Removal of Zn(II) Ion from Aqueous Solution using Activated Carbon Prepared from Rice Husk Treated with Sodium Hydroxide

The study of rice husk as potential activated carbon as a low-cost adsorbent to
remove zinc (Zn) from Zn(II) ion solution was investigated. Raw rice husk as an
agricultural waste was chosen for this project due to its huge amount of production
during milling activities. The scope of this study covers from preparation of the rice
husk activated carbon (RHAC) to the experimental works for removal of Zn(ll) ion
from aqueous solution. The preparation involves three stages which are grinding to
size of 63 11m. digestion and carbonization. 63 ~ raw rice husks were digested with
1.0 M sodium hydrochloride (NaOH) solution for 24 hours. The treated rice husks
were then carbonized at 650°C for I hour in order to remove volatile organic
constituents leaving behind highly porous carbonaceous materials. Once the
activated carbon was prepared, mixing process with Zn(ll) ion solution at various
contact time ranging from 5 to 180 minutes was carried out to study the adsorption
capacity. In this study, pores development in rice husk \\as analyzed using FFSEM
for each stage. Other analyses on rice husk activated carbon were also conducted
using BET Surface Area Analyzer, Fourier Transmitter lnlrarcd Spectroscopy
(FTIR), CHN Elemental Analyzer. X-ray Diffraction (XRD) and Energy-Dispersive
X-ray Spectroscopy (EDX) for characterization study. The adsorption capacity
towards metal ion was determined using Atomic Adsorption Spectroscopy (AAS).
The results obtained from the adsorption study showed that rice husk has a potential
to be converted to adsorbent for the removal of heavy metals.