水生植物酸碱预处理对厌氧发酵联产氢气-甲烷的影响

Hydrogen and methane from pretreatment of acid and base on aquatic plants via anaerobic fermentation

采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇,通过厌氧发酵动力学分析、还原糖变化及微观结构解析,研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明,酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高,酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳,最大氢气、甲烷含量分别达42.65%和52.82%,产氢气速率为4.118 mL/h,产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳,最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明,酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构,有效增加植物与微生物接触面积,有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。

The effect of co-production hydrogen and methane via anaerobic fermentation by acid/alkali pre- treatment of aquatic plants was investigated. The emerged plant of reeds and submerged plant of potamogeton pectinatus obtained from Wuliangsuhai Lake. Anaerobic fermentation kinetics, utilization of reducing sugar and microstructure of aquatic plants were analyzed. Our results show that both the cumulative biogas production and the content of hydrogen and methane increased after acid/alkali pretreatments with higher effect of acid pretreat- ment than that of alkali pretreatment. The effect of potamogeton pectinatus dealt with 0.5 mol/L HC1 is the opti- mal, with the maximal content of hydrogen and methane being 42.65% and 52.82% , respectively, and the pro- duction rates of hydrogen and methane being 4. 118 mL/h and 14. 199 mL/h, respectively. The effect of reed dealt with 1 mol/L HC1 is the optimal, with the maximal content of hydrogen and methane being 32.22% and 65.26% , respectively. The results obtained by means of SEM show that the acid/alkali pretreatments may obvi- ously damage the cellulose structure of aquatic plants, and effectively increase the contact area between plants and microbes, which is beneficial to the rapid start-up and stable operation of the co-production in anaerobic fer- mentation process.