Novel mesoporous chitosan-zirconia-ferrosoferric oxide as magnetic composite for defluoridation of water

Mesoporous chitosan-zirconia-ferrosoferric oxide (Meso-ChZrFe) composite was synthesized using chemical co-precipitation method. The composite showed could be easily separated from the solution by external magnet. The material was characterized using Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, Energy Dispersive X-ray analysis, BET surface area analysis, Thermogravimetry, X-ray diffraction and pH point of zero charge studies. The adsorption studies were carried out by optimizing various parameters as pH, adsorbent dose, adsorption time, initial fluoride concentration and effect of diverse ions. The material showed maximum defluoridation capacity of 17.81 mg g-1 at pH 3.0 within 60 min contact time. The adsorption process followed pseudo second order kinetics in accordance with Langmuir adsorption isotherm. Thermodynamics studies reveal that the process was spontaneous, exothermic and lead to decrease in entropy of the adsorbate. The material was tested for regeneration and could be reused for ten adsorption-desorption cycles with less than 12% reduction in adsorption efficiency.