Novel macroporous cryogels with enhanced adsorption capability for the removal of Cu(II) ions from aqueous phase: Modelling, kinetics and recovery studies

Abstract

Novel macroporous cryogels based on jeffamine with various molecular weights were prepared via freeze-drying method and then functionalized by successful reductive amination to yield reduced cryogels. The reduced cryogels were characterized by FT-IR and SEM and then used as adsorbents for removal of Cu(II) ions from aqueous solution. Preliminary adsorption test revealed that reduced cryogels showed 5 times higher adsorption capacity than non-reduced cryogels. Maximum adsorption capacities for Cu(II) ion removal were determined as 55.00, 46.73, 34.10mg/g depending on the molecular weight of jeffamine used, at pH 5.5, temperature 55°C, dosage 80mg and initial concentration of 100ppm. Adsorption capacity of the reduced cryogels increases with increasing the initial concentration, pH, contact time and temperature but decreased with increasing adsorbent dosage. ΔH° values were calculated from the temperature dependence data and the obtained positive values indicated that the adsorption process was endothermic in nature. Performed recovery tests for the different cryogels resulted in a good response within the range of 56–70% recovery. The experimental adsorption data well fitted to Freundlich isotherm and pseudo-second-order kinetic model. The intraparticle diffusion and Boyd model confirmed that the adsorption process occurred via particle diffusion.