%0 Journal Article
%T Photocatalytic Degradation of 2-Chlorophenol Using Ag-Doped TiO2 Nanofibers and a Near-UV Light-Emitting Diode System
%A Ju-Young Park
%A In-Hwa Lee
%J Journal of Nanomaterials
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/250803
%X This report investigated the photocatalytic degradation of 2-chlorophenol using TiO2 nanofibers and Ag-doped TiO2 nanofibers, synthesized using the sol-gel and electrospinning techniques, and an ultraviolet light-emitting diode (UV-LED) system as a UV light source. The crystallite size of the Ag-doped TiO2 nanofibers was smaller than that of the TiO2 nanofibers, because silver retrained phase transformation not only controls the phase transformation but also inhibits the growth of anatase crystallites. The activation energies for the grain growth of the TiO2 nanofibers and the Ag-doped TiO2 nanofibers were estimated to be 20.84 and 27.01£¿kJ/mol, respectively. The photocatalytic degradation rate followed a pseudo-first-order equation. The rate constants ( ) of the TiO2 nanofibers and the Ag-doped TiO2 nanofibers were 0.056 and 0.144£¿min£¿1, respectively. 1. Introduction TiO2 is the most widely used photocatalyst owing to its photostability, nontoxicity, low cost, and insolubility in water under most environmental conditions [1]. Excitation of TiO2 generates highly reactive electron-hole pairs that subsequently produce highly potent radicals (such as £¿OH and O2£¿£¿) that oxidize organic and inorganic pollutants. However, the optimal design of the reactor and the various operational conditions are major concerns in the development and potential applications of photocatalytic processes. Virtually all previous work on photocatalytic degradation with respect to the removal of pollutants from wastewater has been carried out using broad spectral radiation sources, such as UV lamps, and TiO2 as the photocatalyst. The traditional UV source is a mercury vapor high-pressure lamp, which is also a source of gas discharge [2, 3]. The mercury used in this UV lamp is specified as a hazardous air pollutant by the U.S. Environmental Protection Agency and can damage the brain and kidneys. Ultraviolet light-emitting diodes (UV-LEDs) are a new, safer, and energy efficient alternative to traditional gas discharge sources. LEDs are a directional light source, in which the maximum emitted power is in the direction perpendicular to the emitting surface. A typical lifetime of 100,000£¿h is another advantage of UV-LEDs, whereas the lifetime of gas discharge sources is approximately 1000£¿h. The electrospinning technique has been recognized as a versatile and effective method for the preparation of nanofibers with small diameters and high surface-to-volume ratios [4¨C7], and the fabrication of TiO2 nanofibers by electrospinning was first reported in 2003 [8]. Some researchers have
%U http://www.hindawi.com/journals/jnm/2014/250803/