scholarly journals Sensing of volatile organic compounds in indoor atmosphere and confined areas of industrial environments

2013 ◽  
Vol 10 (2) ◽  
pp. 217-225
Keyword(s):  
Volatile Organic Compounds ◽  
Light Source ◽  
Organic Compounds ◽  
Monochromatic Light ◽  
Chemical Vapour ◽  
Dip Coating ◽  
In Situ Monitoring ◽  
Light Power ◽  
Volatile Organic ◽  
Industrial Environments

A chemical vapour sensor working with a monochromatic light source and based on optical fibre coated with a thin siloxane polymer film has been developed for in situ monitoring of volatile organic compounds, such as ethylbenzene, xylene (o-xylene), heptane, octane, chloroform, carbon tetrachloride, ethanol and butanol in indoor atmosphere and confined areas of industrial environments. The sensor consists on a monomode optical fibre with an end surface coated with a thin polymeric film by dip-coating technique. The light source utilized was a stabilized laser diode at 1550 nm and the light power changes were measured with a photodiode. The sensor was tested for different VOCs and for different individual concentrations regarding stability, sensitivity, repeatability and reversibility of the analytical signal. The response and desorption time have been found to be 30 seconds and good reproducibility and accuracy have been also obtained. Finally, the analytical performance of the developed sensor was also evaluated and found adequate for actual monitoring on indoor atmospheres.

scholarly journals Chemiresistor microsensors for in-situ monitoring of volatile organic compounds : final LDRD report.

2003 ◽  
Author(s):  
Michael Loren Thomas ◽  
Robert Clark Hughes ◽  
Ara S Kooser ◽  
Lucas K McGrath ◽  
Clifford Kuofei Ho ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
In Situ Monitoring ◽  
Volatile Organic

Online sensing of volatile organic compounds in groundwater using mid-infrared fibre optic evanescent wave spectroscopy: a pilot scale test

2003 ◽  
Vol 47 (2) ◽  
pp. 121-126 ◽  
Author(s):  
H. Steiner ◽  
K. Staubmann ◽  
R. Allabashi ◽  
N. Fleischmann ◽  
A. Katzir ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Pilot Plant ◽  
Pilot Scale ◽  
In Situ Monitoring ◽  
Fibre Optic ◽  
Sensor Head ◽  
Sensing System ◽  
Volatile Organic

A prototype sensing system for in-situ monitoring of volatile organic compounds in contaminated groundwater was tested at a pilot scale plant. The sensor consists of a commercially available Fourier transform infrared spectrometer, connected to a 6 m long infrared transparent silver halide fibre optic cable. A 10 cm long core-only section at the centre of the fibre is mounted on a sensor head and coated with a hydrophobic polymer layer, while the remaining fibre is protected by Teflon tubing and thus not in contact with the surrounding media. The sensor head was immersed into the monitoring wells of the pilot plant testing the sensor system under circumstances close to field conditions and typical for in-situ measurements. The pilot plant consists of a 1 m3 cubic tank filled with gravel. A pump is used to circulate water horizontally through the tank, simulating a natural aquifer. The evolution of the concentration of analytes injected into the system is monitored with time using the developed prototype sensing system. The results are validated by corresponding sampling and analysis with headspace gas chromatography.

scholarly journals Development of a Surface Acoustic Wave Sensor for In-Situ Monitoring of Volatile Organic Compounds

Sensors ◽  
2003 ◽  
Vol 3 (7) ◽  
pp. 236-247 ◽  
Author(s):  
Clifford Ho ◽  
Eric Lindgren ◽  
K. Rawlinson ◽  
Lucas McGrath ◽  
Jerome Wright
Keyword(s):  
Volatile Organic Compounds ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Organic Compounds ◽  
In Situ Monitoring ◽  
Acoustic Wave Sensor ◽  
Volatile Organic

scholarly journals Synthesis of ZnO-CuO flower-like hetero-nanostructures as volatile organic compounds (VOCs) sensor at room temperature

2018 ◽  
Vol 36 (3) ◽  
pp. 452-459
Author(s):  
Raad S. Sabry ◽  
Roonak Abdul Salam A. Alkareem
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Room Temperature ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Volatile Organic ◽  
Recovery Times ◽  
Coating Methods ◽  
Response And Recovery

AbstractZnO-CuO flower-like hetero-nanostructures were successfully prepared by combining hydrothermal and dip coating methods. Flower-like hetero-nanostructures of ZnO-CuO were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-Vis. The sensing properties of ZnO-CuO flower-like hetero-nanostructures to volatile organic compounds (VOCs) were evaluated in a chamber containing acetone or isopropanol gas at room temperature. The sensitivity of ZnO-CuO flower-like hetero-nanostructures to VOCs was enhanced compared to that of pure leafage-like ZnO nanostructures. Response and recovery times were about 5 s and 6 s to 50 ppm acetone, and 10 s and 8 s to 50 ppm isopropanol, respectively. The sensing performance of ZnO-CuO flower-like hetero-nanostructures was attributed to the addition of CuO that led to formation of p-n junctions at the interface between the CuO and ZnO. In addition, the sensing mechanism was briefly discussed.

