Removal of Cadmium Using a Novel Nano Composite, Silica Aerogel, Activated Carbon

Abstract

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