Monitoring and exploring electrical resistance changes of activated carbon fibre cloth for the dynamic adsorption of VOCs at elevated relative humidity.

Abstract

Activated carbon fibre cloth (ACFC) adsorbent has been used to monitor adsorption processes based on its changes in electrical resistance after adsorbing volatile organic compounds (VOCs). It is important to investigate the effect of co-adsorption of VOCs and water on resistance changes of ACFC from a practical point of view. In this study, the evolution of resistance changes of ACFC-15 was real-time monitored during adsorption of select VOCs with different inlet concentrations and relative humidity (RH). Resistance of ACFC-15 was affected by adsorption of oxygen from the carrier gas, temperature increase caused by exothermic adsorption, and adsorption of organic compound and/or water. After the completion of all tests, resistances of ACFC-15 are all decreased, which is attributed to the relatively more ordered structure of ACFC-15 after adsorbing organic compound and/or water. The trend of increasing d₀₀₂ of the nanographene sheets declines with increasing boiling point of the organic compounds. The absolute values of change in resistance are consistent with the peak intensities of the (002) plane of ACFC-15 adsorbed organic compound, and/or water. This study provides valuable results to improve the performance of ACFC adsorbent for monitoring single-component VOC adsorption based on its electrical resistance at elevated RH.