Post-synthetic modification of zirconium-based metal-organic frameworks for enhanced simultaneous adsorption of heavy metal ions and organic dyes

Heavy metal and dye pollution pose a serious threat to human health and ecology, and there is an urgent need to develop novel adsorbent materials for wastewater treatment. In this study, a novel functionalized zirconium-based MOF UiO-66-Gd was prepared by a post-synthetic modification strategy and used for the simultaneous removal of Pb2+, Cu2+ and methylene blue (MB) from wastewater. UiO-66-Gd retained the crystalline structure and morphological features before modification. The specific surface area reached 574.94 m2/g, which can provide abundant active sites for adsorption. The effects of several factors on the adsorptive performance of UiO-66-Gd were investigated by batch adsorption experiments. The adsorption of Pb2+ by UiO-66-Gd reached the adsorption equilibrium in only 5 min. The theoretical maximum adsorption capacities for Pb2+, Cu2+ and MB were 833.33, 354.61 and 564.91 mg/g, respectively. In addition, UiO-66-Gd has excellent anti-interference and regeneration properties with potential for practical applications. Competition adsorption experiments showed that UiO-66-Gd had the greatest affinity for Pb2+. The adsorption of UiO-66-Gd on Pb2+ and Cu2+ was mainly through electrostatic interactions and chelation, and on MB mainly through electrostatic interactions, π-π interactions and hydrogen bonding. Overall, UiO-66-Gd has great potential for application in the removal of Pb2+, Cu2+ and MB. Graphical Abstract Caption: Fabrication of functionalized zirconium-based MOF and adsorption properties of Pb2+, Cu2+ and methylene blue (MB) in wastewater. [Display omitted] •A novel high specific surface area functionalized zirconium-based MOF UiO-66-Gd was prepared by a post-synthetic modification strategy.•UiO-66-Gd can efficiently remove Pb2+, Cu2+ and methylene blue (MB) from wastewater simultaneously.•The theoretical maximum adsorption capacity for Pb2+, Cu2+ and MB was 833.33, 354.61 and 564.91 mg/g, respectively.•The adsorption mechanism was explored in detail.