Search results for "PHOTOCATALYSIS"

Heterogeneous photocatalytic degradation of pharmaceuticals in water by using polycrystalline TiO2 and a nanofiltration membrane reactor

2006

Abstract A study of the photodegradation of different pharmaceuticals [furosemide, ranitidine (hydrochloride), ofloxacine, phenazone, naproxen, carbamazepine and clofibric acid] in aqueous medium at various pHs by using a batch photoreactor and a photocatalytic membrane reactor working in recirculation regime was carried out. Polycrystalline TiO 2 was used as the photocatalyst, and different membranes (NTR 7410, PAN GKSS HV3/T, N 30 F, NF PES 10) were tested. A different adsorption of the substrates onto the catalyst surface was observed owing to the hydrophilic/hydrophobic character of the catalyst, depending on the pH. The photodegradation of the seven molecules in the batch reactor was s…

Preparation, Characterisation and Testing of Photocatalytic Polymeric Membranes with Entrapped or Suspended TiO2

2005

Various cellulose triacetate (CTA) or polysulfone (PSf) membranes with entrapped polycrystalline TiO2 were prepared by using different methods of the so-called phase inversion process. Porosity and permeability of the membranes increased by increasing the amount of entrapped TiO2 while rejection decreased. The photoactivity of entrapped TiO2 for the degradation of congo-red was compared with that of the same quantity of suspended TiO2 and the results indicated that TiO2 was always more efficient when used in suspension. A hybrid configuration consisting of a continuous membrane photoreactor with the photocatalyst in suspension showed to be the most promising one.

TiO2-based photocatalysts impregnated with metallo-porphyrins employed for degradation of 4-nitrophenol in aqueous solutions: role of metal and macro…

2007

Photodegradation of organic compounds in water solutions by means of economically advantageous and environment-friendly processes is a topic of growing interest. In recent years a great attention has been devoted to TiO2-based photocatalysts for the oxidative degradation of various organic pollutants. In this context, we have prepared new photo-catalytic polycrystalline TiO2 systems impregnated with sensitizers, i.e., copper, iron or manganese porphyrins, and investigated their photoactivity for 4-nitrophenol oxidation compared with that of bare TiO2. A significant improvement of the photoreactivity was observed in the case of TiO2 impregnated with copper porphyrin, while only a slight bene…

Photocatalytic H2 evolution from aqueous solutions of oxygenated organic compounds in the presence of C3N4/reduced graphene oxide based photocatalysts

2022

Composites of C3N4/reduced graphene oxide have been used as a cheap and promising photocatalysts for triethanolamine and ethanol photo-reforming with H2 generation in aqueous solution. The rate of H2 production over the best performing photocatalysts reached 1,415 μmol·h-1·g-1 which increases up to 57,306 in the presence of 1% of Pt. The apparent quantum efficiency of the optimal material was 7 % by using both LED and natural sunlight irradiation

Fotoutlenianie siarki w obecności wybranych diftalocyjanin lantanowców

2016

Zagadnienie odsiarczania jest problemem zarówno w przemyśle jak i w ochronie środowiska naturalnego, gdyż związki siarki stanowią zagrożenie dla organizmów żywych. Podjęto więc badania nad możliwością wykorzystania fotoaktywnych kompleksów ftalocyjaniny jako potencjalnych aktywatorów w procesie utleniania związków siarki. W pracy badano proces fotoutleniania siarki elementarnej w obecności NdPc2 oraz YbPc2 w roztworze DMF. Otrzymane wyniki wskazują, że jedynie kompleks z Yb efektywnie katalizował badaną reakcję, przy mniejszym natężeniu promieniowania UV. Okazało się, że największy wpływ na przebieg i wydajność procesu fotoutleniania ma intensywność naświetlania układu. Rodzaj użytego fotoa…

Preparation of tungstophosphoric acid/cerium-doped NH2-UiO-66 Z-scheme photocatalyst: a new candidate for green photo-oxidation of dibenzothiophene a…

2021

International audience; The goal of this study was to introduce an effective visible-light induced photocatalytic system with a good ability for photocatalytic oxidative desulfurization (PODS) and denitrogenation (PODN) using molecular oxygen (O2) as an oxidant. In this regard, tungestophosphoric acid (PW12) was supported onto cerium-doped NH2-UiO-66 (PW12/Ce-NUiO-66) and employed for the photo-oxidation of dibenzothiophene (DBT) and quinoline (Qu). Herein, using cerium (Ce) as a “mediator” facilitated the separation of charge carriers, while NH2-UiO-66 remarkably enhanced the surface area with plentiful adsorption sites and shifted the adsorption edge of PW12to the visible region. The sum …

Role of the support and pseudo-liquid phase in the Phosphotungstic Heteropolyacid (photo)catalytic activity

2016

Catalytic and photocatalytic tests for propene hydration to 2-propanol were successfully carried out by using binary materials obtained by supporting a Keggin or Wells-Dawson heteropolyacids via impregnation method to commercial SiO2 or TiO2. (Photo)catalytic hydration was studied in gas-solid regime by using a continuous (photo)reactor working at atmospheric pressure and 80 °C. The alcohol was the main product. The acidity of the cluster accounts for the catalytic role, whereas both the acidity of the cluster and the oxidant ability were responsible for the increase of the reaction rate of the photo-assisted catalytic reaction. Moreover, the presence of a photoactive semiconductor support …

Photocatalytic activity in gas–solid regime of ZnO-ZnAl2O4 composites

2011

Heterogeneous photocatalysis: guidelines on experimental setup, catalyst characterization, interpretation, and assessment of reactivity

2019

Soon after the publication of the first pioneering works on heterogeneous photocatalysis, the number of papers on this topic continuously increased. This intriguing field of research is very complex as it endows with an interdisciplinary overview that involves different aspects of chemistry, physics, material and environmental sciences. Even if photocatalytic applications in real processes are often difficult to be implemented and scaled-up, investigations at laboratory scale are easy to be performed, and in some cases they may give rise to misconceptions. For this reason, the present work aims to sum up most of the common experimental techniques and procedures generally used in heterogeneo…

Structure and Photocatalytic Properties of TiO2-WO3Composites Prepared by Electrophoretic Deposition

2015

In this work TiO2-WO3 composite films containing different oxide concentrations were prepared by electrophoretic deposition on steel substrates. Composite coating structures were analyzed by X -ray diffraction, Raman spectra and scanning electron microscopy. The results showed an even distribution of WO3 particles in the entire composite layer. Light absorption measurements were used for photocatalytic properties evaluation. It was found that the removal ratio of methylene blue depends on the (TiO2):(WO3) concentration ratio. The most effective photodegradation was determined for the sample that was electrophoretically deposited from the suspension with the molar content ratio n(TiO2):n(WO3…