Preparation of ZIF-67/C3N4 composite material and adsorption of tetracycline hydrochloride.

In recent years, wastewater treatment to remove tetracycline hydrochloride (TCH) has received much attention in water treatment problems. ZIF-67/C3N4 composite adsorbent, a nanosheet structured material stacked with MOFs, was prepared by in situ growth method, which has high adsorption activity for tetracycline hydrochloride in wastewater. Comparing the effect of monomeric and composite adsorbents, Z6C2 had the best adsorption effect (206 mg·g-1), which was 77.6% higher than that of ZIF-67 (116 mg·g-1) and 10.8 times higher than that of C3N4 (19 mg·g-1). The structure of ZIF-67 stacked on C3N4 nanosheets has an excellent specific surface area and number of active sites, as well as π-π interactions, electrostatic interactions, and hydrogen bonding interactions between the adsorbent and TCH, which combine to enhance the adsorption performance. The adsorption process is accompanied by a combination of chemisorption, mass transport, and internal diffusion rate-limiting. It was shown that the adsorption process is favorable for monolayer adsorption as well as a heat absorption reaction that proceeds spontaneously. The adsorbent exhibits good stability and adsorption capacity, which may be suitable for efficient and low-cost water purification.