October 30, 2020

Textural characteristics of the coconut shellbased activated carbon

The SEM micrographs ofcoconut shell activated carbons (CSC) and CSAC showed large differences in surface morphology (Figure 2). During carbonisation, most volatile matter was released. However, no pores developed due to the absence of an activating agent. In CSAC, however, hollow pits were observed and these were due to the loss of volatile matter and the effect of KOH activating agent on the carbon material (Wang et al. 2009). According to the International Union of Pure and Applied Chemistry, the pore development of an activated carbon is classified into three groups which are micropores (size < 2 nm), mesopores (2–50 nm) and macropores (size > 50 nm) (Pandolfo & Hollenkamp 2005). Apparently, the detected activation temperature of the process increased significantly with increasing irradiation time (Table 2). The surface area of the CSAC was higher than CSC. Chemical activation had increased the porosity of the surface area of CSAC up to 1768.8 m2 g-1 compared with CSC at only 36.5 m2 g-1. This indicates that the activation process has successfully increased the surface area and porosity of char derivative from carbonised organic precursor (Marin et al. 2009). Table 2 also reveals that time has significant influence on the activation process. The surface area of CSAC increased from 1244.0 to a maximum of 1768.8 m2 g-1. The pore size of CSAC slightly increased from 2.3 to 2.7 nm with increasing irradiation time from 10 to 20 min. As the irradiation time increased to 30 min, the detected activation temperature also increased,desulfurization activated carbon resulting in decreasing surface area of CSAC from 1768.8 to 1399.8 m2 g-1. However, the pore size of CSAC slightly increased from 2.7 to 2.9 nm due to the sintering process which destroyed and widened the pore during the process (Yuen & Hameed 2012). This observation can be explained by two