Facile Synthesis of MgO Nanoparticle-Embedded Fe/N/S Codoped Carbon Materials from Oily Sludge for Efficient CO₂ Capture

Abstract

Oily sludge generated from the modern petrochemical industry is a largescale hazardous solid waste. Pyrolysis with efficient catalysts is considered as a promising technology to convert the oily sludge into value-added chemicals or fuels without significant impact on the environment, but the solid char with spent catalysts does not find an application. In this study, the solid char obtained from catalytic pyrolysis of the oily sludge is applied as an adsorbent for CO 2 capture. The char can be regarded as MgO nanoparticleembedded Fe/N/S codoped carbon (MgO•FeO x @NSC) based on its structure and composition. MgO•FeO x @NSC presents a favorable performance toward CO 2 capture. The maximum CO 2 adsorption capacity is 4.57 mol/kg, and this value remains unchanged for more than 10 cycles of reuse. The mechanism for CO 2 capture is analyzed with Fouriertransform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Physical adsorption and chemical interaction are identified as the primary contributors to the CO 2 adsorption with MgO•FeO x @NSC, in which MgO, nitride-N, and sulfide-S are the main species contributing to the chemical interactions between CO 2 and MgO•FeO