title: Efficient degradation of Acid Orange 7 in aqueous solution by iron ore tailing Fenton-like process.
abstract: An effective method based on iron ore tailing Fenton-like process was studied for removing an azo dye, Acid Orange 7 (AO7) in aqueous solution. Five tailings were characterized by X-ray fluorescence spectroscope (XFS), Brunner-Emmet-Teller (BET) measurement, and Scanning Electron Microscope (SEM). The result of XFS showed that Fe, Si and Ca were the most abundant elements and some toxic heavy metals were also present in the studied tailings. The result of BET analysis indicated that the studied tailings had very low surface areas (0.64-5.68 m(2) g(-1)). The degradation efficiencies of AO7 were positively correlated with the content of iron oxide and cupric oxide, and not related with the BET surface area of the tailings. The co-existing metal elements, particularly Cu, might accelerate the heterogeneous Fenton-like reaction. The effects of other parameters on heterogeneous Fenton-like degradation of AO7 by a converter slag iron tailing (tailing E) which contains highest iron oxide were also investigated. The tailing could be reused 10 times without significant decrease of the catalytic capacity. Very low amount of iron species and almost undetectable toxic elements were leached in the catalytic degradation of AO7 by the tailing E. The reaction products were identified by gas chromatography-mass spectrometry and a possible pathway of AO7 degradation was proposed. This study not only provides an effective method for removing azo dyes in polluted water by employing waste tailings as Fenton-like catalysts, but also uses waste tailings as the secondary resource.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, PR China; Jiangsu Entry Exit Inspection and Quarantine Bureau, Nanjing 210001, PR China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Zheng
authors.affiliation: State Environmental Protection Key Laboratory of Monitoring and Analysis for Organic Pollutants in Surface Water, Nanjing 210036, PR China; Jiangsu Provincial Environmental Monitoring Center, Nanjing 210036, PR China.
authors.forename: Zhanqi
authors.initials: Z
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: He
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, PR China.
authors.forename: Shaogui
authors.initials: S
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, PR China. Electronic address: envidean@nju.edu.cn.
authors.forename: Cheng
authors.initials: C
authors.lastname: Sun
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001557:Benzenesulfonates / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; C045076:Fenton's reagent; D005290:Ferric Compounds; C000499:ferric oxide; D006861:Hydrogen Peroxide; D007501:Iron; C014722:2-naphthol orange
keywords: Acid Orange 7; Catalyst stability; Degradation; Heterogeneous Fenton-like process; Iron ore tailing; Mechanism and pathway