Browsing by Subject "excilamp"

Now showing 1 - 4 of 4
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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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    A new substrate and by-product kinetic model for the photodegradation of 4-chlorophenol with KrCl exciplex UV lamp and hydrogen peroxide
    (Elsevier, 2012-04-01) Murcia Almagro, María Dolores; Gómez, María; Gómez, Elisa; Gómez, José Luis; Hidalgo Montesinos, Asunción María; Christofi, Nick; Ingeniería Química
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    Comparison of alternative treatments for 4-chlorophenol removal from aqueous solutions: Use of free and immobilized soybean peroxidase and KrCl excilamp
    (Elsevier, 2009-09-30) M. Gomez; G. Matafonova; J.L. Gomez; V. Batoev; N. Christofi; Ingeniería Química; Baikal Institute of Nature Management, Siberian Branch of Russian Academy of Sciences; Pollution Research Unit, School of Life Sciences, Edinburgh Napier University
    The removal of 4-chlorophenol (4-CP) from industrial wastewater continues to be an important environmental issue and some interesting results have been obtained using oxidoreductive enzymes such as peroxidases and UV, generated by novel excilamps. In this study enzyme (free and immobilized soybean peroxidase) and UV (produced by a KrCl excilamp) were used to treat 4-CP solutions at concentrations ranging from 50 to 500 mg L-1. It was shown that the excilamp can facilitate higher removal efficiencies in all cases with complete 4-CP elimination taking place between 5 and 90 min. The enzyme removed ~80% of the 4-CP concentrations in both the free and immobilized state up to concentrations of 250 mg L-1. At 500 mg L-1 the immobilised system shows much higher removal efficiency due to increased enzyme stability in the presence of higher formation of by-products.
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    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.