NOM-mineral interaction: Significance for speciation of cations and anions.
NOM-mineral interaction: Significance for speciation of cations and anions.
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DOI：
10.1016/j.scitotenv.2022.153259
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
Jinbo Li;L. Weng;Yingxuan Deng;Jie Ma;Yali Chen;Yongtao Li
中科院分区：
文献类型：
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作者：
Jinbo Li;L. Weng;Yingxuan Deng;Jie Ma;Yali Chen;Yongtao Li
在这项研究中，天然有机物（NOM）在铁（氢）氧化物表面的纳米尺度空间分布及其与氧阴离子（PO 43 −）和金属阳离子（Cd 2+和Cu 2+）吸附到氧化物（针铁矿）和NOM（腐殖酸（HA）或富里酸（FA））的组合的相关性进行了研究与实验和先进的表面络合模拟。线性添加剂多表面模型（MSM）和更复杂的天然有机物电荷分布（NOM-CD）模型被使用。MSM模型忽略了NOM-矿物相互作用对离子吸附的影响，而NOM-CD模型考虑了这种影响。结果表明，随着NOM负载量的增加，PO 43-的MSM模型与NOM-CD模型的偏差变大，而Cd 2+和Cu 2+的MSM模型与NOM-CD模型的偏差变小。含氧阴离子主要与氧化物结合，因此NOM的竞争效应不能被忽略，这解释了这两个模型对PO 43 −的巨大差异。相反，在相对高的NOM负载下，大部分NOM进一步远离氧化物的表面延伸。因此，对于主要与NOM结合的金属阳离子，NOM-矿物相互作用对其吸附的影响很小，MSM和NOM-CD模型的结果相似。在表层土壤中，NOM在氧化物上的负载通常很高，因此线性添加剂MSM适用于许多文献中报道的金属阳离子形态计算。提出了一种基于NOM-CD模型的计算方法，该方法不仅可以计算阳离子和阴离子的宏观固溶分布，还可以提供它们微观表面形态的信息。
In this study, the nano-scale spatial distribution of natural organic matter (NOM) on the surface of iron (hydr)oxides and its relevance to oxyanion (PO43−) and metal cation (Cd2+and Cu2+) adsorption to the assemblage of oxide (goethite) and NOM (humic acids (HA) or fulvic acids (FA)) was investigated with experiments and advanced surface complexation modeling. Both the linear additive Multi-Surface model (MSM) and the more sophisticated Natural Organic Matter-Charge Distribution (NOM-CD) model were used. The MSM model ignores the effects of NOM-mineral interaction on ion adsorption, whereas the NOM-CD model considers this effect. The results showed that with the increase of NOM loading on oxides, deviation between the MSM and NOM-CD model became bigger for PO43−, but smaller for Cd2+and Cu2+. Oxyanions bind mainly to oxides and therefore the competitive effect of NOM cannot be neglected, which explains the large difference between these two models for PO43−. On the contrary, at a relatively high NOM loading, a large fraction of NOM extends further away from the surface of oxides. Thus for metal cations that bind mainly to NOM, the influence of NOM-mineral interaction on their adsorption is small and the results of the MSM and NOM-CD model are similar. In top soils, the NOM loading on oxides is often high, therefore the linear additive MSM is applicable for metal cation speciation calculations as reported in many literatures. An approach based on the NOM-CD model was proposed, which can not only calculate the macroscopic solid-solution distribution of both cations and anions, but can also provide information regarding their microscopic surface speciation.