有机酸预处理对麦秸理化特性及生物产沼气的影响

EFFECTOFORGANICACIDSPRETREATMENTONPHYSICO-CHEMICAL PROPERTY AND BIOGAS PRODUCTION OF WHEAT STRAW

以乙酸、丙酸和丁酸不同混合比例配制的混合酸预处理麦秸,研究预处理对麦秸理化特性、物质结构及厌氧生物产沼气的影响。结果表明:有机酸预处理可促进麦秸有机物的溶出。预处理后,麦秸水浸提液pH值均小幅减小,水浸提液COD浓度大幅增大,乙酸∶丙酸∶丁酸质量比为7∶3∶1.5(T2)、6∶5∶3(T3)、4∶1∶2(T4)和2∶1∶1(T5)的处理分别增加了78.36%、40.79%、52.40%和76.25%,水处理(T1)降低10.28%。对麦秸纤维素、木质素、官能团均无明显影响,但预处理后麦秸纤维素结晶度增强,对纤维素、半纤维素及木质素影响的顺序依次为:半纤维素>纤维素>木质素,其中T3和T5处理对麦秸半纤维素的影响最大,较处理前分别降低18.21%和16.96%,明显高于T2和T4的3.12%和5.58%。厌氧发酵产气的结果表明:无论是水还是有机酸预处理对麦秸产气速率、平均甲烷含量均无明显影响,TS产气量较处理前均不同程度降低。

Wheat straw was pretreated by mixed acid with different mixing ratio of acetic acid, propionic acid and butyric acid, the effect of pretreatment on physico-chemical property, structure of the matter and anaerobic biotransformation biogas was studied. The results show that the organic acid pretreatment of wheat straw can promote organic matter dissolution. After pretreatment, the pH of the aqueous extracts of wheat straw were slightly decreased, the COD concentration of the aqueous extracts was significantly increased, mass ratio of acetate： propionate： butyrate were 7 ： 3：1.5 （T2）, 6：5：3 （T3）, 4：1：2 （T4） and 2：1：1 （T5）, treatment were increased by 78.36%, 40.79%, 52.40% and 76.25%, respectively, water treatment （T1） reduced 10.28%. Wheat straw cellulose, lignin, functional groups were not affected obviously, but the wheat straw cellulose crystallinity was enhanced after pretreatment. The effect on cellulose, hemicellulose and lignin was hemicellulose〉 cellulose〉 lignin according to the size. Wherein the effects of T3 and T5 treatment on wheat straw hemicellulose were the largest, decreased 18.21% and 16.96% than before treatment, respectively, was higher than 3.12% and 5.58% for T2 and T4. The anaerobic digestion results show that there were no obvious affect on improvement of biogas yield and average methane content by water or organic acids pretreatment and TS biogas yield was decreased slightly than without treatment.