The Fluoride-adsorption Capacity and Influencing Factors Study of Zeolite

In modification experiment the best modification method was established. First, natural zeolite was roasted at 600¿ in a muffle furnace for 2h. After cooled to normal temperature, it was soaked in 4% HCl solution on dynamic condition at 65¿ for 1 hour, then soaked in 1mol/L NaOH solution on dynamic condition at 40¿ for 1 hour. The preconditioned zeolite was then was soaked in 10%AlCl3 solution on dynamic condition at 40¿ for 20 hour. In the end, it was treated in water vapour for 1 hour. Static experiment was carried out in order to examine defluorination ability of modified zeolite. The results showed that the adsorption capacity of zeolite was greatly enhanced after being modified, which obtained 0.25mg/g for fluoride solution with 20mg/L concentration. There were many factors affecting the adsorption capacity of modified zeolite. Among all the factors, the pH value and concentration of raw water and the running speed in dynamic experiment had greater influence. The structures of natural zeolite and modified zeolite were observed by SEM, XRD and FT-IR. Based on these, the reason and effect of modification were further analyzed.