Removal of fluoride from groundwater using MnO2 bentonite-smectite rich clay soils composite

A clay based composite adsorbent for fluoride was fabricated by blending the locally available smectite rich clay and MnO2 coated bentonite clay. The efficiency of the material towards fluoride adsorption was evaluated using fixed-bed column experiments. The results from column experiments showed that increasing parameters such as bed height and initial fluoride concentration increases the adsorption capacity whereas increasing flow rate decreases the column adsorption capacity. The paramount adsorption capacity of obtained at breakthrough point 0.6 mg/g when flow rate of 0.65 mL/min, bed height 2.5 cm and adsorbate concentration of 3.75 mg/L were used. The prepared composite was successfully regenerated using 0.01 M Na2CO3 and reused for up to 2 cycles. Thomas breakthrough model confirmed that fluoride adsorption by the prepared composite involves chemical interaction and transfer of ions into the internal layers of the adsorbent particles. The obtained results showed that MnO2 bentonite-smectite rich clay composite has potential for use in groundwater defluoridation.