Sustainable Recovery of Gaseous Mercury by Adsorption and Electrothermal Desorption Using Activated Carbon Fiber Cloth
Journal
Environmental Science and Technology
Journal Volume
54
Journal Issue
3
Pages
1857-1866
Date Issued
2020
Author(s)
Abstract
The present work aims to develop a novel and sustainable approach to adsorb and recover low-concentration Hg0 in the off-gas downstream a distillation/condensation system in the recycling processes for waste Hg-containing devices. Hg0 adsorption and regeneration efficiencies of raw and HNO3-treated activated carbon fiber cloth (ACFC) were examined. The adsorption experiments were conducted with an initial Hg0 concentration of 260-300 μg/m3 at room temperature. The regeneration of ACFC was done by an electrothermal swing process with 20, 40, and 60 W direct currents. The experimental results showed that the Hg0 adsorption efficiency of raw ACFC increased to approximately 90% after the 60 W electrothermal regeneration. After HNO3 treatment, the content of oxygen functional groups on HNO3-treated ACFC increased, which enhanced the Hg0 adsorption performance and resulted in over 90% adsorption efficiency for the samples before and after electrothermal regeneration. Importantly, both raw and HNO3-treated ACFCs retained the high adsorption efficiency after nine cycles of adsorption/regeneration, indicating that both raw and HNO3-treated ACFCs were effective and renewable adsorbents for low-concentration Hg0 adsorption and recovery. A Hg adsorption/regeneration mechanism was proposed to explain the increasing adsorption efficiency after electrothermal regeneration and the great adsorption efficiency of HNO3-treated ACFC.
Other Subjects
Activated carbon; Carbon fibers; Distillation; Efficiency; Electric heating; Mercury (metal); Recovery; Activated carbon fiber cloths; Adsorption and recoveries; Adsorption experiment; Adsorption performance; Electrothermal desorption; Oxygen functional groups; Regeneration efficiency; Treated activated carbons; Adsorption; activated carbon; functional group; mercury; nitric acid; oxygen; carbon fiber; charcoal; activated carbon; adsorption; carbon fiber; desorption; ectothermy; gas; mercury (element); oxygen; recycling; regeneration; adsorption; Article; chemical structure; deconvolution; desorption; direct current; distillation; elemental analysis; hazardous waste; kinetics; photoelectron spectroscopy; recycling; surface area; surface property; titrimetry; adsorption; gas; Adsorption; Carbon Fiber; Charcoal; Gases; Mercury
Type
journal article