108 research outputs found
Advances in Photocatalytic Membrane Reactor
No full textInternational audiencePhotocatalytic membrane reactors (PMRs) are a promising technology that combines the benefits of photocatalysis and membrane separation [...
TRAITEMENT DES COMPOSES ORGANIQUES VOLATILS (COV) PAR ADSORPTION SUR ZEOLITHE. ETUDE DU COUPLAGE ABSORPTION/ADSORPTION APPLIQUE AU TRAITEMENT DE L'AIR
No full textTOULOUSE-INSA (315552106) / SudocSudocFranceF
Ozone Diffusion through a Hollow Fiber Membrane Contactor for Pharmaceuticals Removal and Bromate Minimization
No full textRecently, ozonation has been advocated as a solution to tackle emerging contaminants. Hollow fiber membrane contactors (HFMC) have a lower residual ozone concentration than bubble reactors that could limit the formation of potential ozonation by-products, especially bromates that are regulated in drinking water. The aim of this study was to evaluate ozonation with HFMC for pharmaceutical abatement and bromate minimization compared to bubble columns in wastewater. A HFMC, composed of 65 polytetrafluoroethylene hollow fibers with a 0.45 mm/0.87 mm inner/external diameter and a 0.107 m² exchange surface, was used for the ozonation of real-treated wastewater spiked with 2 µM of p-chlorobenzoic acid (p-CBA) and 3 mg.L−1 of bromide. p-CBA was tracked to monitor the production of strongly-oxidant hydroxyl radicals from the decomposition of the molecular ozone. At 100% p-CBA abatement, 1600 µg.L−1 of bromate was formed with the HFMC, whereas 3486 µg.L−1 was formed with the bubble column. These results demonstrate that HFMC can produce a significant amount of hydroxyl radicals while limiting bromate formation in real-treated wastewater. The test water was also spiked with carbamazepine and sulfamethoxazole to evaluate the abatement efficiency of the process. Short contact times (approximately 2s) achieved high rates of pharmaceuticals removal without bromate formation
Modelling of a falling thin film deposited photocatalytic step reactor for water purification: Pesticide treatment
No full textInternational audiencePhotocatalysis is a process that can mineralize organic pollutants such as pesticides released from agricultural activities. In this work we study the modelling of photocatalytic degradation of metolachlor and chlortoluron in a falling film closed loop step photoreactor. TiO2 was coated on fiber which was deposited on the steps. The modelling was done by introducing an equivalent intermediate (EI) formed by the photo-oxidation of the initial compound to reproduce, partially, the competitive effect of the unknown by-products. The results obtained are satisfactory for describing the degradation kinetics but need improvement for the description of the mineralization. The model was used to simulate the degradation and the mineralization of a commercial pesticide solution (chlortoluron). The fitting gives interesting results but the description of the chemical pathway has to be refined
Photocatalytic degradation of a triazole pesticide, cyproconazole, in water
No full textInternational audienc
Modelling of a falling thin film deposited photocatalytic step reactor for water purification: Pesticide treatment
No full text
Evaluation of an ozone diffusion process using a hollow fiber membrane contactor
No full textInternational audienc
Integration of photocatalysis and biological treatment for azo dye removal--application to AR183.
No full textInternational audienceThe feasibility of coupling photocatalysis with biological treatment to treat effluents containing azo dyes was examined in this work. With this aim, the degradation of Acid Red 183 was investigated. The very low biodegradability of AR183 was confirmed beforehand by measuring the biological oxygen demand (BOD5). Photocatalysis experiments were carried out in a closed-loop step photoreactor. The reactor walls were covered by TiO2 catalyst coated on non-woven paper, and the effluent flowed over the photocatalyst as a thin falling film. The removal of the dye was 82.7% after 4 h, and a quasi-complete decolorization (98.5%) was obtained for 10 h of irradiation (initial concentration 100 mg L(-1)). The decrease in concentration followed pseudo-first-order kinetics, with a constant k of 0.47 h(-1). Mineralization and oxidation yields were 80% and 75%, respectively, after 10 h of pretreatment. Therefore, even if target compound oxidation occurs (COD removal), indicating a modification to the chemical structure, the concomitant high mineralization was not in favour of subsequent microbial growth. The BOD5 measurement confirmed the non-biodegradability of the irradiated solution, which remained toxic since the EC50 decreased from 35 to 3 mg L(-1). The proposed integrated process appeared, therefore, to be not relevant for the treatment of AR183. However, this result should be confirmed for other azo dyes
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