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

The efficient and green separation of heavy metal ions from acidic wastewater is a challenging industrial problem. In this work, a novel acidic adsorbent, beta-cyclodextrin phosphate polymer (beta-CDPP), was synthesized by one-pot method. The beta-CDPP was characterized by FT-IR, SEM, EDS, and XPS. The beta-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 beta-CDPP is a promising candidate for the deep treatment of acidic heavy metal-contained wastewater.

Automated summary

A novel acidic adsorbent, beta-cyclodextrin phosphate polymer (beta-CDPP), was synthesized by one-pot method in this study, showing high efficiency in removing Pb(ii) ions from acidic wastewater. The beta-CDPP exhibits a high maximum Pb(ii) adsorption capacity and good reusability, while also showing good adsorption performance for other heavy metals.