Combining Chlorella vulgaris and metal-organic framework for enhanced Pb²⁺ removal

Both microalgae and metal-organic framework (MOF) demonstrate effective adsorption capabilities for heavy metals, yet their individual performance remains limited under high-concentration conditions. In this study, synergistic system of Chlorella Vulgaris and MOF was employed to remove high-concentration Pb²⁺. When exposed to lethally high initial Pb²⁺ concentration of 100 mg/L, the integrated system achieved remarkable removal efficiency of 90.2 %, substantially outperforming the standalone performances of Chlorella Vulgaris (46.5 %) and MOF (33.9 %). Mechanistic investigations revealed that the enhancement arose from three key factors: (1) MOF initially adsorbed a portion of Pb²⁺, mitigating toxicity and maintaining algal viability; (2) the assembly of MOF onto algal cells stimulated extracellular organic matter production, facilitating additional adsorption; and (3) continuous migration of Pb²⁺ from MOF to algae restored the adsorption capacity of MOF, enabling sustained removal. This study reveals cooperative interactions between Chlorella vulgaris and MOF, highlighting their strong potential for high-concentration Pb²⁺ wastewater treatment.