Cr [2]. Whenever toxic heavy metals are exposed to the natural
eco-system, accumulation of metal ions in human bodies will
occur through either direct intake or food chains. Therefore,
heavy metals should be prevented from reaching the natural
environment [3]. In order to remove toxic heavy metals from
water systems, conventional methods have been used such as
chemical precipitation, coagulation, ion exchange, solvent
extraction and filtration, evaporation and membrane methods
[4]. Adsorption of heavy metals on conventional adsorbents
such as activated carbon have been used widely in many applications
as an effective adsorbent, and the activated carbon
produced by carbonizing organic materials is the most widely
used adsorbent. However, the high cost of the activation process
limits its use in wastewater treatment applications [5].