College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, PR China E-mail:
Water Sci Technol. 2022 May;85(10):2912-2927. doi: 10.2166/wst.2022.134.
Degradation mechanism of methyl orange (MO), a typical azo dye, with pyrite (FeS) activated persulfate (PS) was explored. The results showed that when the initial concentration of MO was 0.1 mM, FeS was 1.6 g/L and PS was 1.0 mM, the removal rate of MO could reach 92.9% in 150 min, and the removal rate of total organic carbon could reach 14.1%. In addition, both pH ≤ 2 and pH ≥ 10 could have an inhibitory effect in the FeS/PS system. Furthermore, Cl and low concentrations of HCO had little effect on the degradation of MO with FeS/PS. However, HPO and high concentrations of HCO could inhibit the degradation of MO in the system. Besides, MO in river water and tap water were not degraded in FeS/PS system, but acidification (pH = 4) would greatly promote the degradation. In addition, the removal rate of MO with FeS/PS could still reach about 90% after five cycles of FeS. Furthermore, the intermediates and possible degradation pathways were speculated by LC-MS, and the degradation mechanism of MO by FeS/PS was that the cycle of Fe(III)/Fe(II) could continuously activate persulfate to produce SO. The results could provide technical support for azo dye degradation in the FeS/PS system.
利用黄铁矿（FeS）活化过硫酸盐（PS）降解典型偶氮染料甲基橙（MO）的降解机制。结果表明，当 MO 的初始浓度为 0.1mM，FeS 为 1.6g/L，PS 为 1.0mM 时，150min 内 MO 的去除率可达 92.9%，总有机碳去除率可达 14.1%。此外，在 FeS/PS 体系中，pH≤2 和 pH≥10 均具有抑制作用。此外，Cl 和低浓度 HCO对 FeS/PS 体系中 MO 的降解影响较小，而 HPO和高浓度 HCO会抑制体系中 MO 的降解。此外，河水和自来水中的 MO 无法在 FeS/PS 体系中降解，但酸化（pH=4）会大大促进 MO 的降解。此外，FeS 经过五次循环后，FeS/PS 对 MO 的去除率仍可达到 90%左右。此外，通过 LC-MS 推测了中间产物和可能的降解途径，并提出了 FeS/PS 降解 MO 的机制是 Fe(III)/Fe(II)循环可不断活化过硫酸盐生成 SO。该结果可为 FeS/PS 体系中偶氮染料的降解提供技术支持。
