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Ahnert, Falk; Arafat, Hassan A.; Pinto, Neville G.

doi:10.1023/a:1026271830072

Cited by 61 publications

(35 citation statements)

References 13 publications

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“…In the current study, the content of surface oxygen functional groups was determined by XPS. In general, the higher content of surface oxygen functional groups, the lower the adsorption capacity of the AC in adsorption of xylene and isooctane 58. The virgin AC which showed higher adsorption capacity exhibits a lower content of surface oxygen functional groups (9.35 %).…”

Section: Resultsmentioning

confidence: 95%

Molecular Dimensions and Porous Structure of Activated Carbons for Sorption of Xylene and Isooctane

et al. 2016

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The sorption of xylene and isooctane was measured by the gravimetric flow sorption method on commercial activated carbons (ACs), namely, virgin and reactivated ACs. Nitrogen physisorption, high-pressure mercury porosimetry, helium pycnometry, iodine number, pH measurement, Raman and X-ray photoelectron spectroscopies were applied for textural, structural, and surface characterization of ACs. The equilibrium geometries of isooctane and xylene molecules were modeled using density functional theory (DFT) calculations. Their dimensions were estimated to be correlated with textural properties of ACs to reveal the effect of size selectivity. The key factors influencing the adsorption capacity of the chosen ACs for both tested volatile organic compounds (VOCs) were found to be the mesopore surface area and the surface basicity.

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Section: Resultsmentioning

confidence: 95%

Molecular Dimensions and Porous Structure of Activated Carbons for Sorption of Xylene and Isooctane

et al. 2016

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“…However, to date they are still not considered analytically or commercially viable alternatives to conventional C18 sorbents, and only few studies have reported on the preconcentration of PCBs, i.e., enriching PCBs from aqueous samples using magnetic MWCNTs graed with a hydrophilic layer, 30 and clean-up of sh extracts using magnetic molecularly imprinted polymers comprising MWCNTs as support material. 28,52,101,153,138,180) in aqueous environments using pristine MWCNTs. Therefore, we report herein an affordable and fully validated MWCNTs-SPE protocol for determination of 6 indicator PCBs (i.e., IUPAC no.…”

Section: Introductionmentioning

confidence: 99%

Multi-walled carbon nanotubes: innovative sorbents for pre-concentration of polychlorinated biphenyls in aqueous environments

Ndunda

Mizaikoff

2015

Anal. Methods

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Carbon nanotubes (CNTs) have demonstrated outstanding chemical and mechanical stability, electrical properties, and strong interactions with aromatic compounds owing to the p-electron system on the graphene sheets. Taking advantage of these unique properties, we have developed a fully validated sample pre-concentration technique for determination of polychlorinated biphenyls (PCBs) in aqueous environments using gas chromatography combined with a micro-cell electron capture detector (GC-mECD). The optimized method using pristine MWCNTs gave recoveries in the range of 46.0-92.5%, 51.4-91.5%, 48.7-77.8% for tap water, river water, and lake water, respectively. Compared to conventional C18 adsorbent and oxidized MWCNTs (oMWCNTs), pristine MWCNTs provided the best recoveries, thereby confirming that MWCNTs are excellent alternatives for C18, with the ability to achieve high performance. The developed protocol achieved method detection limits in the range of 0.002-0.011 mg L À1 and relative standard deviation (RSD) < 15.5%.

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“…Yet for this reaction, and to some extent also for the disproportionation reaction, we would like to emphasize that the effect of water is not as obvious as it may sound. In fact, both the polymer and the activated carbon have hydrophobic surfaces, 47 thus the presence of water was not expected to lead to a such large increase in conversion. Moreover, water is also a by-product of the oxidation reaction (see Schemes 1 and 2) and this should also discourage this high increase in conversion.…”

Section: Methodsmentioning

confidence: 99%

Water as a catalytic switch in the oxidation of aryl alcohols by polymer incarcerated rhodium nanoparticles

Weston

Miyamura

Yasukawa

et al. 2017

Catal. Sci. Technol.

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One of the major goals in the oxidation of organic substrates, and especially for alcohol oxidation, is the use of molecular oxygen as the oxidant under mild conditions. Here we report the synthesis and testing of Rh polymer incarcerated catalysts, using a metal so far not used for alcohol oxidation reactions, in which the catalytic activity towards aryl alcohol oxidation, for substrates like 1-phenylethanol and benzyl alcohol, is switched on by the addition of water as co-solvent in toluene. This is done by using air as oxidant at atmospheric pressure, in one of the mildest reaction conditions reported for this class of reaction. The promoting effect of water to higher conversions was observed also for rhodium over alumina supported catalysts, which were used as a benchmark allowing in all cases high conversion and selectivity to the ketone or the aldehyde within a short reaction time. The effect of water was explained as a medium capable to promote the oxidation of the alcohol to the ketone in a biphasic system assisted by phase transfer catalysis. This is particularly relevant for alcohols like 1-phenylethanol or benzyl alcohol that are not soluble in water at room temperature, and for which alternative oxidation routes are needed, as well as to switch on the catalytic activity of metal nanoparticles in a facile and green manner for the activation of molecular oxygen. Aliphatic alcohols like 1-octanol and 3-octanol were also tested, still showing Rh based catalysts as promising materials for this reaction if toluene only was used as solvent instead.2

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Cited by 61 publications

References 13 publications

Molecular Dimensions and Porous Structure of Activated Carbons for Sorption of Xylene and Isooctane

Molecular Dimensions and Porous Structure of Activated Carbons for Sorption of Xylene and Isooctane

Multi-walled carbon nanotubes: innovative sorbents for pre-concentration of polychlorinated biphenyls in aqueous environments

Water as a catalytic switch in the oxidation of aryl alcohols by polymer incarcerated rhodium nanoparticles

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