Rajapaksha Anushka Upamali, Ahmad Mahtab, Vithanage Meththika, Kim Kwon-Rae, Chang Jun Young, Lee Sang Soo, Ok Yong Sik
Korea Biochar Research Center and Department of Biological Environment, Kangwon National University, Chuncheon, Republic of Korea.
Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, Sri Lanka.
Environ Geochem Health. 2015 Dec;37(6):931-42. doi: 10.1007/s10653-015-9694-z. Epub 2015 Mar 21.
High concentration of toxic metals in military shooting range soils poses a significant environmental concern due to the potential release of metals, such as Pb, Cu, and Sb, and hence requires remediation. The current study examined the effectiveness of buffalo weed (Ambrosia trifida L.) biomass and its derived biochars at pyrolytic temperatures of 300 and 700 °C, natural iron oxides (NRE), gibbsite, and silver nanoparticles on metal immobilization together with soil quality after 1-year soil incubation. Destructive (e.g., chemical extractions) and non-destructive (e.g., molecular spectroscopy) methods were used to investigate the immobilization efficacy of each amendment on Pb, Cu, and Sb, and to explore the possible immobilization mechanisms. The highest immobilization efficacy was observed with biochar produced at 300 °C, showing the maximum decreases of bioavailability by 94 and 70% for Pb and Cu, respectively, which were attributed to the abundance of functional groups in the biochar. Biochar significantly increased the soil pH, cation exchange capacity, and P contents. Indeed, the scanning electron microscopic elemental dot mapping and X-ray absorption fine structure spectroscopic (EXAFS) studies revealed associations of Pb with P (i.e., the formation of stable chloropyromorphite [Pb5(PO4)3Cl]) in the biomass- or biochar-amended soils. However, no amendment was effective on Sb immobilization.
军事射击场土壤中高浓度的有毒金属由于铅、铜和锑等金属可能释放，引发了重大的环境问题，因此需要进行修复。本研究考察了水牛草（豚草）生物质及其在300℃和700℃热解温度下衍生的生物炭、天然铁氧化物、三水铝石和银纳米颗粒在1年土壤培养后对金属固定的效果以及土壤质量。采用破坏性方法（如化学提取）和非破坏性方法（如分子光谱）来研究每种改良剂对铅、铜和锑的固定效果，并探索可能的固定机制。在300℃制备的生物炭表现出最高的固定效果，铅和铜的生物有效性分别最大降低了94%和70%，这归因于生物炭中丰富的官能团。生物炭显著提高了土壤pH值、阳离子交换容量和磷含量。实际上，扫描电子显微镜元素点映射和X射线吸收精细结构光谱（EXAFS）研究表明，在生物质或生物炭改良的土壤中，铅与磷结合（即形成稳定的氯磷灰石[Pb5(PO4)3Cl]）。然而，没有改良剂对锑的固定有效。
