Regeneration, Modification And Reuse Of Perfluorinated Sulfonated Ion Exchange Membrane

Perfluorinated sulfonic acid proton exchange membrane is the most widely used proton exchange membrane in microbial fuel cells.However,the price of the perfluorinated proton membrane has been more expensive because of the higher cost of the material and the more complex process of making the MFC,which makes the price of its application high.In addition,because of the fluorine contained in the membrane materials,the waste products are difficult to degrade and cause environmental problems.At present,the use of the biofuel battery for the perfluorosulfonic acid membrane is basically one time,and there is almost no economic convenience to regenerate the perfluoro sulfonic membrane two times.In this paper,the perfluoro sulfonic acid proton exchange membrane was applied to MFC,and the proton membrane was contaminated by stable operation for 3 periods.Then the membrane was cleaned and recycled through HCl,H₂SO₄,CH₃COOH,NaOH,Ca?OH?₂ and ammonia water to explore the best regenerated solution and its regeneration concentration,temperature and time.In addition,PTFE was used to modify the new membrane and regenerated membrane,and the best concentration and temperature of modification were obtained,and the mechanism was discussed.Finally,the regenerated membranes and modified membranes were applied to MFC,and the effects of regenerated and modified proton membranes on MFC power generation were discussed.The main contents of this paper are as follows.?1?A self-made double chamber MFC reactor was used in this experiment.The cathode and anode materials are all carbon cloth,and the perfluorinated sulfonic acid ion exchange membrane is separated from the cathode and anode chamber.Run the reactor for 1 months,so that the ion exchange membrane is fully polluted.?2?Distilled water,HCl,H₂SO₄,CH₃COOH,NaOH,Ca?OH?₂ and NH₃·H₂O water were used to regenerate the contaminated ion exchange membrane,and the properties of the film under different concentrations,temperature and time were investigated.When the optimum regenerated solution is HCl of 5%concentration,the performance of the regenerated film is obviously improved.The conductivity of perfluorinated sulfonated ion exchange membrane is affected by temperature.When the temperature is higher than 80?,the conductivity will decrease.In the temperature range from 20to 80,the higher the temperature is,the better the membrane performance is.Therefore,the best regeneration temperature is 80 centigrade.The regeneration time is within 0 to 48 hours.When the time reaches 24 hours,the membrane performance basically remains unchanged,so the best regeneration time is 24 hours.Under the optimum conditions,the water absorption of the film was two times higher than that of the polluted membrane,the swelling rate increased by 21.7%,the IEC increased by 1.7 times,and the conductivity increased by 1.5 times.?3?The purchased PTFE was diluted to 5%,10%,20%,30%,40%,50%50mL respectively.5 concentrations of PTFE were smeared evenly on the clean and regenerated ion exchange membranes to control the different time and temperature.The optimum concentration of PTFE modification was 40%,the temperature was 80,and the time was 24 hours.Under the optimum conditions,the water absorption rate of the membranes increased by 46%,the swelling rate increased by 24%,the IEC increased by 50%,and the conductivity increased by 54%.?4?The effect of regenerated perfluorinated sulfonic acid membrane on the power generation performance of MFCs was studied by two compartment microbial fuel cell.The results showed that the power density of MFCs with a new and PTFE modified perfluorosulfonic acid membrane increased by 35%compared to that of the original,and the MFCs power density of the regenerated and PTFE modified perfluorinated sulfonic membrane increased by 18%,while the MFCs power density of the unmodified perfluorinated sulfonic membrane was improved by HCl,but only 5%of the power density of the unmodified perfluorinated sulfonic membrane was improved.Compared with the output voltage,the MFCs output voltage of MFCs with a new and PTFE modified perfluorosulfonic acid membrane and the use of HCl to regenerate the PTFE modified perfluorosulfonic acid membrane increased by40%and 27%compared with the unmodified MFCs,while the unmodified perfluoro sulfonic membrane MFCs increased by 14%with HCl regeneration.