Improving the Removal Efficiency of Elemental Mercury by Pre-Existing Aerosol Particles in Double Dielectric Barrier Discharge Treatments

Abstract

Plasma technology has been employed for the removal of gaseous elemental mercury (Hg 0 ) from simulated flue gases without pre-existing airborne particles. This study developed a double dielectric barrier discharge (DDBD) treatment system, in which two coaxial electrodes were covered by quartz dielectrics, for removing mercury with the presence of aerosol particles. The increase in pre-existing aerosol surface concentration can improve Hg 0 removal efficiency up to 160% in the DDBD device. Inorganic aerosol particles (sodium chloride) perform better than organic ones (sucrose) in improving Hg 0 removal efficiency. These aerosol particles can be collected in the DDBD system. For sodium chloride particles, a collection efficiency of more than 90% was observed in the tested diameter range of 10-100 nm. The improvement in Hg 0 removal with the presence of particles is possibly due to that (i) aerosol particles provide additional surface for surface-induced Hg 0 oxidations, (ii) reactive species (such as Cl) generated by plasma etching particle surface rapidly react with Hg 0 , and (iii) charged particles can in-flight adsorb mercury species.

On the charged aerosols generated by atmospheric pressure non‐equilibrium plasma

“…These airborne particles can be generated by evaporation of liquid droplets leading to micrometre powders through spray dying and pyrolysis [1,2], or gas-to-particle conversion leading to nanometre to sub-micrometre particles [3]. Aerosols are made up of different compositions such as sulphates, nitrates, elemental and organic carbon, metals, biological compounds, and polycyclic aromatic hydrocarbons (PAHs) [4,5], which have side effects on human health and climate [6].…”

Developments in Unipolar Charging of Airborne Particles: Theories, Simulations and Measurements

“…Airborne particles consist of diverse composition including nitrates, sulfates, elemental and organic carbon, polycyclic aromatic hydrocarbons (PAHs), biological compounds, and metals (Cheruiyot et al, 2015;Kim et al, 2015), which causes severe impacts on climate and human health (Li et al, 2015), fine particles have been extensively studied in diverse fields (Aurela et al, 2015;Malaguti et al, 2015). Among them, the charging process of particles plays an essential part in many applications.…”