The Study Of Pollution Control By Fe⁰/TiO₂ Catalytic Cathode Coupled In Microbial Fuel Cell System

In this study, a novel water treatment system coupling (photo-)electrochemical catalysis (PEC or EC) in microbial fuel cell (MFC) was set-up using stainless steel(SS) cathode coated with Fe0/TiO2. Fe0/TiO2 is prepared by a chemical reduction-deposition method and is coated onto SS wire mesh (500 mesh) using a sol technique. We examined and compared the destruction of methylene blue(MB,20 mg/L) and tetracycline(100 mg/L) in different systems, photocatalysis(PC), photoelectrocatalysis(PEC) and our novel system, called MFC-PEC/EC system. The results are as follows:(1) The SS wire mesh coated 1 wt%Fe0/TiO2 performed the best among the series of the prepared catalysts series (0.1%Fe0/TiO2,0.5%Fe0/TiO2,1%Fe0/TiO2,3%Fe0/TiO2,5% Fe0/TiO2). In photocatalysis system, it could remove 70.52% of the MB after 6 hours; in photoelectrocatalysis system, it could remove 78.62% of the MB after 6 hours.(2) In MFC- PEC/EC system (the novel system with SS wire mesh coated 1 wt% Fe0/TiO2), after 120 minutes, our novel system performed best when the microbial anode dosage was 54 g, removing 93.57% of MB. And the removal rate of MB (initial concentration was 20 mg/L) was better in the whole reaction process than when the MB initial concentration was 40 mg/L. And when the pH value was 5.26 the system performed best, removing 94.84% of MB. When the MFC-PEC system used 1 wt% Fe0/TiO2 as photocathode, the system performed best. The ESR study demonstrated that OH was formed in the system both with visible light illumination and without light illumination.(3) The voltage generated by the novel system was decreased at first, then increased and remained stable at last. When the cathode of MFC-PEC had 1 wt% Fe0/TiO2 as catalyst, the cell voltage was about 0.098 V, the power density was about 13.72 mW/m2. The EEO (electrical energy consumption per order of conversion) of MFC-PEC system was about 0.675 kWh/(m3-order), while the MFC-EC system was zero.(4) The comparison of results in PC, PEC and MFC-PEC/EC systems showed that, MFC-PEC had the best performance that removed 94.84% of MB, decreased ratio of remained TOC to TOCo of MB to 0.17. The system also decreased 70% of COD in tetracycline solution after 120 minutes.