Pedro Arroyo | Universidade Estadual de Maringa (original) (raw)

Papers by Pedro Arroyo

Research paper thumbnail of Impregnação do heteropoliácido 12-tungstofosfórico, H3PW12O40, em carvão

Latin American Journal of Development

O heteropoliácido 12-tungstofosfórico foi impregnado em carvão de coco em duas diferentes concent... more O heteropoliácido 12-tungstofosfórico foi impregnado em carvão de coco em duas diferentes concentrações, 20 e 50%, visando avaliar a diferença estrutural da amostra impregnada. Os resultados mostraram que o carvão de coco possui uma elevada área específica, indicando seu potencial como suporte para catalisadores de baixa área específica, e que a metodologia de impregnação utilizada foi eficiente devido à formação da estrutura do ácido nas análises de DRX após a aplicação do mesmo.

Research paper thumbnail of Influência do tempo de sulfatação nas características estruturais e acidez do catalisador zircônia sulfatada

Latin American Journal of Development

Amostras de óxido de zircônio foram preparadas utilizando o método de precipitação em NH3, com co... more Amostras de óxido de zircônio foram preparadas utilizando o método de precipitação em NH3, com controle de pH de precipitação. A sulfatação ocorreu por impregnação dos mesmos óxidos, em soluções 0,5 M de H2SO4, variando-se o tempo, verificando a sua influência na formação da fase tetragonal e monoclínica do catalisador. Os resultados mostram que o tempo de sulfatação possui influência direta na força ácida dos catalisadores, devido a maior intensidade dos picos tetragonais, que se caracterizam por fornecer uma maior acidez para os catalisadores.

Research paper thumbnail of New Insights into the Effect of the Zeolites Framework Topology on the Esterification Reactions: A Comparative Study from Experiments and Theoretical Calculations

Topics in Catalysis

Understanding the catalytic activity of protonic zeolites in biomass conversion allows design cat... more Understanding the catalytic activity of protonic zeolites in biomass conversion allows design catalysts specific for various industrial applications resulting in a strong economic impact. The aim of the present work is to analyze the influence of the pore topology and density of active sites comparing H-ZSM-5, H-Beta and H-Y zeolites as solid acid catalysts for the esterification of oleic acid. The catalysts were characterized using XRF, N2 isotherms, NH3-TPD and, 27Al MAS-NMR techniques, catalytic tests were conducted in a batch reactor (20 bar N2, 100 ℃ and 600 RPM), theoretical investigations by DFT calculations were also performed. Zeolites with lower Al density (H-Y and H-ZSM-5) showed higher acid strength, however, H-Beta showed higher conversion than H-ZSM-5 because in BEA-type structures the Al are found in places that are more accessible. H-Y was highly effective for this reaction (98% conversion) and exhibiting promising recyclability, which could be related to their high specific area, hydrophobicity effect and symbiosis between Brønsted acid sites and the presence of extra-framework aluminum inside the zeolite cavity. H-ZSM-5 showed a 70% conversion yield due to the high Si/Al ratio and the additional porosity of this de-aluminized material. DFT results showed that the channel system of H-Y and H-Beta zeolite framework favor the stabilization of coadsorbed species within their confined environments, and such effect could minimize the activation barrier in consecutive steps of the reaction. Our results suggest the use of protonic zeolites as strategic catalytic material in the recovery of oleaginous residues to obtain products with higher added value.

Research paper thumbnail of Nitrogen-doped activated carbons with high performances for CO2 adsorption

Journal of CO2 Utilization

Research paper thumbnail of DFT calculations for adsorption of H2S and other natural gas compounds on (Fe, Co, Ni, Cu and Zn)–Y zeolite clusters

Microporous and Mesoporous Materials, 2022

Research paper thumbnail of Optimization of Sibipiruna activated carbon preparation by simplex-centroid mixture design for simultaneous adsorption of rhodamine B and metformin

Journal of Hazardous Materials, 2021

The present paper reports the application of augmented simplex-centroid mixture design to obtain ... more The present paper reports the application of augmented simplex-centroid mixture design to obtain a high BET surface area activated carbon using as reactants KOH, K2CO3 and K2C2O4. The optimum mixture composition was 2.51 g of KOH, 0.49 g of K2CO3 and absence of K2C2O4, generating an optimized AC (ACop) with SBET value equals to 1984 m2 g-1. The results herein obtained show that low amounts of K2CO3 can catalyze the pore development in the presence of KOH, increasing the surface area. Furthermore, the fractal dimensions of ACop are greater than 2.72, indicating the material has a complex pore structure with irregularities self-similar upon variations of resolution, as seen by SEM images. The TPD curves showed that the ACop has different oxygenated molecular fragments, which agrees with the pHPZC value (5.05). The ACop was applied in the adsorption of rhodamine B (RhB) and metformin (Met) in both binary and monocomponent systems. The simultaneous adsorption at 30 °C reveals that the adsorption capacity of RhB is 630.94 mg g-1, while for Met the value is 103.83 mg g-1.

