A novel electrospun PVA/ZnO nanofiber adsorbent for U(VI), Cu(II) and Ni(II) removal from aqueous solution

A novel electrospun polyvinyl alcohol (PVA)/zinc oxide (ZnO) nanofiber adsorbent was prepared and its application for sorption of U(VI), Cu(II) and Ni(II) ions from aqueous solutions was investigated. The adsorbent was characterized by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) and Thermal gravimetric (TG) analyses. The influence of several variables such as ZnO contents, contact time, initial concentration of ions and temperature was studied in batch experiments. The equilibrium data showed that the capacity values of 370.86, 162.48 and 94.43 mg/g for sorption of U(VI), Cu(II) and Ni(II) ions, respectively, were obtained at contact time 6 h, temperature 45 °C, adsorbent concentration 1 g/L and pH 5.0. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models and it was found that the kinetic data were perfectly fitted double-exponential kinetic model. Three isotherm models, namely Langmuir, Freundlich and Dubinin-Radushkevich were used for analysis of equilibrium data. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) were evaluated to understand the nature of sorption process for U(VI), Cu(II) and Ni(II) ions.