Study On The Technology Of Collaborative Treatment Of Electroplating Sludge And Hydrochloric Acid Pickling Wastewater Based On Concentration Cell

With the development of economy,the scale of metal surface treatment in China is expanding year by year,and the terminal byproducts electroplating sludge and pickling wastewater is increasing.At present,the disposal of electroplating sludge and pickling wastewater is mainly harmless treatment,and some of them are used as resources,but the synergistic treatment and energy recovery are seldom considered.According to the principle of concentration difference cell,the heavy metal ions in electroplating sludge are released by dissolving H⁺in pickling waste liquid,and the ion concentration gradient promotes the further migration,separation and recovery through cation exchange membrane.At the same time,the energy of salt difference is recovered,so as to explore the technical feasibility of concentration difference cell resource collaborative treatment of electroplating sludge and hydrochloric acid pickling waste liquid.The results are as follows:（1）The migration direction of heavy metals in concentration cell was explored.The results show that Cu,Zn,Ni and Fe can migrate from the concentrated water chamber to the fresh water chamber and react to form precipitation under the promotion of ion concentration gradient;Most of the Cr dissolved from electroplating sludge in concentrated water chamber is Cr（VI）,which exists in the form of Cr₂O₇^2-in acidic solution and cannot pass through cation exchange membrane.Only a small amount of Cr（III）can pass through cation exchange membrane without precipitation.（2）The effect of concentration/fresh water chamber parameters optimization on the efficiency of concentration cell was explored.The results showed that the comprehensive removal rate of heavy metals and the maximum power density of the concentration cell were the best under the conditions of solid/liquid ratio of 40:60 in the concentration chamber and 0.1 mol/L Na HCO₃ electrolyte in the fresh water chamber.（3）The effect of electrode modification on the efficiency of concentration cell was investigated.The results showed that when the modified electrode（EK-11）was calcined at 350℃and soaked in acetone,the comprehensive removal rate of heavy metals and the maximum power density of the cell were the best.（4）The effect of membrane modification on the efficiency of concentration cell was investigated.The results showed that the comprehensive removal rate of heavy metals and the maximum power density of the concentration cell were the best when the silica modified cation exchange membrane（EK-21）was used.In conclusion,the best technological parameters of the technology of concentrated difference cell Resource co-treatment of electroplating sludge and acid washing waste are as follows:the comprehensive removal rate of heavy metals in electroplating sludge and acid washing waste liquid can be achieved when the solid/liquid ratio of concentrated water chamber is 40:60 and that of fresh water room is 0.1mol/L.The comprehensive removal rate of heavy metals in electroplating sludge and acid washing waste liquid can be achieved by using EK-11 modified electrode and silica modified cation exchange membrane,The maximum power density of the cell can reach 14.69W/m².The results of this study provide a new and feasible technical approach for the co-treatment of electroplating sludge and hydrochloric acid pickling waste liquid.