Investigation of the surface and photocatalytic behaviour of copper–iron–molybdate Cu7.26Fe7.26Mo12O48 nanocomposites prepared from discarded printed circuit boards

Abstract

Waste-printed circuit boards (WPCBs) contain reusable precious metals, making them a valuable secondary resource. The effect of moderate substitution of molybdenum disulfide (MoS₂) on the characteristics of WPCB leachate powder to form copper–iron–molybdate (Cu_7.26Fe_7.26Mo₁₂O₄₈, CFM) nanocomposites was investigated in this study. The CFM nanocomposites were synthesized using a solvothermal technique at pH 10 and subsequently heat-treated for 30 minutes at temperatures of 200, 400, 600, and 800 °C. To examine the phase composition, nanosize, morphology, and elemental distribution of the nanocomposites, X-ray diffraction, TEM, and SEM with EDS characterization techniques were used. The optical bandgap values of the CFM-200, CFM-400, CFM-600, and CFM-800 nanocomposites were determined using the Kubelka–Munk function, yielding values of 3.80 eV, 3.32 eV, 3.27 eV, and 3.22 eV, respectively. Under UV exposure, the CFM-800 nanocomposite demonstrated a degradation of 96.5% of the Congo red (CR) dye. These investigations revealed that CFM nanocomposites possess stability and effectiveness as photocatalysts, making them promising candidates for wastewater treatment applications.