Abstract
Photodegradation of 4-chlorophenoxyacetic acid (4-CPA) was systematically investigated using N-doped TiO2(N-TiO2) under commercially available visible light emitting diode (Vis LED) as a novel Vis LED illumination in photocatalysis applications. The synergetic effect of Vis LED/N-TiO2process was studied in detail by varying reaction conditions including the initial concentration of 4-CPA, catalyst dosage, light intensity, and initial pH. Additionally, the influence of inorganic anions and radical scavengers on the performance of the Vis LED/N-TiO2process was also evaluated. The Vis LED/N-TiO2was found to be a promising process in terms of mineralization of 4-CPA. It is interesting to note that the performance of this process was not reduced after successive usage of the recycled catalyst; instead, the reaction rate of 4-CPA decay actually increased by using the spent catalyst. The mechanism behind rate enhancement after/during reuse was explored by XPS and FT-IR analyses and it was proven that hydroxyl groups can be incorporated into the catalyst surface by the repeated wetting of N-TiO2after each reuse. This facilitates the formation of hydrogen bonds between the 4-CPA molecules and N-TiO2, thereby allowing more collisions between the trapped 4-CPA and radicals at the interface of bulk solution and catalyst, respectively.
Original language | English |
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Pages (from-to) | 491-501 |
Number of pages | 11 |
Journal | Journal of Hazardous Materials |
Volume | 338 |
DOIs | |
Publication status | Published - 1 Jan 2017 |
Keywords
- Commercial visible LED
- Herbicides
- Hydrogen bonding
- N-doped TiO 2
- Photodegradation
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Pollution
- Health, Toxicology and Mutagenesis