Browsing by Subject "Kinetic model"

Now showing 1 - 4 of 4
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    Advanced oxidation of PET-derived monomers using excimer radiation and hydrogen peroxide: kinetic and operational insights
    (MDPI, 2026-01-29) Gómez Gómez, María; Montiel Morte, María Claudia; Gómez Gómez, Elisa; Hidalgo Montesinos, Asunción María; Máximo, María Fuensanta; Murcia Almagro, María Dolores; Ingeniería Química; Facultades de la UMU::Facultad de Química
    Growing environmental concern over plastic pollution has increased the need to address the persistence of PET-derived monomers, such as bis(2-hydroxyethyl) terephthalate (BHET) and terephthalic acid (TPA). This work examines the use of excimer radiation lamps combined with hydrogen peroxide (H2O2) to enhance advanced oxidation processes (AOPs) for their degradation. This approach stands out for its high selectivity, absence of mercury, and lower production of toxic byproducts. Experimental tests assessed how different operational factors affect pollutant degradation, such as the initial pollutant concentration (50–200 mg/L), the reaction volume (125–500 mL), and the H2O2:monomer mass ratio (0:1–6:1 for BHET and 0:1–4:1 for TPA). For BHET, the best results occurred with a 5:1 mass ratio, while TPA degraded optimally with a 3:1 ratio, with a 250 mL reaction volume and a 100 mg/L initial concentration for both compounds. Under these conditions, total degradation of the initial monomers was achieved in around 30 and 80 min for BHET and TPA, respectively, and at the end of the reaction, COD decreased by 46% and 32% relative to their initial values. In both cases, hydrogen peroxide was crucial since UV radiation alone led to much lower degradation efficiency. These results emphasize the need to optimize operational conditions for greater efficiency and establish a starting point for future use of excimer technology in the treatment of wastewater contaminated with PET and its derivatives. Additionally, the degradation data closely matched a pseudo-first-order kinetic model (R2 ≈ 1), confirming its reliability for predictive analysis, which is of high importance for the simulation and optimization of the process.
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    Comparison of two excilamps and two reactor configurations in the UV-H2O2 removal process of amaranth
    (2019-11-18) Murcia, M.D.; Gómez, M.; Gómez, E.; Gómez, J.L.; Hidalgo, A.M.; Murcia, S.; Campos, D.; Ingeniería Química
    Nowadays dyes are used in many industrial activities and their presence in wastewater is quite common and involves different environmental and health problems. In addition, dyes are usually recalcitrant compounds and conventional treatment are not appropriate for their removal. So there is great interest in finding alternative removal processes, as the one based on excimer lamp technology for the removal of amaranth dye described in the present work. Two excilamps and two reactor configurations have been tested: a batch reactor with KrCl or XeBr excilamp and a KrCl flow-through photoreactor. After comparing the results for both lamps in the batch reactor, the KrCl excilamp has proven to be more efficient both in terms of conversions achieved and energy consumption and, by this, it has been selected to be used in the flow-through photoreactor. For both reactor configurations, several experimental series were done to analyze the influence of the different operational variables on the photoprocess and the optimal mass ratio between hydrogen peroxide and dye has been established. Also, it has been proven that the use of Fenton reagent improves the process efficiency, particularly in the case of the XeBr lamp. In addition, a kinetic model, based on a previous one developed by the authors for a flow-through photoreactor and slightly modified to can also apply it to batch reactors, has been applied. The model has been validated with an excellent fitting of the experimental data for all series and both reactor configurations.
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    Modelling and experimental checking of the influence of substrate concentration on the first order kinetic constant in photo-processes
    (Elsevier, 2016-09-19) Gómez Gómez, María; Murcia Almagro, María Dolores; Gómez Gómez, Elisa; Ortega Requena, Salvadora; Sánchez, A.; Thaikovskaya, O.; Briantceva, N.; Ingeniería Química; Facultades de la UMU::Facultad de Química
    Most photoprocesses follow a pseudo first order kinetic law and, commonly, the kinetic parameter depends on the initial concentration of the substrate. In this work, a kinetic model, which explains this dependence on the substrate concentration and on the other operational variables, has been developed. In the model, mass transfer of substrate from the bulk solution to the wall of the photoreactor was assumed as the step determining the rate of the process. To check the model, methylene blue (MB) has been used as model substrate and photodegradation experiments have been carried out in an exciplex KrCl flow-through photoreactor, It was observed that the methylene blue conversion improved with a decrease in its initial concentration, in good agreement with the model. Also, by fitting the experimental data to the model, high correlation coefficients and a high degree of agreement between experimental and calculated conversion was obtained, which validates the model.
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    Publication
    Open Access
    Modelling and experimental checking of the influence of substrate concentration on the first order kinetic constant in photo-processes
    (Elsevier, 2016-09-19) Gómez Gómez, María; Murcia Almagro, María Dolores; Gómez Gómez, Elisa; Ortega Requena, Salvadora; Sánchez, A.; Thaikovskaya, O.; Briantceva, N.; Ingeniería Química; Facultad de Química
    Most photoprocesses follow a pseudo first order kinetic law and, commonly, the kinetic parameter depends on the initial concentration of the substrate. In this work, a kinetic model, which explains this dependence on the substrate concentration and on the other operational variables, has been developed. In the model, mass transfer of substrate from the bulk solution to the wall of the photoreactor was assumed as the step determining the rate of the process. To check the model, methylene blue (MB) has been used as model substrate and photodegradation experiments have been carried out in an exciplex KrCl flow-through photoreactor, It was observed that the methylene blue conversion improved with a decrease in its initial concentration, in good agreement with the model. Also, by fitting the experimental data to the model, high correlation coefficients and a high degree of agreement between experimental and calculated conversion was obtained, which validates the model.