Catalytic propensity of biochar decorated with core-shell nZVI@Fe3O4: A sustainable photo-Fenton catalysis of methylene blue dye and reduction of 4-nitrophenol

Abstract

The zerovalent iron nanoparticles (nZVI) tend to agglomerate, therefore, exhibit reduced adsorption and catalytic activity. To overcome this, we decorate novel peach skin-derived fibrous biochar (FBC) with spherical nZVI to develop a sustainable and more robust nano-catalytic material. The nanocatalyst material, hereafter nZVI-FBC was well characterized by FTIR, XRD, TGA, SEM, FE-SEM, TEM, HR-TEM, and XPS analysis. Furthermore, XRD, HR-TEM, and XPS analysis rationalize the surface passivation of nZVI to form nZVI@Fe3O4 core-shell nanostructure. We applied nZVI-FBC particles for the superior photo-Fenton degradation of methylene blue (MB) dye and catalytic reduction of 4-nitrophenol (4-NP) as model contaminants. At optimum batch conditions, temp= 25 oC,initial MB concentration= 20 mgL-1,and pH= 4.5 ± 0.3,the photo-Fenton degradation of MB obey pseudo-first-order kinetic model with a qe,exp value of 19.94 mgg-1. The LC-MS analysis confirms mineralization of MB and ESR studies demonstrate the presence of HO radical as a principal reactive oxygen species (ROS). Furthermore, the cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) studies rationalize the pseudo-capacitive nature of the nanocatalyst with biochar component acting as an electron-donating framework. The-nZVI-FBC exhibit a superfast and superior catalytic performance for the reduction of 4-NP to 4-aminophenol. The nZVI-FBC shows excellent stability and reusability over multiple catalytic cycles.