Fluoride removal from groundwater by FeCl3-activated natural zeolite
载铁活化天然沸石处理高氟地下水

Effects of four anions in groundwater: Cl-, HCO3-, SO42- and PO43- on the capacity of defluoridation of FeCl3-activated natural zeolite were investigated. The mechanism of defluorination and surface composition of adsorbent were analyzed. The results showed that the removal efficiencies of fluoride for different initial fluoride concentrations of water samples were gradually reduced with the increasing concentrations of anions. Effect of Cl- on the adsorbent was tiny with slower decrease of fluorine removal rate. With the increase of HCO3- concentration (from 100 mg / L to 1 000 mg / L), pH of water slowly increased to 9.52 from 8.42, and removal efficiency of flouride tardily declined from 70.36% to 56.73% (2 mg/L). Effects of SO42-and PO43- on the capacity of defluoridation of the modified zeolite were greater, with rapid decrease of fluorine removal rate. And the impact of PO43- was greater than SO42-. The adsorption capacity of FeCl3-activated natural zeolite on Cl-, HCO3-, SO42- and PO43- was PO43->SO42->HCO3->Cl-.