Removal of Fluoride from Aqueous Solution Using Coal-Coated with FeCl3

The fluoride contamination problem of groundwater of the rural areas in India is a serious threat due to unavailability of alternate safe water sources. In the present study, the coal-coated with FeCl3 was used for fluoride mitigation due to abundant availability of the raw coals in the surroundings of the affected areas of Bankura district, West Bengal, India. The raw coal was crushed into particle sizes less than 0.3 mm and further processed for the coating of FeCl3. The characterization of the adsorbent done by XRD, FESEM and EDAX reveals that the adsorption process was physicochemical in nature. The batch, kinetic and column studies results showed that the maximum fluoride removal efficiency, adsorption capacity and performance of the column were found as 96%, 88.6 mg/g and 98%, respectively, and the adsorption mechanism best fit to Freundlich isotherm, pseudo-second order kinetics, and Yoon-Nelson and Thomas breakthrough models. The column had achieved the breakthrough point (i.e. 1.5 mg/L F- conc.) in approximately 20 h at the flow rate of 2 ml/min, initial fluoride conc. of 20 mg/L and bed depth of 5 cm.