Effect of binder ratio on the physical properties of porous carbon pellet for CO2 capture

Abstract

The purpose of this work was to investigate the effect of binder ratio on the physical properties of carbon-based pellets in capturing CO2. The influence of the binder materials was also examined to compare the pellet quality. To make good-quality carbon pellets, tapioca starch (TS) and xanthan gum (XG) were used as organic binders and mixed with activated carbon to form pellets. The physical properties of the carbon pellets were analyzed using different analytical methods: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). In addition, the CO2 adsorption performance of the carbon pellets was investigated by evaluating their adsorption capacity and CO2 breakthrough characteristics. The results revealed no significant changes to the pore development of the carbon pellets after the CO2 adsorption. However, the EDX results for the carbon pellets using the starch binder showed an increase in the oxygen content after the CO2 adsorption. With the addition of water and the binder, both types of carbon pellets (TS-AC and XG-AC) still produced high carbon content. Interestingly, the carbon pellets using the low-cost binder (tapioca starch) shows high performance than xanthan gum binder due to has numerous functional groups, longer breakthrough time and high CO2 adsorption capacity. The TS-AC carbon pellets exhibited a remarkably high breakthrough time and CO2 adsorption capacity of 16.2 min and 21.84 mg/g at 25 ˚C.