Metal-organic framework (MOF) materials and functionalization for targeted adsorption of pb and cd in wastewater: Mechanisms, challenges, and future development prospects

Abstract

With the rapid development of global industrialization, heavy metals(HM) pollution in water bodies worldwide has become one of the key environmental challenges due to its persistent toxicity and bioaccumulation risks. Lead (Pb) and cadmium (Cd), as common and typical representatives of toxic heavy metals, are primarily originating from wastewater discharge from industries such as metallurgy, electroplating, and pesticides. Due to their heightened toxicity risks, membrane separation, precipitation, adsorption, and other technologies have been proposed. Among them, adsorption has been widely recognized due to its simple operation, low cost, and remarkable effectiveness. Adsorption materials are the technical core of adsorption methods. MOF materials are superior to traditional carbon based, silicon-based, natural materials and other adsorption materials due to their high selectivity and controllability. However, there is no systematic comparison of MOF materials for removing Pb and Cd from wastewater. The diversity, adsorption differences and applicable scenarios of these materials make their industrial application difficult. This article systematically summarizes the MOF materials and functionalization methods for removing Pb and Cd from wastewater, and compares their performance indicators such as maximum capacity, selectivity coefficients, and regeneration cycle times. The advantages and disadvantages of the materials are compared, and the applicable scenarios of different materials are clarified. To address the defects and drawbacks of MOF materials, an innovative approach has been proposed to enhancing the synthesis, functionalization, and material recycling of MOF materials through multiple physical fields. This approach precisely regulates the nucleation, pore structure, exposure of active sites, and controllability of functional group grafting in MOF materials. This collaborative strategy is not only expected to break through the limits of traditional material performance, but also to achieve intelligent adsorption systems that respond to extreme environmental stress. This study provides a forward-looking perspective for designing next-generation MOF materials to achieve sustainable water purification.