High-performance flake-like mesoporous magnesium oxide prepared by eggshell membrane template for carbon dioxide capture

Abstract

The utilization of eggshell membrane (ESM) as a template can improve the structural properties of the synthesised adsorbent, further affecting its CO2 uptake capacity. In this study, a flake-like shape mesoporous magnesium oxide (MgO) adsorbent was synthesised via the ESM bio-templating method to form MgO-BT. The prepared adsorbents were characterised by field emission scanning electron microscopy equipped with an energy-dispersive X-ray (FESEM-EDX), X-ray diffraction (XRD), N2 physisorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and CO2-temperature programmed desorption (CO2-TPD). The flake-like shape MgO-BT possesses an improved surface area of 79 m2/g, which is higher than the MgO adsorbent prepared by the thermal decomposition method (MgO-TD). Also, ESM bio-templating method has resulted in the increase of MgO-BT's basic site which mainly composed of strong-basic attachment site. These improved MgO-BT's structural properties have led to the increased CO2 uptake capacity of 1.55 ​mmol/g, which is 6-times higher than MgO-TD (0.23 ​mmol/g) at ambient temperature and pressure under 100% CO2 flow condition. Moreover, under flue gas conditions, the MgO-BT has demonstrated a slight reduction in CO2 uptake (~15%), however, this value is still tremendously higher than MgO-TD. It can be concluded that the utilization of ESM as a bio-template in the MgO preparation stage has significantly influenced the physicochemical properties of the adsorbent, therefore leading to a high CO2 adsorption performance.