Jose Casas - Academia.edu (original) (raw)
Papers by Jose Casas
Catalysis Today, 2016
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Journal of the Science of Food and Agriculture, 2000
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Journal of the Taiwan Institute of Chemical Engineers, 2018
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Journal of Chemical Technology & Biotechnology, 2018
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Applied Catalysis B: Environmental, 2016
Abstract The deactivation of a palladium on activated carbon (Pd/AC) catalyst in the hydrodechlor... more Abstract The deactivation of a palladium on activated carbon (Pd/AC) catalyst in the hydrodechlorination (HDC) of the organochlorinated herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in water under ambient-like conditions has been studied. The loss of activity is attributed to the accumulation of organic species involved in the reaction on the catalyst surface. The analysis of the fresh and used catalysts indicated the possibility of regeneration by thermal or washing (water, NaOH solutions) treatments. Bimetallic catalysts, Pd-Rh/AC and Pd-Pt/AC, showed lower activity than the Pd/AC one but higher stability (slower deactivation). A Pd catalyst supported on an activated carbon modified upon oxidation (Pd/AC OX ) exhibited higher activity and stability which can be due to the high concentration of surface oxygen groups that reduced the uptake of fouling species.
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Separation and Purification Technology, 2015
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Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Quí... more Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, Sección de Ingeniería Química . Fecha de lectura: 17-07-2009 Bibliogr.: p.275-315
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Water Science and Technology, 2010
A catalyst based on Fe supported on γ-Al2O3 has been prepared and tested for catalytic wet peroxi... more A catalyst based on Fe supported on γ-Al2O3 has been prepared and tested for catalytic wet peroxide oxidation (CWPO) of cosmetic wastewaters. The influence of the main operating conditions (space-time, temperature, and H2O2 dose) have been investigated. Working with this self-made Fe/γ-Al2O3 catalyst at 85°C, with a space-time of 9.4 kgcat h/kgCOD and a dose of H2O2, corresponding to 0.5 times the theoretical stoichiometric H2O2/COD ratio, a substantial COD reduction (around 80%) has been reached with a complete consumption of H2O2. The locally allowable limit of COD for industrial wastewaters discharge to the municipal sewer system can be achieved at lower temperature and space-time. The catalyst showed a high stability in 100 h time on stream tests, where COD and TOC reductions around 82 and 60%, respectively, were maintained working at 85°C and 9.4 kgcat h/kgCOD space-time. Fe leaching from the catalyst upon that time on stream was lower than 3% of the initial load.
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Journal of Hazardous Materials, 2007
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Journal of Chemical Technology & Biotechnology, 2010
ABSTRACT BACKGROUND: A highly stable Fe/γ-Al2O3 catalyst for catalytic wet peroxide oxidation has... more ABSTRACT BACKGROUND: A highly stable Fe/γ-Al2O3 catalyst for catalytic wet peroxide oxidation has been studied using phenol as target pollutant. The catalyst was prepared by incipient wetness impregnation of γ-Al2O3 with an aqueous solution of Fe(NO3)3· 9H2O. The influence of pH, temperature, catalyst and H2O2 doses, as well as the initial phenol concentration has been analyzed. RESULTS: The reaction temperature and initial pH significantly affect both phenol conversion and total organic carbon removal. Working at 50 °C, an initial pH of 3, 100 mg L−1 of phenol, a dose of H2O2 corresponding to the stoichiometric amount and 1250 mg L−1 of catalyst, complete phenol conversion and a total organic carbon removal efficiency close to 80% were achieved. When the initial phenol concentration was increased to 1500 mg L−1, a decreased efficiency in total organic carbon removal was observed with increased leaching of iron that can be related to a higher concentration of oxalic acid, as by-product from catalytic wet peroxide oxidation of phenol. CONCLUSION: A laboratory synthesized γ-Al2O3 supported Fe has shown potential application in catalytic wet peroxide oxidation of phenolic wastewaters. The catalyst showed remarkable stability in long-term continuous experiments with limited Fe leaching, < 3% of the initial loading. Copyright
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Journal of Catalysis, 2012
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Food Science and Technology International, 2001
Kinetics of biomass and cysteine proteinase formation during growth of Micrococcussp. INIA 528 in... more Kinetics of biomass and cysteine proteinase formation during growth of Micrococcussp. INIA 528 in batch cultivation were studied. Modeling of cultivation data was carried out using an unstructured model. The logistic equation was found to be adequate to describe microbial growth. Production of cysteine proteinase was described by means of an equation including biomass and substrate concentrations. An overall model based on an equation of substrate consumption dependent on biomass formation and proteinase production was postulated. The kinetic parameters (specific growth rate, maximum biomass, proteinase production rate and proteinase formation yield) were obtained taking into account the influence of pH (6.0–8.0), temperature (28–41 ºC) and the addition of different supplements to the basal culture medium [yeast extract, MgSO 4,glucose, K2HPO4 and (NH4)2SO4]. Kinetic parameters were calculated by fitting experimental data by a nonlinear technique using the algorithm of Marquardt coupled to a fourth-order Runge-Kutta subroutine.
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Chemical Engineering Journal, 2010
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Water Research, 2009
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Journal of Chemical Technology & Biotechnology, 2009
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... Permissions & Reprints. Apparent yield stress in xanthan gum solutions at low concentrati... more ... Permissions & Reprints. Apparent yield stress in xanthan gum solutions at low concentrations. F. García-Ochoa and JA Casas. ... At these concentrations, no direct method of yield stress measurement is available. Therefore, an indirect method fitting to a Carson model was used. ...