Chemical Vapour Deposition (CVD) Technique for Abatement of Volatile Organic Compounds (VOCs)

2020 ◽  
Vol 71 (7) ◽  
pp. 97-113
Author(s):  
Marius Stoian ◽  
Liliana Lazar ◽  
Florent Uny ◽  
Frederic Sanchette ◽  
Ioana Fechete
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Chemical Vapour Deposition ◽  
Noble Metals ◽  
Vapour Deposition ◽  
Active Material ◽  
Combustion Process ◽  
Chemical Vapour ◽  
Morphological Properties ◽  
Volatile Organic

Chemical vapour deposition (CVD) is an important technique that uses volatile precursors to produce thin film deposits on an exposed substrate, having the capability to generate different types of nanostructures (e.g. nanoparticles, nanotubes, nanofibers or nanocomposites) as catalytic materials. The environmental hazard of volatile organic compounds (VOCs) requires efficient methods to reduce their emission into the atmosphere, due to their high potential to cause severe health issues, along with their extended spread in the environment. Catalytic combustion proves to be one of the most effective means for the abatement of VOCs, employing different catalysts, such as noble metals or non-noble metal oxides, to facilitate the oxidation process of the pollutants. These catalysts can be prepared through various methods as multiple steps wet processes or CVD techniques, indicating the superiority of the CVD-prepared catalysts compared to those prepared using the former type of process, due to the ability to achieve high dispersion of the active material, together with enhanced textural and morphological properties. This paper aims to present the various CVD techniques employed in the fabrication of different catalysts with the possibility of generating materials at nano-scale for use in numerous reactions, mostly in combustion process for VOCs decomposition.

Effect of Nanotube Aspect Ratio on Chemical Vapour Sensing Properties of Polymer/MWCNT Composites

2012 ◽  
Vol 21 ◽  
pp. 117-123 ◽  
Author(s):  
G. Sakale ◽  
D. Jakovlevs ◽  
I. Aulika ◽  
Maris Knite
Keyword(s):  
Carbon Nanotubes ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Electrical Resistance ◽  
Chemical Vapour ◽  
Length Change ◽  
Resistance Change ◽  
Sensing Properties ◽  
Multi Wall Carbon Nanotubes ◽  
Volatile Organic

The main topic of this paper is the study of polyisoprene-multi wall carbon nanotubes (PiMWCNT) composites electrical conductivity and volatile organic compound sensing properties with respect to type of multi wall carbon nanotubes used. Electrical percolation parameters like percolation threshold and critical exponent of produced composites are determined and analyzed. PiMWCNT composites exhibit a promising sensitivity to the presence of volatile organic compounds. Therefore the composites sensing mechanism of volatile organic compounds are analyzed in more detail by applying an original measuring technique which enables simultaneous measurement of an electrical resistance, mass and length change measurement of the sample in the presence and subsequent absence of a vapour. Measurement results enabled the evaluation of both vapour diffusion behavior in the composite and electrical resistance change mechanism.

scholarly journals Enhanced the Performance of Fluorescence Gas Sensor of Porphyrin Dye by Using TiO2 Nanoparticles

2008 ◽  
Vol 55-57 ◽  
pp. 269-272 ◽  
Author(s):  
Nurul Huda Yusoff ◽  
Muhamad Mat Salleh ◽  
Muhammad Yahaya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Volatile Organic Compounds ◽  
Tio2 Nanoparticles ◽  
Gas Sensor ◽  
Organic Compounds ◽  
Quartz Substrate ◽  
Emission Spectra ◽  
Dip Coating ◽  
Volatile Organic

Fluorescence gas sensor was developed to identify the presence of volatile organic compounds by using porphyrin dye thin film. The porphyrin dye used was iron (III) meso-tetraphenylporphine chloride. The porphyrin thin film was deposited on quartz substrate using self-assembly through dip coating technique. The sensing properties of the thin films toward volatile organic compounds; ethanol, acetone and 2-propanol were studied using luminescence spectrometer. In presence of air and volatile organic compounds, thin films produced different emission spectra and ease for chemical identification process. To improved the sensing performance, TiO2 nanoparticles colloid were prepared, coated with porphyrin dye and deposited as thin film. It was found that the thin film of TiO2 nanoparticles coated with porphyrin dye has more intensive interaction toward volatile organic compounds than porphyrin thin film, and improved the selective property. This may be due to the nanostructured thin film provided more surface area for dye molecules to react with VOCs.

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