Study On Treatment Of Pickling Waste Liquid Based On Concentration Difference Cell And Microbial Fuel Cell Combined Process

Because hydrochloric acid pickling waste liquor contains a large amount of acid and metal ions,then it is highly corrosive and toxic.So hydrochloric acid pickling waste liquor is a hazardous waste which is produced in the process of iron and steel process,and it is listed as HW34 in the list of hazardous waste.The treatment of waste liquid is usually entrusted to a qualified company or neutralization,recycling acid and iron and so on.However,the expence is high,and the result is not very significant.At the other hand,the salinity gradient turned directly into salt and can not recycle,it will waste a lot of energy.So this article takes steel spent pickling hydrochloric acid liquid as the research object,I take the concentration cell and microbial fuel cell technology for recycling energy and resource.At the same time,To explore efficient method for recycling the hydrochloric acid pickling waste liquor.First,in this paper,the concentration difference cell recycled salinity gradient which was studied.In the process,we analyzed different concentration of salt water to observe the internal resistance of battery as well as the open circuit voltage.The result showed that the internal resistance of cell dropped,then open circuit voltage rised first and dropped as the increasing of water concentration.At the same time,maximum power density increased and finally was tended to be stable.When the concentration of salt water is 0.01 M,the power density of concentration difference cell as well as the open circuit voltage,the internal resistance were ideal.In addition to this,the types of ion exchange membrane were also studied which influence the concentration difference cell.we found that the proton exchange membrane has the biggest resistance and the next one is anion exchange membrane,cation exchange membrane is the smallest.Therefore the open circuit voltage of ion exchange membrane and cation exchange membrane is fairly,but proton exchange membrane is the smallest one.Cation exchange membrane can produce the biggest power density,the anion exchange membrane followed and proton exchange membrane is the minimum.Finally,the salinity gradient and iron were recovered by aerating in the fresh water chamber.The results showed that aeration could reduce the internal resistance of concentration difference cell,raise the open circuit voltage and pH value in the process,and the higher the aeration,the greater the range.Hydrochloric acid pickling waste liquor through concentration difference cell will turn into microbial fuel cell for the next process.After dealing with the microbial fuel cell at different temperature,the pH of hydrochloric acid pickling waste liquor increased,the pH value changed gently,and later pH increase quickly.When we runned 10d at 25 °C,the pH was the largest,followed by 35?,the last is 15?;With running at 25?C and 35°C,precipitation appeared in the cathode chamber,and this didn't happen at 15 ?.The combined process of concentration difference cell and microbial fuel cell treat.Pickling waste liquor of hydrochloric acid which can achieve 68%iron.At the same time,the removal rate of heavy metals is more than 80%,and the removal rate of Cu is the best.The recovery of salinity gradient can be up to 2.24× 10-3 kW ·h/L.