关键词: 微生物电解池, 脱硫, 初始pH, 传质, 生物膜

Abstract:

The use of microbial electrolysis cells (MEC) technology, in conjunction with the cooperative action of electroactive microorganisms on the anode, achieves the removal of sulfides. This is a new process for biogas desulfurization and a research hotspot. For long-term operation of the desulfurization MEC process, non-specific cation competition causes proton transfer from the anode to the cathode to be impeded, resulting in low desulfurization efficiency and unstable operation. In this study, different initial pH values were used to regulate the proton balance in the desulfurization MEC. Through analysis of desulfurization performance, electrochemical performance, and microbial kinetics, the influence of pH regulation on the desulfurization performance of the MEC and the microbial mechanism were elucidated. The findings demonstrated that highly effective and stable anode biofilms capable of removing sulfides could be established at initial pH between 7 and 9, with comparable maximum current densities, sulfide removal efficiencies exceeding 95%, and COD removal rates over 80%. In comparison to initial pH of 8 and 9, pH fluctuation during the desulfurization process was minimized at an initial pH of 7, contributing to greater MEC stability and S^2- removal rates reaching up to 100%. The oxidation-reduction peak of the anode biofilm was pronounced, with accelerated proton and electron transfer rates. Thiomonas and Desulfovibrio microorganisms were dominant, exhibiting higher abundance and primarily involved in the oxidation removal of sulfides. These results underscored the importance of regulating the initial pH of the MEC anode chamber to improve MEC desulfurization efficiency and operational stability while providing valuable technical support for microbial electrochemical biogas desulfurization applications.

Key words: microbial electrolysis cells (MEC), desulfurization, initial pH, mass transfer, biofilm