Sediment Microbial Fuel Cell Based On Shallow Seabed Mud Drives Electro-fenton In-situ To Degrade Heterosigma Akashiwo

With the acceleration of the world's urbanization process and the intensification of global climate warming,red tides occur frequently in the sea area,causing the water ecological environment to lose balance.The sediment microbial fuel cell(SMFC)can use the biodegradable organic matter in the shallow sea mud to generate electricity.In this thesis,the SMFC system is combined with the E-Fenton technology,and the electric energy generated by the SMFC is used to drive the E-Fenton reaction in situ to construct the SMFC-E-Fenton system.This system can not only use the electricity-producing microorganisms in the anode area to convert the biomass energy in the shallow seabed mud into electric energy and transfer it to the cathode,but also remove the organic matter in it,and generate Fenton's reagent through a reduction reaction on the surface of the cathode.The electro-Fenton reaction generates strong oxidizing hydroxyl radicals to degrade Heterosigma akashiwo in water.The specific experimental content and results of this paper are as follows:First,the carbon felt loaded with?-FeOOH was prepared by the immersion method as the cathode,and constant currents of certain intensities were applied to the two ends of the electro-Fenton degradation system to remove Heterosigma akashiwo.In order to prove whether the working electrode can generate hydroxyl radicals under the condition of accepting electrons,in this study,the carbon felt loaded with?-FeOOH was used as the E-Fenton cathode with external constant current.After 240 minutes of treatment,the degradation rate of Heterosigma akashiwo reached 91.3%,90.1%,and 90.1%in the three reactors with 30 m A,20 m A,and 10 m A constant currents,respectively,and the color changed from yellowish brown to transparent.It can be seen from the fluorescence spectrum that the soluble microbial products in the water body have been completely removed.SEM,XRD,XPS and FTIR characterization and analysis of the electrode revealed that the?-FeOOH catalyst had been largely supported on the surface and inside of the electrode.The CV curve and LSV curve analysis of carbon felt and blank carbon felt loaded with?-FeOOH catalyst showed that both exhibited good redox peaks and could cause O₂ to undergo a two-electron reduction reaction to generate H₂O₂.It is proved that the electric Fenton reaction can occur on the surface of the electrode.On the basis of SMFC's anode mud production and E-Fenton reaction at the cathode to degrade Heterosigma akashiwo,the?-FeOOH catalyst-loaded cathode was combined with SMFC to construct the SMFC-E-Fenton system.After 3 cycles of treatment(each cycle is 7days),compared with the blank group,the experimental group has an average degradation rate of 92.1%,94.1%,and 94.5%for the dry weight,chlorophyll and protein of Heterosigma akashiwo.It was found that the experimental group had the most obvious degradation effect on the algae,while the control group had a weaker degradation effect.In addition,the VSS/SS at the beginning of the measurement reaction was 3.97%.After the 3 reaction cycles,the experimental group dropped to 3.55%,which reached 1.33 times and 1.88 times that of the control and blank groups with blank carbon felt cathodes,respectively.The organic matter reduction effect of the experimental group was the best.In addition,the power density curve,polarization curve and electrochemical impedance spectroscopy analysis of the experimental group and the control group showed that the SMFC-E-Fenton system improved the power generation performance of the experimental group.