Photocatalytic degradation mechanisms and kinetics of Acid Red 27 dissolved in water in presence of nano SnO2

Using of organic dyes is expanded in several industries nowadays, including: textile, paper and some other industries which produce a large amount of pollution that can cause serious environmental problems [1]. Besides of the adsorption as a standalone treatment, Advanced Oxidation Processes (AOPs) represent an alternative method of removing organic pollutants from water, which does not entail any of the disadvantages of the adsorptive technologies [2]. Oxide Semiconductors are the most promising semiconductors that have been used in photocatalytic degradation of azo dyes [3]. In this process various parameters like band gap of the semiconductor, specific surface area, crystallinity, concentration of pollutant, etc. affect the photocatalytic efficiency by changing (or interfering) in mechanism of photocatalytic reactions [4]. SnO2 is a wide bang gap semiconductor with the band gap of about 3.8 eV. It has been reported as a good gas sensing oxide and recently has been studied as a promising semiconductor in photocatalytic degradation of waste water [5]. In this paper, the photocatalytic degradation of Acid Red 27 (AR27) has been investigated using UV radiation in presence of SnO2 nanoparticles. SnO2 nanoparticles with low crystallite size and high specific surface area has been synthesised via hydrothermal method and their photocatalytic activity with variation of crystalline size, specific surface area, and photocatalyst and dye charge has been studied