Synthesis of MgO nanoparticle loaded mesoporous Al2O3 and its defluoridation study

MgO nanoparticle loaded mesoporous alumina has been synthesized using a simple aqueous solution based cost effective method for removal of fluoride from water. Wide angle powder X-ray diffraction, nitrogen adsorption desorption analysis, transmission electron microscopy techniques and energy dispersive X-ray spectroscopy were used to characterize the synthesized adsorbents. Synthesized adsorbents possess high surface area with mesoporous structure. The adsorbents have been thoroughly investigated for the adsorption of F− using batch adsorption method. MgO nanoparticle loading on mesoporous Al2O3 enhances the F− adsorption capacity of Al2O3 from 56% to 90% (initial F− concentration = 10 mg L−1). Kinetic study revealed that adsorption kinetics follows the pseudo-second order model, suggesting the chemisorption mechanism. The F− adsorption isotherm data was explained by both Langmuir and Freundlich model. The maximum adsorption capacity of 40MgO@Al2O3 was 37.35 mg g−1. It was also observed that, when the solutions having F− concentration of 5 mg L−1 and 10 mg L−1 was treated with 40MgO@Al2O3, the F− concentration in treated water became <1 mg L−1, which is well below the recommendation of WHO.