Using novel gold nanoparticles-deposited activated carbon fiber cloth for continuous gaseous mercury recovery by electrothermal swing system

Abstract

• AuNPs-deposited ACFC was perfectly synthesized via THPC method. • AuNPs enormously promoted Hg 0 adsorption capacity compared to the raw ACFC. • Hg 0 was physically adsorbed by AuNPs-deposited ACFC via amalgamation. • Great potential for sustainable recovery of Hg 0 by ETS desorption was shown. • Intraparticle diffusion controlled the desorption process of Hg 0 from ACFCs. Novel gold nanoparticles (AuNPs) deposited activated carbon fiber cloth (ACFC) was successfully developed in this study. This material showed great potential in combining with an electrothermal swing (ETS) system to sustainably adsorb and recover low-concentration elemental mercury (Hg 0 ) in gas stream. ACFC with Au loading ratio of 0.5 wt% (0.5 wt%-ACFC-THPC) demonstrated the largest Hg 0 adsorption capacity. Hg temperature-programmed desorption results suggested that Hg 0 was physically adsorbed by AuNPs on Au-ACFC-THPC via amalgamation, while it was both physically and chemically adsorbed by pore structures or carbonyl groups on Raw-ACFC. The Hg 0 adsorption efficiency of 0.5 wt%-ACFC-THPC was approximately 95% and remained stable during the cyclic ETS operation under various Hg 0 inlet concentrations (30, 75, and 100 µg m −3 ); however, the adsorption efficiency of Raw-ACFC greatly decreased to 65–75% as Hg 0 inlet concentration increased to 75 and 100 µg m −3 . Furthermore, the regeneration efficiencies of all ACFCs were >90% within 6 min; indicating the promising application in concentrating Hg 0 vapor and the subsequent recovery process. Mass transfer models for the simulation of Hg 0 desorption within ACFCs were further conducted; the simulation results suggested that intraparticle diffusion dominated the desorption process for both Raw-ACFC and 0.5 wt%-ACFC-THPC.