ZnO Polymeric Composite Films for n-Decane Removal from Air Streams in a Continuous Flow NETmix Photoreactor under UVA Light

Polymeric composite films have been explored for many photocatalytic applications, from water treatment to self-cleaning devices. Their properties, namely, thickness and porosity, are controlled mainly by the preparation conditions. However, little has been discussed on the effect of thickness and porosity of polymeric composite films for photocatalytic processes, especially in gas phase. In the present study, different preparation treatments of ZnO-based polymeric composite films and their effects on its performance and stability were investigated. The polymeric composites were prepared by solution mixing followed by non-solvent induced phase separation (NIPS), using poly(vinylidene fluoride) (PVDF) as the matrix and ZnO-based photocatalysts. Different wet thickness, photocatalyst mass, and treatments (e.g., using or not pore-forming agent and compatibilizer) were assessed. A low ZnO/PVDF ratio and higher wet thickness, together with the use of pore-forming agent and compatibilizer, proved to be a good strategy for increasing photocatalytic efficiency given the low agglomerate formation and high polymer transmittance. Nonetheless, the composites exhibited deactivation after several minutes of exposure. Characterization by XRD, FTIR-ATR, and SEM were carried out to further investigate the polymeric film treatments and stability. ZnO film was most likely deactivated due to zinc carbonate formation intensified by the polymer presence

Intensification of heterogeneous TiO2 photocatalysis using an innovative micro-meso-structured-photoreactor for n-decane oxidation at gas phase

The main goal of this work is to overcome barriers in heterogeneous TiO2 photocatalysis application towards indoor air decontamination by process intensification. The photocatalytic oxidation (PCO) of gas-phase n-decane was studied using a micro-meso-structured-photoreactor irradiated by simulated solar light, consisting of chambers and channels mechanically engraved in an acrylic slab. The network of chambers and channels is sealed with a borosilicate slab, allowing a good light penetration through the entire reactor depth. A sheet of cellulose acetate (CA) coated, in one side, with TiO2-P25 was assembled between the two slabs, allowing high spatial illumination homogeneity over the catalyst surface. The P25 thin film was in contact with the air stream flowing in the network. The reactor contains 1.95 g of TiO2 in contact with the air stream per liter of reactor volume and the illuminated catalyst surface area, in contact with the gas phase, per reactor volume was calculated to be 349 m(2) m(-3), which is similar to 1.4 times higher than that obtained for an annular photoreactor packed with CA monolithic structures coated with TiO2-P25. The PCO reaction rate, r(dec), was assessed under different experimental conditions: amount of TiO2 supported in CA sheets, n-decane feed concentration, feed flow rate, relative humidity and UV irradiance. The highest r(dec) value (0.82 mu mol min(-1)) was achieved when the following conditions were employed: mTiO(2) = 75 mg, C-dec,C-feed = 131 x 10(-2) mol m(-3), Q(feed) = 220 cm(3) min(-1) and I = 38.4 W m(-2). The maximum reactivity of photocatalyst in combination with the photoreactor was 6.93 x 10(-4) mol m(reactor)(-3) s(-1), which is a 21.4 fold increase when compared with the annular photoreactor, highlighting the enhancement of mass and photons transfer