Improved deoxygenation beads for trickle bed-based microbial fuel cells to increase isopropanol and styrene-containing exhaust gas removal efficiency and power production

Abstract

This study is the first to use a trickle-bed microbial fuel cell (TB-MFC) to treat both hydrophilic (isopropyl alcohol) and hydrophobic (styrene) pollutants. During the operation of the TB-MFC, the microorganisms continue to convert pollutants into electrons, improving the removal of hydrophilic and hydrophobic pollutants, and generating electricity. To enhance the growth of electricity-generating bacteria, a novel deoxygenated packing material (DPM) that removes oxygen from the exhaust gas was applied to the TB-MFC. The TB-MFC reached maximum pollutant removal and power generation at a total carbon concentration of 2.20 g/m3, an empty bed residence time of 60 s and a concentration ratio of 1: 1 of isopropanol and styrene. The mean elimination capacity of isopropanol and styrene were 81.5 ± 0.20 g/m3/h and 54.2 ± 0.26 g/m3/h, respectively, and the maximum voltage outputs and power density were 450 mV and 426 mW/m3. A microbial community analysis revealed that the electricity-generating bacteria were mostly Clostridium, Aeromonas, Acinetobacter and Kosakonia. Most of the isopropanol-degrading bacteria (Xanthobacter, Beijerinckia) and styrene-degrading bacteria (Chryseobacterium, Cloacibacterium) were in the TB-MFC. The findings indicate that TB-MFC is capable of generating electricity and treating both hydrophilic and hydrophobic pollutants simultaneously. The improved DPM can be used in the TB-MFC to reduce the concentration of oxygen in industrial emissions and accelerate the growth of electricity-generating bacteria, with the goal of achieving high pollutant removal and electricity generation.