In this study, the role of optimized Jeffamine/diamino hexane reduced cryogel for Cu(II) ion removal from aqueous solutions was investigated. The synthesized adsorbent was characterized by means of FT-IR, C-13 NMR, SEM-EDX and compression techniques. Maximum adsorption for Cu(II) ions was obtained at pH 5.5. The impact of several operating parameters such as metal ion concentration, adsorbent dosage, and temperature were elucidated and optimized by central composite design model of response surface methodology Maximum adsorption capacity was determined as 119.13 mg/g at obtained optimum experimental conditions of initial Cu(II) ion concentration (100 mg/L), adsorbent dosage (80 mg) and temperature (55 degrees C). The isotherm and kinetic data revealed that the Langmuir and pseudo 2nd-order models to be in good agreement with the experimental data. Evaluation of adsorption mechanism by intra-particle diffusion and Boyd model suggested that particle diffusion was the rate limiting step for Cu(II) ion uptake and was mainly due to external mass transport. Thermodynamic parameters Gibbs free energy (Delta G degrees) and enthalpy (Delta H degrees) confirmed the spontaneity and endothermicity of the adsorption process. Theoretical calculations suggested that both physisorption and chemisorption were active processes. Performed consecutive four cycles also show that the cryogel is a good alternative with high reusability and cost-friendly properties. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.