title: Kinetic analysis of photocatalytic oxidation of gas-phase formaldehyde over titanium dioxide.
abstract: Degradation of formaldehyde with different initial concentration over titanium dioxide was carried out in a photocatalytic reactor. Photocatalytic rates were well described by the simplified Langmuir-Hinshelwood model. The kinetic analysis shows that the apparent first-order reaction coefficient is lower and half-life of photocatalysis is longer for low concentration than for high concentration formaldehyde. A network formation model of the photocatalytic products was established. Experimental results and analysis demonstrate that carbon dioxide concentration and carbon monoxide concentration in gas phase vary exponentially with the illumination time and may be even higher than gas-phase formaldehyde concentration if there is much pre-adsorbed formaldehyde in adsorption equilibrium on catalysts before illumination. Carbon monoxide is found to be one of the by-products during formaldehyde photooxidation.
authors.affiliation: Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030, China. lhm@sjtu.edu.cn
authors.forename: Hongmin
authors.initials: H
authors.lastname: Liu
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Lian
authors.forename: Xiaojiang
authors.initials: X
authors.lastname: Ye
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Shangguan
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D004202:Disinfectants / Q000737:chemistry*; D005557:Formaldehyde / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D004202:Disinfectants; C009495:titanium dioxide; D005557:Formaldehyde; D014025:Titanium