ABSTRACT
This work studiesthe adsorption of selected heavy metals from municipal solid waste landfills by cassava peel (Manihot esculenta ash) ash.
Samples of leachates obtained during the dry season (November to Februry, 2018) from some landfill sites in Port Harcourt city and immediate environ (Obigbo) were characterized. The most relatively polluted leachate sample was used in adsorption studies under regulated conditions of pH (2-7); temperature (20-500C); dose (0.05-0.3g), and agitation (50-200rpm). Conditions that gave maximum heavy metal ion percentage uptake, were simulated in synthetic single metal solute (SMS) solution (of concentration ranging from 25-150mg/l to study adsoption Isotherm and kinetic models.
The findings from the study revealed that the optimal adsorption conditions were basically at pH 4; Agitation Speed of 150 rpm; Contact Time of 1 hour and Temperature of 35oc. The maximum percentage uptake of Chromium (CR), Lead (Pb), Nickel (Ni) and Zinc (Zn) ions by the Cassava Ash in leachate samples were 56.54, 70, 60.444, and 65%% respectively. The Freudlich isotherm model adequately described the adsorption process with the lowest Mean Squred Error (MSE) value of 3.94 compared to 6.53 of Langmuir. A qmax of 32.41; 24.76; 25.72 and 54.41/g were obtained for ZN, CR, NI and PB respectively in SMS. The order of adsorption of heavy metals in SMS was the same with leachate samples i.e. Pb >Zn> Ni> Cr. The Pseudo first order Kinectic model better described the adsorption process with Zn taken up faster and followed in the order of Cr, Ni and Pb.
