Synthesis of a Bimetallic Co/Zn Zeolitic Imidazolate Framework-C60 Fullerene Nanowhisker Composite and its Photocatalytic Degradation of Tetracycline Hydrochloride under LED Light Condition

Bimetallic Co/Zn zeolitic imidazolate framework (Co/Zn-ZIF) nanoparticles were prepared via a simple process involving the dissolution of cobalt nitrate hexahydrate (Co(NO3)2·6H2O), zinc nitrate hexahydrate (Zn(NO3)2·6H2O), and 2-methylimidazole (C4H6N2) in methanol (CH3OH) with stirring at 25 °C for 2 h. The resulting solid-state Co/Zn ZIF nanoparticles are collected by centrifugation and dried at 60 °C for 24 h. C60 fullerene nanowhiskers (FNW) were prepared from C60-saturated toluene and isopropyl alcohol using a liquid-liquid interfacial precipitation method. The composite was stirred while adding small amounts of solutions of polyvinylpyrrolidone (PVP, Mw ≈10,000 g/mol), C60 FNW, cobalt(II) nitrate hexahydrate, zinc nitrate hexahydrate, and 2-methylimidazole to afford bimetallic Co/Zn-ZIF-C60 FNW composite which is collected by centrifugation and dried for 24 h in an oven to obtain the bimetallic Co/Zn-ZIF-C60 FNW composite. The bimetallic Co/Zn-ZIF-C60 FNW composite exhibit higher photocatalytic activity than Co/Zn ZIF nanoparticles in the degradation of tetracycline hydrochloride (TCH) under LED light irradiation at 450 nm. The photocatalytic degradation kinetics of TCH in the presence of either Co/Zn ZIF nanoparticles or bimetallic Co/Zn-ZIF-C60 FNW composite under LED light irradiation followed a pseudo-first-order rate law.