Photocatalytic/Microbial fuel cell system based on TiO2-MAR: Study on the degradation performance and mechanism of m-cresol

This graphical abstract intuitively illustrates the core processes and mechanisms of the photocatalytic/microbial fuel cell system (PMFC) for the efficient removal of m-cresol and simultaneous energy production. The left side is the reaction device of the system, which mainly includes the anode carbon brush, cathode carbon cloth, external circuit, UV light source, sludge storage tank, and macroporous adsorption resin (MAR) loaded with TiO 2 photocatalyst (with a SEM image of MAR). The high-efficiency removal performance of m-cresol by PMFC, such as complete removal in approximately 18 h at a concentration of 500 mg/L. The right side first illustrates the degradation process of m-cresol in the PMFC, which generates a series of intermediates and is ultimately mineralized to CO 2 and H 2 O, demonstrating the synergistic effect of photocatalytic oxidation and biological degradation. Secondly, the CV curves obtained from operating the PMFC and MFC systems are shown, indicating that the redox behavior of PMFC is stronger than that of MFC. Finally, the molecular dynamics model was constructed using Materials Studio, which includes m-cresol molecules, water molecules, MAR chains, and TiO 2 layers, used to simulate the diffusion behavior of m-cresol within the adsorbent. This graphical abstract highlights the advantages of PMFC in enhancing the degradation efficiency and power generation performance of m-cresol as well as the synergistic mechanism of “adsorption-photocatalysis-biodegradation”. • A photocatalytic/microbial fuel cell device was constructed. • Added light has increased the power generation capacity of the entire system. • Adsorption kinetics analyzed mass transfer mechanism and diffusion behavior. • Dynamic diffusion process was simulated using Materials Studio software. • Density functional theory predicted m-cresol degradation pathways. The synergistic treatment technology of photocatalysis and microbial fuel cell is used to enhance the removal of heavy pollutant m-cresol in wastewater. A photocatalytic/microbial fuel cell (PMFC) system was constructed based on a microbial fuel cell (MFC), and TiO 2 photocatalyst was loaded onto the macroporous adsorption resin (MAR) used as the biological carrier. The system was characterized using techniques such as Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD). In m-cresol solutions with initial concentrations of 500 mg/L, 800 mg/L, and 1000 mg/L, the m-cresol removal efficiency of the PMFC system was increased by 60 %, 52 %, and 51 % respectively, compared with that of the MFC system. In addition, the maximum voltages of the PMFC and MFC systems were 521.7 mV and 461.7 mV, respectively, and the maximum power densities were 174.47 mW/m 2 and 128.92 mW/m 2 , respectively. The adsorption kinetic model was analyzed using pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models to elucidate the mass transfer mechanism. The intraparticle diffusion (IPD) adsorption kinetic model was employed to investigate the diffusion behavior within the particles. It was found that the process is more consistent with the PFO kinetic model and is primarily controlled by the diffusion step. The dynamic diffusion process was simulated using Materials Studio (MS) software, and the diffusion coefficient was obtained through the mean square displacement (MSD) analysis. In addition, the degradation pathway of m-cresol in the PMFC system was proposed.