title: [Degradation of azo dye acid orange 7(AO7) by heat, ZVI and heat/ZVI activated persulfate].
abstract: Effects of temperatures, PS concentrations and ZVI dosages on AO7 decomposition were investigated in sole heat and ZVI activating systems. The degradation results of two systems were compared for selecting a better activating way for AO7 degradation and finally the two activating ways were combined for getting the optimal AO7 degradation efficiency. The degradation of AO7 by Heat/PS systems followed pseudo first-order kinetics. The reaction rates increased with increasing reaction temperatures (elevated from room temperature to 90 degrees C) and also increased when initial PS concentrations varied from 1 to 12 mmol x L(-1). For ZVI activating systems (ZVI/PS systems), the degradation rate of AO7 was the highest when ZVI dose was 0.2 g, and it reached to 95.6% within 90 min. Comparing ZVI/PS systems with Heat/PS systems, the results showed that the ZVI activation was a more effective way to activate PS than the heat activation for AO7 degradation. AO7 degradation processes by ZVI/heat/PS systems were two-stage pseudo first-order kinetic processes, and the combining of two activating ways significantly increased the reaction rates. By the addition of ZVI to the Heat/PS system, the apparent activation energy E(a) of AO7 degradation reduced from the original 130.26 kJ x mol(-1) to 27.70 kJ x mol(-1).
authors.affiliation: College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006, China. 1010439791@qq.com
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Jin-Quan
authors.initials: JQ
authors.lastname: Wan
authors.forename: Yong-Wen
authors.initials: YW
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Ming-Zhi
authors.initials: MZ
authors.lastname: Huang
mesh_terms: D001391:Azo Compounds / Q000737:chemistry / Q000302:isolation & purification*; D001557:Benzenesulfonates / Q000737:chemistry / Q000302:isolation & purification*; D004396:Coloring Agents / Q000737:chemistry / Q000302:isolation & purification*; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D017680:Potassium Compounds / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D017680:Potassium Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical; C009007:potassium persulfate; D007501:Iron; C014722:2-naphthol orange