Research paper thumbnail of Catalytic improvement of biomass conversion: Effect of adding mesoporosity on MOR zeolite for esterification with oleic acid

Renewable Energy, 2021

Abstract Catalytic processes play an important role in the valorization of biomass for the produc... more Abstract Catalytic processes play an important role in the valorization of biomass for the production of biofuels. In this context, the effect of desilication of MOR zeolite (H-MOR-D) on the esterification of oleic acid as a model reaction for biomass conversion was investigated. Zeolite catalysts were characterized by BET, TG, NH3-TPD, XRD, XRF, FTIR and 27Al MAS NMR analysis and the results showed that the alkaline treatment caused a decrease in crystallinity and removal of sites with greater acid strength of the zeolite precursor. The conversion of oleic acid into methyl oleate catalyzed by H-MOR was less (44%) than that obtained by the treated zeolite H-MOR-D (70%), suggesting that the catalytic activity in the MOR structure does not depend only on the high density of strong acid sites. DFT calculations showed that, bulky molecules suffer molecular distortions within the confined voids, consequently the adsorption enthalpy is highly unstable limiting the formation of intermediates and thus contributing to the lower reaction rate observed experimentally in H-MOR zeolite. Desilication should be considered in projects for the synthesis of new catalysts type zeolite for the conversion of biomass crude or pre-treated, in which bulky molecules prevail.

Research paper thumbnail of Phenomenological modeling of Acutodesmus obliquus microalgae in situ transesterification

Biochemical Engineering Journal, 2019

Research paper thumbnail of Copper-exchanged Y zeolites for gasoline deep-desulfurization

Research paper thumbnail of Removal of H 2 S and CO 2 from biogas in bench scale and the pilot scale using a regenerable Fe-EDTA solution

Research paper thumbnail of Effect of Silylation and Support Porosity of Co/MCM-41 and Co/SiO2 Catalysts in Fischer–Tropsch Synthesis

Topics in Catalysis, 2015

Research paper thumbnail of Mass Transfer Mechanism of Ion Exchange in Fixed Bed Columns

Journal of Chemical & Engineering Data, 2011

Research paper thumbnail of Enhancement of lipase transesterification activity by immobilization on β–cyclodextrin-based polymer

Journal of Sol-Gel Science and Technology, 2019

Research paper thumbnail of CO2 adsorption in hydrochar produced from waste biomass

SN Applied Sciences, 2019

Research paper thumbnail of Synthesis and characterization of pecan nutshell-based adsorbent with high specific area and high methylene blue adsorption capacity

Journal of Molecular Liquids, 2018

Research paper thumbnail of Hydrochars based on cigarette butts as a recycled material for the adsorption of pollutants

Journal of Environmental Chemical Engineering, 2018

Research paper thumbnail of Influence of the chain length of the fatty acids present in different oils and the pore diameter of the support on the catalytic activity of immobilized lipase for ethyl ester production

Brazilian Journal of Chemical Engineering, 2021

In this work, the effect of fatty acid chain length of different oils and the pore diameter of th... more In this work, the effect of fatty acid chain length of different oils and the pore diameter of the biocatalyst were evaluated in the production of ethyl esters. Mesoporous organized silica MCM-41 and SBA-15 with pore diameters of 2.5 nm and 6.7 nm, respectively, were used for the lipase immobilization. The structural and textural characteristics of the supports and biocatalysts were verified by X-ray diffraction and nitrogen physisorption analyses. Pore size was the parameter with the most influence on the lipase loading and SBA-15 adsorbed more lipase. The combination of the chain length of the fatty acids presents in oils and the pore diameter of the biocatalyst influenced the lipase catalyst performance relative to the ethyl ester yield, indicating a preference for the medium-chain length fatty acid.

