Catalytic decomposition of residual hydrogen peroxide in N-methylmorpholine-N-oxide by heteroatom doping modified activated carbon

Abstract

N-methyloxymoroline-N-oxide (NMMO) has been used in large quantities for the production of new solvent-treated cellulose. But, excess HO used in the synthesis of NMMO from N-methylmorpholine (NMM) can adversely affect the quality of the product. This study introduces a novel approach using nitrogen and sulfur co-doped activated carbon (N,S co-doped AC) to catalyze the decomposition of residual HO in NMMO products. Characterization techniques including N adsorption/desorption, Raman, TEM, FT-IR, and XPS were used to study the surface properties and chemistry of activated carbon doped with heteroatoms. The results revealed that AC800NS800 (800 is the calcinate temperature, NS is denoted by the co-doped of N and S) exhibited superior catalytic performance for HO decomposition compared to singly doped activated carbons. Notably, over 95 % of HO in NMMO was decomposed, which the catalytic efficiency of AC800NS800 is no significant loss after ten times reuse. The exceptional catalytic activity of AC800NS800 is attributed to the presence of various functional groups on the surface (graphitic carbon, graphitic nitrogen, and pyrrole nitrogen). EPR tests identified HO• and O as the primary reactive species in the HO decomposition process. This study provides valuable insights into the catalytic decomposition of HO in NMMO solutions and offers a significant reference for the production of high-quality NMMO.