Search results for "PHOTOCATALYSIS"

Blue light activated photodegradation of biomacromolecules by N-doped titanium dioxide in a chitosan hydrogel matrix

2023

The use of photocatalysis activated by titanium dioxide nanostructured materials is a promising solution for many biomedical applications ranging from drug-free antibacterial to anticancer therapies, as well as for innovative hydrogel-supported phototherapies. This makes the effects of photocatalysis on the structure of biomolecules of a great relevance in order to define the applicability of photocatalytic materials in the biomedical fields. In this work, the effects of nitrogen-doped titanium dioxide (N-TiO2) dispersed in a biocompatible chitosan/PEG hydrogel on myoglobin and bovine serum albumin as target model proteins were investigated. The efficiency of this composite biocompatible ma…

Effect of silver deposits on the photocatalytic activity of titanium dioxide samples for the dehydrogenation or oxidation of 2-propanol

1991

Abstract Until now, the effect of the deposition of metal particles onto a powdered semiconductor oxide on its photocatalytic activity has been determined for group VIII transition metals only. In this study, AGTiO2 samples were prepared by photodeposition, characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) and tested, under band-gap illumination, using the oxidation of 2-propanol (neat liquid phase or mixed with water) in the absence or presence of molecular oxygen. The silver deposits were found to be metallic both before and after use, but the size of the particles and their distribution on the support were markedly influenced by the type …

A PERVAPORATION PHOTOCATALYTIC REACTOR FOR THE GREEN SYNTHESIS OF VANILLIN

2012

Abstract Pervaporation is the ideal membrane separation process to be coupled with photocatalysis for the green synthesis of vanillin from ferulic acid. In fact the operative conditions of the two processes are absolutely congruent and the integration is straightforward even operating with separate equipments. The utilization of a highly selective membrane allows the continuous recovery of vanillin by pervaporation from the reacting solution, so that its oxidative degradation is largely avoided and the yield is substantially enhanced. The effects of the main parameters are analyzed resorting to a mathematical model, which is validated by a comparison with the experimental data. In particula…

Photodegradation of Toluene, m-Xylene, and n-Butyl Acetate and Their Mixtures over TiO2 Catalyst on Glass Fibers

2012

The abatement of typical paint solvent compounds as individuals and in mixtures was carried out in an annular TiO2 supported reactor, for concentrations up to 900 mg C m–3. Two different fiberglass supports were compared, and the catalyst supported over a fiber mat showed better performance, with a lower pressure drop (>35% of reduction) and a slightly higher removal efficiency (about 2%) than that supported over glass wool. For every target compound in the whole range of relative humidity studied (4–75%), the photocatalytic activity increased with the air water content. The removal of the compounds in the binary and ternary mixtures was depressed, even >90% for toluene, compared with indiv…

Overview on photoreforming of biomass aqueous solutions to generate H2 in the presence of g-C3N4 based materials

2023

Photoreforming (PR) of biomass can be considered a viable technology under mild experimental conditions to produce hydrogen with a high reaction rate using compounds from renewable resources and waste materials. The application of biomass PR gives rise to both hydrogen generation and biomass waste valorization. The process could be scaled up to obtain hydrogen under natural sunlight irradiation, and research on polymeric carbon nitride (g-C3N4)-based photocatalysts has been widely carried out in recent years. The non-metallic-based carbon nitride materials are economical and (photo)stable polymer semiconductors, and their physicochemical surface and electronic properties are optimal for obt…

Tuning the Photocatalytic Activity of Ti-Based Metal-Organic Frameworks through Modulator Defect-Engineered Functionalization.

2022

Defect engineering is a valuable tool to tune the photocatalytic activity of metal–organic frameworks (MOFs). Inducing defects through the attachment of functionalized modulators can introduce cooperative units that can tune the bandgap of the material and enhance their chemical, thermal, and photostabilities among other properties. However, the majority of defect engineering studies for photocatalytic applications are limited to Zr-based MOFs, and there is still a lack of interrelation between synthetic variables, the resultant MOF properties, and their effect on their photocatalytic performance. We report a comprehensive study on the defect engineering of the titanium heterometallic MOF M…

Photocatalytic glucose conversion to produce hydrogen in the presence of TiO2 based materials.

2015

In the present research commercial anatase (BDH) and anatase/rutile (P25) and home prepared anatase (HPA), rutile (HPR) and brookite (HPB) TiO2 polymorphs and have been used as supports for the deposition of metallic Pt. The Pt-TiO2 samples have been tested in the glucose conversion under anaerobic conditions. The presence of Pt resulted essential for the production of H2 and the home prepared samples resulted more active than the commercial ones.

Keggin heteropolyacid supported on TiO2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration

2017

Abstract (Photo)catalytic propene hydration to 2-propanol and glycerol dehydration to acrolein were carried out by using Keggin heteropolyacids (HPAs) supported on TiO 2 . Binary materials have been prepared by impregnation of H 3 PW 12 O 40 , H 3 PMo 12 O 40 and H 4 SiW 12 O 40 , on TiO 2 Evonik P25. Moreover, a binary material consisting of H 4 SiW 12 O 40 and TiO 2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-ray (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform …

Synthesis of 2,3‐Dihydro‐4‐pyridones, 4‐Quinolones, and 2,3‐Dihydro‐4‐azocinones by Visible‐Light Photocatalytic Aerobic Dehydrogenation

2019

Photocatalytic Processes in Membrane Reactors

2010

Conversion and degradation processes of various substrates in various types of matrices using both artificial and solar light are today very attractive by considering the scarcity and the expensiveness of the conventional energy sources. Coupling of membrane with light has shown to be very powerful and promising hybrid process, especially because a synergistic effect has been often observed. Some examples of reactions carried out to produce useful chemicals or to degrade noxious species in the framework of the green chemistry approach are reported. Fundamentals of heterogeneous photocatalysis, in general, and photocatalytic reactions in membrane reactors, in particular, are treated with a f…