Graduate School of Water Resources, Sungkyunkwan University (SKKU) 2066, Suwon 16419, Korea.
Key Laboratory of the Three Gorges Reservoir Region Eco-Environment, State Ministry of Education, Chongqing University, Chongqing 400045, China.
Int J Environ Res Public Health. 2019 Mar 27;16(7):1092. doi: 10.3390/ijerph16071092.
The presence of natural organic matter (NOM) in drinking water sources can stabilize toxic antimony (Sb) species, thus enhancing their mobility and causing adverse effects on human health. Therefore, the present study aims to quantitatively explore the complexation of hydrophobic/hydrophilic NOM, i.e., humic acid (HA), salicylic acid (SA), and L-cysteine (L-cys), with Sb in water. In addition, the removal of Sb(III, V) species and total organic carbon (TOC) was evaluated with ferric chloride (FC) as a coagulant. The results showed a stronger binding affinity of hydrophobic HA as compared to hydrophilic NOM. The optimum FC dose required for Sb(V) removal was found to be higher than that for Sb(III), due to the higher complexation ability of hydrophobic NOM with antimonate than antimonite. TOC removal was found to be higher in hydrophobic ligands than hydrophilic ligands. The high concentration of hydrophobic molecules significantly suppresses the Sb adsorption onto Fe precipitates. An isotherm study suggested a stronger adsorption capacity for the hydrophobic ligand than the hydrophilic ligand. The binding of Sb to NOM in the presence of active Fe sites was significantly reduced, likely due to the adsorption of contaminants onto precipitated Fe. The results of flocs characteristics revealed that mechanisms such as oxidation, complexation, charge neutralization, and adsorption may be involved in the removal of Sb species from water. This study may provide new insights into the complexation behavior of Sb in NOM-laden water as well as the optimization of the coagulant dose during the water treatment process.
水中天然有机物 (NOM) 的存在会使有毒的锑 (Sb) 物种稳定化，从而提高其迁移性并对人类健康造成不利影响。因此，本研究旨在定量探索疏水性/亲水性 NOM（即腐殖酸 (HA)、水杨酸 (SA) 和 L-半胱氨酸 (L-cys)）与水中 Sb 的络合作用。此外，还评估了以三氯化铁 (FC) 作为混凝剂去除 Sb(III、V) 物种和总有机碳 (TOC) 的效果。结果表明，疏水性 HA 的结合亲和力强于亲水性 NOM。发现去除 Sb(V) 所需的最佳 FC 剂量高于去除 Sb(III)所需的最佳 FC 剂量，这是由于疏水性 NOM 与 Sb(V) 的络合能力高于 Sb(III)。发现疏水性配体的 TOC 去除率高于亲水性配体。高浓度的疏水分子显著抑制 Sb 吸附到 Fe 沉淀物上。等温线研究表明，疏水性配体的吸附能力强于亲水性配体。在有活性 Fe 位存在的情况下，Sb 与 NOM 的结合显著减少，这可能是由于污染物吸附到沉淀的 Fe 上。絮体特性的结果表明，氧化、络合、电荷中和和吸附等机制可能参与了 Sb 物种从水中的去除。本研究可能为 Sb 在 NOM 负载水中的络合行为以及在水处理过程中优化混凝剂剂量提供新的见解。
