Evaluation of photocatalytic activities of supported catalysts on NaX zeolite or activated charcoal

Brites-Nóbrega, Fernanda F.; Polo, Aldino N.B.; Benedetti, Angélica M.; Leão, Mônica Maria Diniz; Santana, Veronice Slusarski; Fernandes-Machado, Nádia Regina Camargo

doi:10.1016/j.jhazmat.2013.07.061

Cited by 37 publications

(17 citation statements)

References 29 publications

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“…Moreover, the dye degradation was less effective (98%) when ZnO evaluated in suspension than when immobilized on NaX (100%). These results confirm the synergistic effect introduced by the support on the supported catalyst (Brites-Nóbrega et al, 2013).…”

Section: Introductionsupporting

confidence: 82%

“…By comparing the activities of two types of support and evaluating the activity of the suspended and immobilized metal oxide, the synergistic effect between catalyst and support is verified. ZnO/NaX and ZnO/activated coal were prepared in order to verify the synergistic effect between oxide and support in the reactive blue dye 5G photomineralization activity (Brites-Nóbrega et al, 2013). Due to the acidic surface characteristics of NaX catalyst, which allows greater electronic excitation, the authors observed that the metal oxide presented a higher interaction with the zeolite when compared to the activated coal.…”

Section: Introductionmentioning

confidence: 99%

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<b>Synergistic effect between oxides semiconductors and zeolites on photobleaching of RB250 textile dye

et al. 2018

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The present work aims to evaluate the activity of semiconductor oxides (TiO 2 , Nb 2 O 5 and ZnO) supported on NaA and NaY zeolites, as well as their synergistic effect on Reactive Blue Dye (RB250) photodegradation process. Prior to deposition, TiO 2 particles size was reduced by ultrasonic scattering followed by filtration. The particles on the filtrate were used to conduct the experiments. The semiconductors were immobilized in concentrations of 2.5, 5 and 10% (w w -1 ) and the photocatalytic tests were performed at catalyst concentrations of 1 and 2 g L -1 . Moreover, supported catalysts were characterized by XRD, textural analysis, zero point of charge and temperature programmed desorption of NH 3 . A comparison between the supported catalysts showed high activity for the ones supported with ZnO and TiO 2 . Zeolite NaY has broader opened channels than NaA, which reduces the dye molecules blockage, and, as a result, increased the catalyst activity. A higher concentration of supported catalysts (2 g L -1 ) provides greater photocatalytic activity, while higher concentration of semiconductors immobilized on supports does not present significant differences.Efeito sinérgico entre óxidos semicondutores e zeólitas no fotoclareamento do corante têxtil RB250 RESUMO. O objetivo deste trabalho foi avaliar a atividade dos óxidos semicondutores (TiO 2 , Nb 2 O 5 & ZnO) suportados nas zeólitas NaA e NaY e seu efeito sinérgico na fotodegradação do corante têxtil azul reativo (RB250). Antes da deposição, o tamanho das partículas de TiO 2 foi reduzido por dispersão em ultrassom seguido por filtração e foram utilizadas as partículas que passaram através do filtro. Os semicondutores foram imobilizados em concentrações de 2,5, 5 e 10% (m m -1 ) e os testes fotocatalíticos foram realizados em concentrações de catalisador de 1 e 2 g L -1 . Os catalisadores suportados foram caracterizados por DRX, análise textural, ponto de carga zero e dessorção por temperatura programada. Os catalisadores suportados com ZnO e TiO 2 mostraram maior atividade do que o Nb 2 O 5 . Os testes fotocatalíticos indicaram um aumento na atividade dos catalisadores suportados em NaY sendo essa com resultados superiores aos encontrados com a zeólita NaA. Isso por causa dos seus canais mais estreitos que dificultam a entrada de moléculas do corante. A maior concentração de catalisadores suportados (2 g L -1 ) proporciona maior atividade fotocatalítica, enquanto a maior concentração de semicondutores imobilizados em suportes não apresenta diferenças significativas.

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Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

<b>Synergistic effect between oxides semiconductors and zeolites on photobleaching of RB250 textile dye

et al. 2018

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“…As regard to only being active in the UV region of the solar light, and thus absorbing only 5% of the sunlight energy, extending of the band gap of ZnO into the visible region, and hence improving of its photocatalytic efficiency is of great importance [9,10]. One of the suggested methods for this purpose is decorating of ZnO nanoparticles (NPs) on a substrate with high surface area such as zeolite, nanoclay or carbon-based materials [11][12][13]. The aforementioned carbon-based materials are divided into two categories:1-Conventional, including graphite, carbon black, and activated carbon which have been studied extensively, and 2-New family comprising carbon nanotube (CNT), fullerenes, and most recently graphene.…”

mentioning

confidence: 99%

ZnO quantum dots-graphene composites: Formation mechanism and enhanced photocatalytic activity for degradation of methyl orange dye

