Green synthesis of pd/fe3 o4 bimetallic nanoparticles: Catalytic in-situ generations of H2 O2 for heterogeneous fenton-like decolorization of basic red 46 and direct red 23

Abstract

In this study, Pd/Fe3 O4 bimetallic nanoparticles (Pd/Fe3 O4 NPs) were biosynthesized by aqueous lemon (Citrus limon (L.) Burm. f.) leaves extract as a reducing agent and were characterized by scanning electron microscopy, dynamic light scattering (DLS), and X-ray diffraction analysis methods. The characterization studies confirmed the synthesis of Pd/Fe3 O4 NPs successfully. According to DLS analysis, the mean hydrodynamic radius of Pd/Fe3 O4 NPs was found to be 64.95 nm. In the second part of the study, Pd/Fe3 O4 NPs were utilized as a common heterogeneous catalyst for both in-situ H2 O2 synthesis by formic acid decomposition in the presence of oxygen and heterogeneous Fenton-like decolorization of Basic Red 46 (BR 46) and Direct Red 23 (DR 23) azo dyes. To determine the decolorization efficiency of heterogeneous Fenton-like reaction which was carried out by in-situ H2 O2 synthesis, the effects of reaction parameters such as the concentration of formic acid, initial pH of dye solutions, initial dye concentrations and catalyst concentration were investigated for both dye decolorization processes. Consequently, Pd/Fe3 O4 NPs displayed high decolorization performances for BR 46 and DR 23 in the range of 25–200 mg/L BR 46 concentration and in the range of 25–75 mg/L DR 23 concentration.