State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China.
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China.
Water Res. 2016 Oct 15;103:215-223. doi: 10.1016/j.watres.2016.07.041. Epub 2016 Jul 20.
In this study, we systematically investigated the potential applicability of potassium permanganate for removal of triclosan (TCS) in water treatment. A series of kinetic experiments were carried out to study the influence of various factors, including the pH, oxidant doses, temperature, and presence of typical anions (Cl(-), SO4(2-), NO3(-)), humic acid (HA), and fulvic acid (FA) on triclosan removal. The optimal reaction conditions were: pH = 8.0, [TCS]0:[KMnO4]0 = 1:2.5, and T = 25 °C, where 20 mg/L of TCS could be completely degraded in 120 s. However, the rate of TCS (20 μg/L) oxidation by KMnO4 ([TCS]0:[KMnO4]0 = 1:2.5) was 1.64 × 10(-3) mg L(-1)·h(-1), lower than that at an initial concentration of 20 mg/L (2.24 × 10(3) mg L(-1)·h(-1)). A total of eleven products were detected by liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) analysis, including phenol and its derivatives, benzoquinone, an organic acid, and aldehyde. Two main reaction pathways involving CO bond cleavage (-C(8)O(7)-) and benzene ring opening (in the less chlorinated benzene ring) were proposed, and were further confirmed based on frontier electron density calculations and point charges. Furthermore, the changes in the toxicity of the reaction solution during TCS oxidation by KMnO4 were evaluated by using both the luminescent bacteria Photobacterium phosphoreum and the water flea Daphnia magna. The toxicity of 20 mg/L triclosan to D. magna and P. phosphoreum after 60 min was reduced by 95.2% and 43.0%, respectively. Phenol and 1,4-benzoquinone, the two representative degradation products formed during permanganate oxidation, would yield low concentrations of DBPs (STHMFP, 20.99-278.97 μg/mg; SHAAFP, 7.86 × 10(-4)-45.77 μg/mg) after chlorination and chloramination. Overall, KMnO4 can be used as an effective oxidizing agent for TCS removal in water and wastewater treatment.
在这项研究中，我们系统地研究了高锰酸钾在水处理中去除三氯生（TCS）的潜在适用性。进行了一系列动力学实验，研究了各种因素的影响，包括 pH 值、氧化剂剂量、温度以及典型阴离子（Cl(-)、SO4(2-)、NO3(-)）、腐殖酸（HA）和富里酸（FA）对三氯生去除的影响。最佳反应条件为：pH=8.0，[TCS]0:[KMnO4]0=1:2.5，T=25°C，在此条件下，20mg/L 的 TCS 可在 120s 内完全降解。然而，KMnO4 氧化 TCS（20μg/L）的速率（[TCS]0:[KMnO4]0=1:2.5）为 1.64×10(-3)mg L(-1)·h(-1)，低于初始浓度为 20mg/L 时的速率（2.24×10(3)mg L(-1)·h(-1)）。通过液相色谱-四极杆飞行时间质谱（LC-Q-TOF-MS）分析共检测到 11 种产物，包括苯酚及其衍生物、苯醌、有机酸和醛。提出了两条主要的反应途径，涉及 CO 键断裂（-C(8)O(7)-）和苯环打开（在氯代较少的苯环中），并通过前沿电子密度计算和点电荷进一步证实。此外，通过发光细菌发光杆菌和水蚤，评估了 TCS 被 KMnO4 氧化过程中反应溶液毒性的变化。60min 后，20mg/L 三氯生对水蚤和发光杆菌的毒性分别降低了 95.2%和 43.0%。高锰酸钾氧化过程中形成的两种代表性降解产物苯酚和 1,4-苯醌，在氯化和氯化胺化后会产生低浓度的 DBPs（STHMFP，20.99-278.97μg/mg；SHAAFP，7.86×10(-4)-45.77μg/mg）。总体而言，KMnO4 可作为一种有效氧化剂，用于去除水中和废水中的 TCS。