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Catalysis Today, 2016
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Journal of the Science of Food and Agriculture, 2000
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Journal of the Taiwan Institute of Chemical Engineers, 2018
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Journal of Chemical Technology & Biotechnology, 2018
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Applied Catalysis B: Environmental, 2016
Abstract The deactivation of a palladium on activated carbon (Pd/AC) catalyst in the hydrodechlor... more Abstract The deactivation of a palladium on activated carbon (Pd/AC) catalyst in the hydrodechlorination (HDC) of the organochlorinated herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in water under ambient-like conditions has been studied. The loss of activity is attributed to the accumulation of organic species involved in the reaction on the catalyst surface. The analysis of the fresh and used catalysts indicated the possibility of regeneration by thermal or washing (water, NaOH solutions) treatments. Bimetallic catalysts, Pd-Rh/AC and Pd-Pt/AC, showed lower activity than the Pd/AC one but higher stability (slower deactivation). A Pd catalyst supported on an activated carbon modified upon oxidation (Pd/AC OX ) exhibited higher activity and stability which can be due to the high concentration of surface oxygen groups that reduced the uptake of fouling species.
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Separation and Purification Technology, 2015
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Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Quí... more Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada, Sección de Ingeniería Química . Fecha de lectura: 17-07-2009 Bibliogr.: p.275-315
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Water Science and Technology, 2010
A catalyst based on Fe supported on γ-Al2O3 has been prepared and tested for catalytic wet peroxi... more A catalyst based on Fe supported on γ-Al2O3 has been prepared and tested for catalytic wet peroxide oxidation (CWPO) of cosmetic wastewaters. The influence of the main operating conditions (space-time, temperature, and H2O2 dose) have been investigated. Working with this self-made Fe/γ-Al2O3 catalyst at 85°C, with a space-time of 9.4 kgcat h/kgCOD and a dose of H2O2, corresponding to 0.5 times the theoretical stoichiometric H2O2/COD ratio, a substantial COD reduction (around 80%) has been reached with a complete consumption of H2O2. The locally allowable limit of COD for industrial wastewaters discharge to the municipal sewer system can be achieved at lower temperature and space-time. The catalyst showed a high stability in 100 h time on stream tests, where COD and TOC reductions around 82 and 60%, respectively, were maintained working at 85°C and 9.4 kgcat h/kgCOD space-time. Fe leaching from the catalyst upon that time on stream was lower than 3% of the initial load.
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Journal of Hazardous Materials, 2007
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Journal of Chemical Technology & Biotechnology, 2010
ABSTRACT BACKGROUND: A highly stable Fe/γ-Al2O3 catalyst for catalytic wet peroxide oxidation has... more ABSTRACT BACKGROUND: A highly stable Fe/γ-Al2O3 catalyst for catalytic wet peroxide oxidation has been studied using phenol as target pollutant. The catalyst was prepared by incipient wetness impregnation of γ-Al2O3 with an aqueous solution of Fe(NO3)3· 9H2O. The influence of pH, temperature, catalyst and H2O2 doses, as well as the initial phenol concentration has been analyzed. RESULTS: The reaction temperature and initial pH significantly affect both phenol conversion and total organic carbon removal. Working at 50 °C, an initial pH of 3, 100 mg L−1 of phenol, a dose of H2O2 corresponding to the stoichiometric amount and 1250 mg L−1 of catalyst, complete phenol conversion and a total organic carbon removal efficiency close to 80% were achieved. When the initial phenol concentration was increased to 1500 mg L−1, a decreased efficiency in total organic carbon removal was observed with increased leaching of iron that can be related to a higher concentration of oxalic acid, as by-product from catalytic wet peroxide oxidation of phenol. CONCLUSION: A laboratory synthesized γ-Al2O3 supported Fe has shown potential application in catalytic wet peroxide oxidation of phenolic wastewaters. The catalyst showed remarkable stability in long-term continuous experiments with limited Fe leaching, < 3% of the initial loading. Copyright
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Journal of Catalysis, 2012
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Food Science and Technology International, 2001
Kinetics of biomass and cysteine proteinase formation during growth of Micrococcussp. INIA 528 in... more Kinetics of biomass and cysteine proteinase formation during growth of Micrococcussp. INIA 528 in batch cultivation were studied. Modeling of cultivation data was carried out using an unstructured model. The logistic equation was found to be adequate to describe microbial growth. Production of cysteine proteinase was described by means of an equation including biomass and substrate concentrations. An overall model based on an equation of substrate consumption dependent on biomass formation and proteinase production was postulated. The kinetic parameters (specific growth rate, maximum biomass, proteinase production rate and proteinase formation yield) were obtained taking into account the influence of pH (6.0–8.0), temperature (28–41 ºC) and the addition of different supplements to the basal culture medium [yeast extract, MgSO 4,glucose, K2HPO4 and (NH4)2SO4]. Kinetic parameters were calculated by fitting experimental data by a nonlinear technique using the algorithm of Marquardt coupled to a fourth-order Runge-Kutta subroutine.
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Chemical Engineering Journal, 2010
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Water Research, 2009
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Journal of Chemical Technology & Biotechnology, 2009
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... Permissions & Reprints. Apparent yield stress in xanthan gum solutions at low concentrati... more ... Permissions & Reprints. Apparent yield stress in xanthan gum solutions at low concentrations. F. García-Ochoa and JA Casas. ... At these concentrations, no direct method of yield stress measurement is available. Therefore, an indirect method fitting to a Carson model was used. ...
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