Optimizing the preparation of xanthate-modified polyvinyl alcohol adsorbent and its adsorption to Cu (II)

To enhance the adsorption capacity of polyvinyl alcohol (PVA) for heavy metals, PVA was selected as raw material and used glutaraldehyde as a crosslinking agent to obtain crosslinked polyvinyl alcohol (SPVA). Under alkaline conditions, SPVA and CS₂ reaction was used to introduce the xanthate acid group into the SPVA polymer chain to prepare a new xanthate-modified polyvinyl alcohol adsorbent (DT-SPVA). The preparation conditions of DT-SPVA were optimized through single factor experiments, and response surface methodology (RSM). Fourier infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM-EDS) were used to evaluate the chemical structure and morphology of DT-SPVA. The results revealed that the optimal preparation conditions for DT-SPVA were: m(SPVA): m(CS₂): m(NaOH) = 1:0.67:2.70, preparation temperature of 47 ℃ and preparation time of 180 min. DT-SPVA exhibited a maximum removal rate of Cu (II) from the solution at 99.94% and an adsorption amount of 16.65 mg/g. The modification reaction in DT-SPVA preparation primarily occurs on the hydroxyl group (-OH) of the PVA molecular structure. The adsorption mechanism of Cu (II) depends on the coordination effect of the acid group (-CSSH) and hydroxyl (-OH) on Cu (II) as well as the ion exchange reaction. These results indicate that DT-SPVA has potential applications for the treatment of Cu (II) and other heavy metal ions.