Diôgo Bezerra - Academia.edu (original) (raw)
Papers by Diôgo Bezerra
Applied Surface Science, 2014
Adsorption Science & Technology, 2014
Adsorption, 2011
Adsorption may be a potentially attractive alternative to capturing CO 2 from stationary sources ... more Adsorption may be a potentially attractive alternative to capturing CO 2 from stationary sources in the context of Carbon Capture and Sequestration (CCS) technologies. Activated carbon and zeolites are state-of-art adsorbents which may be used for CO 2 adsorption, however physisorption alone tends to be insignificant at high temperatures. In the present work, commercial adsorbents have been impregnated with monoethanolamine (MEA) and triethanolamine (TEA) in order to investigate the effect of the modified surface chemistry on CO 2 adsorption, especially above room temperature. Adsorption isotherms for CO 2 , N 2 and CH 4 were measured in a gravimetrically system in the pressure range of UHV to 10 bar, at 298 and 348 K for activated carbon and zeolite 13X supports. The adsorbed concentration of CO 2 was significantly higher than those of CH 4 and N 2 for both adsorbents in the whole pressure range studied, zeolite 13X showing a remarkable affinity for CO 2 at very low pressures. However, at 348 K, the adsorbed concentration of CO 2 decreases significantly. The supports impregnated with concentrated amine solutions and dried in air suffered a detrimental effect on the textural properties, although CO 2 uptake became much less susceptible to temperature increase. Impregnations carried out with dilute solution followed by drying in inert atmosphere yielded materials with very similar textural characteristics as compared to the parent support. CO 2 isotherms in such materials showed a significant change with similar capacities at 348 K as com
A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industri... more A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industriais. Grande preocupacao com os efluentes industriais contaminados com metais pesados gerou uma legislacao mais atuante e rigorosa, alem de politicas publicas no sentido de incentivar pesquisas e desenvolvimento nesta tematica. Logo, o projeto visa o estudo de adsorvente sintetico a base de carbono aplicado na purificacao/separacao de ions cobre. Para tanto sera realizado caracterizacao da quimica superficial dos adsorventes por tecnica de pH por potencial de carga zero, alem de analises da capacidade de adsorcao em solucoes de ion cobre por metodo de batelada.
A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industri... more A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industriais. Grande preocupacao com os efluentes industriais contaminados com metais pesados gerou uma legislacao mais atuante e rigorosa, alem de politicas publicas no sentido de incentivar pesquisas e desenvolvimento nesta tematica. Das tecnologias disponiveis atualmente, destaca-se a adsorcao por apresentar baixo custo e facilidade operacional. Contudo, ha necessidade do desenvolvimento de materiais porosos adsorventes potencialmente estruturados para tal aplicacao. Neste sentido, este projeto visa o estudo de adsorventes sinteticos e comerciais a base de carbono aplicados na purificacao/separacao de metais pesados de efluentes industriais. Para tanto foram realizado caracterizacao da quimica superficial dos adsorventes, alem de analises da capacidade de adsorcao em solucoes de metais pesados (chumbo) por metodo de batelada.
O aumento nos niveis de CO2 na atmosfera tem acarretado um notavel impacto sobre o efeito estufa,... more O aumento nos niveis de CO2 na atmosfera tem acarretado um notavel impacto sobre o efeito estufa, aquecimento global e a problematica das mudancas climaticas. Na literatura tecnico-cientifica, tem-se abordado frequentemente a separacao de CO2 de correntes gasosas emitidas por fontes estacionarias associadas a processos de combustao. Varias tecnicas de separacao vem sendo estudadas, entre elas a de adsorcao em solidos porosos. Os mecanismos de adsorcao podem variar de uma fraca fisissorcao a uma forte interacao quimica. Para sua implantacao, e fundamental que o adsorvente utilizado apresente alta seletividade pelo CO2, grande capacidade de adsorcao e mantenha suas propriedades aproximadamente constantes em uso continuado (ciclos de adsorcao e dessorcao). Este estudo avaliou a utilizacao de carbonos ativados e zeolitos comerciais, como tais e modificados com impregnacao de aminas, objetivando determinar a capacidade de adsorcao e seletividade por CO2. Foi realizada a caracterizacao te...
