A study on removal of fluorides from drinking water by adsorption onto low-cost materials

Various low-cost materials like kaolinite, bentonite, charfines, lignite and nirmali seeds were investigated to assess their capacity for removal of fluorides from water by batch adsorption studies. Studies were also conducted to determine optimum operating-system parameters; such as contact time, pH, dose and size of the adsorbent. Present study has indicated that materials like nirmali seeds and lignite are not effective (removal 6 to 8%); whereas removal by kaolinite clay was slightly higher (18.2%). Charfines and bentonite exhibited highest removal capacity of 38 and 46%, respectively, at optimum system conditions. Chemical pre-treatment of charfines did not result in enhanced removal of fluoride from water.