Preparation of hierarchical porous carbon derived from averrhoa bilimbi and its diffusion properties

Abstract

In this study, a hierarchically porous carbon was prepared from a natural material, Averrhoa bilimbi, also known as bilimbi. The bilimbis were cut into preferred shape and size before drying by freeze drying method. The bilimbis were then subjected to pyrolysis at temperature of 400°C and transformed to porous carbon. Scanning electron microscopy (SEM) revealed that the bilimbis have a hierarchically porous structure in the macro-range. The diameter of the porosity decreased inwards from 30 to 8μm. Different types of motor oil, which were used to represent bulky molecules, were employed to test the diffusivity of these molecules from the bilimbi. It was found that the oils were able to diffuse through the hierarchically porous bilimbi in 2 to 3 hours, depending on the viscosity of the oils. Therefore, it can be concluded that, Averrhoa bilimbi possesses hierarchical porous structure with interconnected pores and capability to diffuse bulky molecules.