Comparison of Multi-walled Carbon Nanotubes (MWNTs) and Activated Carbon (AC) as Adsorbents in Heavy Metal Adsorption

The present study was undertaken to investigate the ability of granulated charcoal activated carbon (AC) and multi-walled carbon nanotubes (MWNTs) as adsorbents in adsorption process of removing heavy metals from aqueous solutions. The analyses of heavy metal removal are performed on three operational parameters which are agitation time, initial ion concentration and pH. The experiments were carried out at room temperature (25 degrees C) and metal solutions were agitated on a rotary shaker at constant speed range between 200 to 240 rpm. BET surface area of AC and MWNTs were found to be 898 m(2)/g and 213 m(2)/g, respectively. Metals adsorptions by both adsorbents were well fitted to Freundlich isotherm. Batch adsorption test showed that metal uptake increases as agitation time increases which are the optimum time are 3 hours and 4 hours by using AC and MWNTs, respectively. Cadmium adsorption by both adsorbents showed the same behaviour where as initial metal ion concentration increases, cadmium adsorption percentage increases. As for nickel, when using AC as adsorbent, as the initial ion concentration increases, the nickel adsorption percentage decreases. Adsorption was found to be low at acidic pH and kept on increasing as pH increased.