School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Environ Sci Technol. 2011 Jun 1;45(11):4884-9. doi: 10.1021/es103752u. Epub 2011 May 4.
Biochar produced from waste biomass is increasingly being recognized as a green, cost-effective amendment for environmental remediation. This work was to determine the ability of biochar to immobilize heavy metal Pb and organic pesticide atrazine in contaminated soils. Biochar prepared from dairy manure was incubated with contaminated soils at rates of 0, 2.5, and 5.0% by weight for 210 d. A commercial activated carbon (AC) was included as a comparison. The AC was effective in immobilizing atrazine, but was ineffective for Pb. However, biochar was effective in immobilizing both atrazine and Pb and the effectiveness was enhanced with increasing incubation time and biochar rates. After 210 d, soils treated with the highest rate of 5.0% biochar showed more than 57% and 66% reduction in Pb and atrazine concentrations in 0.01 M CaCl(2) extraction, respectively. Lead and atrazine concentrations in the toxicity characteristic leaching procedure solutions were reduced by 70-89% and 53-77%, respectively. Uptake of Pb and atrazine by earthworms (Eisenia fetida) was reduced by up to 79% and 73%. Phosphorus originally contained in biochar reacted with soil Pb to form insoluble hydroxypyromorphite Pb(5)(PO(4))(3)(OH), as determined by X-ray diffraction, which was presumably responsible for soil Pb immobilization, whereas atrazine stabilization may result from its adsorption by biochar demonstrated by the significant exponential decrease of extractable atrazine with increasing organic C in biochar (r(2) > 0.97, p < 0.05). The results highlighted the potential of dairy-manure biochar as a unique amendment for immobilization of both heavy metal and organic contaminants in cocontaminated soils.
生物炭由废生物质制成，越来越被认为是一种绿色、经济有效的环境修复改良剂。本研究旨在确定生物炭固定污染土壤中重金属 Pb 和有机农药莠去津的能力。以牛粪为原料制备的生物炭，按重量比 0、2.5 和 5.0%的比例与污染土壤混合，培养 210 天。同时，还将商业活性炭（AC）作为对比。AC 能有效固定莠去津，但对 Pb 无效。然而，生物炭对莠去津和 Pb 的固定效果都很好，并且随着培养时间和生物炭添加量的增加，固定效果增强。210 天后，用最高添加量 5.0%的生物炭处理的土壤，在 0.01 M CaCl2 提取液中，Pb 和莠去津浓度分别降低了 57%和 66%以上。毒性特征浸出程序溶液中 Pb 和莠去津的浓度分别降低了 70-89%和 53-77%。土壤中添加生物炭，可降低蚯蚓（赤子爱胜蚓）对 Pb 和莠去津的摄取量，最大降幅分别达 79%和 73%。生物炭中原来含有的磷与土壤中的 Pb 反应，生成不溶性羟磷铅矿 Pb(5)(PO(4))(3)(OH)，这可能是导致土壤中 Pb 固定的原因，而莠去津的稳定可能是由于其被生物炭吸附，这可以从生物炭中可提取莠去津与有机 C 呈显著指数下降关系中看出（r2>0.97，p<0.05）。研究结果突出了牛粪生物炭作为一种独特的改良剂，可同时固定污染土壤中的重金属和有机污染物。
