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Polymeric films and in particular polypropylene (PP) films could be selected as excellent substrates for photocatalytic applications based on TiO2. However, hydrophobic surface of PP makes very difficult the adhesion of TiO2 particles on its surface. In this work corona pre-treated PP was used as a support for commercial TiO2 in order to remove organic dye methylene blue (MB) from aqueous solution under UV irradiation. In details, the pre-treated polypropylene PP films were coated with TiO2 particles by dip-coating technique. The corona pre-treatment is a practical and effective method to increase the wettability of organic polymers due to the introduction of negative groups (COO- , –O–O- ) onto the surfaces, which results in a better adhesion of the photocatalyst. The obtained coated films were characterized with different techniques sand the photocatalytic effect under UV light was analyzed in the degradation of MB dye. The photocatalytic tests were carried out in a batch photoreactor irradiated by a UV lamp (nominal power of 8 W and wavelength emission 365 nm). The experimental results showed that the coating of TiO2 onto PP films allowed to achieve a MB discoloration of 47% after about 180 min of UV irradiation. In contrast the unfunctionalized PP film did not shown any photocatalytic activity under the same irradiation conditions.

Nowadays one of the most significant environmental problems is related to wastewater treatment because the release of pollutants into the environment has posed a risk to natural ecosystems and human health. Therefore, it is necessary to treat wastewater in appropriately way. Three main steps are applied in wastewater treatments that are commonly called preliminary, secondary and tertiary treatment. The preliminary and secondary treatment steps are based on physical and chemical processes. However, in most cases these types of processes are not enough alone. Among tertiary process treatment, compared to the common processes used for wastewater disinfection, new methods without the formation of disinfection by-products have been recently investigated by researchers. In this sense, among advanced oxidation process (AOPs), heterogeneous photocatalysis is a powerful alternative technique to treat polluted water because it is able to mineralize many organic compounds through the generation of hydroxyl radicals thanks to the presence of a semiconductor activated by a light source. For engineering applications, the immobilization of catalyst powders onto a suitable solid inert support is required. In this work, ZnO immobilized on macroscopic polystyrene pellets has been prepared, characterized and studied in the photocatalytic treatment of four wastewaters samples coming from secondary and tertiary processes of wastewater treatment plant by leather industries. The efficiency of the system has been determined by measuring chemical oxygen demand (COD) and total organic carbon (TOC). Photocatalytic results showed in all cases a significant COD and TOC reduction, after 7 h of UV light irradiation.

In this work the photocatalytic hydrogen production from aqueous solution containing organic compounds, using perovskite based photocatalyst supported on magnetic particles, was studied. In particular a photocatalyst based on Ru doped LaFeO3 was used. The photocatalyst was prepared by solution combustion synthesis using citric acid as organic fuel, and it was characterized by different techniques, such as XRD, UV-Vis DRS and Raman spectroscopy. This semiconductor has shown photocatalytic activity in presence of visible light and it was supported on Fe2O3 magnetic particles in order to remove it easily at the end of the process. The Fe2O3 particles were prepared by combustion flame synthesis, using citric acid as organic fuel and metal nitrate as iron oxide precursor. The Ru-LaFeO3 photocatalyst was coupled with magnetic Fe2O3 particles by a physical mixture in order to ensure a tight contact between the two solid phases (Ru-LaFeO3/Fe2O3). Photocatalytic tests were carried out in a pyrex cylindrical reactor equipped with a N2 distributor device and irradiated by visible-LEDs. Different aqueous solution containing organic compounds such as ethanol, glycerol or methanol were tested. The experimental results evidenced that the higher hydrogen production (about 10000 µmol L-1 after 4 h of irradiation time) was obtained in presence of methanol. The magnetic composite showed a very high stability also after several reuse cycles.

The hydrolysis of carbonyl sulfide (COS) was studied in a gas-liquid reactor at room temperature and ambient pressure in presence of alkanolamines, such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and diisopropylamine (DIPA). The activity and stability of the different amines was investigated at fixed COS inlet concentration and reaction volume. The highest removal efficiency of COS was obtained in presence of DEA aqueous solution (25 %), while the lowest COS conversion was observed with the tertiary amine MDEA (< 10 %). A greater COS removal was obtained in presence of the higher reaction volume (400 cm3) that was equal to 25 % for DEA and 26 % for DIPA, respectively. Finally, the evaluation of the kinetic constant for the COS hydrolysis reaction with DEA was performed.

The aim of this work was to evaluate the effectiveness of TiO2 pellets for the photocatalytic oxidation of As(III) to As(V) under UV light with simultaneous adsorption of As(V) in a continuous packed bed photoreactor. In particular commercial cylindrical pellets of TiO2 were used as photocatalyst. Experimental photocatalytic tests were carried out in a cylindrical pyrex photoreactor (irradiated by UV-LEDs) which operates in continuous mode in order to treat aqueous solution contaminated with arsenic at different initial As(III) concentration. Preliminary tests conducted in a batch configuration showed that TiO2 pellets adsorb As(V) produced from the photoreaction, without leading to a deactivation of the active sites and evidencing that the As(V) produced is completely released into the solution. Moreover, TiO2 pellets maintained an excellent photoactivity and durability after several cycles making it a very promising catalyst to be employed in continuous reactors for the photocatalytic treatment of water polluted by arsenic, obtaining 98% As(III) oxidation yield after only 15 min of UV-LEDs irradiation. Moreover, the use of a continuous packed bed reactor filled with the stable TiO2 catalyst pellets irradiated by UV light allows to reach a steady state As(III) concentration without any deactivation phenomena. Finally, with 1 mg L-1 As(III) initial concentration, no As(V) release was observed from TiO2 surface during the irradiation time evidencing that the total arsenic removal could be achieved thanks to the photocatalytic properties and adsorption ability of the TiO2 pellets.

Photo)catalytic propylene hydration to 2-propanol and glycerol dehydration to acrolein reactions were carried out by using Keggin heteropolyacids (HPAs) supported on TiO2. Binary materials have been prepared by impregnation of H3PW12O40, H3PMo12O40 and H4SiW12O40, on TiO2 Evonik P25. Moreover, a binary material consisting of H4SiW12O40 and TiO2 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-rayand (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The supported Keggin HPA species played a key role both for the catalytic and for the photo-assisted catalytic reactions due to their strong acidity and ability to form strong oxidant species under UV irradiation.