Fullerenes-extracted soot: a new adsorbent for collecting volatile organic compounds in ambient air

Synergistic Effect between Ni and Ce Dual Active Centers Initiated by Activated Fullerene Soot for Electro−Fenton Degradation of Tetracycline

The degradation of a high concentration of organic pollutants has long been a challenge to water restoration, and the development of electro−Fenton catalysis offers a practical approach to solving this problem. In this study, a novel electro−Fenton catalyst, activated fullerene soot−loaded NiO−doped CeO2 (0.4(0.4NiO−CeO2)−AFS) nanoparticles, was prepared through the impregnation of 0.4NiO−CeO2 particles and activated fullerene soot (AFS). When applied for the degradation of 200 mg/L of tetracycline, this catalyst demonstrated a degradation rate as high as 99%. Even after 20 cycles, the degradation rate was more than 80%. Moreover, it was concluded that AFS could initiate the synergistic effect between Ni and Ce dual active centers in the degradation of tetracycline; this can be ascribed to the extremely large specific surface area of AFS.

Selective formation and structural properties of rhombic dodecahedral [70]fullerene microparticles formed by reaction with aliphatic diamines

We have accomplished the selective formation of rhombic dodecahedral microparticles on the submicrometer to micrometer scale by the reaction of [70]fullerene (C(70)) with primary aliphatic diamines. The morphology of the resultant microparticles was analyzed by scanning electron microscopy, powder X-ray diffraction, and other spectroscopic methods, demonstrating that the resultant particles held a rhombic dodecahedral shape having a simple cubic lattice structure and that primary aliphatic amines were mostly trapped inside the particles through electronic interaction between C(70) and amines. Furthermore, we have discovered interesting structural characteristics in which the incorporated amines could be removed from the C(70) microparticles or exchanged with other primary aliphatic diamines.

Supercritical fluid chromatography and two-dimensional supercritical fluid chromatography of polar car lubricant additives with neat CO2 as mobile phase

Car lubricant additives are added to mineral or synthetic base stocks to improve viscosity and resistance to oxidation of the lubricant and to limit wear of engines. Their total amount in the commercial lubricant varies from a few percents to 20-25%. As they belong to various chemical classes and are added to a very complex medium, the base stock, their detailed chromatographic analysis is very difficult and time consuming as it should involve sample treatment and preparative scale separations in order to simplify the sample. The aim of this work is to determine the feasibility of the separation of low molecular weight lubricant additives using various packed columns with pure CO(2) as a mobile phase to enable implementation of flame ionisation detection as universal detector. This is part of a hypernated system including more sophisticated specific detectors, such as AED, FTIR or MS to obtain detailed structural information of compounds. This paper is devoted to the comparison of some stationary phases supposed to provide hydrocarbon group type separation (silica and normal phase) or separations on alkyl-bonded silica in non-aqueous mode of some selected classes of additives in test mixtures or in base stocks. Adsorption chromatography allows partial separation of additives from the base stocks while the direct elution of test additives can only be obtained on reversed phase supports having a very efficient silanol group protection so the interaction of the more polar compounds is much reduced. A two-dimensional scheme of analysis is also described. It combines adsorption chromatography to separate most of the polar additives from the base stock and alkyl-bonded silica for more detailed separation of the additives. However, overlapping between groups of compounds and the lack of resolution between some additives and the base stock should be addressed by the implementing of selective detectors.

Evaluation of multi-walled carbon nanotubes as an adsorbent for trapping volatile organic compounds from environmental samples

A type of purified multi-walled carbon nanotubes (PMWCNTs) prepared by catalytic decomposition of methane, with a surface area of 98 m2/g, was evaluated as an adsorbent used for tapping volatile organic compounds (VOCs). The performance in evaluation was based on breakthrough volumes (BTVs) and recoveries of selected VOCs. PMWCNTs were also used as a trap packing material to adsorb VOCs purged from spiked water sample. Due to their porous structure, PMWCNTs were found to have much higher BTVs than that of Carbopack B, a graphitized carbon black with the same surface area as PMWCNTs. The recoveries of the tested VOCs trapped on PMWCNTs ranged from 80 to 110%, and not affected by the humidity of purge gas. The results indicate that PMWCNTs are a potential useful adsorbent for direct trapping VOCs from air samples and may be a supplement to VOCARB 3000, a commercially available trap, in purge-and-trap system to preconcentrate VOCs from water samples.