Modular Microbial Fuel Cell Degrades Oily Water Of Engine Room

In this paper,the oily water in the engine room of the ship was used as the anode liquid,and the prepared biochar was used as the anode material,to construct and start the single chamber microbial fuel cell(MFC).Conductive polyaniline(PANI)was used to modify the anode material to improve the output performance of MFC from the aspects of power generation and degradation of MFC;Further,the biochar anode under the optimal conditions was obtained by single factor experiment and response surface method;The response surface method was used to optimize the reaction conditions of the single-module MFC device and improve the degradation rate of the single-module MFC to the oily water of the ship engine room;The dual-module 2D-MFC and multimodule 4D-MFC devices were further designed,and the effects of electrode connection,the distance between cathode and anode,cathode support material,water distribution method,water flow rate and oscillation are studied.Finally,the multi-module 4D-MFC device was applied on the ship to measure its output performance.The main research contents and results are as follows:(1)Firstly,the almond biochar(BD-300)was prepared by carbonizing almond shell at high temperature,and the PANI/BD-300 anode suitable for MFC was prepared by chemical modification of BD-300 with polyaniline(PANI).Through characterization,it was found that PANI had been successfully modified on the surface of almond biochar.The PANI/BD-300,BD-300 and CF were used as the anodes of MFC to treat the oily water of the ship engine room,and the 7 d degradation rate of the ship oily water were67.20%,56.25% and 39.00% respectively.In order to further improve the degradation rate of MFC,the PANI/BD-300 anode was optimized by response surface method and used as the anode of MFC to treat engine room oily water.The results showed that the degradation rate of MFC in 7 days could reach 78.63%,which was 39.63% higher than that of CF anode and 11.43% higher than that of PANI/BD-300 anode.(2)In order to further improve the degradation rate of MFC,response surface method was used to optimize and improve the degradation performance of single module MFC.Three main influencing conditions of single-module MFC were screened out,and the optimal interaction conditions were obtained by controlling single-factor experiment and response surface method: when pH was 7.43,sodium chloride concentration was 29.66 g/L,and temperature was 35.78℃,the 7 d degradation rate of single-module MFC device was 82.7%,which was 4.07% higher than the original single-module MFC,and the accuracy of the model was as high as 99.04%.(3)In order to further improve the treatment capacity and output voltage of singlemodule MFC for engine room oily water,the single-module MFC was designed as a 2-MFC device.The study found that the 7 d degradation rate of the 2-MFC-C device connected in series with electrodes was 82.1%,which was 0.5% higher than that connected in parallel with electrodes.The maximum output voltage of the 2-MFC-C device connected in series with electrodes was 0.66 V,which was 0.33 V higher than that of the 2-MFC-B device connected in parallel with electrodes.This showed that the2-MFC device connected in series with electrodes was more conducive to improving the output performance than that connected in parallel with electrodes.Further research found that when the distance between cathode and cathode was 2 mm,the distance between anode and cathode was 2 cm,and the area ratio between anode and cathode was 10:63,the 7 d degradation rate of 2-MFC device was 83.1%,which was 0.4%higher than that of single-module MFC device,and the maximum output voltage was0.71 V,which was 0.38 V higher than that of the single-module MFC device.(4)In order to further improve the output performance of modular MFC in the treatment of oily water of ship engine room,the amplified single-module D-MFC device,double-module 2D-MFC and multi-module 4D-MFC were designed.In order to avoid cathode deformation,three cathode plates with different shapes and three cathode gaskets with different apertures were designed.The experimental results showed that when the cathode gasket with aperture of 12 mm and thickness of 3 mm was selected for 2D-MFC,the 7 d degradation rate could be increased to 84.9%.After that,a multimodule 4D-MFC device was further designed,and the effects of electrode seriesparallel connection,water distribution series-parallel connection,oily water flow rate and oscillation frequency on the 4D-MFC device were studied.The experimental results showed that the degradation rate and maximum output voltage of the 4D-MFC device were 79.92% and 1.06 V respectively when the electrodes were connected in series and water was distributed in parallel at a flow rate of 2 m L/h;The degradation rates reached85.2% and 84.96% respectively when sway and surge were applied for 10 times/min.(5)The output performance of the 4D-MFC device in the ship was tested.The degradation rate could reach 85.1%,which was 46.1% higher than that of the singlemodule MFC using CF anode,and 17.9% higher than that of the single-module MFC using PANI/BD-300 anode;The maximum output voltage could reach 1.08 V,which was 0.75 V higher than that of the single-module MFC using PANI/BD-300 anode.The design of 4D-MFC device provides technical support for the application of singlechamber MFC in ships,and provides a new way to solve the problem of engine room oily water pollution.