Lead adsorption using TEOS-Functionalized multiwalled carbon nanotubes

Heavy metal ions in water have been a worldwide concern for many years because of their toxicity toward aquatic-life, plants, animals, human beings and the environment. Water contaminated by heavy metal ions had become much more serious with a rapid development of industries and competitive use of fresh water in many parts of words. Therefore, heavy metal ions removal from water has become an important subject today[1]. Many technologies and methods for heavy metal ions removal from wastewaters have been developed, such as ion-exchange, evaporation and concentration, chemical precipitation, reverse osmosis, adsorption, and electrodialysis. Considering from economy and efficiency point of view, adsorption is regarded as one of the most promising and widely used methods. In current years, carbon nanotubes have shown a high potential for absorbing lead [2-4]. In this study, multiwalled carbon nanotubes (MWCNTs) were modified by strong oxidizing agents and were functionalized with tetra-ethoxy-silane )TEOS). These MWCNTs were used to remove lead ions from aqueous solution. The pristine and functionalized MWCNTs were characterized by Fourier transform infrared, scanning electron microscopy and X-ray diffraction. The optimal conditions of experimental such as pH, amount of adsorbent and contact time were investigated. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. The results suggest that functionalized MWCNTs can be good Pb(II) adsorbers and have great potential applications in environmental protection.