Browsing by Subject "UV"

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    A KrCl exciplex flow-through photoreactor for degrading 4-chlorophenol:Experimental and modelling
    (Elsevier, 2012) M. Gomez; M.D. Murcia; J.L. Gomez; E. Gomez; M.F. Maximo; A. Garcia; Ingeniería Química
    A KrCl exciplex flow-through photoreactor has been used for the removal of 4- chlorophenol. UV/H2O2 and photo-Fenton processes were tested. Considering the degradation of the different compounds, the molar ratio H2O2:4-chlorophenol did not show a significant influence on 4-chlorophenol while an optimum ratio of 25:1 was established for the photoproducts. The presence of the Fenton reagent led to a considerable improvement in the photodegradation of both the substrate and by- products, and an optimum Fe2+ concentration of 5 mg L-1 was determined. Under these conditions, total degradation was attained for a range of substrate concentrations between 50 and 150 mg L-1 and for reaction volumes of 500 mL. A photodegradation mechanism was also proposed, based on the formation of two intermediate compounds that quickly degrade to the primary photoproducts previously identified. A kinetic model was developed and theoretical conversion values of the 4-chlorophenol and the photoproducts were compared with the experimental ones, reaching a high degree of agreement (xcalc = 0.9964 xexp, R2 = 0.9986) and validating the proposed model. This system simulation using relatively high reaction volumes and including the by-products in the kinetic equations represents a first approach with a view to operating in continuous or semi-continuous systems that allow the scaling up of the process.
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    Open Access
    Testing a KrCl excilamp as new enhanced UV source for 4-chlorophenol degradation: experimental results and kinetic model.
    (Elsevier, 2010) M. Gomez; M.D. Murcia; J.L. Gomez; G. Matafonova; V. Batoev; N. Christofi; Ingeniería Química; Baikal Institute of Nature Management, Siberian Branch of Russian Academy of Sciences, Russia; Pollution Research Unit, School of Life Sciences, Napier University, Merchiston Campus, Edinburgh
    Excilamps are new UV sources with great potential for application in wastewater treatment. In the present work, a KrCl excilamp emitting radiation at 222 nm has been used for the photodegradation of 4-chlorophenol within a range of concentrations from 50 to 500 mg L-1. The photodegradation process has been shown to form two main photoproduct intermediates, benzoquinone and hydroquinone. Total removal of 4- chlorophenol was shown for all concentrations assayed, and, for both main intermediates, residual concentrations of 20–30 % of the initial concentration of 4-chlorophenol remained. Their increasing presence with increasing initial concentrations of 4-chlorophenol had the effect of decreasing the removal efficiency of the photoproducts. In order to simulate the process and scale-up a simplified kinetic model has been developed and validated from the experimental data.