Desulfurization of Petroleum Products Using Nano Polyoxometalete/Titanium dioxide Catalytic System

Petroleum products contain significant amounts of organic sulphur, such as mercaptanes, benzothiophenes, poly sulphons, disulphides and etc. Sulphur combustion, cause conversion of them to sulphoxides and results problems to human and environment health [1]. Oxidative desulphurization (ODS) method leads to proper sulphur conversions at low temperature and pressure, and relatively easily combinable with separation processes [2]. Nowadays, we investigate heterogeneous polyoxometalates/Titanium dioxide (POMs/TiO2) catalysts. Various types of Nano POMs; (Molybdophosphoric acid, tungstophosphoric acid, tungstomolybdophosphoric acid) were synthesized; and POMs/TiO2 nano composites obtained via bottom-up method [3]. Prepared catalysts were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM). The catalysts activities were measured by the total sulphur content of petroleum products before and after desulphurization. The effects of kinds of POMs, amount of catalyst loading, reaction time, oxidized content, temperature, pH value, and sulfoxide separator material were investigated. Results showed that POM/TiO2 has the higher catalytic activities than that of pure nano TiO2 and nano POMs. Among various synthesized nano composites, HPW/TiO2 nano-composite was found to be the best sulphur removal catalyst. Desulfurization increased on the pH value (2-3) and the best results were obtained on the temperature 105 °C. The sulfoxide can be readily separated from the end production using extractor, without changing their properties.