表面活性剂添加量对微生物电合成转化二氧化碳的影响

Effect of surfactants on microbial electrosynthesis conversion of carbon dioxide

微生物电合成(MES)是生物阴极驱动的过程,其中自养微生物可以直接从阴极吸收电子或通过H 2间接吸收电子作为能源,将CO_(2)还原为化学品。为研究表面活性剂对MES性能的影响,以基因改造的杨氏梭菌作为菌株,以非离子表面活性剂聚乙二醇(PEG)作为研究对象,对其添加量进行优化。结果表明:添加体积分数1.0%的PEG的性能最好,其乙酸和丁酸质量浓度能分别达到(0.73±0.11)和(0.18±0.01)g/L,是空白对照组(CF)的1.58和1.21倍,而添加体积分数4%的PEG会抑制微生物的生长,从而导致低的乙酸和丁酸产率。扫描电镜(SEM)和电化学分析结果显示:1.0%的PEG可以促进电极上微生物的附着,并且电催化活性也是最高的。进一步通过析氢性能和还原当量测试发现:在实验过程中,1.0%的PEG的H 2含量最高,具有高的还原当量,从而有利于CO_(2)向乙酸和丁酸的转化。通过研究添加不同体积分数的PEG对MES中产物浓度的影响,为MES中如何提高电子传递速率提供了方向。

Microbial electrosynthesis is a biocathode-driven process,where autotrophic microorganisms can directly absorb electrons from the cathode or indirectly absorb electrons through H 2 as energy to reduce CO_(2)to chemicals.In order to study the effect of surfactants on the performance of microbial electrosynthesis,transgenic Clostridium ljungdahlii was used as the strain,the non-ionic surfactant polyethylene glycol was used as the research object,and its addition amount was optimized.Results show that the performance of polyethylene glycol at 1.0%was the best.The concentrations of acetate and butyrate were(0.73±0.11)and(0.18±0.01)g/L,respectively,which were 1.58 times and 1.21 times that of the control group.The addition of 4%polyethylene glycol inhibited microbial growth,resulting in lower acetate and butyrate.Scanning electron microscope and electrochemical analysis results show that 1.0%polyethylene glycol promoted microbial adhesion on the electrode,and the electrocatalytic activity was also the highest.Furthermore,hydrogen evolution performance and reduction equivalent test results show that the 1.0%polyethylene glycol had the highest hydrogen content during the experiment,and had the highest reduction equivalent,which was conducive to the conversion of carbon dioxide to acetate and butyrate.Our findings provide a direction to improve the election transfer rate in microbia electrosythesis.