Rapid and reversible adsorption of BTX on mesoporous silica thin films for their real time spectrophotometric detection in air at ppm levels.

Rapid and reversible adsorption of BTX on mesoporous silica thin films for their real time spectrophotometric detection in air at ppm levels. Talanta. 2019 Oct 01;203:269-273 Authors: Hamdi K, Martin P, Etienne M, Hébrant M Abstract Benzene, toluene and xylenes (BTX) are among the most toxic volatile organic compounds that can be emitted into the environment of different workplaces. Regulations to protect workers continue to strengthen permissible exposure limit (PEL), and short-term exposure limit (STEL) for any 15-min period are defined for BTX that should be controlled with rapid, selective and sensitive on-site sensors. For that purpose, a real-time analysis of BTX is described here, using the UV spectrometric determination of instantaneously concentrated pollutants in a thin film of mesoporous and transparent silica deposited onto quartz plates. A new optical cell has been designed to achieve the lowest detection limits, up to the ppm level in air for benzene, toluene and p-xylene. The sensor was equipped with an air dryer to detect BTX in the presence of humidity and major interfering volatile organic compounds (acetone, ethanol, butanone and cyclohexane). The sensor has detection limits below defined PEL and STEL for benzene, toluene and xylenes. The adsorption properties of BTX on the sensor surface were quantitatively analyzed using the Freundlich equation, showing the singular behavior of benzene adsorption on the surface ...
Source: Talanta - Category: Chemistry Authors: Tags: Talanta Source Type: research