Environmentally friendly fabrication of new β-Cyclodextrin/ZrO_2 nanocomposite for simultaneous removal of Pb(Ⅱ) and BPA from water

摘要

Heavy metals and endocrine disrupters often co-exist in wastewater, while their possible competition behaviours make uptake removal more challenging. Therefore, β-Cyclodextrin based nanocomposite adsorbent was successfully fabricated (β-Cyclodextrin/ZrO_2) for the simultaneous uptake of Pb(Ⅱ) and Bisphenol A from wastewater. FTIR, XRD, and XPS confirmed the successful fabrication of the β-Cyclodextrin/ZrO_2 nanocomposite. In this setting, oxygen-containing groups are primarily responsible for the Pb(Ⅱ) binding, while the β-Cyclodextrin cavities adsorb Bisphenol A through host-guest interaction, enabling the simultaneous removal of Pb( II) and Bisphenol A. In the mono contaminant system, the nanocomposite displayed prominent removal ability toward Pb(Ⅱ) and Bisphenol A with adsorption characteristics of pseudo-second-order, Langmuir, and Freundlich isotherm model. The maximum adsorption capacities were identified for Pb(Ⅱ) and Bisphenol A to be 274.4 mg/g and 174.9 mg/g at 298 K, respectively. Most importantly, the β-Cyclodextrin/ZrO_2 could efficiently attain simultaneous removal of Pb(Ⅱ) and Bisphenol A by avoiding their competitive behaviours was due to the different adsorption mechanisms (electrostatic interaction and host-guest interaction). Moreover, the adsorbed Pb(Ⅱ) and Bisphenol A could be successfully recovered with a slight decline in nanocomposite removal performance even after 4 cycles in the binary-component system. All these findings provide insights into the fabrication of highly effective adsorbent with separated adsorption sites to treat wastewater bearing heavy metal and endocrine disrupters.