Efficient hydrogen production from food waste leachate using single-chamber microbial electrolysis cell

The aim of this study was to develop an efficient strategy for enhancing H2 production in the single-chamber microbial electrolysis cell (MEC) using food waste leachate as a substrate. Different pH (8.5, 9.5, 10.5, and 11.2), applied voltage (0.8, 1.2, 1.5, 1.8, 2.0, 2.2, 2.3, and 2.4 V) and negative pressure control (-50 kPa) were tested in the single-chamber MEC. Suitable pH adjustment could greatly promote electricity generation and H2 production rather than negative pressure control. Under pH of 11.5 and 2.4 V, the maximum current density reached 121.9 f 10.9 A/m3 with an average H2 concentration of 91.9 f 3.2% in a 1.2-L single-chamber MEC within 30 continuous cycles of operation (-607 h), which was constructed with carbon brushes as the anode and stainless steel brushes as the cathode. The maximum H2 production rate reached 853.2 f 70.3 L/m3 center dot d with an H2 yield of 26.3 mmol center dot H2/g center dot COD. The COD removal of 68.3 f 6.8% and three-dimensional excitation-emission matrix spectra of the effluent in the MEC within 21 f 3h indicated efficient organics degradation in the leachate. Our results should provide a promising way to enhance the H2 production of MEC during leachate treatment.