Eco-friendly synthesis of CuO/g-C₃N₄/Fe₃O₄ nanocomposites for efficient magnetic micro-solid phase extraction (M-μ-SPE) of trace cadmium from food and water samples.

In this study, a green synthesis method for synthesizing a novel nanocomposite (CuO/g-C₃N₄/Fe₃O₄) utilizing renewable dragon fruit peels as the primary raw material was developed. Hydrothermal and thermal decomposition techniques were used for nanocomposite synthesis. This nanocomposite was subsequently employed for the separation and preconcentration of Cd(II) from various environments, including food and water samples. Characterization of the nanocomposite was conducted utilizing FTIR, XRD, and SEM, which confirmed the successful combination of both metal oxides with g-C₃N₄ within the composite structure. The method exhibited efficient extraction of Cd (II) with a limit of detection (LOD) of 0.65 μg L and high recovery values (84-108 %) in real sample analyses. Optimization of parameters, including pH (8.0), adsorbent quantity (10 mg), and vortex mixing times (1 min for both), were studied to enhance extraction efficiency. This method demonstrates significant potential for environmental applications and provides a low-cost and sustainable approach for separating/enriching trace heavy metals, like Cd (II), with minimal environmental impact.