Performance and reaction kinetics of NO absorption by Fe(II)EDTA in a multistage zeolite absorption column-H2-MBfR system

Abstract

Efficient NOX complexation absorption is a key to biological flue gas denitrification. In this study, the influencing factors, efficiency, and kinetic parameters of Fe(II)EDTA absorption of NO in a multistage zeolite absorption column were evaluated. The response surface methodology (RSM) was used to determine the ideal absorption conditions. Based on these results, a combined process of a multistage zeolite absorption column and a hydrogen-based membrane biofilm reactor (H2-MBfR) was built to verify the efficiency of denitrification. The optimal conditions for achieving maximum efficiency in the absorption of NO by Fe(II)EDTA were obtained as pH of 6.5, Fe(II)/EDTA molar ratio of 1:1.1, and temperature of 30 ℃. The kinetic parameters, including liquid phase mass transfer coefficient (KNO,L) and gas phase mass transfer coefficient (KNO,G), all increased with temperature, while the NO interfacial-area concentration (aNO) exhibited the opposite trend. The reaction for Fe(II)EDTA absorption of NO was a conjugation reaction, and its activation energy was 50.38 kJ·mol-1. More than 90 % of NO in flue gas on 14 days was removed in the combined multistage zeolite absorption column-H2-MBfR process, which provided a sustainable NO treatment solution without secondary pollutants or CO2 emissions and demonstrated its potential for NO removal in industrial applications.