Preparation And Mechanism Of Natural Fluoride Removal Adsorbent Modified

As natural macromolecule, chitosan has excellent bioactivity and selectivity. This study investigated the feasibility of its modified materials for fluoride removal from drinking water and magnetic chitosan beads were prepared with high uptake capacity for the first time. Candidates of other natural macromolecules that modified bone char, tourmaline and established methods were also compared. Experimental results showed that both of magnetic adsorbent and bone char had better adsorbing ability than activated alumina. At pH 7 and the equilibrium concentrations were 78mg/L and 120mg/L respectively, the uptake capacity of the magnetic chitosan and bone char were 17.68mg/g and 18.11mg/g. Batch and Column experiments were also conducted to describe the adsorbing process. Empirical models and instrumental analysis showed that the adsorption of the magnetic adsorbent to fluoride is a chemical process. The environmental scanning electron microscope indicated Fe3+, Ca2+ ions were included after modification. So the adsorbing process was enhanced by the magnetic field, which was produced by the magnetic particles themselves. Particles with higher ratio saturated magnetizing strength or fewer diameters had higher uptake capacity. Furthermore, through second regeneration, the efficiency of the magnetic adsorbent and bone char could also attain 98% and 98.5%. The results indicated that the composite adsorbents, which were the modified adsorbents of natural materials, satisfied the fundamental requests of environmental materials, and bone char had gotten successfully application in the practice.