冻融循环对猪粪粒径及有机质变化的影响

为探究冻融过程对畜禽粪便的粒径分布及其有机质组成的影响,通过湿筛法分析了经历冻融循环前后猪粪粒径分布的变化,并采用傅里叶变换红外光谱和13C核磁共振光谱对冻融循环处理前后猪粪中提取的有机质组分(溶解性有机质、腐植酸、木质素和蛋白质)的结构进行了表征。结果表明:冻融循环使猪粪的大颗粒发生破碎,并且随着冻融循环次数的增加,破碎的效果也更加明显,经过30次冻融循环处理的猪粪与未经冻融的样品相比,>1000μm的颗粒含量降低了6.73%,38~75μm和<38μm的颗粒含量则分别增加了5.94%和6.13%;冻融循环使猪粪的总有机质含量降低,溶解性有机质含量升高,不饱和有机质增加,并产生了更多的氨基酸以及—COO—和C=O基团。其中,溶解性有机质的芳香度降低,腐植酸和木质素的芳香度基本不变,而蛋白质的芳香度增加。研究表明,冻融循环可能会增加畜禽粪便在自然环境中的溶解度和流动性。

Effects of freeze-thaw cycles on particle size, structure and organic matter composition of pig manure

To explore the effects of freeze-thaw cycles on particle size distribution and organic matter composition of livestock manure,changes in the particle size distribution of pig manure before and after freeze-thaw cycle treatments were studied using the wet screening method;organic matter components(dissolved organic matter,humic acid,lignin,and protein)were extracted from pig manure before and after freeze-thaw cycle treatments and their structure was characterized using Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance spectroscopy.The results showed that freeze-thaw cycles resulted in the breaking of large particles of pig manure,and the breaking effect became significant with an increase in freeze-thaw cycle times.Compared with samples without freeze-thaw cycle treatment,particlesize>1000μm in pig manure treated with 30 freeze-thaw cycles decreased by 6.73%,and particlesize of 38~75μm and<38μm increased by 5.94% and 6.13%,respectively.Freeze-thaw cycles reduced the total organic matter content and increased the dissolved and unsaturated organic matter content of pig manure.Moreover,pig manure produced more amino acids and —COO—and C=O functional groups after freeze-thaw cycle treatment.Aromatic degree of dissolved organic matter decreased,remained unchanged for humic acid and lignin,and increased for protein.Studies have shown that freeze-thaw cycles may increase the solubility and mobility of livestock manure in natural environment.