A multifunctional ascorbic acid-based bio-MOF for sustainable water purification: efficient malachite green adsorption, antibacterial activity, and biocompatibility

Access to safe and clean water remains a critical global challenge, with synthetic dyes released from textile industries representing a major source of aquatic pollution due to their persistence, toxicity, and potential risks to both ecosystems and human health. In this study, bioactive ascorbic acid-based metal-organic frameworks (Bio-MOFs), designated as BioZnAA, were synthesized using different Zn 2+ -to-ascorbic acid molar ratios (BioZnAA2:1, BioZnAA1:1, and BioZnAA1:2) and evaluated as multifunctional adsorbents for the removal of malachite green (MG) from aqueous solutions. Ascorbic acid served as the organic linker, while Zn 2+ ions acted as metal nodes to construct stable MOF-like architectures. Among the synthesized materials, BioZnAA2:1 exhibited the highest adsorption performance, achieving a maximum adsorption capacity of 1429 mg/g according to the Langmuir isotherm model, along with 94% MG removal efficiency, which was significantly higher than BioZnAA1:2 (47%) and BioZnAA1:1 (9.5%). Adsorption equilibrium was well described by the Langmuir isotherm model, while the adsorption kinetics followed a pseudo-second-order model, indicating predominantly monolayer chemisorption. Furthermore, BioZnAA2:1 demonstrated excellent biocompatibility toward L929 fibroblast cells, maintaining high cell viability (89–96%) over the tested concentration range of 125–1000 mg/L. The material also exhibited pronounced antibacterial activity against Staphylococcus aureus and Escherichia coli , with minimum inhibitory concentrations (MICs) of 3.125 and 12.5 mg/mL, respectively. The outstanding adsorption efficiency, combined with favorable biocompatibility and broad-spectrum antibacterial activity, highlights BioZnAA2:1 as a multifunctional Bio-MOF with significant potential for sustainable water purification and pathogen control. These findings demonstrate that ascorbic acid-based Bio-MOFs represent a promising platform for the development of environmentally benign multifunctional materials for integrated environmental remediation and biomedical applications.