活性炭和蒙脱石对猪粪好氧堆肥过程中铜和锌钝化效果研究

Study on the passivation effect of activated carbon and montmorillonite on copper and zinc during aerobic compostingprocess of pig manure

为了探究在猪粪堆肥过程中添加不同剂量活性炭与蒙脱石对猪粪中重金属的钝化效果,试验采用猪粪和粉碎玉米秸秆为堆肥底物,以活性炭和蒙脱石为钝化剂进行好氧堆肥研究,即将堆肥底物分为H1、H2、H3、M1、M2、M3、对照(CK)组,其中H1、H2、H3、M1、M2、M3组分别添加1%、2%、5%(占干物质的比例)的活性炭及5.0%、7.5%、10.0%(占干物质的比例)的蒙脱石,CK组不添加活性炭和蒙脱石,每组3个重复,好氧堆肥21 d,分别在堆肥前和堆肥第7,14,21天测定堆肥样品含水率和pH值,在堆肥第21天测定堆肥样品种子发芽率,以及在堆肥前和堆肥第21天测定堆肥样品中不同形态重金属铜(Cu)和锌(Zn)含量、分配率和钝化率。结果表明:随着堆肥时间的延长,各组含水率呈下降趋势,在堆肥第21天时,各组含水率与堆肥前相比均显著降低(P<0.05);随着堆肥时间的延长,各组pH值均大致呈现先增高后降低的趋势,在堆肥第21天时,除H1组pH值显著高于CK组外(P<0.05),其余各组与CK组均差异不显著(P>0.05);堆肥结束时(堆肥第21天),除CK组以外,其余各组堆肥已达到腐熟状态;Cu的可交换态钝化率从大到小依次为M3组>M2组>H2组>M1组>H3组>H1组>CK组,其中M2与M3组Cu钝化率分别52.52%和63.36%,显著高于其他组(P<0.05);可交换态Zn的钝化率从大到小依次为M2组>M3组>M1组>CK组>H3组>H2组>H1组,其中M2组钝化率显著高于其他组(P<0.05),M2组和M3组的钝化率分别为20.00%和16.60%。说明在猪粪好氧堆肥过程中添加7.5%~10.0%的蒙脱石对猪粪中的重金属有很好的钝化效果。

In order to explore the passivation effect of adding different doses of activated carbon and montmorillonite on heavy metals during pig manure composting,pig manure and crushed corn straw were used as composting substrates,and activated carbon and montmorllonite were used as passivating agents for aerobic composting research,that is,the compost substrates were divided into H1,H2,H3,M1,M2,M3 and the control(CK)groups,in which H1,H2,H3,M1,M2,M3 groups were added with 1%,2%and 5%activated carbon and 5.0%,7.5%,and 10.0%montmorillonite,respectively,according to the percentage of dry matter,while CK group was not supplemented with activated carbon and montmorillonite.There were three replicates in each group.The aerobic composting lasted for 21 days.The moisture content and pH value of the compost samples were measured before composting and on the 7th,14th,and 21st days of composting,and the seed germination rate of the compost samples were measured on the 2lst day of composting,as well as the content,distribution rate,and passivation rate of different forms of heavy metals Cu and Zn in the compost samples were determined before composting and on the 2lst day of composting.The results showed that the moisture content of each group decreased with the extension of composting time.On the 21st day of composting,the moisture content in each group was significantly decreased compared with that before composting(P<0.05).With the extension of the composting time,the pH value of each group roughly increased first and then decreased.On the 21st day of composting,the pH value in the Hl group was significantly higher than that in the CK group(P<0.05),but there was no significant difference between the other groups and the CK group(P>0.05).At the end of composting(the 21st day of composting),the compost of other groups had reached the state of decomposition except for CK.The passivation rate of exchangeable Cu in descending order was M3 group>M2 group>H2 group>M1 group>H3 group>H1 group>CK group,and the passivation rate of Cu in the M2 and M3 groups were 52.52%and 63.36%,respectively,which was significantly higher than that in other groups(P<0.05).The passivation rate of exchangeable Zn in descending order was M2 group>M3 group>M1 group>CK group>H3 group>H2 group>H1 group,and the passivation rate in the M2 group was significantly higher than that in the other groups(P<0.05);the passivation rates in the M2 group and M3 group were 20.00%and 16.60%,respectively.The results indicated that the addition of 7.5%~10.0%montmorillonite in the aerobic composting process of pig manure had a good passivation effect on the heavy metals in it.