Volume 15, No. 4, August 2015, Pages 1506-1513 PDF(492 KB)
Improving the Removal Efficiency of Elemental Mercury by Pre-Existing Aerosol Particles in Double Dielectric Barrier Discharge Treatments
Qing Li1, Jingkun Jiang1,2, Lei Duan1, Jianguo Deng1, Lun Jiang3, Zhen Li1, Jiming Hao1,2
1 State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
2 State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
3 Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Double dielectric barrier discharge (DDBD) system was developed to remove Hg0.
- Pre-existing aerosols in DDBD treatment can improve the Hg0 removal efficiency.
- Inorganic aerosol particles perform better than organic ones.
- These pre-existing aerosol particles can be collected in the DDBD system.
- Possible mechanisms have also been discussed for the high removal efficiency.
Plasma technology has been employed for the removal of gaseous elemental mercury (Hg0) 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 Hg0 removal efficiency up to 160% in the DDBD device. Inorganic aerosol particles (sodium chloride) perform better than organic ones (sucrose) in improving Hg0 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 Hg0 removal with the presence of particles is possibly due to that (i) aerosol particles provide additional surface for surface-induced Hg0 oxidations, (ii) reactive species (such as Cl) generated by plasma etching particle surface rapidly react with Hg0, and (iii) charged particles can in-flight adsorb mercury species.
Mercury removal; Aerosol particles; Plasma; DDBD; Pollution control.