At present,the technology of uptaking potassium from seawater mainly concentrated in the extraction from bittern and seawater [1].But the concentrated solution,which as the intermediate product,has the polyvalent ions,especially Ca2+.It is essential to remove Ca2+ from the solution before the evaporation process.Ion exchange is a well-established technique,particularly in water purification,the concentration and removal of metal ions at low concentrations in chemical process industries [2].A chelating ion-exchange resin,LSC-500 has been investigated for its adsorption properties to Ca2+ from the concentrated solution.Experiments were conducted at different temperature values through batch adsorption.The maximum ion exchange capacity was found to be 58.43mmol/100g for Ca2+.It was also observed that the adsorption of Ca2+ increased with increasing temperature.The applicability of both the Langmuir and Freundlich isotherms were analyzed on the obtained equilibrium data.The Langmuir isotherm showed better performance than the Freundlich isotherm for the adsorption process (R2>0.99).Thermodynamic parameters such as free energy (△G),enthalpy (△H),and entropy (△S) were also calculated.The kinetic data correlated with the pseudo-first-order model and the pseudo-second-order model both well (R2>0.99).Moreover,the pseudo-second-order model showed a better fitting to the experimental data (R2>0.999).