Membrane-less Paired Electrolysis for Cooperative Conversion of Complex NO in a Complexing Absorption System

The complexing absorption method serves as an important wet process for potential application in NO removal of industrial exhaust gas. However, gradual saturation of the absorbent severely limits its continuous operation and denitration efficiency. Herein, a membrane-less paired electrolysis (MLPE) process was first introduced for cooperative conversion of complex NO, thereby regenerating the absorbent. Fe(II)EDTA(NO) was converted on the anode and cathode directly and indirectly; namely, complex NO was not only oxidized to NO3-, but also reduced to NH4+, N2, and N2O. Furthermore, NO3- and NH4+ acted as the potentially valuable products for further reclamation and utilization. Compared with membrane anodic electrolysis (MAE) and membrane cathodic electrolysis (MCE) systems, the MLPE system achieved the lowest energy consumption and highest conversion efficiency of Fe(II)EDTA(NO). Finally, the influences of key process parameters on the complex NO electro-conversion were investigated. The MLPE process provided an efficient and convenient strategy for electro-conversion of complex NO together with absorbent regeneration and NO resource utilization.