Aqueous Fluoride Adsorption of Compound Phosphates and Its Affecting Factors

Effects of co-precipitates of Ca /Al, Fe /Al andMn /Al phosphates of different ratios in removing fluoride from synthetic solution were studied with the static adsorp tion method. Results show that the co-precipitate of Fe /Al phosphate was the best in effect of removing fluoride, andMn ions significantly inhibited the effect of aluminium phosphate. Affecting factors, such as duration of exposure, pH and amount of the adsorbent used, were also studied, using the co-precipitate of Fe /Al phosphate, 1∶100 in ratio as adsorbent. Itwas found that the absorption rate of the adsorbent reached as high as 217 mg·g-1 when the fluorinated waterwith its initial fluoride concentration being 10 mg·L -1 and pH ranging between 6 - 8 and the adsorbent app lication rate at 215 g·L -1 was shaken for 90 minutes at the temperature of 25 ℃.