Anais do XX Congresso Brasileiro de Engenharia Química, Feb 1, 2015
Chemical Engineering Journal, 2015
ABSTRACT Amine-containing carbon catalysts were synthesized to study the production of α,β-unsatu... more ABSTRACT Amine-containing carbon catalysts were synthesized to study the production of α,β-unsaturated esters by Knoevenagel condensation of buthyraldehyde and ethyl cyanoacetate. The solids were characterized by XRD, XPS, FTIR, elemental analyses, CO2 adsorption measurements and N2 adsorption-desorption isotherms. Monoethanolamine-functionalization on the carbon led to structural changes while keeping relatively high surface areas. Although a great number of basic sites provided a good performance in the reaction, leaching of these sites at elevated temperatures accounted for deactivation of the catalyst. The best performance towards ethyl 2-cyano-3-propylacrylate ester was obtained for ACN10 (conversion = 10.7%; selectivity = 100%) at 348 K, being reused for five times.
Applied Surface Science, 2014
The adsorption of CO 2 on Zeolite 13X functionalized with amino groups was studied. Adsorbent fun... more The adsorption of CO 2 on Zeolite 13X functionalized with amino groups was studied. Adsorbent functionalization was carried out by grafting with different loads of monoethanolamine (MEA). The adsorbents were characterized by N 2 adsorption/desorption isotherms at 77 K, x-ray diffraction, TGA, in situ FTIR, XPS and adsorption microcalorimetry. CO 2 isotherms were studied in a gravimetric device up to 10 bar at 298 and 348 K. It was found that increasing loads of amine to the adsorbent tend to reduce micropore volume of the resulting adsorbents by pore blocking with MEA. There is experimental evidence that part of the loaded MEA is effectively covalently bonded to the zeolitic structure, whereas there is also physisorbed excess MEA which will eventually be desorbed by raising the temperature beyond MEA boiling point. Heats of adsorption at nearly zero coverage indicate that some of the adsorbed CO 2 reacts with available amino groups, which agrees with the finding that the adsorption capacity increases with increasing temperature for the modified zeolite with the highest MEA load.
Applied Surface Science, 2014
Adsorption Science & Technology, 2014
Adsorption, 2011
Adsorption may be a potentially attractive alternative to capturing CO 2 from stationary sources ... more Adsorption may be a potentially attractive alternative to capturing CO 2 from stationary sources in the context of Carbon Capture and Sequestration (CCS) technologies. Activated carbon and zeolites are state-of-art adsorbents which may be used for CO 2 adsorption, however physisorption alone tends to be insignificant at high temperatures. In the present work, commercial adsorbents have been impregnated with monoethanolamine (MEA) and triethanolamine (TEA) in order to investigate the effect of the modified surface chemistry on CO 2 adsorption, especially above room temperature. Adsorption isotherms for CO 2 , N 2 and CH 4 were measured in a gravimetrically system in the pressure range of UHV to 10 bar, at 298 and 348 K for activated carbon and zeolite 13X supports. The adsorbed concentration of CO 2 was significantly higher than those of CH 4 and N 2 for both adsorbents in the whole pressure range studied, zeolite 13X showing a remarkable affinity for CO 2 at very low pressures. However, at 348 K, the adsorbed concentration of CO 2 decreases significantly. The supports impregnated with concentrated amine solutions and dried in air suffered a detrimental effect on the textural properties, although CO 2 uptake became much less susceptible to temperature increase. Impregnations carried out with dilute solution followed by drying in inert atmosphere yielded materials with very similar textural characteristics as compared to the parent support. CO 2 isotherms in such materials showed a significant change with similar capacities at 348 K as com
A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industri... more A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industriais. Grande preocupacao com os efluentes industriais contaminados com metais pesados gerou uma legislacao mais atuante e rigorosa, alem de politicas publicas no sentido de incentivar pesquisas e desenvolvimento nesta tematica. Logo, o projeto visa o estudo de adsorvente sintetico a base de carbono aplicado na purificacao/separacao de ions cobre. Para tanto sera realizado caracterizacao da quimica superficial dos adsorventes por tecnica de pH por potencial de carga zero, alem de analises da capacidade de adsorcao em solucoes de ion cobre por metodo de batelada.
