Modified Adsorbents for Removal of Heavy Metals from Aqueous Environment: A Review

The fatally ill consequences of the bioaccumulation of heavy metals in living beings call for an immediate remediation of wastewater. The adsorption is an effective and growing technique for the scavenging of the contaminants from the wastewater. Industrial waste/by-products are potential materials for the adsorptive scavenging of heavy metal ions such as Cu(II), Zn(II), Ni(II), Cr(III), Cr(VI), Cd(II), etc. in wastewater. The abundant and inexpensive industrial waste/by-products are a good alternative to costly adsorbents, which are available commercially and naturally. The major industrial by-products/waste includes slag, sludge, red mud, lignin and fly ash, which have contributed enormously to effective and economical treatment of wastewater containing heavy metals. This review reports the potential of industrial waste/by-products-based composites as the adsorbents for the removal of heavy metals from wastewater. Detailed investigations onto the adsorption mechanism and the role of the different adsorption parameters have also been discussed.