Oxygen-enriched surface modification for improving the dispersion of iron oxide on a porous carbon surface and its application as carbon molecular sieves (CMS) for CO2/CH4 separation

Nur Indah Fajar Mukti; Teguh Ariyanto; Wahyudi Budi Sediawan; Imam Prasetyo

doi:10.1039/d1ra07481d

Oxygen-enriched surface modification for improving the dispersion of iron oxide on a porous carbon surface and its application as carbon molecular sieves (CMS) for CO₂/CH₄ separation

RSC Adv. 2021 Nov 16;11(58):36782-36791. doi: 10.1039/d1ra07481d. eCollection 2021 Nov 10.

Authors

Nur Indah Fajar Mukti^{1

2

3}, Teguh Ariyanto^{1

3}, Wahyudi Budi Sediawan¹, Imam Prasetyo^{1

3}

Affiliations

¹ Department of Chemical Engineering, Faculty of Engineering, Universitas Gadjah Mada Yogyakarta 55281 Indonesia imampras@ugm.ac.id.
² Department of Chemical Engineering, Faculty of Industrial Technology, Universitas Islam Indonesia Yogyakarta 55584 Indonesia.
³ Carbon Material Research Group, Department of Chemical Engineering, Universitas Gadjah Mada Yogyakarta 55281 Indonesia.

Abstract

The separation of CO₂/CH₄ can be enhanced by impregnating porous carbon with iron oxide. Dispersion of iron oxide is one of the critical factors which supports the separation process performance. Iron oxide dispersion can be enhanced by enriching the oxygen functional groups on the carbon surface. This study investigates three distinct oxidation processes: oxidation with a 10% H₂O₂ solution, ozonation with distilled water, and ozonation with a 10% H₂O₂ solution. The research steps included the following: (i) oxidation, (ii) impregnation of iron oxide followed by calcination, (iii) material characterization, and (iv) material performance analysis. Materials were characterized using N₂ sorption analysis, X-ray diffraction analysis (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy analysis (SEM-EDX), and Fourier transform infrared analysis (FT-IR). Iron oxide was well dispersed on the carbon surface, as evidenced by the elemental mapping of materials. In addition, the oxygen functional groups increased significantly in the range of 28.6-79.7% following the oxidation process, as indicated by the elemental component using SEM-EDX analysis. The impregnation of iron oxide on oxidized carbon ozonated with distilled water (COA-Fe) obtained a maximum CO₂ uptake capacity of 3.0 mmol g^-1 and CO₂/CH₄ selectivity increased by up to 190% at a temperature of 30 °C and pressure of 1 atm. Furthermore, the enhancement of CO₂/CH₄ separation up to 1.45 times was the best performance achieved by COA-Fe. Thus, improving iron oxide dispersion on oxidized carbon surfaces has a potential application in CO₂/CH₄ separation.