Sustainable Synthesis of Electroplating Sludge-Derived MOFs for CO₂ Adsorption and Antibacterial Applications

This study presents a sustainable strategy for converting electroplating sludge (EPS) into functional metal-organic frameworks (MOFs) for environmental applications. Two EPS-derived MOFs, namely, EPS-MOF-D (Cu-BDC type) and EPS-MOF-T (HKUST-1 type), were successfully synthesized using acid-leached EPS as the metal source. Among them, EPS-MOF-T exhibited a high BET surface area of 617.8 m²/g and enhanced crystallinity. CO₂ adsorption measurements demonstrated that EPS-MOF-T achieved a maximum uptake of 1.07 mmol/g at 20 °C, significantly outperforming EPS-MOF-D. The adsorption behavior followed an exothermic physisorption mechanism (ΔH ≈ - 22 kJ/mol), supported by isotherm modeling using the Redlich-Peterson equation. In addition to gas adsorption, both MOFs exhibited antibacterial activity against Escherichia coli, which is primarily attributed to controlled Cu²⁺ ion release, with ligand-associated reactive oxygen species (ROS) generation acting as a complementary pathway. This work highlights the potential of waste-derived MOFs as multifunctional materials for integrating carbon capture and antimicrobial performance, providing a sustainable approach for electroplating sludge valorization.