Adsorptive removal of Zn (II) from aqueous solution using rice husk-based activated carbon.

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 ofthe rice
husk activated carbon (RHAC) to the experimental works for removal of Zn(II) ion
from aqueous solution. The preparation involves three stages which are preparation
ofraw rice husk to size of 63um, digestion and carbonization. 63um raw rice husks
were digested with 1.0 M sodium hydroxide (NaOH) solution for 24 hours. The
treated rice husks were then carbonized at 500°C for 1 hour in order to remove
volatile organic constituents leaving behind highly porous carbonaceous materials,
Once the activated carbon was prepared, mixing process with Zn(II) ion solution at
various contact time ranging from 5 to 120 minutes was carried out to study the
adsorption capacity. In this study, pores development in rice husk was analyzed
using FESEM for each stage. Other analyses on rice husk activated carbon were also
conducted using BET Surface Area Analyzer, Fourier Transmitter Infrared
Spectroscopy (FTIR), CHN Elemental Analyzer, and X-ray Diffraction (XRD) for
the characterization study. The adsorption capacity towards metal ion was
determined using Atomic Adsorption Spectroscopy (AAS). Isotherm models are also
developed, which is Langmuir and Freundlich Isotherm. The results obtained from
the adsorption study showed that rice husk has a potential to be converted to
adsorbent for the removal ofheave metals.