Humic acid (HA) and iron oxide (such as Fe₃O₄) nanoparticles are widely distributed in soil, and their complex embedded in soil might affect the transport and fate of Cu²⁺ in the vadose zone, while Cu²⁺ is a serious threat to the underlying groundwater. In this study, we synthesized a composite of Fe₃O₄ nanoparticles coated with HA () using as an amendment a packed sand matrix in the transport column experiments. The impacts of HA content and ion strength (IS) on Cu²⁺ transport in the unsaturated columns were investigated. The results showed that HA exhibited a stronger inhibition effect on Cu²⁺ transport, and a higher IS enhanced the mobility of Cu²⁺ in an unsaturated porous medium in the presence of [email protected] The recovery ratio (R_r) of Cu²⁺ breakthrough in the column decreased from 66.56% to 3.94% while the mass concentration ratio C_HA/C_NPs increased from 0 to 50 in the [email protected] complex. The R_r increased by 1.64 times while the IS increased from 0 to 100 mM. Batch adsorption experiments, kinetics and isotherm models, and Fourier transform infrared (FTIR) spectra analysis were implemented to elucidate the underlying mechanism. It was found that HA embedded in the sand matrix could bind Cu²⁺ by forming stable chelate, while the IS-dependent Cu²⁺ transport could be attributed to the competitive adsorption between Na⁺ and Cu²⁺. Our study demonstrates that the physicochemical environment, as well as the presence of iron oxide nanoparticles and natural organic matter, can significantly impact Cu²⁺ transport in unsaturated porous medium. View Full-Text

中文翻译：

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腐殖酸/氧化铁纳米粒子（Fe3O4）修正对不饱和多孔介质中Cu2 +的迁移

腐殖酸（HA）和氧化铁（Fe ₃ O ₄）纳米粒子广泛分布在土壤中，它们的复合物嵌入土壤中可能会影响渗流区Cu ²⁺的运输和结局，而Cu ²⁺是对底层地下水的严重威胁。在这项研究中，我们在运输塔实验中使用填充的砂基质作为修正物，合成了用HA（）包覆的Fe ₃ O ₄纳米颗粒复合材料。研究了HA含量和离子强度（IS）对不饱和柱中Cu ²⁺迁移的影响。结果表明，HA对Cu ^2+的抑制作用较强。[email protected]的存在下，较高的IS迁移率和更高的IS增强了Cu ²⁺在不饱和多孔介质中的迁移率柱中Cu ²⁺突破的回收率（R _r）从66.56％降至3.94％，而[受电子邮件保护]复合物中的质量浓度比C _HA / C _NPs从0增加到50。的[R _[R ，而从0增加至100毫米增加了1.64倍。批量吸附实验，动力学和等温线模型，以及傅立叶变换红外（FTIR）光谱分析被用来阐明其潜在机理。发现包埋在砂基质中的HA可以结合Cu ²⁺通过形成稳定的螯合物，而IS依赖性的Cu ²⁺转运可归因于Na ⁺和Cu ²⁺之间的竞争性吸附。我们的研究表明，理化环境以及氧化铁纳米颗粒和天然有机物的存在会显着影响不饱和多孔介质中Cu ^2+的迁移。查看全文