Study on NO x removal from simulated flue gas by an electrobiofilm reactor: EDTA-ferrous regeneration and biological kinetics mechanism

The regeneration of EDTA-Fe II is a key step in electrobiofilm reduction-integrated systems for NO x removal from industrial boiler flue gas. The current and carbon sources are proposed to be the two crucial electron donors for EDTA-Fe II regeneration. These parameters strongly influence the reactivity of EDTA-Fe II -generated products in the system. Therefore, their effects on EDTA-Fe II -NO and EDTA-Fe III reduction and the EDTA-Fe II generation mechanism were studied. The results showed that the electrobiofilm method has obvious advantages over biological or electrochemical methods used alone for EDTA-Fe II regeneration. Under the optimal conditions at a current of 22.9A m −3 net cathode chamber, the rate of EDTA-Fe II regeneration reached 98.35%. The glucose concentration is the primary factor influencing the reduction of both EDTA-Fe II -NO and EDTA-Fe III , while the current significantly promotes both processes. Comparison of the K m values of the two substrates indicated that microbial activity was crucial to the reduction of EDTA-Fe II -NO, but the biological reduction of EDTA-Fe III had a competitive influence on EDTA-Fe II -NO reduction, which limited the abundance and effectiveness of the bacteria responsible for EDTA-Fe II -NO reduction in the electrobiofilm system.