title: Cu-TiO2/Ti dual rotating disk photocatalytic (PC) reactor: dual electrode degradation facilitated by spontaneous electron transfer.
abstract: A Cu-TiO2/Ti dual rotating disk photocatalytic (PC) reactor has been developed based on our single rotating disk photoelectrocatalytic (PEC) reactor (Y. Xu, et al, Environ. Sci. Technol. 2008, 42, 2612-2617), and successfully applied to the treatment of laboratory and industrial dye wastewater. Round TiO2/Ti and Cu disks of the same size are connected by a Cu wire and fixed parallel on an axis continually rotating at 90 rpm. High treatment efficiency is obtained due to direct photooxidation on the TiO2/Ti photoanode as well as additional degradation on the Cu cathode, which is speculated via indirect hydrogen peroxide (H2O2) oxidation and direct electro-reduction of dye on cathode. The mechanism of the Cu-TiO2/Ti dual rotating disk PC reactor was investigated. In a 20 mg L(-1) Rhodamine B (RB) solution, approximately 100 mV of potential and 10 microA of current were measured between the Cu and TiO2/Ti electrode during PC treatment. Such phenomenon was explained by spontaneous electron transfer based on the same principle of establishing a Schottky barrier. On the Cu electrode surface, the photoelectrons either reduced dye molecules directly or reacted with dissolved oxygen (DO) to form H2O2. Rotation of electrodes out of the solution enhanced the mass transfer of target compound and kept the aqueous film fresh. The Cu-TiO2/ Ti dual rotating disk PC reactor is a simple and effective device for the treatment of RB dye wastewater.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China.
authors.forename: Yunlan
authors.initials: Y
authors.lastname: Xu
authors.forename: Yi
authors.initials: Y
authors.lastname: He
authors.forename: Jinping
authors.initials: J
authors.lastname: Jia
authors.forename: Dengjie
authors.initials: D
authors.lastname: Zhong
authors.forename: Yalin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002384:Catalysis / Q000528:radiation effects; D003116:Color; D003300:Copper / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004583:Electrons; D006861:Hydrogen Peroxide / Q000737:chemistry; D007220:Industrial Waste; D008027:Light; D010100:Oxygen / Q000737:chemistry; D012235:Rhodamines / Q000302:isolation & purification; D012399:Rotation; D012666:Semiconductors; D013784:Textiles; D014025:Titanium / Q000737:chemistry*; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D007220:Industrial Waste; D012235:Rhodamines; C009495:titanium dioxide; D003300:Copper; D006861:Hydrogen Peroxide; D014025:Titanium; C029773:rhodamine B; D010100:Oxygen