The use of bimetallic metal-organic frameworks as restoration materials for pollutants removal from water environment

Bimetallic metal-organic frameworks (BMOFs) are a class of functional porous materials constructed by coordination between nodes containing two different metal ions and organic ligands. Studies have shown that the catalytic activity of BMOFs is greatly improved owing to the adjustment of charge distribution and the increase of active sites as well as the synergistic effect between the bimetals, and the advantages of their large specific surface area, high porosity, unique structure and dispersed active centres make them available as important organic materials applied in the field of wastewater treatment. In this review, the preparation and construction methods for BMOFs in recent years are summarized, and we focus on their removal of different types of pollutants in the aqueous environment, including ions, dyes, pharmaceuticals or personal care products, phenolic compounds and microorganisms, as well as their corresponding removal mechanisms. In addition, we provide an outlook on their future opportunities and challenges in wastewater treatment.

A high valence binary metal-organic framework as an electrode material for aqueous asymmetric supercapacitors

This study presents the chemical transformation of nickel-based metal-organic frameworks into binary metal-organic frameworks by introducing cobalt metal ions. The resulting NiCo-BDC hierarchical nanostructure exhibited higher oxidation states, resulting in an impressive capacitance of 1431 F g-1. Additionally, the device based on this material exhibited exceptional capacity retention over 3000 cycles.

Highly fluorescent nickel based metal organic framework for enhanced sensing of Fe3+ and Cr2O72- ions

Heavy metal contamination has sparked widespread concern among the populace. The significant issues necessitate the creation of high-performance fluorescent pigments that can identify harmful elements in water. The present study deals with metal organic framework [MOF] based on nickel [Ni-BDC MOF]. The Ni-BDC MOF was prepared by facile solvothermal method using nickel nitrate hexahydrate and terephthalic acid ligand as precursors. The MOF was characterized by various techniques in order to examine the crystal, morphological, structural, composition, thermal and optical properties. The detailed characterizations revealed that the synthesized Ni-BDC MOF are well-crystalline with high purity and possessing 3D rhombohedral microcrystals with rough surface. The MOF demonstrate good luminescence performance and excellent water stability. According to the Stern Volmer plot, the tests set up under optimized conditions demonstrate a linear correlation between the fluorescence intensity and concentration of both ions, i.e. Fe³⁺, and Cr₂O₇^2- ions. The linear range and detection limit for Fe³⁺ and Cr₂O₇^2- were found to be 0-1.4 nM and 0.159 nM, and 0-1 nM and 0.120 nM, respectively. The mechanisms for the selective detection of cations and anions were also explored. The recyclability for the prepared MOF was checked up to five cycles which showed excellent stability with just a slight reduction in efficiency. The constructed sensor was also used to assess the presence of Fe³⁺ and Cr₂O₇^2- ions in actual water samples. The results of the different experiments revealed that the prepared MOF is a good material for detecting Fe³⁺ and Cr₂O₇^2- ions.