施用猪炭对土壤吸附Pb^(2+)的影响

Dead pig-derived biochar treatments and soil adsorption of Pb^(2+)

利用650℃高温炭化炉热裂解病死猪,制成生物质炭(猪炭);通过批处理恒温振荡平衡法探索施用不同质量分数(0,1%和5%)的猪炭对熟化红壤和新垦红壤吸附溶液中铅离子(Pb^(2+))的影响。结果表明:施用猪炭能显著提高土壤pH值和阳离子交换量(P<0.05);土壤对Pb^(2+)的吸附量随猪炭施用量的增加而增大,施用猪炭的熟化红壤吸附容量为12.71～14.49 mg·g^(-1),较未施加猪炭对照提高了12.2%～27.9%;施用猪炭的新垦红壤吸附容量为7.15～11.45mg·g^(-1),较未施加猪炭对照提高了39.7%～123.8%,说明对有机质质量分数较低的新垦红壤施加猪炭,土壤吸附Pb^(2+)性能的提高效果更明显。与未施猪炭的对照相比,施加质量分数为1%的猪炭时,熟化红壤和新垦红壤对Pb^(2+)吸附能力分别提高1.21倍和1.40倍,施加量为5%时,熟化红壤和新垦红壤对Pb^(2+)吸附能力分别提高1.28倍和2.24倍。由此认为猪炭有助于土壤对Pb^(2+)的吸附和固定,施用质量分数5%的猪炭能有效提高土壤对Pb^(2+)的吸附。

A laboratory study was conducted to evaluate the effects of dead pig biochar(PB)on adsorption o lead ions(Pb2+)in two soils with contrasting properties.A batch equilibration method[(25±1)℃,180 r·min-124 h]was used to investigate the adsorption of Pb2+on soils amended with biochar derived from dead pigs pyrolyzed at a peak temperature of 650℃.Two soils,including a vegetable garden soil with high organic matter content and an uncultivated soil with low organic matter content,which were adjacent in village in Lin’an,the experimental samples(0-20 cm)were chosen randomly,natural air drying and sifting,were treated with biochars mixed at three application rates(0,1%,and 5%,w/w),6 treatments in all,3 repetitions in each treatment,soils without biochar were taken as the control.ANOVA and LSD(least significant difference)were used to statistic analysis.Langmuir isotherms were used to describe the results of adsorption processes.Results showed that both soil pH and cation exchange capacity values significantly(P<0.05)increased with the biochar treatments.The Pb2+adsorption capacity(Qm)increased in both soils when they were amended with biochars,and significantly increased(P<0.05)with the increase of biochar dosage.In comparison to the control,Qmvalues of the soil with high organic matter content ranged from 12.71 to 14.49 mg·g^-1and increased12.2%-27.9%;whereas,the Qmvalues of the soil with low organic matter content ranged from 7.15 to 11.45mg·g^-1and increased 39.7%-123.8%.When 1%pig biochar was applied to soils,adsorption capacity of Pb2+in the high organic matter content soil increased 1.21 times and in the low organic matter soil increased 1.40times;when 5%of pig biochar was applied in the two types of soils,the Qmincreased 1.28 times in the high organic matter content soil and 2.24 times in the low organic matter soil.Therefore,pig biochar was a suitable adsorption material for Pb2+immobilization in soils,particularly at the 5%application rate.[Ch,2 fig.3 tab40 ref.].