Amongst all the treatment processes mentioned, adsorption using sorbents is one of the most popular and effective processes for the removal of heavy metals from wastewater.
The adsorption process offers flexibility in design and operation and in many cases produces treated effluent suitable for re-use, free of colour and odour. In addition, because
adsorption is sometimes reversible, the regeneration of the adsorbent with resultant economy of operation may be possible (Kelleher, 2001).