title: Degradation of azo and anthraquinone dyes by a low-cost Fe 0/air process.
abstract: Degradation of two different kinds of dyes, anthraquinone Reactive Blue 4 (RB4) and azo Reactive Black 5 (RB5), by low-cost zero valent iron (Fe(0)) in a N(2) bubbling system (Fe(0)/N(2) process) and air bubbling system (Fe(0)/air process) was investigated. The operating parameters, including initial solution pH, dye concentration and Fe(0) dose, were also evaluated. The Fe(0)/air process shows a higher decolorization rate compared to the Fe(0)/N(2) process. Both RB4 and RB5 solutions at 100 mg L(-1) were rapidly decolorized by Fe(0)/air process within 9 and 3 min, respectively, at initial solution pH 3, Fe dose of 50 g L(-1) and air flow rate of 5 L min(-1). The optimal initial solution pH was 3. The Fe(0)/N(2) process removed only <17% of COD. However, significant COD removals were achieved for RB 4 (87%) and RB5 (43%) by the Fe(0)/air process after 9 min of treatment. Spectra analysis results indicated that the Fe(0)/N(2) process destroyed only the anthraquinone group (A(594)) for the RB4 solution and decreased the azo (A(596)) and naphthalene group (A(310)) for the RB5 solution. However, the Fe(0)/air process rapidly removed A(594), A(370), A(296) (anthraquinone group) and A(256) (aromatic and dichlorotriazine group) for RB4, and A(597) and A(310) (naphthalene group) for RB5. The results indicated that the low-cost Fe(0)/air process is a potential technique for rapid degradation of RB4 and RB5 solutions.
authors.affiliation: Department of Public Health, Chung-Shan Medical University, Taichung 402, Taiwan, ROC. shchang@csmu.edu.tw
authors.forename: Shih-Hsien
authors.initials: SH
authors.lastname: Chang
authors.forename: Kai-Sung
authors.initials: KS
authors.lastname: Wang
authors.forename: Shu-Ju
authors.initials: SJ
authors.lastname: Chao
authors.forename: Tzu-Huan
authors.initials: TH
authors.lastname: Peng
authors.forename: Lung-Chiu
authors.initials: LC
authors.lastname: Huang
mesh_terms: D000388:Air; D000880:Anthraquinones / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D004396:Coloring Agents / Q000737:chemistry*; D003365:Costs and Cost Analysis; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D009282:Naphthalenesulfonates; D014227:Triazines; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D001391:Azo Compounds; D004396:Coloring Agents; D007220:Industrial Waste; D009282:Naphthalenesulfonates; D014227:Triazines; D014874:Water Pollutants, Chemical; C036598:procion blue MX-R; D007501:Iron; C063421:Remazol black B