Preparation of polydopamine-modified zeolitic imidazolate framework-8 functionalized electrospun fibers for efficient removal of tetracycline.

This work shows a simple and environmental friendly methodology to obtain a kind of polydopamine coating assisted preparation of zeolitic imidazolate framework-8 (ZIF-8) functionalized composite electrospun fiber (ZIF-8/PDA/PAN fibers) adsorbent. Characterization of the composite electrospun fiber was carried out and the tetracycline (TC) adsorption properties from water were also studied in detail. At the same time, principle adsorption mechanisms were thoroughly studied. The results show that the pseudo-second-order model can simulate sorption kinetics well, while sorption isotherms are able to significantly conform to the Freundlich model, and the adsorption capacity of the fibers can reach 478.18 mg/g at 298 K. In addition, the Weber-Morris model indicates that the processes of adsorption of ZIF-8/PDA/PAN fibers for TC involve surface adsorption as well as intraparticle diffusion, and the limit rate step is not only the intraparticle diffusion but also the binding of the sorbate to the sorbent. Moreover, the adsorption efficiency toward TC by ZIF-8/PDA/PAN fibers still reached over 85% of its initial adsorption capacity after five adsorption/desorption cycles, which signified that the adsorbents is stable and recyclable. This work indicates that the obtained ZIF-8/PDA/PAN fibers have practical application prospects in the field of antibiotic adsorption.