engleski

Predictive models for environmental pollutants degradation by solar photocatalysis in compound parabolic collector (CPC) reactor

The most challenging aspect of water treatment is to remove the recalcitrant trace organic pollutants from wastewaters. In this study, we report the application of photocatalytic oxidation process for the degradation of residual pollutants often found in surface water. The presence of these ecotoxic substances in the aquatic environment is given full consideration in the frame of on-going EU regulations as priority and emerging substances that need to be reduced (amendments to the Water Framework Directive). On the other hand, TiO2 photocatalysis is listed as emerging best available technique (BAT) in the reference document for common wastewater and waste gas treatment/management systems in the chemical sector [1]. Widespread research has been made into the photocatalytic properties of TiO2 because of its ability to break down and destroy many types of pollutants. However, outdoor applications of this technology are still developing, primarily due to small quantum efficiencies and the lack of simple methods for the design, optimization and scale-up of photocatalytic reactor systems. Semi-pilot scale compound parabolic collector (CPC) reactor was fabricated to study the solar photocatalytic degradation of common organic pollutants: 1H-benzotriazole, carbamazepine, imidacloprid, 17-estradiol and ibuprofen over TiO2 (titanium dioxide) and TiO2/CNT (nanocomposite of titanium dioxide and carbon nanotubes) thin-film supported on glass fibers by modified sol-gel method [2]. The CPC reactor represents an optimal reactor and is recognized as the state-of-the-art from the aspect of reactor geometry and incident irradiation usage. Reactor system can be easily scaled-up and installed at the outlet of municipal water treatment plants and industrial wastewaters or be used as emerging system for water purification on terrain sites. The modular panel with the full-spectra solar lamps having appropriate UVB and UVA irradiation levels was used as a simulation of sunlight. The experimental results consisted of comprehensive data of primary pollutants and their by-products analysis using LC/Q-TOF/MS technique. The predictive models were developed to estimate the pollutant degradation in flat-plate reactors independent on the reactor size and capacity. The comprehensive model was consisted of three sub- models: radiation emission, fluid-dynamics in a rectangular open channel in a cascade set-up and the reaction kinetics coupled with irradiation absorption and combined with the appropriate mass balance. The “intrinsic” photocatalytic reaction constants for targeted pollutants, independent of irradiance levels, reactor geometry and hydrodynamics were presented.

solar photocatalysis, compound parabolic collector (CPC) reactor, environmental pollutants, LC/Q-TOF/MS

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