Research paper thumbnail of Mononuclear Iron(III) Piperazine-Derived Complexes and Application in the Oxidation of Cyclohexane

Catalysis in Industry, 2021

Research paper thumbnail of Biomass productivity of Chlorella vulgaris cultivated in fish and dairy cattle wastewaters

Semina: Ciências Agrárias, 2021

The biomass productivity and nutrient composition of microalgae, such as Chlorella vulgaris, depe... more The biomass productivity and nutrient composition of microalgae, such as Chlorella vulgaris, depend on the cultivation process and the nutrient content of growth media. Thus, in this study aimed to investigate the biomass productivity of C. vulgaris cultivated in fish and dairy cattle wastewaters. Thirty wastewater samples (2.5 L) were collected from system of production. Microalgae were cultivated in Erlenmeyer flasks containing 10 mL of microalgae and 1,790 mL of wastewater under constant light of 5,000 lux for 16 days at 25 ± 2.0 °C. Wastewater samples differed in composition. Biomass productivity was 47 % higher (P<0.0001) in dairy cattle than in fish wastewater, reaching 67.61 g m?3 day?1 (dry matter basis, DM) when compared by Student’s t-test (P<0.05). Cultivation media also had an effect on biomass chemical composition. The C. vulgaris grown in dairy cattle wastewater was higher in crude protein and ash contents (359.6 g kg?1 DM and 230.4 g kg?1 DM, respectively), wher...

Research paper thumbnail of INFLUÊNCIA DO NACl E KCl NA ADSORÇÃO DO CORANTE BF - 5G POR CARVÃO ATIVADO DE OSSO

RESUMO: Em virtude do alto consumo de água na industria têxtil, este tornou-se um problema devido... more RESUMO: Em virtude do alto consumo de água na industria têxtil, este tornou-se um problema devido a contaminação ocasionado por poluentes como sólidos suspensos, matéria orgânica, surfactantes e moléculas de corante sob forma de complexos, dentre estes destacam-se os corantes têxteis que são utilizados no processo de tingimento. Como possível tratamento de remoção do corante destacamos a possibilidade de adsorção por carvão ativado de osso bovino, devido a sua eficácia. Neste processo de adsorção estudamos o comportamento da adição dos sais NaCl e KCl na solução de corante. Dessa forma, os ensaios foram realizados em batelada para encontrarmos o tempo de equilíbrio e posteriormente obtermos as isotermas que indicaram um aumento favorável na quantidade adsorvida de corante com a adição de sal.

Research paper thumbnail of Impregnação do heteropoliácido 12-tungstofosfórico, H3PW12O40, em carvão

Latin American Journal of Development

O heteropoliácido 12-tungstofosfórico foi impregnado em carvão de coco em duas diferentes concent... more O heteropoliácido 12-tungstofosfórico foi impregnado em carvão de coco em duas diferentes concentrações, 20 e 50%, visando avaliar a diferença estrutural da amostra impregnada. Os resultados mostraram que o carvão de coco possui uma elevada área específica, indicando seu potencial como suporte para catalisadores de baixa área específica, e que a metodologia de impregnação utilizada foi eficiente devido à formação da estrutura do ácido nas análises de DRX após a aplicação do mesmo.

Research paper thumbnail of Influência do tempo de sulfatação nas características estruturais e acidez do catalisador zircônia sulfatada

Latin American Journal of Development

Amostras de óxido de zircônio foram preparadas utilizando o método de precipitação em NH3, com co... more Amostras de óxido de zircônio foram preparadas utilizando o método de precipitação em NH3, com controle de pH de precipitação. A sulfatação ocorreu por impregnação dos mesmos óxidos, em soluções 0,5 M de H2SO4, variando-se o tempo, verificando a sua influência na formação da fase tetragonal e monoclínica do catalisador. Os resultados mostram que o tempo de sulfatação possui influência direta na força ácida dos catalisadores, devido a maior intensidade dos picos tetragonais, que se caracterizam por fornecer uma maior acidez para os catalisadores.

