TiO2/LDPE composites: A new floating photocatalyst for solar degradation of organic contaminants

Magalhães, Fabiano; Moura, Flávia C.C.; Lago, Rochel M.

doi:10.1016/j.desal.2011.03.061

Cited by 110 publications

(51 citation statements)

References 19 publications

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“…Thermal sintering has been previously demonstrated to promote strong adhesion of immobilized TiO 2 to glass supports [21][22][23], although reducing specific surface area of the TiO 2 in the process [24]. Floating photocatalysts synthesized previously have used plastic supports susceptible to photocatalytic degradation [25][26][27][28][29][30], or fragile materials such as perlite [31][32][33], which sink upon breaking. The floating photocatalyst (FPC) composites prepared herein are entirely inorganic and resistant to photodissolution, and thus more suitable towards long term emplacement in a passive treatment system.…”

Section: Resultsmentioning

confidence: 99%

Floating Photocatalysts for Passive Solar Degradation of Naphthenic Acids in Oil Sands Process-Affected Water

Leshuk

Krishnakumar

Livera

et al. 2018

Water

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Abstract:Oil sands process-affected water (OSPW), generated from bitumen extraction in the Canadian oil sands, may require treatment to enable safe discharge to receiving watersheds, as dissolved naphthenic acids (NAs) and other acid extractable organics (AEO), identified as the primary toxic components of OSPW, are environmentally persistent and poorly biodegradable. However, conventional advanced oxidation processes (AOPs) are impractically expensive to treat the volumes of OSPW stockpiled in the Athabasca region. Here we prepared floating photocatalysts (FPCs) by immobilizing TiO 2 on glass microbubbles, such that the composite particles float at the air-water interface for passive solar photocatalysis. The FPCs were demonstrated to outperform P25 TiO 2 nanoparticles in degrading AEO in raw OSPW under natural sunlight and gentle mixing conditions. The FPCs were also found to be recyclable for multiple uses through simple flotation and skimming. This paper thus demonstrates the concept of a fully passive AOP that may be scalable to oil sands water treatment challenges, achieving efficient NA reduction solely through the energy provided by sunlight and natural mixing processes (wind and waves).

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Section: Resultsmentioning

confidence: 99%

Floating Photocatalysts for Passive Solar Degradation of Naphthenic Acids in Oil Sands Process-Affected Water

Leshuk

Krishnakumar

Livera

et al. 2018

Water

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“…Until today, as per other literature surveys, it appears that the polymer-based TiO 2 is fabricated with a high loading of TiO 2 and sometimes in the presence of different sensitizer additives, such as dyes and noble metals. The prepared low dosage of PMMA/TiO 2 can be an effective photocatalyst for the degradation of the methylene blue dye, overcoming the main drawback of the previously developed polymer/TiO 2 nanocomposite published by Magalhaes et al 7 They prepared a low density polyethylene (LDPE)/TiO 2 photocatalyst with various TiO 2 concentrations (32, 68, 82 wt%). To the best of our knowledge, we found that no research papers have reported on very low concentrations of TiO 2 in polymer composites.…”

Section: Introductionmentioning

confidence: 99%

Applications of a new type of poly(methyl methacrylate)/TiO2 nanocomposite as an antibacterial agent and a reducing photocatalyst

Salabat

Mirhoseini

2015

Photochem Photobiol Sci

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A new type of poly(methyl methacrylate) (PMMA)/TiO2 nanocomposite film sensitized by ionic liquids with a low dosage of TiO2 nanoparticles was prepared based on a microemulsion method. The photocatalytic activity, via the photoreduction of 4-nitrophenole (4-NP) to 4-aminophenole (4-AP) by NaBH4, and the photocatalytic-based antibacterial activity, for the destruction of Escherichia coli and Staphylococcus aureus, of the prepared nanocomposite film were investigated. The conditions for the maximum efficiency in the presence of visible light irradiation have been evaluated. The rate constant of the photoreduction of 4-NP to 4-AP was calculated and the maximum rate constant was found with the 0.01 wt% of TiO2 dosage in the photocatalyst and a solution pH of 7.5. The photocatalytic antibacterial maximum activity against Gram-negative bacteria was also obtained for the 0.01 wt% of TiO2 concentration of the photocatalyst. A notable result of this work is that PMMA/TiO2 nanocomposite films show efficient photocatalytic activity at very low loadings of TiO2, in contrast to other previous reports.

