酸碱预处理辣椒秸秆与羊粪混合厌氧发酵特性

为实现辣椒秸秆等农业废弃物的资源化利用,通过批式厌氧发酵试验,分别研究了经不同体积分数(2%、4%、6%、8%)的H₂SO₄和不同质量分数(2%、4%、6%、8%)的Ca(OH)₂预处理的辣椒秸秆与羊粪混合厌氧发酵的产甲烷特性。结果表明,随着预处理中Ca(OH)₂质量分数的升高,辣椒秸秆与羊粪混合厌氧发酵的甲烷产率升高,经8%Ca(OH)₂预处理的甲烷产率最高(188.56 mL·g^-1),显著(P<0.05)高于其他处理,较对照提高了61.26%。但随着预处理中H₂SO₄体积分数的升高,辣椒秸秆与羊粪混合厌氧发酵的甲烷产率降低,且显著(P<0.05)低于对照。利用修正的冈珀茨(Gompertz)模型能较好地拟合各处理的产甲烷过程,其中,经Ca(OH)₂预处理的最大甲烷产率(V_m)值较大,说明Ca(OH)₂预处理辣椒秸秆能有效提高其与羊粪混合发酵的水解速率。酸、碱预处理均对辣椒秸秆木质纤维素有一定的降解作用,其中,Ca(OH)₂预处理的降解效果更好。

Effect of acid and alkali pretreatment on anaerobic co-digestion characteristics of pepper straw and sheep manure

To realize resource utilization of agricultural wastes, batch anaerobic fermentation experiments were performed to compare the effects of H₂SO₄ pretreatment (volume fraction of 2%, 4%, 6%, 8%) and Ca(OH)₂ pretreatment (mass fraction of 2%, 4%, 6%, 8%) of pepper straw on the characteristics of methane production during anaerobic co-digestion of pepper straw and sheep manure. It was shown that methane yield in the anaerobic fermentation increased with higher Ca(OH)₂ mass fraction in the pretreatment, and the maximum methane yield of 188.56 mL·g^-1 was achieved with 8% Ca(OH)₂ pretreatment, which was significantly (P<0.05) higher than those of the other treatments, and the methane yield was 61.26% higher than that of control. In contrast, the increased volume fraction of H₂SO₄ in pretreatment resulted in reduced methane yield, all of which were significantly (P<0.05) lower than that of control. The modified Gompertz model could fit the methanogenesis process. The maximum methane yield (V_m) was higher with Ca(OH)₂ pretreatment, which indicated that the pretreatment of pepper straw with Ca(OH)₂ could effectively increase the hydrolysis rate. Moreover, both acid and alkali pretreatment exhibited a certain degradation effect on the lignocellulose of pepper straw, yet Ca(OH)₂ pretreatment showed higher degradation effect.