Green synthesis of Ag/Ni-MOF nanocomposite using hydrophobic deep eutectic solvent for bifunctional applications in heavy metal extraction and dye degradation

In line with green sustainable chemistry principles, a novel adsorbent, silver/nickel (Ag/Ni)-Metal-Organic Framework (MOF), was prepared for the dispersive micro-solid phase extraction (D mu SPE) of copper and lead metal ions from environmental samples (e.g., wastewater, food), and the photocatalytic degradation of indigo carmine. The Ag/Ni-MOF was synthesized using a hydrophobic deep eutectic solvent (HDES) composed of menthol and octylamine, providing a green and sustainable alternative to conventional organic solvents. Key analytical parameters were optimized, achieving limits of detection values of 2.9 mu g L- 1 for lead and 2.04 mu g L- 1 for copper, with a relative standard deviation (RSD) of less than 6% for both metals. The certified reference materials confirmed the accuracy of the recommended method with recoveries over 92%. Additionally, a photocatalytic performance evaluation of the HDES@Ag/Ni-MOF revealed a significant degradation efficiency of 98.6% for indigo carmine in 45 min. The bimetallic material exhibited superior visible light absorption, enhanced surface area, and a reduced band gap energy, which facilitated improved electron transfer and photocatalytic activity. The HDES@Ag/Ni-MOF material is an eco-friendly material with excellent potential for heavy metal preconcentration and dye remediation processes.