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“…É possível que com a utilização de outros tipos de reatores, como os empacotados 17 e os reatores tipo filme, esta eficiência possa ser aumentada, além de ser possível tratar um maior volume de efluente e operar em regime contínuo. Adicionalmente estudos promissores vêm sendo realizados para o desenvolvimento de catalisadores imobilizados em matrizes de baixa densidade, 18,19 o que permite a flutuação do fotocatalisador mantendo-o na superfície do meio reacional, otimizando o contato das partículas de TiO 2 com a radiação UV e com o oxigênio dissolvido. Logo, o uso de fotocatalisadores inseridos em matrizes diversas tem sido uma prática muito estudada, 17 como o uso de polímeros, por exemplo de alginato de cálcio, que vem sendo explorados como matrizes para imobilização do TiO 2 .…”

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Degradação fotocatalítica de tartrazina com TiO2 imobilizado em esferas de alginato

Dalponte¹,

Mathias²,

Jorge³

et al. 2016

Quim. Nova

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PHOTOCATALYTIC DEGRADATION OF TARTRAZINE WITH IMMOBILIZED TiO 2 IN ALGINATE BEADS. The potential of heterogeneous photocatalysis using TiO 2 immobilized in alginate beads was evaluated for the degradation of tartrazine yellow azo dye. The treatment was performed under the action of a high-pressure mercury vapor lamp of 125 W and the degradation performance was investigated with the absorbance supplied by a photocolorimeter. Alginate beads with TiO 2 were prepared and the catalyst was quantified by thermogravimetric analysis (TG) and characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and specific area analysis (BET). The immobilization was performed as a very simple and reproductible technique. The bead diameter was approximately 1 mm and its surface presented a homogeneous dispersion of catalytic sites containing about 1-2% (w/w) of TiO 2 . The TiO 2 /alginate beads presented low density and can be easier separated than the TiO 2 dispersed from the reacting medium, remaining available to be reused in another batch. The dye degradation reached 30% after 120 minutes of irradiation, for the following conditions: alcaline pH (pH=9.0), 3 g of TiO 2 /alginate beads and 20 mol L -1 dye concentration.Keywords: heterogeneous photocatalysis; calcium alginate; azo dye. INTRODUÇÃOO descarte de efluentes com alto índice de coloração leva a alterações na quantidade e qualidade da luz que penetra nas camadas mais profundas dos corpos hídricos, alterando as condições da biota aquática, diminuindo a transparência da água e a penetração da luz solar, o que pode afetar a atividade fotossintética e o regime de solubilidade dos gases, principalmente próximos às regiões de descarga.1,2 Devido ao alto grau de aromaticidade das moléculas de corantes e à sua alta estabilidade, os métodos de tratamento biológi-cos são ineficientes para a descoloração e degradação. Esta estrutura recalcitrante também inibe o metabolismo de certos microrganismos presentes no tratamento biológico.3,4 Logo, outras técnicas de tratamento físico-químico se fazem necessárias, tais como coagulação com agentes químicos, adsorção em carvão ativado, ultrafiltração, osmose reversa, remoção com uso de resinas de troca iônica, etc. Todavia, essas operações constituem técnicas não destrutivas, uma vez que transferem os compostos orgânicos da água para outra fase, causando então uma poluição secundária. 5Neste contexto, a fotocatálise heterogênea surge como uma tecnologia muito efetiva e limpa, e que tem se destacado para a eliminação definitiva de poluentes orgânicos tóxicos de efluentes, sendo capaz de promover a degradação total de inúmeros compostos orgânicos a dióxido de carbono, água e íons inorgânicos provenientes de heteroátomos.5-8 O dióxido de titânio está muito próximo de ser um catalisador ideal para o processo de fotooxidação, pois apresenta muitas vantagens: não é tóxico, tem baixo custo, é abundante, é de simples obtenção e é resistente a processos fotocorrosivos. 5,7 No processo da fotocatálise, o TiO 2 pr...

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TiO2/LDPE composites: A new floating photocatalyst for solar degradation of organic contaminants

Cited by 110 publications

References 19 publications

Floating Photocatalysts for Passive Solar Degradation of Naphthenic Acids in Oil Sands Process-Affected Water

Floating Photocatalysts for Passive Solar Degradation of Naphthenic Acids in Oil Sands Process-Affected Water

Applications of a new type of poly(methyl methacrylate)/TiO2 nanocomposite as an antibacterial agent and a reducing photocatalyst

Degradação fotocatalítica de tartrazina com TiO2 imobilizado em esferas de alginato

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