高温条件下生物炭强化丙酸与乙酸产甲烷的动力学及热力学机制  

Kinetic and thermodynamic mechanisms of methane production from propionate and acetate enhanced by biochar at high temperature

作　　者：张佩云 赵丹阳 丁丽姿 尤少文 李倩[1,2] 陈荣[1] 李玉友[2] ZHANG Peiyun;ZHAO Danyang;DING Lizi;YOU Shaowen;LI Qian;CHEN Rong;LI Yuyou(Department of Environment and Municipal Engineering,Xi’an University of Architecture and Technology 710055,China;Department of Civil and Environmental Engineering,Graduate School of Engineering,Tohoku University Sendai 980-8579,Japan)

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055 [2]东北大学工程研究生院土木与环境工程系,日本仙台980-8579

出　　处：《环境工程学报》2023年第6期1955-1966,共12页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(52070148);陕西省重点研发计划资助项目(2022KWZ-25);日本学术振兴会海外特别研究员资助项目(P20794)。

摘　　要：针对生物炭强化互营产甲烷的动力学及热力学作用机制不明晰的问题,通过乙酸、丙酸的高温降解产甲烷批次实验,结合降解产甲烷动力学、微生物生长动力学和过程热力学分析,探究了生物炭强化乙酸、丙酸互营产甲烷的增效机制。结果表明,与对照组相比,生物炭加快了乙酸、丙酸互营产甲烷过程的降解速率和产甲烷速率,乙酸与丙酸的降解速率分别提高了8.4%和3.7%,产甲烷速率分别提高了31.3%和23.1%。微生物生长分析表明,生物炭可为微生物生长提供适宜的环境,同时也能促进微生物生长,添加生物炭使得丙酸降解过程的产甲烷微生物最大比生长速率提高了113.8%。反应过程热力学分析表明,生物炭降低了乙酸与丙酸互营产甲烷过程40.6%与19.4%的氢分压,从而降低了与氢分压相关反应的自由能,推动了种间氢转移(interspecies hydrogen transfer,IHT)反应的进行。此外,生物炭显著提升了体系内的电子传递效率,这可能是由于其自身氧化还原官能团所引发的直接种间电子转移(direct interspecies electron transfer,DIET)作用导致的,这不仅可以提高反应的电子转移效率,同时也能改善热力学效能,从而推动IHT反应并进一步强化互营产甲烷。生物炭可以通过促进微生物生长、改善热力学促进IHT以及强化DIET作用,共同提升互营产甲烷过程效能。本研究结果可为生物炭在厌氧消化中进一步的实际应用提供参考。In order to address the issue that the kinetic and thermodynamic mechanism of methane production boosted by biochar is unclear,the synergistic mechanism of biochar enhanced methane production by acetate and propionate was investigated using batch tests of methane production by high temperature degradation of acetate and propionate,combined with the analysis of thermodynamic reaction kinetics,microbial growth kinetics,and batch experiments.The results showed that compared with the control group,biochar accelerated the degradation rate and methane production rate of acetate and propionate.The degradation rates of acetate and propionate increased by 8.4% and 3.7%,respectively,while the methane production rates increased by 31.3%and 23.1%,respectively.According to microbial growth studies,biochar might offer an environment that was conducive to microbial growth and microbial growth.The addition of biochar increased the maximum specific growth rate of methanogens using propionate by 113.8%.Thermodynamic analysis of the reaction process revealed that biochar decreased the hydrogen partial pressure of the syntrophic methanogenic reaction of acetate and propionate by 40.6% and 19.4%,thereby reducing the free energy of reactions related to hydrogen partial pressure and promoting the interspecific hydrogen transfer(IHT).In addition,biochar considerably increased the system's electron transfer efficiency.It might be because of the direct interspecific electron transfer(DIET)generated by its own redox functional groups,which might not only increase the reaction's efficiency in terms of electron transfer but also in terms of thermodynamic efficiency,hence promoting the IHT reaction and enhancing the syntrophic methanogenic process.In conclusion,biochar can promote the IHT process and DIET by increasing microbial growth and thermodynamic improvement,as well as improving the efficiency of the syntrophic methanogenesis process.The results of this study can provide a reference for the further practical application of biochar in a

关 键 词：互营产甲烷 挥发性脂肪酸 高温 动力学 吉布斯自由能 生物炭 

分 类 号：X705[环境科学与工程—环境工程]