重金属在猪粪堆肥过程中的化学变化

 运用DTPA浸提、化学分级提取、透析及G-75凝胶色谱分离等方法研究不同堆肥工艺及不同原料对猪粪混合堆肥重金属化学形态的影响及其机理.结果表明,堆肥后,树叶+翻DTPA-Cu、DTPA-Zn、DTPA-Pb浓度占其金属总浓度比例的减少量分别为3.36%、8.63%和4.68%,木糠+通翻分别为3.35%、7.45%和4.36%,均显著大于木糠+翻;树叶+翻有机态Cu的增加量为4.49%,木糠+通翻残渣态Zn的增加量为8.42%,均显著大于木糠+翻;木糠+翻及树叶+翻两处理<8000Da组分Zn增加,>25000Da组分Zn减少,而木糠+通翻的变化正好相反;Cu更易与大分子腐殖质组分结合,而且结合较紧密;Zn更易与小分子腐殖质组分结合,但结合不紧密.总的来说,加入树叶或采用强制通风结合翻堆的通风方式有助于降低猪粪堆肥的重金属活性.

Chemical changes of heavy metals in the process of pig manure composting

DTPA soak extract, chemical fractionation extract, dialysis and G-75 gel chromatography separation techniques were utilized to study the influence of chemical form of heavy metals and its mechanism in the pig manure co-composting with different composting technologies and raw materials. After composting, the concentrations of DTPA-Cu, DTPA-Zn and DTPA-Pb of leave turning occupied the decrease amounts of the total metal concentration ratio were 3.36%, 8.63% and 4.68% respectively; those of sawdust aeration turning were 3.35%, 7.45% and 4.36%, respectively, all higher than those of sawdust turning obviously. The amount of organic Cu of leave turning increased 4.49%; and that of residual Zn of sawdust aeration turning increased 8.42%, all higher than that of sawdust turning obviously. Component Zn increased in <8000Da sawdust turning and leave turning, and decreased in >25000Da; while the change of sawdust aeration turning was just the adverse. Cu combined more easily and closely with large molecular humic substance component; while Zn combined easily but weakly with small molecular humic substance component. In general, addition of leave or adoption of forced aeration combined with turning helped to decrease the heavy metals activity of pig manure composting.