Zhou Shi, Ni Xue, Zhou Houlang, Meng Xiangmin, Sun Huimin, Wang Jun, Yin Xianqiang
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
Political and Law Commission of Chengwu County Party committee, Heze, Shandong 274200, PR China.
Ecotoxicol Environ Saf. 2021 Nov 11;228:112971. doi: 10.1016/j.ecoenv.2021.112971.
The development and application of nano-biochar synthesized by ball milling technology is still challenging in the field of environmental remediation because of its higher activity with pollutants. The purpose of this study was to investigate the transport behavior of two kinds of biochar nanoparticles (nanobiochar (NBC) and nZVI-modified nanobiochar (nZVI-NBC)) and Cd in clay mineral (kaolinite, illite, and montmorillonite)-coated quartz sand columns. The interaction between biochar nanoparticles and Cd in saturated porous media was studied in cotransport experiments. Then, the effect of biochar nanoparticles on the release of Cd in contaminated media was explored by elution experiments. The cotransport experiments showed that the mobility of Cd was enhanced by two kinds of biochar nanoparticles, while the transport of biochar was limited due to the presence of Cd. The elution experiments showed that the transport of biochar nanoparticles can be inhibited by Cd previously immobilized in the sand column, and Cd can be rereleased by biochar nanoparticles. The rerelease ability of nZVI-NBC to Cd is weaker than that of NBC because nZVI is more easily retained in the sand column after oxidation, thus strengthening the immobilization of Cd. In general, the recoveries of NBC, nZVI-NBC and Cd in saturated porous media were reduced by the presence of clay minerals. The experimental results describing the stability of biochar nanoparticles in sand columns are consistent with those predicted by the Derjaguin-Landau-Verwey-Overbeek theory. The transport behavior of Cd and biochar nanoparticles in sand columns can be well simulated by advection-dispersion-reaction. These findings reveal the interaction between biochar nanoparticles and heavy metals in the soil environment and provide new insights into the transport and fate of environmental remediation materials and pollutants in the underground environment.
由于通过球磨技术合成的纳米生物炭与污染物的活性较高，其在环境修复领域的开发和应用仍然具有挑战性。本研究的目的是研究两种生物炭纳米颗粒（纳米生物炭（NBC）和nZVI改性纳米生物炭（nZVI-NBC））以及镉在粘土矿物（高岭土、伊利石和蒙脱石）包覆的石英砂柱中的迁移行为。在共迁移实验中研究了饱和多孔介质中生物炭纳米颗粒与镉之间的相互作用。然后，通过洗脱实验探讨了生物炭纳米颗粒对污染介质中镉释放的影响。共迁移实验表明，两种生物炭纳米颗粒均增强了镉的迁移能力，而由于镉的存在，生物炭的迁移受到限制。洗脱实验表明，预先固定在砂柱中的镉可以抑制生物炭纳米颗粒的迁移，而生物炭纳米颗粒可以使镉重新释放。nZVI-NBC对镉的重新释放能力比NBC弱，因为nZVI在氧化后更容易保留在砂柱中，从而加强了对镉的固定。总体而言，粘土矿物的存在降低了饱和多孔介质中NBC、nZVI-NBC和镉的回收率。描述生物炭纳米颗粒在砂柱中稳定性的实验结果与Derjaguin-Landau-Verwey-Overbeek理论预测的结果一致。平流-弥散-反应可以很好地模拟镉和生物炭纳米颗粒在砂柱中的迁移行为。这些发现揭示了土壤环境中生物炭纳米颗粒与重金属之间的相互作用，并为环境修复材料和污染物在地下环境中的迁移和归宿提供了新的见解。
