Pb(II) adsorption from the water using adsorbents such as acid and/or base activated walnut shell and lemon peel was carried out in a continuous stirring batch system. The original and activated adsorbents were characterized by SEM-EDS and FTIR analyses. SEM photographs of both adsorbents showed that while the presence of irregularly shaped and layered structures were observed before activation, more porous and curved surfaces were observed after activation. Adsorption studies showed that the activation was effective for increasing the adsorption efficiency and while more than 50% of the lead ions were removed at the first 10 min, the equilibrium was reached at 180 min. Furthermore, they showed that the adsorption rate was determined by a pseudo second order kinetic model. Additionally, Freundlich and Langmuir isotherm models were investigated for Pb(II) adsorption on WS-NaOH and LP-HNO3 adsorbents and it was found that the equilibrium data were more suitable for Freundlich model.