Hierarchically porous ZIF-8 for tetracycline hydrochloride elimination

Herein, hierarchically porous ZIF-8 (HZIF-8) adsorbents were prepared successfully with the assistance of sodium dodecyl sulfonate (SDS) through a facile one-pot self-assembly method at room temperature, and their adsorption of tetracycline hydrochloride (TCH) was studied in water by bath adsorption experiments. The structural characteristics of the adsorbents were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and N-2 adsorption/desorption measurements. The research results indicated that the final hierarchically porous ZIF-8 with a large Brunauer-Emmett-Teller (BET) specific surface area (1423.78 m(2) g(-1)) had a higher TCH adsorption capacity (574.71 mg g(-1)) than microporous ZIF-8 by improving the mass transfer rate. The adsorption isotherm was expressed well by the Freundlich isotherm model and the kinetic data fit the pseudo-second-order kinetic model better. Mechanistic studies implied that coordinate bonds, pi-pi interactions and electrostatic interactions played vital roles in the TCH adsorption process based on the effect of pH, zeta potential of adsorbents, and X-ray photoelectron spectroscopy (XPS). Moreover, the addition of SDS altered the ZIF-8 porosity and exposed more active sites of adsorbents. As synthesized, the hierarchically porous ZIF-8 displayed excellent regenerability and could be expected to expand the application range regarding the removal of antibiotics from aqueous solution. [GRAPHICS] .