A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industri... more A poluicao ambiental tornou-se um problema constante nos diversos segmentos de processos industriais. Grande preocupacao com os efluentes industriais contaminados com metais pesados gerou uma legislacao mais atuante e rigorosa, alem de politicas publicas no sentido de incentivar pesquisas e desenvolvimento nesta tematica. Das tecnologias disponiveis atualmente, destaca-se a adsorcao por apresentar baixo custo e facilidade operacional. Contudo, ha necessidade do desenvolvimento de materiais porosos adsorventes potencialmente estruturados para tal aplicacao. Neste sentido, este projeto visa o estudo de adsorventes sinteticos e comerciais a base de carbono aplicados na purificacao/separacao de metais pesados de efluentes industriais. Para tanto foram realizado caracterizacao da quimica superficial dos adsorventes, alem de analises da capacidade de adsorcao em solucoes de metais pesados (chumbo) por metodo de batelada.
O aumento nos niveis de CO2 na atmosfera tem acarretado um notavel impacto sobre o efeito estufa,... more O aumento nos niveis de CO2 na atmosfera tem acarretado um notavel impacto sobre o efeito estufa, aquecimento global e a problematica das mudancas climaticas. Na literatura tecnico-cientifica, tem-se abordado frequentemente a separacao de CO2 de correntes gasosas emitidas por fontes estacionarias associadas a processos de combustao. Varias tecnicas de separacao vem sendo estudadas, entre elas a de adsorcao em solidos porosos. Os mecanismos de adsorcao podem variar de uma fraca fisissorcao a uma forte interacao quimica. Para sua implantacao, e fundamental que o adsorvente utilizado apresente alta seletividade pelo CO2, grande capacidade de adsorcao e mantenha suas propriedades aproximadamente constantes em uso continuado (ciclos de adsorcao e dessorcao). Este estudo avaliou a utilizacao de carbonos ativados e zeolitos comerciais, como tais e modificados com impregnacao de aminas, objetivando determinar a capacidade de adsorcao e seletividade por CO2. Foi realizada a caracterizacao te...
Anais do XX Congresso Brasileiro de Engenharia Química, Feb 1, 2015
Chemical Engineering Journal, 2015
ABSTRACT Amine-containing carbon catalysts were synthesized to study the production of α,β-unsatu... more ABSTRACT Amine-containing carbon catalysts were synthesized to study the production of α,β-unsaturated esters by Knoevenagel condensation of buthyraldehyde and ethyl cyanoacetate. The solids were characterized by XRD, XPS, FTIR, elemental analyses, CO2 adsorption measurements and N2 adsorption-desorption isotherms. Monoethanolamine-functionalization on the carbon led to structural changes while keeping relatively high surface areas. Although a great number of basic sites provided a good performance in the reaction, leaching of these sites at elevated temperatures accounted for deactivation of the catalyst. The best performance towards ethyl 2-cyano-3-propylacrylate ester was obtained for ACN10 (conversion = 10.7%; selectivity = 100%) at 348 K, being reused for five times.
Applied Surface Science, 2014
The adsorption of CO 2 on Zeolite 13X functionalized with amino groups was studied. Adsorbent fun... more The adsorption of CO 2 on Zeolite 13X functionalized with amino groups was studied. Adsorbent functionalization was carried out by grafting with different loads of monoethanolamine (MEA). The adsorbents were characterized by N 2 adsorption/desorption isotherms at 77 K, x-ray diffraction, TGA, in situ FTIR, XPS and adsorption microcalorimetry. CO 2 isotherms were studied in a gravimetric device up to 10 bar at 298 and 348 K. It was found that increasing loads of amine to the adsorbent tend to reduce micropore volume of the resulting adsorbents by pore blocking with MEA. There is experimental evidence that part of the loaded MEA is effectively covalently bonded to the zeolitic structure, whereas there is also physisorbed excess MEA which will eventually be desorbed by raising the temperature beyond MEA boiling point. Heats of adsorption at nearly zero coverage indicate that some of the adsorbed CO 2 reacts with available amino groups, which agrees with the finding that the adsorption capacity increases with increasing temperature for the modified zeolite with the highest MEA load.