Effect of Pluronic P103 Concentration on the Simple Synthesis of Ag and Au Nanoparticles and Their Application in Anatase-TiO2 Decoration for Its Use in Photocatalysis

Silver and gold nanoparticles were synthesized under environmentally-friendly reaction conditions by using a biodegradable copolymer and water as a solvent. The triblock copolymer Pluronic P103 was utilized as a stabilizing agent or soft template to produce Ag and Au nanoparticles (NPs) of different sizes. Moreover, in the synthesis of Au NPs, the polymer acted as a reducing agent, decreasing the number of reagents used and consequently the residues produced, hence, rendering the procedure less complicated. It was observed that as the concentration of the polymer increased, the size of the metallic NPs augmented as well. However, AgNPs and AuNPs prepared with 1 and 10 wt% Pluronic P103, respectively, showed a significant decrease in particle size due to the presence of polymeric soft templates. The hybrid materials (metal/polymer) were characterized by UV-Vis spectroscopy, DLS, and TEM. The pre-synthesized nanoparticles were employed to decorate anatase-TiO2, and the composites were characterized by DRS, XRD, BET surface area measurements, the TEM technique with the EDS spectrum, and XPS spectroscopy to demonstrate NPs superficial incorporation. Finally, methylene blue was used as a probe molecule to evidence the effect of NPs decoration in its photocatalytic degradation. The results showed that the presence of the NPs positively affected methylene blue degradation, achieving 96% and 97% removal by utilizing TAg0.1 and TAu10, respectively, in comparison to bare anatase-TiO2 (77%).

Optimization of opeation parameters for methylene blue degradation by UV/TiO2/H2O2 process in an annular reactor

In this study, the degradation of methylene blue (MB) by UV/TiO2/ H2O2 process was ivestigated in an annular reactor. The effects of the factors: TiO2 concentration, H2O2 dosage, UV density, and hydrodynamic conditions on the reaction rate constant were evaluated by the response surface methodology. The results showed that TiO2concentration, H2O2dosage and UV density had a great influence on the kapp, hydrodynamics had a lower influence. Design Expert V.11 software is used to optimize the reaction conditions, the optimal apparent reaction rate constant is 0.168 min-1 under the following conditions: TiO2 concentration of 0.2 g/l, H2O2 dosage is 0.063 mol/l, UV density of 287 W/m2 and Re number is 10000.

The Influence of pH on the Nitrogen-doped TiO2 Structure and Its Photocatalytic Activity on Methylene Blue Degradation

The mesoporous nitrogen-doped titania (N-doped TiO2) has been synthesized through sol-gel method by refluxing the precursor mixture, continued by hydrolysis process, and then followed by annealing in air at the desired temperature. The pH of precursor mixture solution before hydrolysis process has been varied to study their influence on the resulting N-doped TiO2. The resulting material were characterized using X-Ray Diffraction (XRD), N2 Gas Sorption Analyzer (GSA), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and UV Vis Spectrophotometer. The XRD analysis result showed that the pH and water content played an important role on the crystal formation of the N-doped TiO­2. The result showed that a high acidity condition resulted in a favored tendency of anatase crystalline phase, while lowering acidity leaded to the rutile formation. Porosity analysis showed the significant influence of pH in the synthesis process on the pore characteristic and pore size distribution of the resulting material. The photocatalytic activity was tested on the methylene blue degradation system comparing to pure TiO2 and commercial Degussa P25 and the result showed that the synthesized N-doped TiO2 provided better photocatalytic activities.