a b s t r a c t
Heavy metal pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment.
In recent years, various methods for heavy metal removal from wastewater have been extensively
studied. This paper reviews the current methods that have been used to treat heavy metal wastewater
and evaluates these techniques. These technologies include chemical precipitation, ion-exchange,
adsorption, membrane filtration, coagulationeflocculation, flotation and electrochemical methods.
About 185 published studies (1988e2010) are reviewed in this paper. It is evident from the literature
survey articles that ion-exchange, adsorption and membrane filtration are the most frequently studied
for the treatment of heavy metal wastewater.
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