Sodium alginate/polyvinyl pyrrolidone/zinc oxide @silica Schiff-base nanofiber membrane for single and binary removal of copper and nickel cations from aqueous medium

A functionalized sodium alginate/polyvinyl pyrrolidone/zinc oxide @silica Schiff base (SA/PVP/ZnO@SiO 2 SB) nanofiber membrane was prepared by electrospinning technique to study the single and binary adsorption of Cu(II) and Ni(II) cations from aqueous systems. Several analyses containing XRD, FTIR, FESEM, TEM, BET and TGA were applied to evaluate the structure of prepared samples. The mechanical strength and swelling tests were also investigated. To investigate the effect of Schiff base ligands and ZnO@SiO 2 nanoparticles on the adsorption of Cu(II) and Ni(II) cations, the batch experiments were performed in a single batch system. It was found that Schiff base ligands play an important role in adsorption process. Furthermore, the effect of significant parameters such as solution pH, nanoparticle contents, contact time, initial cation concentration and adsorption temperature was studied. The double-exponential model was the best model to describe the kinetic data. The results of equilibrium isotherms showed that a monolayer adsorption was dominant. The maximum adsorption capacity of SA/PVP/ZnO@SiO 2 Schiff base nanofiber membrane for Cu(II) and Ni(II) cations was 289.5 and 101.9 mg/g, respectively, at 45 °C. The endothermic and spontaneous adsorption was obtained from thermodynamic data. The SA/PVP/ZnO@SiO 2 Schiff base nanofiber adsorbent was easily reused without remarkable decrease in adsorption capacity for both Cu(II) and Ni(II) cations after 5 steps. In a binary system, the adsorption capacity was reduced with increasing the other metal cation concentrations indicating an antagonistic adsorption effect.