Document Type : Research Paper
A novel composite adsorbent, Silica aerogel activated carbon was synthesized by sol-gel process at
ambient pressure drying method. The composite was characterized by Fourier transform infrared
spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry
(DSC) and Nitrogen adsorption / desorption isotherms (BET).
In the present study, the mentioned adsorbent was used moderately for removal of cadmium ions
from aqueous solutions and was compared with two other adsorbents of cadmium, activated
carbon and silica aerogel. The experiments of Cd adsorption by adsorbents were performed at
different initial ion concentration, pH of the solution, adsorption temperature, adsorbent dosage
and contact time. Moreover, the optimum pH for the adsorption was found to be 6.0 with
corresponding adsorbent dosage level of 0.1 g at 60°C temperature. Subsequently, the equilibrium
was achieved for Cd with 120 minutes of contact time.
Consequently, the results show that using this composite adsorbent could remove more than 60%
of Cd under optimum experimental conditions. Langrnuir and Freundlich isotherm model was
applied to analyze the data, which the adsorption equilibrium data were correlated well with the
Freundlich isotherm model and equilibrium adsorption capacity (qe) was found to be 0.384mg/g in
the 3mg/L solution of cadmium.