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

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.