Liaoning Engineering Research Center for Treatment and Recycling of Industrially Discharged Heavy Metals, Shenyang University of Chemical Technology, Shenyang, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2021;56(13):1428-1434. doi: 10.1080/10934529.2021.2006544. Epub 2021 Dec 6.
Natural organic matter (NOM) has been considered a critical substance in the transport and transformation of arsenic. NOM is a complex mixture of multifunctional organic components with a wide molecular weight (MW) distribution, and it is necessary to understand the complexation of arsenic with MW-dependent NOM fractions. In this study, humic acid (HA) was chosen as the representative fraction of NOM to investigate the complexation mechanism with arsenic. The bulk HA sample was fractionated to five fractions by ultrafiltration technology, and the complexing property of HA fractions with arsenic was analyzed by the dialysis method. We observed that the acidic and neutral conditions favor the complexation of HA fractions with arsenate (As(V)). The HA fractions with molecular weight > 100 kDa, 1-10 kDa, and <1 kDa have the stronger complexing capacity of As(V) than the other HA fractions. The bound As(V) percentage was positively associated with carboxyl content, phenolic content, and especially total acidity. A two-site ligand-binding model can describe the complexing capacity of arsenic onto HA fractions. The results can provide some fundamental information about the complexation of arsenic with MW-dependent HA fractions quantitatively.
天然有机物（NOM）已被认为是砷迁移和转化的关键物质。NOM 是一种具有多种功能的有机成分的复杂混合物，分子量（MW）分布广泛，有必要了解砷与 MW 依赖型 NOM 分数的络合作用。在这项研究中，选择腐殖酸（HA）作为 NOM 的代表性组分，研究其与砷的络合机制。通过超滤技术将大量 HA 样品分为五个馏分，通过透析法分析 HA 馏分与砷的络合性质。我们观察到在酸性和中性条件下有利于 HA 馏分与砷酸盐（As(V)）的络合。分子量>100 kDa、1-10 kDa 和<1 kDa 的 HA 馏分比其他 HA 馏分具有更强的 As(V)络合能力。结合的 As(V)百分比与羧基含量、酚类含量呈正相关，尤其是总酸度。双位点配体结合模型可以描述砷与 HA 馏分的络合能力。研究结果可为定量研究砷与 MW 依赖型 HA 馏分的络合作用提供一些基本信息。
