LEAD AND CADMIUM REMOVAL FROM AQUEOUS SOLUTION USING GROUNDWATER TREATMENT PLANT SLUDGE

The adsorption of Pb (II) and Cd (II) ions onto groundwater treatment plant sludge
(GWTS) in aqueous solution was studied in batch system. GWTS was dried and ground
before the adsorption experiments. The ground GWTS was characterized by X-ray
Fluorescent (XRF). The effects of pH, initial concentration of Pb (II) and Cd (II) ion of
the solution, contact time and amount of adsorbent and on adsorption have been
investigated. Removal of Pb (II) and Cd (II) ions was found as highly dependent on the
pH of the solution. pH 5.5 and 7.5 were found to be the optimum value for maximum
uptake of Pb (II) and Cd (II) from the solution respectively. The removal efficiency of Pb
(II) and Cd (II) was found to correlate with the initial concentration, adsorbent dosage as
well as the contact time between Pb (II) and Cd (II) and the adsorbent. In kinetics studies,
both Pb (II) and Cd (II) were described by pseudo first order and pseudo second order
kinetic model. The equilibrium data were analyzed using both Langmuir and Freundlich
isotherm model. Pb (II) was found to conform to Langmuir Equation (R2 = 0.9497) than
Freundlich isotherm (R2 = 0.5188), while Cd (II) better fitted to Freundlich isotherm with
R2 - 0.8836 lager than R2 =0.7821 ofLangmuir model.