Selective adsorption of Ag(I) ions with poly(vinyl alcohol) modified with thiourea (TU-PVA)

A novel poly(vinyl alcohol) modified with thiourea adsorbent (TU-PVA) was successfully prepared and characterized. The spectrum of FT-IR implies that the thiourea group has been modified on the primary hydroxyl of PVA in TU-PVA. The adsorption behavior for Ag(I) ions on TU-PVA follows the Langmuir model, and the adsorption kinetic data are fitted with the pseudo-second-order model. The maximum adsorption capacity for Ag(I) ions on TU-PVA calculated by the Langmuir model was 66.93 mg·g− 1. Thermodynamic parameters indicate that the adsorption process for Ag(I) ions on TU-PVA is spontaneous and endothermic in nature. The selectivity coefficient of Ag(I) ions and other metal cations onto TU-PVA indicated an overall preference for Ag(I) ions, and the selectivity and adsorption capacity was much higher than that of poly(vinyl alcohol). The selective adsorption mechanism of Ag(I) ions on TU-PVA was coordinated. The study of repeating and selectivity adsorption indicates that TU-PVA exhibits good durability and selectivity for Ag(I) ions. Thus, the adsorbent has potential application in recycling of Ag(I) ions in complex wastewater.