Removal of fluoride by combined technology of electrocoagulation-flotation-filtration
电絮凝-气浮-砂滤组合工艺除氟

This paper investigated the removal of fluoride from aqueous solution using the combined technology of electrocoagulation-flotation-filtration.Effects of the voltage,hydraulic retention time(HRT) and initial fluoride concentration on the efficiency of fluoride removal were systematically evaluated.Results showed that the fluoride concentration was reduced to 0.92 mg/L with the initial fluoride concentration of 1.5 mg/L,HRT of 10 min and voltage of 15 V;the fluoride concentration was reduced to 0.98 mg/L with the initial fluoride concentration of 2.5 mg/L,HRT of 15 min and voltage of 15 V.The change of aluminum species in the effluent with time was characterized by Al-Ferron timed complex-colorimetric method.The result indicated that the content of Ala in the effluent of electrocoagulation unit rapidly decreased below 5% with the increase of time;the content of Alb in the effluent of both electrocoagulation and floatation units was above 50%;the content of Alc in the effluent of both units increased with time.