Phosphate-crosslinked β-cyclodextrin polymer for highly efficient removal of Pb(ii) from acidic wastewater

Abstract

The efficient and green separation of heavy metal ions from acidic wastewater is a challenging industrial problem. In this work, a novel acidic adsorbent, β-cyclodextrin phosphate polymer (β-CDPP), was synthesized by one-pot method. The β-CDPP was characterized by FT-IR, SEM, EDS, and XPS. The β-CDPP can effectively remove more than 95% Pb(II) from acidic wastewater (pH = 3). The adsorption of Pb(II) reached equilibrium in 20 min, and the maximum Pb(II) adsorption capacity calculated by the Sips isotherm model was as high as 576.92 mg g⁻¹. FT-IR and XPS analysis revealed that the adsorption mechanism of Pb(II) depends on the chelating effect and electrostatic interaction. The adsorbent showed good reusability evidenced by eight cycles of adsorption/desorption experiments. Meanwhile, the low concentration of Na(I), K(I), and Ca(II) had little effect on the adsorption of Pb(II). Moreover, the adsorbent can effectively remove a variety of mixed heavy metals from acidic wastewater including Pb(II), Cu(II), Cd(II), Zn(II), Co(II), and Ni(II). The results indicate that β-CDPP is a promising candidate for the deep treatment of acidic heavy metal-contained wastewater.