Preparation of Mg-Al hydrotalcite and its adsorption effect on fluoride ions in water
This article prepared Mg-Al hydrotalcite through coprecipitation method,and studied the effect of magnesium aluminum molar ratio on the lattice structure,microstructure and spectral properties of Mg-Al hydrotalcite.Using NaF solution as a simulated fluorine-containing wastewater,the adsorption capacity and re-moval rate of Mg-Al hydrotalcite on fluoride ions in water were tested.The corresponding adsorption process and mechanism were studied through adsorption models.The research results indicate that the appearance of Mg-Al hydrotalcite is a layered structure,with interlaminar stacking between layers.As the magnesium alumi-num ratio increases,the interlayer spacing of Mg-Al hydrotalcite increases.The saturated adsorption capacity and removal rate of fluoride ions by hydrotalcite show a trend of first increasing and then decreasing with the in-crease of magnesium aluminum ratio.The adsorption capacity approaches saturation at 80 minutes,and the sat-urated adsorption capacity of 3Mg-Al hydrotalcite reaches the maximum value of 43.16 mg/g.The removal rate reaches the maximum value of 90.5％at 120 min.After 5 cycles of adsorption regeneration,the removal rate of fluoride ions by 3Mg-Al LDH decreased to 69.4％,and the retention rate reached 76.69％,demonstrating good reusability.By fitting the adsorption data of fluoride ions by hydrotalcite,it is shown that the adsorption process of fluoride ions by Mg-Al hydrotalcite is more consistent with the quasi-second-order kinetic model,which is mainly based on chemisorption.
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维普
