model was found to be more suitable than the pseudo first order to describe the adsorption kinetics. The low correlation coefficient value of R² = 0.596 for the intra-particle diffusion model indicates that the intra-particle diffusion model does not apply to the present studied. The maximum fluoride removal was observed to be 89% under the optimum conditions which indicated that Red Mud can be used as efficient, cheap, and ecofriendly adsorbent for the removal of fluoride from wastewater.

Keywords: Adsorption, Red Mud, Isotherm, Kinetics, pH.