Microbial electrolysis cell powered by an aluminum-air battery for hydrogen generation, in-situ coagulant production and wastewater treatment

• Published in: International journal of hydrogen energy 2018-04, Vol.43 (16), p.7764-7772
• Main Authors: Han, Xiaoyu, Qu, Youpeng, Dong, Yue, Zhao, Jiayi, Jia, Liming, Yu, Yanling, Zhang, Peng, Li, Da, Ren, Nanqi, Feng, Yujie
• Format: Article
• Language: English
• Subjects: Aluminum-air battery; Coagulation; Hydrogen; Microbial electrolysis cell
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.02.170

Microbial electrolysis cells (MECs) are an efficient technology for generating hydrogen gas from organic matters, but an additional voltage is needed to overcome the thermodynamic barrier of the reaction. A combined system of MEC and the aluminum-air battery (Al-air battery) was designed for hydrogen generation, coagulant production and operated in an energy self-sufficient mode. The Al-air battery (28 mL) produced a voltage ranged from 0.58 V to 0.80 V, which powered an MEC (28 mL) to produce hydrogen. The hydrogen production rate reached 0.19 ± 0.01 m3 H2/m3/d and 14.5 ± 0.9 mmol H2/g COD. The total COD removal rate was 85 ± 1%, of which MEC obtained 75 ± 1% COD removal and 10 ± 1% COD removal was achieved by in-situ coagulating process. The microorganisms removal of MEC effluent was 97 ± 2% through ex-situ coagulating process. These results showed that the Al-air battery-MEC system can be operated in energy self-sufficient mode and recovered energy from wastewater with high quality effluent. •An MEC-Al-air battery combined system was designed for hydrogen generation.•The Al-air battery provided energy for MEC and reduced the system energy consumption.•The effluent quality was improved by coagulating process with Al-air battery.