Preparation and application of KCC-1@ZIF-8 for the solid extraction of tetracycline with high adsorption capacity†

Abstract

In this study, three different materials were prepared: dendritic fiber-type silica (KCC-1), zeolitic imidazolate framework-8 (ZIF-8), and a new composite material called KCC-1@ZIF-8. These materials were synthesized using microemulsion, stirring, and coating methods, respectively. The properties of the materials were characterized using various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), TGA and X-ray diffraction (XRD). The results showed that KCC-1@ZIF-8 exhibited a significant increase in the BET surface area and pore size compared to the individual components KCC-1 and ZIF-8. These improved properties of the composite material were beneficial for enhancing the adsorption capacity. The effects of initial concentrations, solution pH and reaction time on the adsorption capacity were investigated. The adsorption kinetics and isothermal data of ZIF-8 and KCC-1@ZIF-8 fitted well with pseudo-second-order and Langmuir isotherm models. The results of adsorption thermodynamics show that the adsorption process is spontaneous and endothermic. KCC-1@ZIF-8 exhibited a very high adsorption capacity (751.46 mg g⁻¹) at an initial TC hydrochloride concentration of 80 mg L⁻¹ in an aqueous solution at 301.15 K, and the value was higher than that of ZIF-8 (549.80 mg g⁻¹) under the same conditions. KCC-1 exhibited a relatively lower capacity (37.860 mg g⁻¹). Based on these findings, KCC-1@ZIF-8 was considered a promising adsorbent for the treatment of wastewater contaminated with TC hydrochloride. Additionally, the composite material, when combined with high-performance liquid chromatography (HPLC), could be used as a solid-phase extraction adsorbent for the adsorption of TC hydrochloride in animal foodstuff samples. The calibration curves showed a linear range of 20–500 μg L⁻¹, and the recovery rate ranged from 85.216% to 90.717%. No one has made adsorbents with this new structure before, and KCC-1@ZIF-8 possessed excellent adsorption properties, which make it a potential candidate for environmental remediation and analytical applications involving TC hydrochloride.