Preparation of thiosemicarbazide-modified polyvinyl alcohol and its selective adsorption of Cu(II)

Abstract

In this work, thiosemicarbazide (TSC) was grafted onto the surface of Poly(vinyl alcohol) (PVA) via a two-step method to obtain a new type of heavy metal adsorbent, TSC-PVA. Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and scanning electron microscope Energy Dispersive Spectrometer (SEM-EDS) analysis showed that amino, imino, and thiourea functional groups were uniformly distributed on TSC-PVA. The isothermal adsorption results of TSC-PVA were consistent with the Langmuir isotherm adsorption model, and the maximum adsorption capacity for Cu(II) was 82.36 g/kg at 30 °C. The calculated adsorption thermodynamic parameters indicated that adsorption was spontaneous and endothermic (ΔG° = −17.52, ∆H° = 58.88, T = 30 °C). The adsorption kinetics of TSC-PVA was consistent with the Elovic kinetic model (R2 = 0.989), indicating that chemical adsorption occurred on the adsorbent surface. TSC-PVA exhibited a high adsorption performance and selectivity to Cu(II). These results indicate that the new adsorbent has potential applications for the selective separation of Cu(II) from other metal ions.