摘要
以葡萄糖为唯一碳源,通过调节进水基质碱度提高反应器内部pH值,使生物制氢反应器内的发酵类型发生连续转化,重点考察了发酵菌群从乙醇型发酵演替为丁酸型发酵的转化规律,并对液相末端产物、产氢速率、氧化还原电位(ORP)以及生物量的变化进行了比较分析。在进水有机负荷恒定的情况下,乙醇型发酵经15d转化为丁酸型发酵,转化顺序为乙醇型-丙酸型-混合酸型-丁酸型。乙醇型发酵在稳定运行的情况下比产氢速率平均为22mol·kg^(-1)·d^(-1),明显高于丁酸型的12mol·kg^(-1)·d^(-1),丙酸型和混合酸型比产氢速率较低,但酸化率高于乙醇型和丁酸型,酸化率在混合酸发酵时达到最高,为85．6%。从投碱量上看,丁酸型发酵对碱的需求量(NaOH)为乙醇型的7．5倍。反应体系pH和ORP呈现负相关性,由最初的4．2、-476mV转为6．8、-562mV。
Fermentative types were changed continuously in hydrogen production reactor by adjusting inlet water alkalinity to increase its pH level utilizing glucose as exclusive carbon source. Conversion role was studied for fermentative microflora from ethanol type to butyric acid type. Terminal aqueous productions, hydrogen production rate, ORP and biomass were analyzed simultaneously. In the instance of constant organic loading for inlet water ethanol fermentative type turned to butyric acid type after 15 days. Conversion sequence was ethanol type,propionic acid type, mixed acid type,butyric acid. In stable operation condition the average specific hydrogen production rate was 22 mol· kg^-1· d^-1 for ethanol fermentation but that for butyric acid fermentation was 12 mol·kg^-1·d^-1. The specific hydrogen production by ethanol fermentation was remarkably higher than that by butyric acid type. Hydrogen production rates for propionic acid and mixed acid types were relatively low but the acidification rate was high for mixed acid type about 85.6%. From the alkalinity dosage point of view, the amount of requisite alkalinity for maintaining butyric acid fermentation was 7.5 times bigger than that for ethanol fermentation. The pH level was negatively corelative to ORP and the original pH and ORP was 4.2 and -476mV but turned to 6.8 and -562mV finally.
出处
《净水技术》
CAS
2006年第6期55-59,共5页
Water Purification Technology
基金
国家自然科学基金(30470054)
国家863项目(2001AA515030)
