Recovery of methane and acetate during ex-situ biogas upgrading via novel dual-membrane aerated biofilm reactor

• Published in: Bioresource technology 2023-08, Vol.382, p.129181-129181, Article 129181
• Main Authors: Wu, Kai-Kai, Zhao, Lei, Zheng, Xiao-Chuan, Sun, Zhong-Fang, Wang, Zi-Han, Chen, Chuan, Xing, De-Feng, Yang, Shan-Shan, Ren, Nan-Qi
• Format: Article
• Language: English
• Subjects: Biological biogas upgrading; Carbon dioxide conversion; Liquid chemicals recovery
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129181

[Display omitted] •dMBfR improved ex-situ biogas upgrading and acetate recovery efficiency.•The maximum CH4 content of 97.6% was obtained.•The acetate production rate reached 34.5 mmol L−1d−1.•Clostridium was the biggest contributor to the bioconversion of CO2/H2 to acetate. Biological biogas upgrading has been well-proven to be a promising approach for renewable bioenergy recovery, but hydrogen (H2)-assisted ex-situ biogas upgrading is hindered by a large solubility discrepancy between H2 and carbon dioxide (CO2). This study established a new dual-membrane aerated biofilm reactor (dMBfR) to improve the upgrading efficiency. Results showed that dMBfR operated at 1.25 atm H2 partial pressure, 1.5 atm biogas partial pressure, and 1.0 d hydraulic retention time could significantly improve the efficiency. The maximum methane purity of 97.6%, acetate production rate of 34.5 mmol L−1d−1, and H2 and CO2 utilization ratios of 96.5% and 96.3% were achieved. Further analysis showed that the improved performances of biogas upgrading and acetate recovery were positively correlated with the total abundances of functional microorganisms. Taken together, these results suggest that the dMBfR, which facilitates the precise CO2 and H2 supply, is an ideal approach for efficient biological biogas upgrading.