Modification Of Electrode Materials And The Application In Wastewater Treatment Of The Bioelectrochemical System

Bioelectrochemical systems?BES?is a widely concerned green process which can save the secondary energy while saving costs.It was widely used in the production capacity,waste water treatment and other fields,but has less application for degradation the refractory organic pollutants 4-chloronitrobenzene?4-CNB?.The exoelectrogenic bacteria in BES mainly consists of dissimilatory metal-reducing bacteria?DIRB?.It has been experimentally demonstrated that outer membrane c-type cytochromes have a high binding affinity to iron???oxides.And the iron???can be recognized by DIRB and utilized as extracellular exectron acceptor to be reduced.Based on the BES system,we conducted the sutdy of MFC anode material modification and use the MEC degradation the toxic and hazardous organic pollutants4-chloronitrobenzene?4-CNB?.The main contents are as follows:In this paper,NiFe₂O₄ samples were prepared by hydrothermal method,and then use the rolling process prepared the NiFe₂O₄ modified anode,and MFC was assembled to observe the effect of NiFe₂O₄ doping on the production performance of MFC.The results showed that when the dopped content of NiFe₂O₄ was 3%,5%,7%,the performance of the modified MFC was respectively 13%?26%?15%higher than the control group.When the doping content was 5%,power density of the MFC reach maximum?806.43±9.6 mW/m²?,It can be seen that the performance of MFC is the best when the dopped content of NiFe₂O₄ is 5%.The electrochemical EIS test and Tafel curve analysis also show that NiFe₂O₄ doping improves the kinetic activity of MFC anode and improves the production performance of MFC.The composite anode has the best electrochemical performance while the NiFe₂O₄ doping content is 5%.In the aspect of MEC,this paper mianly investigated the effects of 4-CNB initial concentration and different applied voltage on the degradation of 4-CNB by the MEC.First,we compared the 4-CNB degradation situation in the MEC system,BS system and ECS system,then carried out the first order kinetic simulation.The first order kinetic constantswas K_MEC>K_BS>K_ECS.It can be seen that the biological cathode plays an important role in the degradation of 4-CNB,and the bioelectrochemical system can more effectively degrade the 4-CNB.It was found that the removal rate of 4-CNB can finally reach 99%under different initial concentration.This indicating that the anaerobic functional bacteria has a better tolerance to the4-CNB.With the increase of the applied voltage?0.1 V⁰.9 V?,the removal rate of4-CNB fluctuates with the voltage,but finally the removal rate can reach more than99%.The main product of 4-CNB degradation is 4-CAN.With the increase of initial concentration of 4-CNB,the production rate of 4-CNB decreases.With the increase of the applied voltage,the production rate of 4-CNB first increase and then decrease.Under 0.5 V,the production rate of 4-CAN reach maximun,so 0.5 V is the optimum degradation voltage for 4-CNB.