title: Rapid enhanced photocatalytic degradation of dyes using novel N-doped ZrO2.
abstract: A novel N-doped ZrO2 (N-ZrO2) photocatalyst is synthesized through thermal decomposition of zirconium hydroxide-urea complex and is characterized using various techniques, including XRD, FTIR, TGA, SEM, TEM, UV-DRS, XPS, XANES, and BET. The N-ZrO2 possesses pure monoclinic structure with high crystallinity. By using the proposed facile route of synthesis, both interstitial and substitutional N doping with high dopant stability can be realized. The optical properties of the catalyst are significantly altered after N doping, giving an optical response in the visible and near infrared regions and an additional strong absorption peak in the UVA region. The N-ZrO2 showed a higher photocatalytic activity than pristine ZrO2 for the degradation of amaranth (AM) and methylene blue (MB) under visible or UV light irradiation, which could be attributed to the band gap narrowing, higher specific area, smaller crystalline size, and higher availability of surface hydroxyl groups. Due to its molecular structure and light absorption characteristics, MB is easier to degrade than AM. Overall removal efficiencies, including adsorption and photolysis, for AM and MB by N-ZrO2 at pH 7 with initial dye concentration of 10 mg/L, catalyst concentration of 1 g/L, and visible light irradiation of 144.7 W/m(2) are 67.2 and 96%, respectively. Using UVA light of only 3.5 W/m(2) under identical experimental conditions, complete removal of MB and AM is obtained. The photocatalytically treated solution of either AM or MB is nontoxic against Bacillus cereus, an agriculturally important soil microorganism.
authors.affiliation: School of Biochemical Engineering and Technology, Sirindhorn International Institute of Technology, Thammasat University, P. O. Box 22, Pathum Thani 12121, Thailand.
authors.forename: Hanggara
authors.initials: H
authors.lastname: Sudrajat
authors.affiliation: School of Biochemical Engineering and Technology, Sirindhorn International Institute of Technology, Thammasat University, P. O. Box 22, Pathum Thani 12121, Thailand. Electronic address: sandhya@siit.tu.ac.th.
authors.forename: Sandhya
authors.initials: S
authors.lastname: Babel
authors.affiliation: Department of Urban Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakai
authors.affiliation: Department of Urban Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takizawa
mesh_terms: D000327:Adsorption; D000548:Amaranth Dye / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D001409:Bacillus cereus / Q000187:drug effects; D002384:Catalysis; D004396:Coloring Agents / Q000032:analysis / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D008751:Methylene Blue / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D010782:Photolysis; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000548:Amaranth Dye; D004396:Coloring Agents; D006878:Hydroxides; D008751:Methylene Blue; D014025:Titanium; D062065:Wastewater; D014874:Water Pollutants, Chemical; D015040:Zirconium; C470523:zirconium hydroxide
keywords: Amaranth; Methylene blue; N-doped ZrO(2); Photostable; Visible light active