Search results for "photocatalysi"
showing 10 items of 626 documents
Effect of Urea–Hydrogen Peroxide Content on the Photocatalytic Activity of Zinc Oxide Nanoparticles
2021
ZnO nanoparticles (NPs) were synthesized using zinc acetate dihydrate, ethanol, and oxalic acid as precursor, solvent, and complexing agent, respectively, and urea–hydrogen peroxide (UHP) as, simultaneously, nitrogen precursor and oxygen donor. The structural, morphological, textural, and optical properties of ZnO photocatalysts were investigated using different characterization methods such as XRD, SEM, BET, and UV-Vis-DRS. The XRD patterns showed that the products consisted of ZnO and revealed the presence of nitrogen. SEM images revealed the agglomeration and aggregation of NPs. The photocatalytic activity of ZnO samples was estimated based on the photo-oxidation of 2-propanol under UV i…
Visible light active self-cleaning materials based on porphyrin-sensitised titanium dioxide
2017
Starting from second half of last century, nanostructured semiconductors have had a crucial function in the material science because of their wide application field going from renewable energy to organic/hybrid electronics up to photocatalysis. Among those materials, titanium dioxide is probably the most used because of some important characteristics like the chemical/mechanical stability, environmental sustainability, its low cost and versatility. Indeed, it has been successfully employed as photo- and electro-active component in electronic devices as well as photocatalytic agent1 in water de-pollution application. Interestingly and importantly together, titanium dioxide may also be applie…
Photocatalysis: a promising route for 21st century organic chemistry
2007
One of the main goals of 21st century chemistry is to replace environmentally hazardous processes with energy efficient routes allowing to totally avoid the use and production of harmful chemicals and to maximise the quantity of raw material that ends up in the final product. Selective photocatalytic conversions will play a major role in this evolution and this account shows how photocatalysis is offering an alternative green route for the production of organics.
Genetic Algorithm Modeling for Photocatalytic Elimination of Impurity in Wastewater
2019
The existence of C.I. Acid Yellow 23 (AY23) in water causes a great danger to people and society. Here, we suggest an advanced technique which predicts the photochemical deletion of AY23. The genetic algorithm (GA) technique is suggested in order to predict the photocatalytic removal of AY23 by implementing the Ag-TiO\(_{2}\) nanoparticles provided under appropriate conditions.
Guidelines for the assessment of the rate law of slurry photocatalytic reactions
2017
Abstract The assessment of the rate law of slurry photocatalytic reactions appears to be a hard task, mainly because in this type of reactions the average rate of reaction, which is experimentally observed in a real reactor, could be very different from the “true” (intrinsic) rate of reaction, which cannot be measured directly. In the present work, it is shown how a proper mathematical model allows the utilization of the differential and/or the integral methods of kinetic analysis. The mathematical model must take into account not only the momentum and the mass balances, but also the radiative transfer equation. However, the discrimination among different proposed kinetic laws remains diffi…
Process intensification in a photocatalytic membrane reactor: Analysis of the techniques to integrate reaction and separation
2017
Abstract Different methods to integrate reaction and separation in a membrane reactor are studied in the present work, with the aim being to highlight the pros and cons of the different alternatives and the effects of the intervening parameters. The coupling of the two processes can take place inside a single apparatus or using separate units. If a single apparatus is utilized, the coupling is more direct, but separate units offer higher degrees of freedom for the design with more opportunities to optimize the system without constraints. However, when using separate units, the integration of the two unit operations depends largely on the parameters intervening in the coupling procedure. The…
Optical properties of TiO2 suspensions: Influence of pH and powder concentration on mean particle size
2007
WOS: 000250584100025
A reaction engineering approach to kinetic analysis of photocatalytic reactions in slurry systems
2016
Abstract The knowledge of the rate equation is fundamental for the assessment of the activity of the photocatalytic material and for the study, design and optimization of photocatalytic reactors. In the case of photocatalytic reactions, the local volumetric rate of photon absorption (LVRPA) affects the reaction rate and its inherently uneven distribution within a “slurry” reactor makes complex a correct kinetic analysis. In the present work it is shown which are the critical aspects of the kinetic analysis in slurry reactors and how to carry out photocatalytic experiments to minimize the misinterpretations of the experimental results. In particular, the influence of the type of illumination…
Quasi-isoactinic reactor for photocatalytic kinetics studies
2007
Photochemical reactors characterized by almost uniform values of the local volumetric rate of photon absorption (LVRPA), i.e., quasi-isoactinic photoreactors, are particularly suitable for assessing the influence of radiant field intensity in kinetic studies. In this work, Monte Carlo simulations have been performed to obtain LVRPA values in a flat photoreactor irradiated on both sides. This configuration appears to be particularly suitable for obtaining quasi-isoactinic conditions. The influence of catalyst albedo and scattering phase function is assessed, and the conditions for obtaining iso-actinicity are discussed. Finally, these conditions are related to an easy-to-measure parameter, n…
Co doped ZnO nanowires as visible light photocatalysts
2016
Abstract High aspect ratio cobalt doped ZnO nanowires showing strong photocatalytic activity and moderate ferromagnetic behaviour were successfully synthesized using a solvothermal method and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), vibrating sample magnetometry (VSM) and UV–visible absorption spectroscopy. The photocatalytic activities evaluated for visible light driven degradation of an aqueous methylene orange (MO) solution were higher than for Co doped ZnO nanoparticles at the same doping level and synthesized by the same synthesis route. The rate constant for MO visi…