title: Wet air oxidation of a reactive dye solution using CoAlPO(4)-5 and CeO(2) catalysts.
abstract: Wet air oxidation of a prepared reactive dye solution was performed to assess the efficacy of CoAlPO(4)-5 and CeO(2) as catalysts in the reaction. Via adsorption and oxidation of dye, CoAlPO(4)-5 effectively decreased American Dye Manufacturers Institute and chemical oxygen demand (COD) values in the dye solution. At a reaction temperature of 135 degrees C and an applied pressure of 1.0 MPa, color and COD removal were as high as 95% and 90%, respectively, after 2 h. Active sites on the outer surface of CoAlPO(4)-5 are responsible for adsorption and decomposition of dye while active sites in the pores dominate further destruction and oxidation of intermediate products. Since the outer surface only represents a minor part of the total surface, the color removal does not increase appreciably with loading of CoAlPO(4)-5. The CeO(2) catalyst, calcined from cerium chloride under high thermal impact (type A CeO(2)) was very effective in removing color and COD from the solution. This catalyst demonstrated near 100% color removal at temperatures above 135 degrees C and the COD removal could be above 95% at 165 degrees C. With both CoAlPO(4)-5 and CeO(2) catalysts, COD rose and then fell back during the reaction, a feature typical of a consecutive reaction. In contrast to prepared CeO(2), a commercial CeO(2) did not exhibit any catalytic ability for the removal of color and COD. The durability of both CoAlPO(4)-5 and prepared CeO(2) is considered to be fair.
authors.affiliation: Department of Environmental Engineering and Health, Chia-Nan University of Pharmacy and Science, 717, Tainan, Taiwan. mdong@mail.chna.edu.tw
authors.forename: Dong Jang
authors.initials: DJ
authors.lastname: Chang
authors.forename: I Pin
authors.initials: IP
authors.lastname: Chen
authors.forename: Ming Ten
authors.initials: MT
authors.lastname: Chen
authors.forename: Shiow Shyung
authors.initials: SS
authors.lastname: Lin
mesh_terms: D000327:Adsorption; D017607:Aluminum Compounds / Q000737:chemistry*; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013696:Temperature; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D017607:Aluminum Compounds; D004396:Coloring Agents; D002563:Cerium; C030583:ceric oxide; D010100:Oxygen