The Characteristics of Fluorine Removal by Coagulation with Aluminum Salts

The characteristics of defluorination by coagulation with aluminum salt coagulants were studied via the jar test and the experiment of fluorine adsorption by and release from flocs.The variation of defluorination efficiency with the change of operation parameters such as coagulant dosage,pH,etc,and different forms of aluminum salt coagulants were investigated.The results show that the defluorination effect of aluminum salt coagulants is very sensitive to coagulation pH,achieving best performance under pH 5.8~7.0.Under the same dosage and optimum coagulation conditions,the defluorination effect of monomeric aluminum salt is better than polyaluminum salts,but the former's floc has a worse ability of remaining fluorine.