“…This technology has been widely preferred to other conventional methods such as ion -exchange, chemical precipitation, electro dialysis, membrane separations, reverse osmosis and solvent extraction in the removal of pollutants from wastewater due to its cost effectiveness, simple to design, ease of operation, availability and environmental friendliness (Adebisi et al, 2017). Various adsorbents such as clay mineral (Barbooti, 2015), activated carbons from agricultural waste materials (Amarasinghe and Williams, 2007;Choudhary et al, 2015;Garba et al, 2016;Olayinka et al, 2009;P. Sarma et al, 2015), magnesium oxide nanoparticles (Dargahi et al, 2016), vegetable waste biomass (Nadeem et al, 2014) as well as biological adsorbents (Ali and Alrafai, 2016;Deepa and Suresha, 2014;Lima et al, 2013) have been reported in the literature for lead and chromium removal from wastewater.…”