Photocatalytic degradation of phenol by iodine doped tin oxide nanoparticles under UV and sunlight irradiation

Keywords: Tin oxide Sol–gel process Nanoparticle Photocatalysis Phenol degradation Visible light a b s t r a c t Iodine doped tin oxide (SnO 2 :I) nanoparticles were prepared by sol–gel synthesis and their photocatalytic activities with phenol as a test contaminant were studied. In the presence of the catalysts, phenol degradation under direct sunlight was comparable to what was achieved under laboratory conditions. Photocatalytic oxidation reactions were studied by varying the catalyst loading, light intensity, illumination time, pH of the reactant and phenol concentration. Upon UV irradiation in the presence of SnO 2 :I nanoparticles, phenol degrades very rapidly within 30 min, forming carboxylic acid which turns the solution acidic. Phenol degradation rate with 1% iodine doped SnO 2 nanoparticles is at least an order of magnitude higher compared to the degradation achieved through undoped SnO 2 nanoparticles under similar illumination conditions.crine disrupting compounds, phthalates and benzoic acids are all severe environmental pollutants [1–3] that are introduced into the environment from chemical and pharmaceutical industries [4]. Advanced oxidative processes (AOPs) are one of the most effective technologies suitable for the treatment of organic pollutants to harmless end products. The reactions are activated through the generation of very reactive species such as hydroxyl radicals. Significant progress has been made in recent years in synthesizing nanoparticles as environmental purification photocatalysts [5,6]. Many researchers reported that titanium dioxide (TiO 2), zinc oxide (ZnO) and tin dioxide (SnO 2) are the most active catalysts for the degradation of dyes, phenols and pesticides [7–11]. In addition, these semiconductors have been recognized as preferable materials for photocatalytic processes due to their photosensitivity, non-toxicity, low cost and high chemical stability [7,12,13]. Several studies have been carried out on the application of TiO 2 and ZnO for mineralization of organics [14–18]. A new class of activated iodine doped TiO 2 was found to enhance photocatalytic oxidation of phenol under UV and visible light illumination [19]. In another work, catalytic activity of iodine doped titanium dioxide was enhanced by modifying with tin dioxide [20]. The light response range and photo-efficiency of TiO 2 is limited because of its wide band gap [18,21]. It has been reported that TiO 2 doped with non-metals extends the absorption wavelengths from UV to visible region that enhances visible light photocatalytic activity [22,23]. TiO 2 nanoparticles and co-doped with iodine and fluorine showed better degradation of organic compounds under visible light irradiation [24]. …