Tayyebi

Outokesh

Tayebi

et al. 2016

Journal of Alloys and Compounds

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The current study demonstrates homogenous decorating of zinc oxide quantum dots (QDs) onto graphene oxide (GO) surface via simple chemical method. The AFM image exhibited that the prepared graphene was 0.8 nm thick and hence practically monolayer. Average size of the ZnO QDs was estimated by transmission electron microscopy around 3 nm. Instrumental and chemical analyses demonstrated formation of a strong bond between ZnO QDs and GO, through CO -Zn and C-Zn bridges. The UV-visible spectra displayed that the introduction of graphene sheets to ZnO QDs resulted in higher absorption intensity of UV as well as widening of adsorption window toward visible light for ZnO-Graphene due to chemical bond between ZnO QDS and graphene surface. Results showed that adding of graphene up to 30% can improve resistance of ZnO against acids however for keeping the activity of catalyst, the recommended pH is near neutral (pH ≈6-7.2). In addition, the presence of graphene on the surface of the ZnO could significantly suppress the photocorrosion effect. The ZnO-Graphene hybrids indicated enhanced photocatalytic activity for degradation of methyl orange (MO) with the following order: ZnO-5% Graphene > ZnO-10% Graphene > ZnO QDs > ZnO30%-Graphene. This enhancement of photocatalytic activity may be attributed to the extended absorption of visible light, reducing of electron-hole recombination rate, and adsorption of MO molecules onto the huge surface area of graphene, where they are kept at vicinity of ZnO for decomposition.

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“…A conscientização sobre os efeitos nocivos da descarga de resíduos sólidos e líquidos no ambiente, bem como o desenvolvimento de novos métodos de tratamento, tornaram-se necessários (De Brites-Nóbrega et al, 2013), devido à implementação de leis ambientais mais rigorosas visando a gestão ambiental e ao fato dos corantes serem detectados visualmente, mesmo presentes em pequenas concentrações após os tratamentos tradicionais. Entre os métodos alternativos de tratamento, a fotocatálise heterogênea tem se destacado por proporcionar a mineralização dos poluentes, convertendo-os em H2O, CO2 e sais minerais (Prado, 2003).…”

Section: Introductionunclassified

“…O uso de catalisadores suportados tem a vantagem da reutilização dos catalisadores e a redução do custo com a separação do catalisador do efluente após o processo (De Brites-Nóbrega et al, 2013;Merg et al, 2010). Dentre os diferentes tipos de suportes que podem ser utilizados, as zeólitas se destacam por apresentarem características como excelente capacidade de troca iônica e adsorção, considerável estabilidade térmica, elevada área superficial, estrutura única e sistema uniforme de poros e canais (Brites-Nóbrega et al, 2015;Merg et al, 2010).…”

Section: Introductionunclassified

DEGRADAÇÃO DO EFLUENTE DO TINGIMENTO DE PELES DE PEIXE NA PRESENÇA DE Fe+2 EM SOLUÇÃO E Nb2O5 SUPORTADO EM ZEÓLITAS NaA E NaX (DEGRADATION OF THE FISH SKINS DYEING WASTEWATER IN THE PRESENCE OF Fe+2 IN SOLUTION AND Nb2O5 SUPPORTED ON NaA AND NaX ZEOLITES)

et al. 2017

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Resumo: A necessidade de se dar um destino adequado às peles, subproduto do processo de filetagem, motivou o desenvolvimento do processo de curtimento de peles de peixe. Este processo consome grande quantidade de água e consequentemente, gera volumes elevados de efluentes líquidos, os quais devem ser tratados adequadamente. Desta forma, o objetivo deste trabalho foi avaliar o efeito da presença de Fe +2 em solução na degradação do efluente da etapa de tingimento de peles de peixe por fotocatálise usando Nb2O5 suportado em zeólitas NaX e NaA. Catalisadores suportados com 5 e 10% (% mássica) de Nb2O5 foram preparados pelo método da impregnação úmida e caracterizados por análise textural, DRX e espectroscopia fotoacústica. Os testes consistiram em irradiar 300 mL do efluente com ou sem 1 g L -1 do catalisador durante 3, 6 e 10 h na presença de 40 mg de Fe +2 em solução. Os resultados mostraram redução na turbidez do efluente e aumento significativo na

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Evaluation of photocatalytic activities of supported catalysts on NaX zeolite or activated charcoal

Cited by 37 publications

References 29 publications

<b>Synergistic effect between oxides semiconductors and zeolites on photobleaching of RB250 textile dye

<b>Synergistic effect between oxides semiconductors and zeolites on photobleaching of RB250 textile dye

ZnO quantum dots-graphene composites: Formation mechanism and enhanced photocatalytic activity for degradation of methyl orange dye

DEGRADAÇÃO DO EFLUENTE DO TINGIMENTO DE PELES DE PEIXE NA PRESENÇA DE Fe+2 EM SOLUÇÃO E Nb2O5 SUPORTADO EM ZEÓLITAS NaA E NaX (DEGRADATION OF THE FISH SKINS DYEING WASTEWATER IN THE PRESENCE OF Fe+2 IN SOLUTION AND Nb2O5 SUPPORTED ON NaA AND NaX ZEOLITES)

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