A novel approach for the production of nitrogen doped TiO2 nanoparticles

In this study a visible light active nitrogen doped nanostructure titanium dioxide was synthesized by a simple mixing of Degussa P25 and Urea powder and further thermal treatment under the adequate conditions. Photocatalytic activity of produced nanoparticles was verified by providing of photocatalytic degradation of phenol aqueous solution. Mainly this work was focused on the investigation of the following effects: urea concentration, temperature treatment, catalyst loading and initial phenol concentration. Kinetics study was also carried out. The approach appears to be successful and may be applied for example during the photocatalytic treatment of wastewater streams without or with a limited aid of UV lamps. Copyright © 2015, AIDIC Servizi S.r.l

Production of nanostructured TiO2 for photocatalysis application

In recent years heterogeneous photocatalysis has attracted a great interest because of its potential to remove aqueous and air pollutants through complete mineralization. Even though the technologies for the synthesis of photocatalysts for industrial production already exist, there are a number of technological problems concerned with the industrial-scale using of TiO2. First of all, TiO2 (anatase) can be excited only with UV light which is quite expensive and requires special protective measures to use it. Then, the missing of recovery of the TiO2 nanoparticles from the treated wastewater leads both to the treatment cost and the presence of TiO2 powder dispersion inside the purified solution stream. The objective of this research work was focused to face both the above mentioned two disadvantages. In order to recover the used nanoparticles it was developed a technology for the production of composite core/shell/shell Fe3O4/SiO2/TiO2 nanoparticles by wet chemical synthesis. These nanoparticles were recovered by using an electromagnetic trap and successfully re-used. Moreover, in order to accomplish the photocatalysis by using visible the doping of TiO2 was studied and a process procedure was developed and successfully applied, with regard to a sol-gel material adopted for coating. The core/shell/shell nanoparticles operation process was realized in three steps: 1) Fe3O4 magnetic nanoparticles precipitation by Spinning Disc Reactor, 2) Fe3O4/SiO2 core/shell nanoparticles synthesis by using of the Stöber method, 3) TiO2 external layer production by sol-gel method. Synthesis of the nitrogen-doped titanium dioxide was carried out by using 2- ethylmethylamine as dopant and its subsequent immobilization on the glass spheres was obtained by applying a deep-coating technique. The activity of the developed photocatalysts was checked by degradation of the methylene blue, phenol and 2-chlorophenol in aqueous solutions, olive mill wastewater and ethylene in gas phase. Composite core/shell/shell photocatalyst demonstrated high catalytic activity (more than 90% in case of MB and 2-CP degradation, 50% of OMWW degradation) and very reproducible results. 57% of OMWW degradation under the visible light and more than 60% of phenol degradation was achieved as a result of photocatalysis assisted by nitrogen doped titanium dioxide immobilized on the glass beads. Nitrogen doped titanium dioxide demonstrated a slight photocatalytic activity under the visible light irradiation in gas phase. Different models such as pseudo-first order, second order, Langmuir-Hinshelwood and Hugul were adopted to describe the kinetics of the photo-chemical reactions

Photocatalytic treatment of olive mill waste water by magnetic core titanium dioxide nanoparticles

The photocatalytic degradation of organic compounds of olive mill wastewater (OMWW) was investigated by using core-shell-shell Fe 3O4/SiO2/TiO2 nanoparticles as catalyst. The preparation of nanoparticles was performed by coating onto magnetic nanoparticles a SiO2 layer, using Stober method and TiO 2 layer, using sol-gel method. The photo catalyst was characterized by dynamic light scattering (DLS), zeta-potential measurement, UV-visible spectroscopy, energy-dispersive X-ray diffraction (EDX), scanning electron microscopy (SEM). Batch photo reactor, irradiated by an UV lamp of 45 W, was used to check the photocatalytic activity of the produced nanoparticles. The organic content of OMWW was evaluated by COD measurements. The photo degradation process was optimized by using 1.5 g/L core-shell-shell nanoparticles. The obtained results showed a high activity of synthesized nanoparticles for photocatalytic degradation of the OMWW organic compounds. Moreover, the recovery of the magnetic cor