Yang Shi, Liu Zu-Wen, Long Bei, Bi Yong-Shun, Lin Yuan, Zuo Hua-Wei
School of Civil and Surveying & Mapping Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China.
Jiangxi Key Laboratory of Environmental Geotechnology and Engineering Disaster Control, Ganzhou 341000, China.
Huan Jing Ke Xue. 2022 Mar 8;43(3):1567-1576. doi: 10.13227/j.hjkx.202105181.
Using navel orange peels and natural graphite as raw materials, biochar-supported graphene oxide (BGO) material was prepared using an improved hummer and co-pyrolysis method. The effects of BGO on the forms of heavy metals in the soil of a rare earth mining area were investigated via a soil passivation experiment. The soil column leaching experiment was carried out to explore the change characteristics of heavy metal content in leaching filtrate and the vertical migration law of heavy metals in soil, and the accumulation and release model of heavy metals under leaching conditions was determined. The results showed that pH value and organic matter content of soil with BGO composite increased, and acid-extractable Pb of raw ore and tailings soil decreased by 17% and 8.6%, respectively. The content of Mn form in the raw ore soil did not change significantly, whereas the content of acid-extractable, reducible, and oxidizable state in tailings soil decreased. The accumulation and release characteristics of heavy metals in soil could be divided into two stages:rapid release stage and slow stage. The release rate of heavy metals in soil with BGO composite was lower than that without addition, and the Pb and Mn removed from the tailings soil decreased by 2.5% and 28.4%, respectively, compared with that of the control group, whereas the raw ore soil decreased by 5.7% and 1.1%, respectively. The release of heavy metals in soil is a complex reaction process controlled by a variety of diffusion mechanisms. BGO composites can effectively inhibit the migration of heavy metals by increasing soil pH, surface complexation, and precipitation.
以脐橙皮和天然石墨为原料，采用改进的Hummer法和共热解方法制备了生物炭负载氧化石墨烯（BGO）材料。通过土壤钝化试验研究了BGO对稀土矿区土壤中重金属形态的影响。进行了土柱淋溶试验，探讨淋溶滤液中重金属含量的变化特征以及重金属在土壤中的垂直迁移规律，并确定了淋溶条件下重金属的累积和释放模型。结果表明，添加BGO复合材料的土壤pH值和有机质含量增加，原矿和尾矿土壤中酸可提取态Pb分别降低了17%和8.6%。原矿土壤中Mn形态含量变化不显著，而尾矿土壤中酸可提取态、可还原态和可氧化态含量降低。土壤中重金属的累积和释放特征可分为两个阶段：快速释放阶段和缓慢阶段。添加BGO复合材料的土壤中重金属释放速率低于未添加的土壤，尾矿土壤中去除的Pb和Mn与对照组相比分别降低了2.5%和28.4%，原矿土壤中分别降低了5.7%和1.1%。土壤中重金属的释放是一个受多种扩散机制控制的复杂反应过程。BGO复合材料可通过提高土壤pH值、表面络合和沉淀作用有效抑制重金属的迁移。
