Induced adsorption and agglomeration under bipolar corona discharge to enhance the simultaneous removal of trace mercury and fine particles

Abstract

• The induced adsorption of Hg 0 was enhanced by the bipolar corona discharge through sorbent. • The addition of MnO x sorbent promoted the agglomeration of fine particles in electric field. • The corona discharge had a guidance effect on the migration of mercury-carried particles. Fine particulate matter (PM 2.5 ) and gaseous mercury emitted from industrial flue gas are highly toxic to humans and the environment. Promoting the enrichment of non-condensable gaseous elemental mercury (Hg 0 ) and enhancing the nucleation growth of fine particles can cause them to be simultaneously removed in dust removal devices. However, the sorbent itself is also a fine particle, and the fate of the mercury-carried sorbent is unclear. Herein, we propose a novel method that uses manganese oxides (MnO x ) for the induced adsorption of Hg 0 to coagulate the sorbent and fine particles, assisted by bipolar corona discharge. The results showed that Hg 0 removal efficiencies increased from 10.2% to 32.2% with sorbent injection when the corona discharge was +21 kV and −24 kV. Simultaneously, the fine particle removal efficiencies increased from 23.6% to 46.3%. The distribution results confirmed that mercury was enriched on the particles through sorbent and fine particle agglomeration, and the mercury-carried particle proportion was concentrated in the size range of 0.5–2.5 μm. The induced adsorption performances were enhanced under bipolar corona discharge through the MnO x sorbent. In addition, the agglomeration of fine particles was enhanced as the average particle size increased by 43% when the MnO x sorbent was injected into the simulated gas. This study provides valuable guidance for clarifying the relationships between the fine particles and carried substances, and it contributes to achieving the synergistic removal of multiple contaminants.