Removal of emerging pollutants by Ru/TiO2-catalyzed permanganate oxidation

• Published in: Water research (Oxford) 2014-10, Vol.63, p.262-270
• Main Authors: Zhang, Jing, Sun, Bo, Xiong, Xinmei, Gao, Naiyun, Song, Weihua, Du, Erdeng, Guan, Xiaohong, Zhou, Gongming
• Format: Article
• Language: English
• Subjects: Aniline; Applied sciences; Catalysis; Competitive oxidation; Diclofenac; Drinking water and swimming-pool water. Desalination; Electron-rich organic moiety; Endocrine disrupting chemicals; EPS; Exact sciences and technology; Freshwater; General purification processes; Hydrogen-Ion Concentration; Kinetics; Manganese Compounds - chemistry; Metal Nanoparticles - chemistry; Oxidation; Oxidation-Reduction; Oxides - chemistry; Permanganates; Pharmaceuticals; Pollutants; Pollution; Rate constants; Ruthenium - chemistry; Titanium - chemistry; Titanium dioxide; Waste Disposal, Fluid - methods; Wastewaters; Water Pollutants, Chemical - chemistry; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2014.06.028

TiO2 supported ruthenium nanoparticles, Ru/TiO2 (0.94‰ as Ru), was synthesized to catalyze permanganate oxidation for degrading emerging pollutants (EPs) with diverse organic moieties. The presence of 1.0 g L−1 Ru/TiO2 increased the second order reaction rate constants of bisphenol A, diclofenac, acetaminophen, sulfamethoxazole, benzotriazole, carbamazepine, butylparaben, diclofenac, ciprofloxacin and aniline at mg L−1 level (5.0 μM) by permanganate oxidation at pH 7.0 by 0.3–119 times. The second order reaction rate constants of EPs with permanganate or Ru/TiO2-catalyzed permanganate oxidation obtained at EPs concentration of mg L−1 level (5.0 μM) underestimated those obtained at EPs concentration of μg L−1 level (0.050 μM). Ru/TiO2-catalyzed permanganate could decompose a mixture of nine EPs at μg L−1 level efficiently and the second order rate constant for each EP was not decreased due to the competition of other EPs. The toxicity tests revealed that Ru/TiO2-catalyzed permanganate oxidation was effective not only for elimination of EPs but also for detoxification. The removal rates of sulfamethoxazole by Ru/TiO2-catalyzed permanganate oxidation in ten successive cycles remained almost constant in ultrapure water and slightly decreased in Songhua river water since the sixth run, indicating the satisfactory stability of Ru/TiO2. Ru/TiO2-catalyzed permanganate oxidation was selective and could remove selected EPs spiked in real waters more efficiently than chlorination. Therefore, Ru/TiO2-catalyzed permanganate oxidation is promising for removing EPs with electron-rich moieties. [Display omitted] •Ru/TiO2 + MnVII can degrade EPs with electron-rich moieties effectively.•EPs at μg/L are degraded by Ru/TiO2 + MnVII with larger k (M−1 s−1) than those at mg/L.•Ru/TiO2 + MnVII is more effective for detoxifying EPs than MnVII.•Ru/TiO2 + MnVII destructs EPs spiked in real waters more effectively than HClO.