The performance of urea-intercalated and delaminated kaolinites-adsorption kinetics involving copper and lead

brazilian kaolinite clay was used to study urea intercalation (kur) and delamination (kur/dl) processes. the intercalated sample was delaminated by ultrasonic treatment in acidic solution. the basal distance changed from 0.72 to 1.08 nm with increasing surface area from 20.3 to 90.5 m2 g-1 for kur and kur/dl. suspended pristine, intercalated and delaminated clays at ph 5.0 adsorbed copper and lead cations at the solid/liquid interface. the langmuir, redlich-peterson and toth adsorption isotherm models were employed in linear and nonlinear regression processes, to give b and kl values for all kaolinites. the highest adsorption capacity of 12.8 mmol g-1 was obtained with delaminated kaolinite. the kinetic parameters analyzed by the lagergren and elovich models gave a good fit for a pseudo-second order reaction with k2 in the 5.0 to 11.0 and the 4.9 to 13.0 mmol-1 min-1 ranges for copper and lead cations, respectively.