Photodegradation of Methyl Orange Molecules Using Laser Photocatalysis

Abstract

In this work, a UV light emitting diode (LED) with a wavelength of 365 nm and power 1200 mW was used as UV source for the photodegradation of methyl orange molecules by stimulating zinc oxide, as a catalyst, to interact with methyl orange molecules. Methyl orange was added to the water and then different weights of zinc oxide were added and the mixture was subjected to ultraviolet radiation with different irradiation times. The absorption spectra of the methyl orange substance were recorded before adding the semi- conductive material (ZnO) prior to irradiation. The absorption spectra were recorded after irradiation at different times and after adding different weights of zinc oxide. A comparison was made between the absorption spectra in both cases to determine whether methyl orange molecules were degraded or not. The results showed that the increment of weight of the catalyst and the time of irradiation increased the degradation of the methyl orange molecules exponentially. The lowest degradation was when 1000 mg of zinc oxide was added and time of exposure of 10 minutes, while the methyl orange molecules was completely degraded when 2000 mg of zinc oxide was added with exposure time of 30 minutes. This study showed that methyl orange molecules were degraded exponentially with increasing the amount of the catalyst and increasing the irradiation time