Xiong Wenming, Huang Qixuan, Li Langlang, Li Yongjun
Guangzhou Vocational College of Technology & Business, Guangzhou 511442, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
Toxics. 2024 Nov 25;12(12):845. doi: 10.3390/toxics12120845.
Geogenic arsenic (As) contamination in groundwater poses a significant public health risk in many regions worldwide. Previous studies have reported hydrogen peroxide (HO) concentrations ranging from 5.8 to 96 μmol L in rainwater, which may contribute to the oxidation and removal of As. However, the influence of natural organic matter, such as humic acid (HA), on rainwater-borne HO-induced Fenton processes for the oxidation and removal of As remains unclear. In this study, the Fenton process was employed to investigate changes in As(V), As(III), and their mixtures, both in the presence and absence of HA. The results showed that low concentrations of HA (0-10 mg/L) promoted the oxidation of As(III) and removal of As(V) when As(V) and As(III) were present individually. However, when As(V) and As(III) coexisted, HA inhibited the Fenton process for As(V) removal. This inhibition was likely due to As(III) competing strongly with HA for hydroxyl radicals in the Fenton reaction system. Additionally, the presence of HA hindered the Fe(III)-driven removal of As(V), a product of the Fenton reaction. These findings further enhance our understanding of the potential role of rainwater-borne HO in the transformation of As species in open water environments.
地下水中的地质成因砷污染在全球许多地区构成了重大的公共卫生风险。先前的研究报告称，雨水中过氧化氢（HO）的浓度范围为5.8至96 μmol/L，这可能有助于砷的氧化和去除。然而，天然有机物，如腐殖酸（HA），对雨水中HO引发的芬顿过程中砷的氧化和去除的影响仍不清楚。在本研究中，采用芬顿过程来研究在有和没有HA的情况下，As(V)、As(III)及其混合物的变化。结果表明，当单独存在As(V)和As(III)时，低浓度的HA（0 - 10 mg/L）促进了As(III)的氧化和As(V)的去除。然而，当As(V)和As(III)共存时，HA抑制了去除As(V)的芬顿过程。这种抑制可能是由于As(III)在芬顿反应体系中与HA强烈竞争羟基自由基。此外，HA的存在阻碍了芬顿反应产物Fe(III)驱动的As(V)的去除。这些发现进一步加深了我们对雨水中HO在开放水环境中砷形态转化中潜在作用的理解。
