removal of pb (ii) from aqueous solutions using waste tea leaves

background: the presence of lead in natural waters has become an important issue around the world. lead has been identified as a highly toxic metal that can cause severe environmental and public health problems and its decontamination is of utmost importance. the aim of this work was to evaluate the adsorption of lead (pb(ii)) on waste tea leaves as a cheap purification method. methods: in this experimental study, prepared waste tea leaves were used as adsorbent for the removal of pb(ii) from aqueous solutions. adsorption experiments were carried out as batch studies at different contact time, ph, amount of adsorbent, initial metal concentration and temperature. results: the results showed that maximum removal efficiency was observed at ph 6. also the adsorption of pb(ii) ions increased with decreasing initial metal concentration. the langmuir isotherm model fits well with the equilibrium adsorption isotherm data and its calculated maximum monolayer adsorption capacity was 166.6 mg g-1 at a temperature of 25±0.1˚c. the kinetic data obtained have been analyzed using pseudo-first-order and pseudo-second-order models. the best fitted kinetic model was found to be pseudo-second-order. conclusion: the results suggest that tea wastes could be employed as cheap material for the removal of lead from aqueous solutions.