School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong Province, China.
School of Biotechnology and Health Science, Wuyi University, Jiangmen 529020, Guangdong Province, China.
Water Res. 2021 Oct 15;205:117669. doi: 10.1016/j.watres.2021.117669. Epub 2021 Sep 16.
Herein, permanganate [Mn(VII)] was activated by simulated solar (SS) (SS/Mn(VII)), resulting in rapid degradation of micropollutants in several minutes, with rates of target micropollutants outnumbered those in the Mn(VII) alone and SS. To explore the mechanism in this process, 4-cholorphenol (4-CP), p-hydroxybenzoic acid (p-HBA), and enrofloxacin (ENR) were selected as model compounds. Lines of evidence indicated that reactive manganese species (RMnS) (i.e., Mn(III) and Mn(V)) rather than radicals from Mn(VII) photolysis participated in the conversion of model compounds. Interestingly, roles of RMnS differed among three model compounds, suggesting their selectivity toward micropollutants. Increasing Mn(VII) dosage proved greater micropollutant degradation, while impacts of pH on SS/Mn(VII) performance varied among model compounds. P-HBA and ENR showed the lowest degradation efficiency at alkaline, whereas 4-CP demonstrated the best performance at alkaline, indicating the reactivity of RMnS varied toward micropollutants at different pH values. The quantum yield of Mn(VII) was 8.36 ± 0.03 X 10 mol Einstein at pH 7.0. Effects of common co-existing constituents (Cl, HCO, and humic acid (HA)) on micropollutant degradation by SS/Mn(VII) were examined. Specifically, HCO positively influenced the 4-CP and p-HBA degradation, whereas ENR was not affected, likely owing to the selectivity of RMnS-HCO complexes. HA was conducive to degrade p-HBA due to the production of RMnS-HA complexes, but unfavorable for ENR and 4-CP degradation because of the competitive light absorption and Mn(VII). Furthermore, a number of degradation products of 4-CP, p-HBA, and ENR were identified and possible pathways were proposed accordingly. The effectiveness of this process for micropollutant degradation in real waters, natural sunlight, ultraviolet and visible light via cut-off filtering SS emission was confirmed. This work revealed a great potential of applying SS/Mn(VII) for the marked degradation of micropollutants and facilitated the understandings of Mn(III)/Mn(V) behaviors.
在此，通过模拟太阳光（SS）（SS/Mn(VII)）激活高锰酸盐[Mn(VII)]，导致在几分钟内快速降解微量污染物，目标微量污染物的降解速率超过单独的 Mn(VII)和 SS。为了探究这一过程中的机制，选择 4-氯苯酚（4-CP）、对羟基苯甲酸（p-HBA）和恩诺沙星（ENR）作为模型化合物。多种证据表明，反应性锰物种（RMnS）（即 Mn(III)和 Mn(V)）而非 Mn(VII)光解产生的自由基参与了模型化合物的转化。有趣的是，RMnS 在三种模型化合物中的作用不同，表明其对微量污染物具有选择性。增加 Mn(VII)剂量可提高微量污染物的降解效率，而 pH 值对 SS/Mn(VII)性能的影响因模型化合物而异。p-HBA 和 ENR 在碱性条件下的降解效率最低，而 4-CP 在碱性条件下的降解效率最高，表明 RMnS 对不同 pH 值下的微量污染物的反应性不同。在 pH 7.0 时，Mn(VII)的量子产率为 8.36±0.03×10−2mol Einstein。研究了常见共存成分（Cl、HCO 和腐殖酸（HA））对 SS/Mn(VII)降解微量污染物的影响。具体而言，HCO 对 4-CP 和 p-HBA 的降解有积极影响，而 ENR 不受影响，这可能归因于 RMnS-HCO 络合物的选择性。HA 有利于生成 RMnS-HA 络合物，从而降解 p-HBA，但不利于 ENR 和 4-CP 的降解，因为这两种物质会竞争光吸收和 Mn(VII)。此外，鉴定了 4-CP、p-HBA 和 ENR 的一些降解产物，并据此提出了可能的途径。通过截止过滤 SS 发射的自然光、紫外线和可见光证实了该工艺在实际水样中对微量污染物降解的有效性。这项工作揭示了 SS/Mn(VII)用于显著降解微量污染物的巨大潜力，并促进了对 Mn(III)/Mn(V)行为的理解。