Research paper thumbnail of New Insights into the Effect of the Zeolites Framework Topology on the Esterification Reactions: A Comparative Study from Experiments and Theoretical Calculations

Topics in Catalysis

Understanding the catalytic activity of protonic zeolites in biomass conversion allows design cat... more Understanding the catalytic activity of protonic zeolites in biomass conversion allows design catalysts specific for various industrial applications resulting in a strong economic impact. The aim of the present work is to analyze the influence of the pore topology and density of active sites comparing H-ZSM-5, H-Beta and H-Y zeolites as solid acid catalysts for the esterification of oleic acid. The catalysts were characterized using XRF, N2 isotherms, NH3-TPD and, 27Al MAS-NMR techniques, catalytic tests were conducted in a batch reactor (20 bar N2, 100 ℃ and 600 RPM), theoretical investigations by DFT calculations were also performed. Zeolites with lower Al density (H-Y and H-ZSM-5) showed higher acid strength, however, H-Beta showed higher conversion than H-ZSM-5 because in BEA-type structures the Al are found in places that are more accessible. H-Y was highly effective for this reaction (98% conversion) and exhibiting promising recyclability, which could be related to their high specific area, hydrophobicity effect and symbiosis between Brønsted acid sites and the presence of extra-framework aluminum inside the zeolite cavity. H-ZSM-5 showed a 70% conversion yield due to the high Si/Al ratio and the additional porosity of this de-aluminized material. DFT results showed that the channel system of H-Y and H-Beta zeolite framework favor the stabilization of coadsorbed species within their confined environments, and such effect could minimize the activation barrier in consecutive steps of the reaction. Our results suggest the use of protonic zeolites as strategic catalytic material in the recovery of oleaginous residues to obtain products with higher added value.

Research paper thumbnail of Nitrogen-doped activated carbons with high performances for CO2 adsorption

Journal of CO2 Utilization

Research paper thumbnail of DFT calculations for adsorption of H2S and other natural gas compounds on (Fe, Co, Ni, Cu and Zn)–Y zeolite clusters

Microporous and Mesoporous Materials, 2022

Research paper thumbnail of Optimization of Sibipiruna activated carbon preparation by simplex-centroid mixture design for simultaneous adsorption of rhodamine B and metformin

Journal of Hazardous Materials, 2021

The present paper reports the application of augmented simplex-centroid mixture design to obtain ... more The present paper reports the application of augmented simplex-centroid mixture design to obtain a high BET surface area activated carbon using as reactants KOH, K2CO3 and K2C2O4. The optimum mixture composition was 2.51 g of KOH, 0.49 g of K2CO3 and absence of K2C2O4, generating an optimized AC (ACop) with SBET value equals to 1984 m2 g-1. The results herein obtained show that low amounts of K2CO3 can catalyze the pore development in the presence of KOH, increasing the surface area. Furthermore, the fractal dimensions of ACop are greater than 2.72, indicating the material has a complex pore structure with irregularities self-similar upon variations of resolution, as seen by SEM images. The TPD curves showed that the ACop has different oxygenated molecular fragments, which agrees with the pHPZC value (5.05). The ACop was applied in the adsorption of rhodamine B (RhB) and metformin (Met) in both binary and monocomponent systems. The simultaneous adsorption at 30 °C reveals that the adsorption capacity of RhB is 630.94 mg g-1, while for Met the value is 103.83 mg g-1.

Research paper thumbnail of Catalytic improvement of biomass conversion: Effect of adding mesoporosity on MOR zeolite for esterification with oleic acid

Renewable Energy, 2021

Abstract Catalytic processes play an important role in the valorization of biomass for the produc... more Abstract Catalytic processes play an important role in the valorization of biomass for the production of biofuels. In this context, the effect of desilication of MOR zeolite (H-MOR-D) on the esterification of oleic acid as a model reaction for biomass conversion was investigated. Zeolite catalysts were characterized by BET, TG, NH3-TPD, XRD, XRF, FTIR and 27Al MAS NMR analysis and the results showed that the alkaline treatment caused a decrease in crystallinity and removal of sites with greater acid strength of the zeolite precursor. The conversion of oleic acid into methyl oleate catalyzed by H-MOR was less (44%) than that obtained by the treated zeolite H-MOR-D (70%), suggesting that the catalytic activity in the MOR structure does not depend only on the high density of strong acid sites. DFT calculations showed that, bulky molecules suffer molecular distortions within the confined voids, consequently the adsorption enthalpy is highly unstable limiting the formation of intermediates and thus contributing to the lower reaction rate observed experimentally in H-MOR zeolite. Desilication should be considered in projects for the synthesis of new catalysts type zeolite for the conversion of biomass crude or pre-treated, in which bulky molecules prevail.

