Dynamic detection of saturated distribution of activated carbon adsorbed volatile organic compounds based on electrical impedance tomography

Abstract

The electrical impedance tomography (EIT) has been achieved for the dynamic detection of the adsorption saturation distribution in activated carbon. Volatile organic compounds (VOCs) emitted by industries pose a serious threat to human health and environmental quality. Therefore, adsorption method is widely used to treat such organic compounds. Activated carbon, as a commonly used adsorbent material, plays a crucial role in the efficient utilization and management of the adsorption process. Traditional adsorption detection methods suffer from information loss and discontinuity. We can obtain the conductivity distribution information during the current passing through the material by measuring the potential changes on the boundary of interest field, and analyze the saturation distribution information of VOCs adsorbed on activated carbon based on the conductivity distribution image. The feasibility of the technology in monitoring the saturation distribution of the adsorption process in activated carbon was verified by principle and simulation. For experimental verification, fixed bed and fluidized bed experiments were carried out, taking into account the special case of impedance change factors of activated carbon particles in the static and flow states. The experimental results confirm that in fixed-bed adsorption, the adsorption impedance change response can be effectively obtained at an excitation frequency of 1.0 MHz, while in a fluidized bed, a good adsorption impedance change response can be achieved at an excitation frequency of 4 kHz. By selecting the appropriate excitation frequency according to the change in the adsorbent’s state, stable imaging of the saturation distribution can be achieved. This study introduces a new method for visualizing the monitoring process of activated carbon adsorption.