Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
J Hazard Mater. 2022 Aug 15;436:129155. doi: 10.1016/j.jhazmat.2022.129155. Epub 2022 May 16.
The heteroaggregation mechanism of nZVI with four types of natural soil nanoparticles (SNPs) extracted from representative soils in northern and southern China was investigated. Heteroaggregation rates between nZVI and SNPs were quantified by dynamic light scattering and evaluated as a function of ionic strength at pH 7. The nZVI-SNPs heteroaggregates were stable with hydrodynamic diameters (D) ranging from 400 to 600 nm in 0.1 mM solution. Based on the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, nZVI underwent heteroaggregation with SNPs to form stable nZVI-SNPs nanohybrid due to the attachment of nZVI on the SNPs. However, with enhanced ionic strength, SNPs accelerated the aggregation of nZVI and formed large heteroaggregates with D in the range from 1200 to 2000 nm, owing to insignificant electrostatic repulsions and oppositely charged patches. In addition, the differences in the heteroaggregation rates of nZVI with four SNPs were negligible, caused by the negligible impacts of SNPs components such as soil organic matter and Fe/Al oxyhydroxides on the heteroaggregation of nZVI in the 10 mM NaCl solution. These findings are helpful for understanding the interaction between nZVI and SNPs and of significance to groundwater remediation using nZVI.
研究了四种从中国北方和南方有代表性土壤中提取的天然土壤纳米颗粒（SNP）与纳米零价铁（nZVI）的异质聚集机制。通过动态光散射定量了 nZVI 与 SNP 之间的异质聚集率，并在 pH 7 下作为离子强度的函数进行了评估。nZVI-SNP 异质聚集体在 0.1 mM 溶液中的水力直径（D）范围从 400nm 到 600nm，非常稳定。基于扩展的德加古林-兰德劳-弗韦尔贝克（DLVO）理论，由于 nZVI 附着在 SNP 上，nZVI 与 SNP 发生异质聚集，形成稳定的 nZVI-SNP 纳米杂化物。然而，随着离子强度的增加，SNP 加速了 nZVI 的聚集，并形成了 D 值在 1200nm 到 2000nm 范围内的大异质聚集体，这是由于静电排斥作用不明显和带相反电荷的斑块。此外，由于在 10mM NaCl 溶液中 SNP 成分（如土壤有机质和 Fe/Al 氢氧化物）对 nZVI 异质聚集的影响可以忽略不计，因此四种 SNP 与 nZVI 的异质聚集率差异可以忽略不计。这些发现有助于理解 nZVI 与 SNP 之间的相互作用，对利用 nZVI 进行地下水修复具有重要意义。