Research paper thumbnail of Phenomenological modeling of Acutodesmus obliquus microalgae in situ transesterification

Biochemical Engineering Journal, 2019

Research paper thumbnail of Copper-exchanged Y zeolites for gasoline deep-desulfurization

Research paper thumbnail of Removal of H 2 S and CO 2 from biogas in bench scale and the pilot scale using a regenerable Fe-EDTA solution

Research paper thumbnail of Effect of Silylation and Support Porosity of Co/MCM-41 and Co/SiO2 Catalysts in Fischer–Tropsch Synthesis

Topics in Catalysis, 2015

Research paper thumbnail of Mass Transfer Mechanism of Ion Exchange in Fixed Bed Columns

Journal of Chemical & Engineering Data, 2011

Research paper thumbnail of Enhancement of lipase transesterification activity by immobilization on β–cyclodextrin-based polymer

Journal of Sol-Gel Science and Technology, 2019

Research paper thumbnail of CO2 adsorption in hydrochar produced from waste biomass

SN Applied Sciences, 2019

Research paper thumbnail of Synthesis and characterization of pecan nutshell-based adsorbent with high specific area and high methylene blue adsorption capacity

Journal of Molecular Liquids, 2018

Research paper thumbnail of Hydrochars based on cigarette butts as a recycled material for the adsorption of pollutants

Journal of Environmental Chemical Engineering, 2018

Research paper thumbnail of Influence of the chain length of the fatty acids present in different oils and the pore diameter of the support on the catalytic activity of immobilized lipase for ethyl ester production

Brazilian Journal of Chemical Engineering, 2021

In this work, the effect of fatty acid chain length of different oils and the pore diameter of th... more In this work, the effect of fatty acid chain length of different oils and the pore diameter of the biocatalyst were evaluated in the production of ethyl esters. Mesoporous organized silica MCM-41 and SBA-15 with pore diameters of 2.5 nm and 6.7 nm, respectively, were used for the lipase immobilization. The structural and textural characteristics of the supports and biocatalysts were verified by X-ray diffraction and nitrogen physisorption analyses. Pore size was the parameter with the most influence on the lipase loading and SBA-15 adsorbed more lipase. The combination of the chain length of the fatty acids presents in oils and the pore diameter of the biocatalyst influenced the lipase catalyst performance relative to the ethyl ester yield, indicating a preference for the medium-chain length fatty acid.

Research paper thumbnail of Mononuclear Iron(III) Piperazine-Derived Complexes and Application in the Oxidation of Cyclohexane

Catalysis in Industry, 2021

Research paper thumbnail of Biomass productivity of Chlorella vulgaris cultivated in fish and dairy cattle wastewaters

Semina: Ciências Agrárias, 2021

The biomass productivity and nutrient composition of microalgae, such as Chlorella vulgaris, depe... more The biomass productivity and nutrient composition of microalgae, such as Chlorella vulgaris, depend on the cultivation process and the nutrient content of growth media. Thus, in this study aimed to investigate the biomass productivity of C. vulgaris cultivated in fish and dairy cattle wastewaters. Thirty wastewater samples (2.5 L) were collected from system of production. Microalgae were cultivated in Erlenmeyer flasks containing 10 mL of microalgae and 1,790 mL of wastewater under constant light of 5,000 lux for 16 days at 25 ± 2.0 °C. Wastewater samples differed in composition. Biomass productivity was 47 % higher (P<0.0001) in dairy cattle than in fish wastewater, reaching 67.61 g m?3 day?1 (dry matter basis, DM) when compared by Student’s t-test (P<0.05). Cultivation media also had an effect on biomass chemical composition. The C. vulgaris grown in dairy cattle wastewater was higher in crude protein and ash contents (359.6 g kg?1 DM and 230.4 g kg?1 DM, respectively), wher...

Research paper thumbnail of INFLUÊNCIA DO NACl E KCl NA ADSORÇÃO DO CORANTE BF - 5G POR CARVÃO ATIVADO DE OSSO

RESUMO: Em virtude do alto consumo de água na industria têxtil, este tornou-se um problema devido... more RESUMO: Em virtude do alto consumo de água na industria têxtil, este tornou-se um problema devido a contaminação ocasionado por poluentes como sólidos suspensos, matéria orgânica, surfactantes e moléculas de corante sob forma de complexos, dentre estes destacam-se os corantes têxteis que são utilizados no processo de tingimento. Como possível tratamento de remoção do corante destacamos a possibilidade de adsorção por carvão ativado de osso bovino, devido a sua eficácia. Neste processo de adsorção estudamos o comportamento da adição dos sais NaCl e KCl na solução de corante. Dessa forma, os ensaios foram realizados em batelada para encontrarmos o tempo de equilíbrio e posteriormente obtermos as isotermas que indicaram um aumento favorável na quantidade adsorvida de corante com a adição de sal.