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垃圾堆肥富含N、P、K、有机质等植物所需的营养物质,但同时也含有大量的重金属,需要钝化处理。纳米炭黑具有吸附性,在钝化修复重金属方面具有应用前景;但纳米炭黑是疏水性的非极性吸附剂,为了提高其钝化能力,需进行改性处理。本实验采用2种氧化性无机酸、酸性高锰酸钾、3种无机碱对纳米炭黑进行了改性处理,并按5%的比例添加到垃圾堆肥产品中,研究了改性纳米炭黑对堆肥重金属不同形态含量的影响。结果表明,改性纳米炭黑均可显著降低重金属的可交换态及碳酸盐结合态比例,其中,KMnO4改性纳米炭黑对Cr、Pb最为有效,分别比对照降低了71.13%和73.48%;而HNO3改性纳米炭黑使Cu和Zn的可交换态及碳酸盐结合态比例分别比对照降低了67.67%和74.33%。另外,3种氧化改性纳米炭黑降低了Fe/Mn氧化物结合态重金属含量,增加有机物及硫化物结合态含量,而3种碱改性纳米炭黑的结果正好相反。改性纳米炭黑明显降低了堆肥结合态重金属的总含量,增加了残渣态重金属的含量,使重金属从植物易吸收态向不易吸收态转化。
Garbage compost is rich in N, P, K, nutrients required by the organic matter and other plants, but also contains a lot of heavy metals, the need for passivation. Nano-carbon black has adsorbability, and has potential applications in passivating and repairing heavy metals. However, nano-carbon black is a hydrophobic non-polar adsorbent. In order to improve its passivation ability, it needs to be modified. In this experiment, two kinds of oxidative inorganic acid, acid potassium permanganate, three kinds of inorganic alkali were used to modify the nano-carbon black and added to the composting products at a rate of 5%. The effects of modified nano-carbon black Effect of different forms of heavy metals in composting. The results showed that the modified nano-carbon black can significantly reduce the exchangeable state of heavy metals and the ratio of carbonate bound state, of which KMnO4 modified nano-carbon black is the most effective Cr, Pb, respectively, 71.13% and 73.48% While that of HNO3 modified carbon black reduced the exchangeable and carbonate bound states of Cu and Zn by 67.67% and 74.33% respectively compared with the control. In addition, the three kinds of oxidized modified carbon blacks reduced the contents of bound heavy metals in Fe / Mn oxides and increased the contents of organic compounds and sulfide bounds. The results of the three kinds of alkali modified carbon blacks were the opposite. The modified nano-carbon black significantly reduces the total content of heavy metals in composting and increases the content of heavy metal in the residue so that the heavy metals can be transformed from easily-absorbed plants to less-readily-absorbable ones.