Defluoridation of water by nanotechnology

Nowadays, people are interested in nanoscale materials (less than 100 nm in size), since their properties are different from those of large scale molecules of the same material due to their greater surface area. This paper deals with a novel, effective and low cost technique for defluoridation of water using nanotechnology. Nanocrystalline calcium hydroxide and calcium carbonate powder have been prepared through combustion route using calcium nitrate and sodium hydroxide. The combustion-derived nano calcium hydroxide and calcium carbonate powders have been characterized by using XRD and SEM. The powder X Ray Diffraction (XRD) pattern confirms the crystallanity and phase purity. The results of scanning electron microscope (SEM) reveal the powder is an agglomeration of fine particles. The particle size of the powder is found to be in the range of 12–20 nm with a large surface area. The synthesized nano calcium hydroxide and calcium carbonate powder is used for defluoridation of water samples with stirring time (1 hr–16 hrs), adsorbent quantity (3–50 mg/L) and pH (6–9) as experimental parameters. It is found that fluoride levels could be removed by using 50 mg of nano powder from 20 mg/L of 1litre standard sodium fluoride solution. In this technique, 90% minimization of sludge could be achieved.