Treatment of desulfurization wastewater by electrocoagulation and its application in the pretreatment of reverse osmosis

In order to investigate the effect of electrocoagulation on desulfurization wastewater and its role as reverse osmosis pretreatment technology，the desulfurization wastewater was pretreated by electrocoagulation. Furthermore，the effects of key parameters on the removal efficiency were investigated. Then the reverse osmosis method was used to further treat the effluent，and the membrane performance with and without electrocoagulation was compared. The floc and cathode deposition were tested by characterization technique to study the electrocoagulation mechanism. The results showed that using Fe-Al anode，large removal efficiency could be achieved within a short time. The optimum conditions were as follows：electrocoagulation time 60 min，initial pH=8，current density 8 mA/cm2.Pollutants were removed by oxidation，reduction and flocculation. Using electrocoagulation before reverse osmosis，the membrane flux stabled at 36.4 L/（m2·h） and the removal efficiency of zinc，lead，magnesium，calcium and chloride ions by electrocoagulation-reverse osmosis process were 99.5%，99.3%，95.3%，91.0% and 80.2% respectively. Electrocoagulation pretreatment could effectively reduce membrane pollution and improve the efficiency of reverse osmosis of desulfurization wastewater. The experimental results showed that the electrocoagulation was effective in the treatment of desulfurization wastewater. As a pretreatment step of reverse osmosis，it could effectively reduce membrane pollution and improve efficiency.