Study on Modification and Fluoride-Adsorption Capacity of Zeolite

This Adsorption and ion exchange is thought to be an effective method. Zeolite is a kind of normal adsorber. The adsorption capacity of natural zeolite is low, so it must be activated in order to attain a higher adsorption capacity. On this condition, a study on modification of natural zeolite and its defluorination ability was carried out. 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. The adsorption isotherm of modified zeolite conformed to Freundlich equation, and the rate of adsorption conformed to Banerm equation.