College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225009, People's Republic of China.
School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha, 410114, People's Republic of China.
Environ Geochem Health. 2024 Jun 7;46(7):222. doi: 10.1007/s10653-024-01995-4.
In previous studies, iron-based nanomaterials, especially biochar (BC)-supported sulfidized nanoscale zero-valent iron (S-nZVI/BC), have been widely used for the remediation of soil contaminants. However, its potential risks to the soil ecological environment are still unknown. This study aims to explore the effects of 3% added S-nZVI/BC on soil environment and microorganisms during the remediation of Cd contaminated yellow-brown soil of paddy field. The results showed that after 49 d of incubation, S-nZVI/BC significantly reduced physiologically based extraction test (PBET) extractable Cd concentration (P < 0.05), and increased the immobilization efficiency of Cd by 16.51% and 17.43% compared with S-nZVI and nZVI/BC alone, respectively. Meanwhile, the application of S-nZVI/BC significantly increased soil urease and sucrase activities by 0.153 and 0.446 times, respectively (P < 0.05), improving the soil environmental quality and promoting the soil nitrogen cycle and carbon cycle. The results from the analysis of the 16S rRNA genes indicated that S-nZVI/BC treatment had a minimal effect on the bacterial community and did not appreciably alter the species of the original dominant bacterial phylum. Importantly, compared to other iron-based nanomaterials, incorporating S-nZVI/BC significantly increased the soil organic carbon (OC) content and decreased the excessive release of iron (P < 0.05). This study also found a significant negative correlation between OC content and Fe(II) content (P < 0.05). It might originate from the reducing effect of Fe-reducing bacteria, which consumed OC to promote the reduction of Fe(III). Accompanying this process, the redistribution of Cd and Fe mineral phases in the soil as well as the generation of secondary Fe(II) minerals facilitated Cd immobilization. Overall, S-nZVI/BC could effectively reduce the bioavailability of Cd, increase soil nutrients and enzyme activities, with less toxic impacts on the soil microorganisms.
在之前的研究中，铁基纳米材料，特别是生物炭（BC）负载硫化纳米零价铁（S-nZVI/BC），已被广泛用于污染土壤的修复。然而，其对土壤生态环境的潜在风险尚不清楚。本研究旨在探讨 3%添加量的 S-nZVI/BC 在修复稻田黄棕壤 Cd 污染过程中对土壤环境和微生物的影响。结果表明，在 49 d 的孵育期内，S-nZVI/BC 可显著降低生理基础提取试验（PBET）可提取 Cd 浓度（P < 0.05），与单独使用 S-nZVI 和 nZVI/BC 相比，Cd 的固定效率分别提高了 16.51%和 17.43%。同时，S-nZVI/BC 的应用可显著提高土壤脲酶和蔗糖酶活性，分别提高了 0.153 倍和 0.446 倍（P < 0.05），改善了土壤环境质量，促进了土壤氮循环和碳循环。16S rRNA 基因分析结果表明，S-nZVI/BC 处理对细菌群落的影响较小，没有明显改变原始优势细菌门的物种。重要的是，与其他铁基纳米材料相比，S-nZVI/BC 的加入显著增加了土壤有机碳（OC）含量，并减少了铁的过度释放（P < 0.05）。本研究还发现 OC 含量与 Fe(II)含量之间存在显著负相关（P < 0.05）。这可能源于铁还原菌的还原作用，铁还原菌消耗 OC 来促进 Fe(III)的还原。伴随这一过程，土壤中 Cd 和 Fe 矿物相的重新分布以及次生 Fe(II)矿物的生成促进了 Cd 的固定。总体而言，S-nZVI/BC 能有效降低 Cd 的生物可利用性，增加土壤养分和酶活性，对土壤微生物的毒性影响较小。
