The enhancement mechanism of the microwave-assisted toluene desorption for activated carbon regeneration based on the constructive interference

Abstract

Reducing energy consumption is a crucial issue in adsorbent regeneration process, while regulating temperature distribution during regeneration is expected to solve this problem. In this study, we propose a novel enhancement mechanism based on the enhanced constructive interference for microwave-assisted regeneration of the activated carbons via a facile method for preparing activated carbons. We prepared activated carbons with similar adsorption characteristics (qe ≈ 0.20 g g−1 with a toluene concentration of 376 mg m−3) and different dielectric properties (29.96 < εr' < 84.18 and 20.21 < εr'' < 36.36) to investigate the effect of dielectric properties on microwave-assisted regeneration. Moreover, we obtained a high regeneration efficiency (>95%) and reduced energy consumption (∼50% of maximum value) in AC-450 with an input power of 40 W. A series of experiments and numerical simulations revealed that the reduced energy consumption was due to the enhanced constructive interference governed by dielectric properties. Further, a decreased dimensionless parameter affected by dielectric properties, fp, can enhance constructive interference. In summary, this work proposes an enhancement mechanism based on the enhanced constructive interference for microwave heating technology and provides a facile method for reducing energy consumption in microwave-assisted regeneration.