Biphasic oxidation promoted by magnetic amphiphilic nanocomposites undergoing a reversible emulsion process

Teixeira, Ivo F.; Oliveira, Aline Almeida da Silva; Christofani, Taís; Moura, Flávia C.C.

doi:10.1039/c3ta11535f

Cited by 47 publications

(37 citation statements)

References 27 publications

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“…6 The results are shown in Fig. The biphasic oxidative extraction of N-containing petrol contaminants was investigated using a 500 ppm quinoline-hexane (10 mL) solution mixed with 1.6 mL of aqueous H 2 O 2 (1.65 mmol L −1 ) containing FeCl 2 ·4H 2 O (5.6 mmol L −1 ) and formic acid (5 mmol L −1 ).…”

Section: Magnetic Amphiphilic Hybrid Carbon Nanotube Synthesis and Chmentioning

confidence: 99%

“…[1][2][3] In general, the use of a surfactant is necessary to improve the phase transfer, but this introduces several operational, technical and economical drawbacks. [5][6][7][8][9] Given that the development of robust amphiphilic nanostructures highly efficient in promoting emulsions has been very recently identified as an important challenge for colloidal materials, 10 we believe that further research in this area is of considerable interest. Recently, composites based on hydrophobic carbon nanomaterials supported on hydrophilic oxide particles have been used to stabilize water-oil emulsions and catalyze reactions at the liquidliquid interface.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

et al. 2015

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In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and a metal-catalyzed aqueous oxidation of heptanol with molecular oxygen.

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Section: Magnetic Amphiphilic Hybrid Carbon Nanotube Synthesis and Chmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

et al. 2015

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“…7 The ODS process consists of the oxidation of organosulfur compounds to obtain highly polar benzothiophenic sulfones and sulfoxides, which can be easily removed by extraction or adsorption. 36 In this context, the objective in the present study was to explore a novel amphiphilic material and use it as a catalyst in the biphasic oxidation of S-and N-containing contaminants in the petroleum industry. Most of the oxidative desulfurization studies have focused on using oxidants such as peroxyacetic acid, 19 tert-butyl hydroperoxide, 20,21 hydrogen peroxide [22][23][24][25][26] and others.…”

Section: Introductionmentioning

confidence: 99%

Fe/C and FeMo/C hybrid materials for the biphasic oxidation of fuel contaminants

et al. 2017

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In the present work, hybrid magnetic nanoparticles based on Fe and FeMo coated with carbon nanostructures (Fe/C and FeMo/C) were produced by catalytic chemical vapor deposition at different temperatures using ethanol as the carbon source. Scanning electron microscopy, thermal analysis, Raman spectroscopy, X-ray diffraction, and Mössbauer spectroscopy analyses suggested that hematite was reduced by ethanol at 700 and 900 1C, producing carbon nanostructures such as nanofibers and nanotubes. The Fe/C and FeMo/C hybrid composites showed remarkable magnetic and amphiphilic properties. The composites were successfully used to oxidize sulfur and nitrogen contaminants present in fuels in a biphasic system.

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“…Catalysts with these properties can promote reactions at the LL interface by increasing the contact between both phases (maximizing the interfacial area) and ensuring a higher mass transfer of the pollutants between these phases. It should be noted that the oxidation of lipophilic pollutants present in an oily wastewater with hydrogen peroxide leads to more hydrophilic products, enhancing their transfer to the aqueous phase, thus cleaning the oil phase [6,25].…”

Section: Introductionmentioning

confidence: 99%

Janus amphiphilic carbon nanotubes as Pickering interfacial catalysts for the treatment of oily wastewater by selective oxidation with hydrogen peroxide

et al. 2020

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Janus-like amphiphilic carbon nanotubes (CNTs) were tested as catalysts in the oxidation of 2-nitrophenol (2-NP) with hydrogen peroxide. A biphasic oil-water medium was used to simulate oily wastewater contaminated with the lipophilic model pollutant 2-NP. The CNTs were synthesized by sequentially feeding ethylene and/or acetonitrile, used as carbon and carbon/nitrogen precursors, respectively. The results obtained for 2-NP removal using biphasic systems were compared with those obtained by CWPO using aqueous solutions. The most active catalyst in the CWPO of 2-NP in aqueous solution was the CNT synthesized only with ethylene. This was explained by its high lipophilic character, allowing the complete removal of 2NP after 24 h of reaction at 50°C, pH 0 = 3, C cat = 0.25 g L −1 , C 2-NP,0 = 0.5 g L −1 and the stoichiometric quantity of H 2 O 2 needed for the total mineralization of 2-NP. For the oxidation of 2-NP in biphasic medium, only the Janus-like amphiphilic CNTs (containing a lipophilic undoped section synthetized from ethylene and a hydrophilic N-doped section synthetized from acetonitrile) revealed catalytic activity for the removal of 2-NP. The conversion of 2NP reached in biphasic oxidation conditions was 76.7% after 24 h of reaction at 50°C, considering pH 0 = 3, C cat = 2.27 g L −1 of total volume (water/oil ratio of 16:50 v/v) and C 2-NP,oil,0 = 5 g L −1. This removal was ascribed to the formation of Pickering emulsions, by maximizing the interfacial area through an increased contact between the catalyst and both liquid phases. A kinetic model is proposed to accurately predict the experimental data and evaluate the rate constants of the process and its variation with the prepared CNTs.

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Biphasic oxidation promoted by magnetic amphiphilic nanocomposites undergoing a reversible emulsion process

Abstract: Magnetic amphiphilic nanocomposites (MANCs) based on nanoalumina and carbon nanostructures were produced and applied as catalysts for biphasic reactions. These amphiphilic composites (MANCs) exhibit an

Cited by 47 publications

References 27 publications

Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

Fe/C and FeMo/C hybrid materials for the biphasic oxidation of fuel contaminants

Janus amphiphilic carbon nanotubes as Pickering interfacial catalysts for the treatment of oily wastewater by selective oxidation with hydrogen peroxide

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