Zeolite Imidazolate Framework-8 Metal–Organic Frameworks Embedded with Bimetallic Fe/Pd Nanoparticles for Reductive Dechlorination

Bimetallic Fe/Pd nanoparticles are often used for reductive dechlorination. However, the disadvantage of using bimetallic nanoparticles is their potential aggregation, and hence reduced reactivity. To address these problems, a zeolite imidazolate framework-8 (ZIF-8) embedded with bimetallic Fe/Pd nanoparticles was successfully synthesized. Results revealed that 85.2% of 2,4-dichlorophenol was removed by ZIF-8-Fe/Pd at a pH value of 6 within 120 min and 78.8% by ZIF-8 and 46.3% by Fe/Pd, respectively. The surface composition and morphology were subsequently characterized by a variety of techniques. X-ray diffraction revealed a ZIF-8 encapsulating Fe0 with 2θ of 44.9°, while Fourier transform infrared showed that incorporating Fe/Pd did not destroy the ZIF-8 structure. Scanning electron microscopy, energy-dispersive spectrometry, and transmission electron microscopy demonstrated that Fe/Pd nanoparticles were uniformly distributed in ZIF-8 and the composite was highly crystalline. X-ray photoelectron spectroscopy indicated that Fe0 was presented inside the composite. Finally, a mechanism for the formation of ZIF-8-Fe/Pd was proposed. Testing of both the stabilization and reusability of ZIF-8-Fe/Pd indicated that ZIF-8-supported Fe/Pd nanoparticles have the potential for removing organic contaminates such as 2,4-dichlorophenol by reductive dechlorination.