Preparation Of MFC Anode Material Based On Carbon Cloth Modification And Its Application In BOD_Q Detection

Microbial Fuel Cell（MFC）biosensors have good stability and self-sustainability,and their applications in rapid detection of Biological oxygen demand（BOD）have attracted more and more attention.Anode material is very important in the overall performance of MFC.The properties of electrode material will affect the growth of microbial film and the capture of electric quantity,which is the key to improve the function and efficiency of MFC sensor.In this study,three kinds of MFC anode materials were prepared based on carbon cloth modification,and the key factors to improve the detection accuracy,precision and stability of different anode materials were explored when MFC sensors were applied to the BOD_Qtest system,providing a new idea for the improvement of the BOD_Qtest system of MFC sensors.In this study,pure carbon cloth anode（CC anode）was modified by coating method and in situ synthesis method,and three types of carbon-based electrode materials were prepared,which were applied to BOD_Qtest system to detect BOD value.The materials were characterized by scanning electron microscopy（SEM）,elemental analysis（EDS）,specific surface area measurement（BET）,Fourier infrared spectroscopy（FT-IR）,cyclic voltammetry（CV）and alternating current impedance spectroscopy（EIS）.These materials were applied to the anode of MFC sensor to construct the BOD_Qtest system.The influences of electrode effective area,biocompatibility,material conductivity and other factors on the BOD_Qtest were explored from a variety of factors affecting material properties.The influence of anode material properties on BOD_Qtest system is systematically analyzed from the aspects of Cullen efficiency,detection accuracy,precision and stability.The main research contents are as follows:In this study,first of all,CSC/CC anodes and pure carbon cloth anodes with different electrode area sizes were prepared for BOD_Qtest of MFC sensor.Compared with CC anode,BOD₅of Coconut shell carbon cloth anode with larger specific surface area was 200 for 5days The BOD_Qvalue of simulated wastewater atmg/L was 197.5mg/L,the response time was 21 h,the detection error range and relative standard deviation（RSD）were 0.43%～1.95%and 1.19%,respectively In order to compare the influence of different apparent electrode areas,the BOD_Qtest results of different sizes of carbon cloth anode were compared.The results showed that the detection value of the 2.5 2.5cm carbon cloth anode（2.5CC）reactor was 189.7mg/L,and the detection error range and RSD were 4.91%～5.29%and0.20%,respectively The detection error range and RSD of 2.0 2.0cm carbon cloth anode reactor are 15.24%～16.86%and 0.97%,respectively Compared with 2.0CC anode and 2.5CC anode,CSC/CC anode has better accuracy and precision,mainly because CSC/CC anode has larger specific surface area compared with CC anode,and coconut shell carbon has abundant surface functional groups,which is more conducive to the attachment and growth of microorganisms The relative abundance of C.biofilm on CSC/CC anodic surface reached60.23%,which was higher than that of 53.01%and 56.96%on 2.0CC and 2.5CC anodic surface The increase of the anode effective electrode area makes the anode surface have more attachment sites,which is conducive to the growth of microflora,and the content of electrogenic bacteria is also increased,which significantly improves the coulomb efficiency,which makes the BOD_Qtest of the reactor more accurateTourmaline carbon cloth anode（TM/CC anode）was prepared by coating method and used for BOD_Qtest of MFC sensor.Compared with CC anode,TM/CC anode can significantly improve the electronic capture efficiency of BOD_Qsensor,which makes the sensor have higher accuracy and precision.The simulated wastewater test standard solution（BOD₅200mg/L）was used for the detection of TM/CC anode BOD_Qsensor,and the test value was 208.6mg/L,RSD 3.12%,and the high precision could be maintained at the concentration of 50-250mg/L.The abundant mineral elements on the surface of TM/CC anode were beneficial to the growth of microflora and the change of surface biofilm.Microbial analysis showed that TM/CC material could increase the biomass on the anode surface(OD₆₀₀=0.35)and significantly increase the abundance of electroproducing bacteria on the electrode surface,in which the proportion of Bacterobacteria reached 65.17%,thus improving the Coulomb efficiency.The BOD_Qdetection is more accurate.3.Using in situ polymerization to synthesize polyaniline carbon cloth anode（PANI/CC anode）,and used for BOD_Qtest of MFC sensor.After PANI/CC anode is used for BOD_Qsensor,the high electrical conductivity of the anode significantly improves the electrochemical activity of the reactor,reduces the electron transfer barrier,improves the electron transfer efficiency of the sensor,and then enhances the coulombic efficiency of the reactor.The Coulomb efficiency of PANI/CC anode reactor with the concentration range of50-250mg/L was stable above 65%,and the microbial analysis results showed that the relative abundance of Bacterobacteria on the surface of PANI/CC anode was 63.25%,which made the sensor have higher accuracy and precision.The BOD_Qhas a good stability in the long-term operation of the reactor.The average detection value of BOD_Qfor seven consecutive cycles is 207.7mg/L,and the corresponding RSD is 1.19%,which shows a good application prospect.Compared with the pure carbon cloth anode system,the performance of the MFC sensor BOD_Qtest system constructed by the three anode materials prepared in this study has been improved,and the accuracy and precision of the test values have been significantly improved.The simulated wastewater within the BOD concentration range of 50～250mg/L can be accurately measured,and it has a good sensitivity to wastewater of different concentrations.Overall,the reactor is more accurate in the high concentration test.The reactor can maintain the stability of the coulomb efficiency in the multi-cycle test.The measured values have good repeatability and have the possibility of long-term operation.