title: Kinetics of degradation of allura red, ponceau 4R and carmosine dyes with potassium ferrioxalate complex in the presence of H(2)O(2).
abstract: The degradation of title dyes with ferrioxalate and H(2)O(2) couple has been investigated spectrophotometrically. In the absence of either one of the oxidizing agents no degradation occurred. The reaction rate was proportional to moderate concentrations of the dye and H(2)O(2). At high concentration of the dye and H(2)O(2) the reaction rate decreased. With regard to the concentration of the ferrioxalate complex the rate of reaction increased even over a wide range of complex concentration. Degradation of dyes does not occur in acidic medium. It is slow in neutral but thoroughly fast in alkaline medium. The reaction rate reaches a maximum value at pH 11.5. This behavior was again observed if HCl or NaOH were added. With HCl the reaction rate decreases with increasing acid concentration but greatly increases with NaOH concentration. Isopropanol showed inhibiting effect due to scavenging the in situ generated hydroxyl radical (()OH). Oxalate ion enhanced the rate, confirming an outer sphere mechanism. The activation parameters of the reaction are estimated and a possible mechanism is proposed. The mechanism is well confirmed with data simulation procedure.
authors.affiliation: Department of Chemistry, Tanta University, Egypt. masalem51@yahoo.com
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Salem
authors.forename: Shaker T
authors.initials: ST
authors.lastname: Abdel-Halim
authors.forename: Abd El-Hamid M
authors.initials: Ael-H
authors.lastname: El-Sawy
authors.forename: Ahmed B
authors.initials: AB
authors.lastname: Zaki
mesh_terms: D001391:Azo Compounds / Q000737:chemistry / Q000378:metabolism*; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D052918:Environmental Restoration and Remediation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009282:Naphthalenesulfonates; D010070:Oxalates / Q000737:chemistry*; D013696:Temperature
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D009282:Naphthalenesulfonates; D010070:Oxalates; C034942:ferrioxalate; C005915:Allura Red AC Dye; D006861:Hydrogen Peroxide; C576297:ponceau 4R