# The Effect of Chemical Activating Agent on the Properties of Activated Carbon from Sago Waste
## 4 Discussion  
There is a strong development of porosity on activation of a lignocellulosic precursor with the chemical agents [54]. Consequently, a degree of activation produces the maximum volumes of micropores, namely include 0.101, 0.152, 0.225, and 0.194 cm\({}^{3}\)/g for KOH, KMnO\({}_{4}\), ZnCl\({}_{2}\), and H\({}_{3}\)PO\({}_{4}\), respectively. Treatment with ZnCl\({}_{2}\) acid impregnation produces activated carbon with the highest surface area of 546.61 m\({}^{2}\)/g, the strong base KOH successfully fabricated the fined structure and morphology, with the highest fixed carbon and the lowest ash content of 43.78% and 10.90%, respectively. KMnO\({}_{4}\) and H\({}_{3}\)PO\({}_{4}\) activating agents showed poor performance with a low fixed carbon value of 2.56% and 14.02%, and a high moisture content of 15.20% and 17.04%, respectively.  
The morphology images showed that ash was dominant over pores, and the carbon prepared from the KMnO\({}_{4}\) activating agents had no peak in the X-ray diffraction pattern.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Wavenumber (cm\({}^{-1}\))**} & & \\ \hline \(\mathbf{H_{3}PO_{4}}\) & \(\mathbf{ZnCl_{2}}\) & \(\mathbf{KMnO_{4}}\) & \(\mathbf{KOH}\) & **Assignment** \\ \hline - & 2660 & - & 2660 & \(\
u\) (O-H) carboxylates group \\
1554 & 1554 & 1546 & 1553 & \(\
u\) (C=C) aromatic group \\
1164 & - & 1163 & - & \(\
u\) (C-O) ether group \\ - & 1072 & - & 1135 & \(\
u\) (C-O) phenol group \\
673; 486 & 890; 575 & 674; 486 & - & \(\
u\) (C-H) alkanes group \\ \hline \hline \end{tabular}
\end{table}
Table 4: The Fourier-transform infrared peaks identification of activated carbons from sago prepared using various chemical activating agents.  
Figure 5: The Fourier-transform infrared spectra of activated carbons from sago prepared using various chemical activating agents.  
Furthermore, the KMnO\({}_{4}\) impregnation damaged the carbon structure, as indicated by the absence of the amorphous phase of carbon. This result can be confirmed from the element composition results, where KMnO\({}_{4}\) activated carbon has a very small carbon composition of 57.06 %. This may yield that the KMnO\({}_{4}\) is not effective enough to activate sago waste carbon. The surface chemistry was influenced by the chemical activating agent. Both ZnCl\({}_{2}\) and KOH activated carbon revealed phenol and carboxylate groups, while the H\({}_{3}\)PO\({}_{4}\) and KMnO\({}_{4}\) showed vibration from the ether group. The carbon prepared from KOH also demonstrated an intense aromatic ring, due to acid washing, and thorough rinsing with distilled water [55].  
The acid-activating agents tend to develop more micropore, while the base treatment develops fine mesopore-activated carbons. Generally, activated carbon has a pore structure in the form of microporous, mesoporous, and macroporous. The activated microporous carbon is more effective against pollutants in the form of gas, mesoporous carbon is effective for liquid, while macroporous carbon is not efficient for both forms [56]. The pore structure of activated carbon characteristics is highly important, it may direct potential application of activated carbon from sago waste in the future.  
The commercial-grade activated carbon has a surface value between 500-1500 m\({}^{2}\)/g [57]. Thus, the highest value obtained from this study can be categorized into commercial activated carbon. Therefore, this study suggested ZnCl\({}_{2}\) and KOH as suitable activators for sago waste precursor material. Further study on the effect of activation temperature and contact time on ZnCl\({}_{2}\) and KOH activators may elevate the pore size of the activated carbon [55].