Highly efficient, selective and reversible capture of sulfur dioxide by methylated-polyethylenimine supported on graphitic carbon nitride

Abstract

Supported polytertiary amine compounds have shown promising application in the capture of SO2 from industrial tail gas. In this work, we proposed to use graphic carbon nitride (g-C3N4) as the support of methylated polyethylenimine (mPEI) for SO2 capture. g-C3N4 can not only be facilely synthesized from cheap reactants, but also accommodate large amount of mPEI owing to the presence of abundant flexible nanopores. A series of mPEI@g-C3N4 samples were thus prepared, characterized and investigated for SO2 capture performance. It is found that the SO2 capacities of mPEI@g-C3N4 samples are very impressive, with the values of 11.82 ~ 15.88 mmol/g at 25 °C and 1 bar, and 4.03 ~ 5.67 mmol/g at 25 °C and 0.002 bar. mPEI@g-C3N4 samples also have excellent ability for selective adsorption of SO2 from CO2 and N2, based on pure and mixed gas adsorption experiments. In addition, mPEI@g-C3N4 samples have good reversibility for SO2 adsorption, according to the repeated mixed gas adsorption experiments.