初始pH对木薯酒精废水高温厌氧产氢的影响

Effect of Initial pH on Thermophilic Fermentative Hydrogen Production From Cassava Ethanol Wastewater

摘要:

通过间歇实验，考察了初始pH(4.0~10.0)对木薯酒精废水高温(60℃)厌氧产氢的影响.结果表明,初始pH 6.0为高温厌氧产氢的最佳值,累积产氢量为383 mL,单位基质产氢量为70 mL·g-1.挥发性有机酸(VFA)和乙醇的总量随着pH的升高而升高,乙酸的含量越来越大,但丁酸始终占优势.接种污泥在90℃的水浴中加热1 h不能有效地抑制产甲烷菌和同型产乙酸菌的活性,当初始pH 在6.0~10.0时,发现不同程度的氢消耗,并且在初始pH 9.0和10.0时,发酵末期均检测到甲烷.发酵过程中对底物变化的跟踪分析表明,氢气主要在丁酸生成过程中产生,与乙酸关系不大.

Abstract:

The effect of initial pH(4.0~10.0) on thermophilic fermentative hydrogen production from cassava ethanol wastewater was investigated in batch experiments.Results show maximum hydrogen product (383 mL) is obtained at initial pH 6.0 and the corresponding hydrogen yield is 70 mL·g-1.The total amount of VFA /ethanol and the proportion of acetic acid in the VFA increase with the increase of pH.The distribution of aqueous products is always dominated by butyrate.The heat-pretreatment at 90℃ for 1h cannot completely inhibit the activities of methanogenic bacteria and homoacetogenic bacteria.Hydrogen consumption at different degrees was observed at initial pH 6.0~10.0,and methane was detected at initial pH 9.0~10.0 during the fermentative process.The degradation of substrates in cassava ethanol wastewater and fermentative products further demonstrate that the hydrogen is generated from the production of butyrate,resulted from the carbohydrate degradation.