Surface Characters and Adsorption Behavior of Pb(II) onto a Mesoporous Titanosilicate Molecular Sieve

Removal of Pb2+ ions from aqueous solution using the adsorption process onto Ti-MCM-41 has been investigated. A simplified surface complexation model was used to calculate the conditional binding constants for surface complexation of Pb2+ ions onto Ti-MCM-41. Dynamic modeling of the adsorption showed that the first-order reversible kinetic model held for the adsorption process. The overall rate constant k', the adsorption rate constant k1, the desorption rate constant k2, and the equilibrium constant Ke for the adsorption process were calculated from the results of the thermodynamic analysis, and standard free energy DeltaG degrees, standard enthalpy DeltaH degrees, and standard entropy DeltaS degrees of the adsorption process were also calculated. Equilibrium modeling of the adsorption showed that the adsorption of Pb2+ ions was fitted to a Freundlich isotherm. Copyright 1999 Academic Press.