Floatable cellulose acetate beads embedded with flower-like zwitterionic binary MOF/PDA for efficient removal of tetracycline

Abstract

Removal of pharmaceutical wastes, especially antibiotics from aquatic systems is an imperative issue from both human-health and ecological perspectives. Herein, zwitterionic UiO-66/ZIF-8 binary MOF/polydopamine@cellulose acetate composite (UiO-66/ZIF-8/PDA@CA) were fabricated in the form of floated beads for the adsorptive removal of tetracycline (TC). The formulated composite beads were characterized by FTIR, XRD, SEM, BET, Zeta potential and XPS analysis tools. Under optimum adsorption conditions, the UiO-66/ZIF-8/PDA@CA composite beads demonstrated large specific surface area, good adsorption performance with a relatively short equilibrium time (60 min) and ease separation. Furthermore, the adsorption data fit Temkin > Langmuir > Freundlich with a maximal adsorption capacity of 290.69 mg/g at 25 °C, while the adsorption kinetics were well-described by pseudo-second order kinetics. The thermodynamics studies refereed that the adsorption process was endothermic and spontaneous. Besides, the floated UiO-66/ZIF-8/PDA@CA beads displayed better adsorption property for eight reuse cycles with a maximal removal (%) reached 67%, reflecting its promising applicability as reusable adsorbent for efficient removal of antibiotics from water bodies.