Study on preparation of La-loaded active alumina andfactors affecting fluoride removal for fluorine-containing wastewater

In order to improve the fluoride removal performance of activated alumina and expand the application of mine water defluorination,the active alumina adsorbent was modified by lanthanum and the La-loaded active alumina was prepared by impregnation roasting.The preparation conditions were discussed.The adsorption properties were studied in removing fluorine from wastewater.The results show that the adsorption performance is the best when the La(NO3)3 concentration is 0.15 mol/L,the roasting temperature is 350 ℃ and the roasting time is 2.5 h.The removal rate of 12.0 mg/L fluoride wastewater is 93% when the adsorbent dosage is 2.0 g/L,the adsorption time is 120 min,the pH value is 6.5～7.5 and the stir speed is 180 r/min.The ln C-t curve in the process of adsorption and fluoride removal with La-loaded activated alumina is basically linearly related and the adsorption belongs to the first-order reaction in macroscopic adsorption kinetics.