where Smax (mmol kg1) is the maximum amount of Pb sorbed; K
(L mmol1) and Kf (mmol(1n) Ln kg1) are the Langmuir adsorption
constant related to the interaction bonding energies and the Freundlich
equilibrium constant, respectively; C (mmol L1) is the
equilibrium solution concentration of the sorbate; and n is the Freundlich
linearity constant.