冻融交替对小麦秸秆降解特性的影响

Effects of Freeze-thaw Alternation on Degradation Characteristics of Wheat Straw

针对未来星球基地中植物类固废的资源化循环利用问题,以受控生态生保系统中的主要固废小麦秸秆为实验材料,探究了冻融交替对其降解特性的影响。选取冷冻温度、冷冻时间、冻融次数3个影响因子,开展了三因素三水平正交实验L_(9)(3~4)。测定秸秆冻融前后可溶性总碳、总氮含量的变化,根据结果选取部分组别进一步开展微观形貌观察、纤维素结晶度以及化学结构特性的测定。结果表明:冻融交替会提高小麦秸秆的可溶性总碳、总氮含量,改变秸秆表面的微观形貌,提高纤维素结晶度,打断秸秆中的-OH、C-H、C-O等键。此外,在冷冻温度-80℃,冷冻时间4 h,冻融次数3次的条件下,小麦秸秆中可溶性总碳、总氮含量最高,比对照组分别提高了51.4%和74.4%,说明在此条件下小麦秸秆各降解特性改变最大,更有利于其后续的生物降解。

Targeting the problem of resource recycling of plant solid waste in the future extraterrestrial base,wheat straw,the main solid waste in the Controlled Ecological Life Support System,was used as the experimental material to investigate the effect of freeze-thaw alternation on its degradation characteristics.Three influencing factors of freezing temperature,freezing time,and the number of freezing and thawing were selected to carry out a three-factor,three-level orthogonal experiment L_9(3~4).The changes of total soluble carbon and total soluble nitrogen contents of straw before and after freezing-thawing alternation were determined.According to the results,some groups were selected for further micro-morphological observation,crystallinity of cellulose and chemical structural properties.The results showed that the alternation of freezing and thawing increased the contents of total soluble carbon and total soluble nitrogen of wheat straw,changed the microscopic morphology of the straw surface,increased the crystallinity of cellulose,and broke the bonds of-OH,C-H and C-O in the straw.In addition,under the conditions of-80 ℃,4 h,and 3 times,the total soluble carbon and total soluble nitrogen contents of wheat straw were higher,which were 51.4% and 74.4% higher than that of the control group,respectively.These results indicated that the degradation characteristics of wheat straw changed the most under these conditions,which was more conducive to its subsequent biodegradation.