Green synthesis, characterization and catalytic activity of 4-nitrophenol reduction and formation of benzimidazoles using bentonite supported zero valent iron nanoparticles

Abstract

In this work, we report the green synthesis and characterization of a green catalyst by the immobilization of zero-valent iron nanoparticles (ZVIN) on the surface of bentonite clay using Eucalyptus leaf extract as both reducing and stabilizing agent and it is abbreviated as ZVIN. As-synthesized B-ZVIN catalyst was characterized by Fourier transformed infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) and Brunauer-Emmett-Teller (BET) techniques for the investigation of optical, structural and surface morphology properties. The size and surface area of synthesized B-ZVIN were observed around less than 50 nm and 62.47 m2/g by the TEM and BET analysis, respectively. Afterward, the catalytic activity of the synthesized catalyst was tested for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in an aqueous medium with remarkable results. The reduction reaction of 4-NP in water follows the pseudo-first order kinetics. B-ZVIN was also used as a catalyst for the synthesis of benzimidazoles in various solvents and solvent-free conditions.