Synthesis of microsize Fe/Cu bimetallic particles using in situ acid-mediated coating: Application on decolorization of azo dye acid orange 7

Iron-based bimetallic particle has become an attractive material in environmental remediation, particularly for wastewater treatment. However, it is yet to be applied in large scale processes, mainly due to the requirement of multistep syntheses for the desired materials, as well as the rigorous control of the conditions for its synthesis. This study introduces a facile methodology to synthesize micro-size iron/copper bimetallic particles (mFe/Cu-BPs) by in situ coating of Cu on the surface of Fe in an acidic media for the removal of azo dye Acid Orange 7 (AO7) in aqueous media. Morphological analyses showed that Cu planted on the surface of the particles exhibit a dense leaf-like structure with great connectivity and electron movement between Fe⁰ core and Cu shell. In addition, the effects on the decolorization of AO7 via key parameters such as theoretical Cu mass loading (TML_Cu), initial pH, dosage, and initial AO7 concentration were assessed. Experimental results revealed that the decolorization efficiency of AO7 was highly dependent on the operational conditions. Under optimal conditions (TML_Cu of 0.6 g Cu/g Fe, initial pH of 3.0, mFe/Cu-BP dosage of 45 g/L, and initial AO7 concentration of 1000 mg/L), decolorization of AO7 as a function of reaction time was investigated via UV-vis spectrometry, which confirmed that the azo bond of AO7 successfully cleaved by mFe/Cu-BPs. The maximum decolorization, COD, and TOC removal efficiencies were found to be 99.55, 83.91, and 73.81% after 30 min of reaction time, respectively. Lastly, the potential mechanism for the decolorization of AO7 is proposed.