Application Of Functionalized Metal Organic Skeleton Materials In Adsorption Of Heavy Metal Ions

Metal-organic frameworks (MOFs) have a lot of potential special properties, especially in the ultra-high purity of the isolated new functional materials and other new development of materials. Due to the large specific surface area of the metal-organic frameworks (MOFs) and can still maintain the integrity of the skeleton after removing the solvent molecules of the pores. This paper studied the synthesis and characterization of functionalized metal-organic framework, as well as used as adsorption efficient and selective removal of metal ions from aqueous solution. The main parts of results are summarized below:1、Functionalized metal-organic framework as a new platform for efficient and selective removal of cadmium (Ⅱ) from aqueous solutionIn this work, we illustrate how to anchor-SO3H functional groups onto the pore surface of MOF for cadmium removal from aqueous solution via the approach of sequential post-synthetic modification and oxidation as exemplified in the context of functionalizing the MOF, Cu3(BTC)2 with sulfonic acid. The resultant sulfonic acid functionalized MOF, Cu3(BTC)2-SO3H demonstrates a high cadmium uptake capacity of 88.7 mg/g, surpassing that of the benchmark adsorbents. In addition, it exhibits a fast kinetics with the kinetic rate constant k2 of 0.6818 g/mg/min, which is 1-3 orders of magnitude higher than existing adsorbent materials for adsorbing cadmium ions from aqueous solution. Moreover, it demonstrates high selectivity of cadmium ions in the presents of other background metal ions, and can be readily regenerated and recycled without significant loss of cadmium uptake capacity. Our work thus paves a way for developing functionalized MOFs as a new type of platform for removing cadmium from wastewater.2、Effective removal of Cu (Ⅱ) ions from aqueous solution by thiol functional metal-organic frameworkThe development of metal organic framework based adsorbents for fast and efficient removal of heavy metals from aqueous media still remains a significant challenge. Here, mesoporous zirconium metal organic frameworks functionalized with thiol groups was synthesized by a solvent-assisted ligand incorporation technique and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherms, and scanning electron microscopy (SEM). The resultant material was then used as a novel adsorbent for the removal of Cu(II) from aqueous solution. Kinetic studies revealed that the adsorption process achieved equilibrium within 15 min and followed a pseudo-second -order rate equation. The isothermal data correlated with the Langmuir model better than the Freundlich model. Thermodynamic data indicated the spontaneous and endothermic nature of the process. A maximum Cu(II) adsorption capacity could reach up to 42.70 mg/g. Quantitative recovery of Cu(II) was achieved with 0.1 mol/L HCl and no significant decrease in Cu(II) adsorption capability was observed even after 30 consecutive adsorption/desorption cycles. Given its high adsorption capacity, fast adsorption efficienty, and exceptional stability, the functionalized mesoporous zirconium metal organic frameworks can be used as a promising candidate material for heavy metal ions removal and water treatment.