One-step synthesis of a β-cyclodextrin derivative and its performance for the removal of Pb(II) from aqueous solutions

A new multifunctional β-cyclodextrin-sodium xanthogenate (β-CDX) was successfully synthesized by a one-step process and applied to remove Pb(II) from aqueous solutions. The characteristics and chelation mechanisms of β-CDX were investigated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the influences of various operating parameters such as pH (lime dosage), the order of the additions, β-CDX dosage, and the initial concentration of Pb(II) on the removal capacity of β-CDX and the characteristics of the products were systematically evaluated. The results demonstrated that the optimal removal effect for Pb(II) was achieved when β-CDX was used rather than using lime alone. In addition, it was more effective to add β-CDX to the working solutions prior to adding the lime than adding β-CDX after the lime. The use of 0.05 g/L of β-CDX was effective for the removal of Pb(II) according to the residual concentration when the initial concentration was 100 mg/L at different pH values. The maximum removal rate of the Pb(II) ions was 98% for all initial concentrations and the products were larger (size = 137.9 μm) and looser ( D f  = 1.73) at an optimum pH range from 9 to 12. The characterization results confirmed that the RC(S)SNa in the β-CDX was the main contributor to the chelation of the Pb(II). These properties of β-CDX make it a promising compound for the treatment of wastewater contaminated by hazardous metal ions.