Starch-based activated carbon micro-spheres for adsorption of methane with superior performance in ANG technology

Abstract

In current research work, Nano porous carbon spheres were synthesized for efficient methane (CH4) adsorption. To this end, starch was employed as the starting carbon source which was carbonized at 800 °C. Therefore, in order to activate the carbonized samples, different ratios of KOH were used. The activation process was performed using Carbon: KOH ratios of 1:1, 1:2, and 1:4 at 800 °C. The prepared adsorbents were characterized by different techniques including FESEM, X-ray diffraction, FTIR, and BET. Furthermore, CH4 adsorption experiments were carried out on the prepared adsorbents which yielded very good performance. It was found that increasing the KOH content in the activation process increases both the specific surface area and total pore volume, which in turn enhanced the CH4 uptake. As a result of activation method, the best nano porous sample with Carbon:KOH ratio of 1:4 showed high specific surface area and pore volume up to 2222.3 m2/g and 1.72 cm3/g, respectively. The adsorbents had superior adsorption capacity of 12.81 mmole/g at 35 bar, which is much higher than those of literature. This adsorbent with excellent CH4 adsorption performance can be exploited in Adsorbed Natural Gas (ANG) technology to ensure energy storage and usage of high efficiencies.