Comparison of Adsorbents Containing Carbon Nanotubes for Express Pre-Concentration of Volatile Organic Compounds from the Air Flow

Oleg Rodinkov,Alexandra Bugaichenko,Sergey Lanin,Andrey Vlasov,Valery Spivakovskyi,Roman Shilov,Svetlana Slastina,Ekaterina Znamenskaya,Pavel Nesterenko,Victor Postnov

doi:10.3390/separations8040050

Oleg Rodinkov, Alexandra Bugaichenko + Show 8 more

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https://doi.org/10.3390/separations8040050

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Abstract

New composite adsorbents including silica supports (silica, aerosilogel, and diatomite) and carbon materials (multiwall carbon nanotubes and pyrolytic carbon) have been prepared and characterized. The analytical capabilities of the produced sorbents have been evaluated by their efficiency in the express pre-concentration of volatile organic compounds (butanol and phenols) from the air stream. The prepared surface-layered adsorbents containing multiwall carbon nanotubes placed onto the surface of aerosilogel by use of the carbon vapor deposition method with preloading cobalt nanostructures as a catalyst were found significantly more efficient than traditionally used graphitic carbon-based adsorbents Carbopacks B, C, and X. Additionally, a new adsorbent composed of diatomite Porochrome-3 support coated with a pyrocarbon layer was prepared. This low surface area composited adsorbent allowed both quantitative pre-concentration of phenol and isomeric cresols from the air and their thermal desorption. The developed adsorbents provided fast pre-concentration of selected phenols with a concentration factor of 2 × 103 in 5 min and were used for gas chromatographic determination of analytes in the air at low concentration levels starting from several μg/m3 with a flame ionization detector.

Highlights

Determination of most pollutants in the atmospheric air and the air of living accommodations necessitates pre-concentration of analytes [1]
On this account it is preferable to resort to a dynamic solid-phase extraction (SPE) based on passing analyzed gas through a tube filled with a sorbent, a routine being followed by thermo-desorption or desorption by an organic solvent with consequent determination by gas chromatography (GC) or high-performance liquid chromatography (HPLC) [2,3,7]
The shortcoming of the method consists in a multistage synthesis, low content of Carbon nanotubes (CNTs) in the sorbents [19], and the presence of residual reactive aminopropyl- and silanol groups, deteriorating the specificity of sorption

Summary

Introduction

Determination of most pollutants in the atmospheric air and the air of living accommodations necessitates pre-concentration of analytes [1]. Are restricted with a relatively small mass of the active absorbing phase (0.2–2.0 mg), and, relatively small adsorptive capacity of concentrators regarding concentrated analytes, the situation being insufficient for attaining low detection limits [5,6]. On this account it is preferable to resort to a dynamic SPE based on passing analyzed gas through a tube filled with a sorbent, a routine being followed by thermo-desorption or desorption by an organic solvent with consequent determination by GC or HPLC [2,3,7].

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Conclusion