四种含木质纤维素原料在牛粪液中的酸化

为了有效转化木质纤维素原料,提高其资源化、能源化利用潜力,研究了干稻秸、玉米秸、草坪草、新鲜状态玉米秸和风干玉米秸这4种木质纤维素原料在牛粪液环境中的酸化发酵规律。监测发酵过程,以质量减少率分析了原料降解效率,以溶解性化学需氧量(soluble chemical oxygen demand,SCOD)评价酸化产物的积累。结果表明,4种原料在牛粪液中的降解效果明显,规律不同。草坪草的质量减少最快且最多,质量减少率为73.25%。稻秸在10d时与草坪草质量减少率均达到50%,总质量减少率为72.01%。鲜玉米秸在18d时质量减少率为68.36%,接近草坪草和稻秸,总质量减少率为71.64%。干玉米秸总质量减少率最低,为57.6%;木质纤维素总量的降解效率依次为:稻秸>草坪草>鲜玉米秸>干玉米秸。其成分中,各原料半纤维素的降解效率最好,其次为纤维素和木质素;干、鲜玉米秸产生有机酸种类和数量较多,稻秸、草、鲜玉米秸、干玉米秸的产生挥发性脂肪酸(volatile fatty acid,VFA)总量最大值依次为3.91、0.54、7.16、10.99g/L。将酸化产物作为厌氧发酵原料角度分析,稻秸和草坪草在酸化过程中可实现SCOD积累,对厌氧发酵有利,而干、鲜玉米秸的酸化作用对厌氧发酵不利。

Acidification of four kinds of lignocelluloses materialsin cow dung liquid

In this study, the law of acidification of dry rice straw, turf grass, dry corn straw and fresh corn straw in cow dung liquid was investigated. The property change of digestive solution during digestion process was evaluated, the rate of weight loss and soluble chemical oxygen demand (sCOD) change were used to analyze the efficiency of raw materials degradation and acidified product respectively. The results indicated that the degradation effects of four kinds of lignocelluloses materials in cow dung liquid were obvious, while the processes were different. The total weight loss of turf grass was the fastest and most with 73.25%; The weight loss of dry rice straw was 50%, close to that of turf grass with total loss of 72.01% on the 10th day; The weight loss of fresh corn straw was also close to that of turf grass and dry rice straw, which reached up to 68.36% on the 18th day and 71.64% by the end; The dry corn straw had the smallest weight loss of 57.6%. The decomposition rate of lignocelluloses of four kinds of materials were in order of rice >turf grass>fresh con straw>dry corn straw, and the hemicelluloses decomposition rates were best of all, cellulose and lignin were followed. The volatile fat acids produced by fresh or dry corn straw were more than that of rice straw and turf grass, the maximum total VFA of rice straw, turf grass, fresh corn straw and dry corn straw were in order of 3.91, 0.54, 7.16 and 10.99 g/L. The accumulation of acidification product was achieved from dry rice straw and turf grass, which was favorable, but the dry or fresh corn straw were unfavorable.