温度和初始pH对农业固体废物暗发酵产氢的影响

以猪粪、鸡粪、玉米秸秆、餐厨垃圾和厨余垃圾等5种农业固体废物为底物，采用修正的Gompertz模型，研究了典型农业固体废物暗发酵产氢动力学和代谢产物变化规律，探讨了不同温度和初始pH条件下的主要产氢代谢途径。结果表明：温度和初始pH对农业固体废物暗发酵产氢具有显著影响；高温组累积产气量和氢气百分含量显著高于中温组。在55 ℃高温且pH为6.0的条件下，餐厨垃圾暗发酵产氢效果最佳，累积产气量和氢气百分含量最大，为1 100 mL和73.58%，最大产氢速率和产氢潜力分别为37.11 mL·h⁻¹和660.30 mL；厨余垃圾暗发酵产氢效果次之，鸡粪产氢潜力最差。在暗发酵产氢末期，以鸡粪为底物的代谢产物的氨氮浓度最高，过高的氨氮浓度可能抑制了产氢过程。VFA分析表明：不同底物和条件下丁酸浓度均最高，且含有少量乙醇、乙酸、丙酸等；暗发酵产氢代谢途径是以丁酸型发酵为主的混合型发酵。通过温度、初始pH等非生物性控制因素的优化调控，显著提高了农业固体废物暗发酵产氢潜力和底物利用效率，为生物制氢的技术研发与工程应用提供参考。

Effects of temperature and initial pH on the hydrogen production by dark fermentation of agricultural solid waste

In this study, five kinds of typical agricultural solid wastes including pig feces, chicken feces, corn stover, food waste and kitchen waste were taken as substrates, and the effects of temperature and initial pH on their hydrogen production potential by dark fermentation were determined by using the modified Gompertz model, and the main pathways of hydrogen production and metabolism were analyzed. The results showed that temperature and initial pH had significant effects on the hydrogen production by dark fermentation of agricultural solid wastes. The cumulative gas production and hydrogen content in high temperature group were significantly higher than those in medium temperature group. At high temperature of 55 ℃ and pH 6.0, the best dark fermentation effect of food wastes was achieved, and the highest cumulative gas production and hydrogen content were obtained with respective value of 1 100 mL and 73.58%, and the maximum hydrogen production rate and hydrogen production potential were 37.11 mL·h−1 and 660.30 mL, which were followed by kitchen waste, while chicken feces had the worst hydrogen production potential. The concentration of ammonia nitrogen was the highest at the end of hydrogen production by dark fermentation of chicken feces. Excessive concentration of ammonia nitrogen might inhibit the hydrogen production process. VFA analysis showed that the concentration of butyric acid was the highest under different substrates and conditions, and it also contained a small amount of ethanol, acetic acid, propionic acid. The hydrogen production pathway was a mixed fermentation based on butyric acid fermentation. Through optimizing and controlling the non-biological control factors such as temperature and initial pH, the potential of hydrogen production by dark fermentation of agricultural solid wastes and the utilization efficiency of biomass were significantly improved, which provided a theoretical basis for the research and development of biological hydrogen production technology and engineering application.