Gómez Gómez, Elisa

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Gómez Gómez, Elisa

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Gómez Gómez, Elisa

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Universidad de Murcia. Departamento de Ingeniería Química

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Continuous tank reactors in series: an improved alternative in the removal of phenolic compounds with immobilized peroxidase
(Taylor and Francis Group, Taylor and Francis, 2012-01-24) Gómez Gómez, Elisa; Máximo, María Fuensanta; Montiel Morte, María Claudia; Gómez Gómez, María; Murcia Almagro, María Dolores; Ortega Requena, Salvadora; Ingeniería Química; Facultad de Química
Immobilized derivatives of soybean peroxidase, covalently bound to a glass support, were used in a continuous stirred tank reactor in series, in order to study the removal of two phenolic compounds: phenol and 4-chlorophenol. The use of two reactors in series, rather than one continuous tank, improved the removal efficiencies of phenol and 4-chlorophenol. The distribution of different amounts of enzyme between the two tanks showed that the relative distributions influenced the removal efficiency reached and the degree of the enzyme deactivation. The highest removal percentages were reached at the outlet of the second tank for a distribution of 50% of the enzyme in each tank. However, with a distribution of 75% in the first tank and 25% in the second, the elimination percentage in the second tank was slightly lower than in the previous case, and the effects of deactivation of the enzyme in the first tank were less pronounced. In all the distributions assayed it was observed that the first tank acts as a filter for the second one, which receives a feed with a smaller load of phenolic compounds, thus diminishing enzyme deactivation in the second tank.
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; 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.
Open Access
Comparative analysis of kinetic parameters of sustainable branched esters obtained from lauric acid
(American Chemical Society, 2026-02-03) Gómez Gómez, María; Murcia Almagro, María Dolores; Gómez Gómez, Elisa; Hidalgo Montesinos, Asunción María; Máximo, María Fuensanta; Montiel Morte, María Claudia; Ingeniería Química; Facultad de Química
A comparison between four esterification reaction systems to obtain new sustainable branched esters using Novozym 435 as a biocatalyst, the same acid (lauric acid), and four alcohols with different chain lengths and side chains (2-hexyl-1-decanol, 2-ethyl-1-hexanol, 2-butyl-1-octanol, and 3,7-dimethyl-1-octanol) has been carried out. The parameters of the reaction have been optimized in 0.5 g of biocatalyst, temperature of 70 °C, and the stoichiometric molar ratio (1:1). Under these conditions, conversion values of >90% are obtained in the four reactions. Using a kinetic model developed by the authors and based on a Bisubstrate Ping-Pong mechanism, where internal diffusional limitations are considered, the kinetic parameters for each reaction system were determined and the theoretical conversion values closely matched the experimental results, validating the model for this wide range of substrates. Attending at the conversion values obtained, where both the reaction rate and transport rate are considered, the esterification with 3,7-dimethyl-1-octanol leads to the highest average rate, followed by the reactions with 2-ethyl-1-hexanol, 2-butyl-1-octanol, and, finally, 2-hexyl-1-decanol. In the first two systems, the ones with alcohols of shorter side chain and chain length, respectively, the kcat values are very high (49.526 and 90.13 Mh–1 g–1, respectively) and so is the reaction rate, leading to a high average rate. However, when 3,7-dimethyl-1-octanol is used, the conversion values decrease at long reaction times, due to the high volatility of this alcohol. In the reaction system with 2-butyl-1-octanol, there is mixed control of the reaction and transport stages with higher values of the effectiveness factor (above 0.5 in most cases). Finally, in the reaction with 2-hexyl-1-decanol, the alcohol with the longest chain length and side chain, and the highest molecular weight and viscosity, internal diffusional limitations are very high (with low values of the effectiveness factors as expected, around 0.2 for all conditions tested), and the reaction rate is quite low as well, which explains the low average rates obtained. The obtained branched esters are of interest in the biolubricant sector, and the kinetic parameters calculated in this study can be useful to allow simulation, further optimization, and scale up of the esterification process.
Open Access
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.
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.