Synthesis of Metal–Organic Framework ZnO_x-MOF@MnO₂ Composites for Selective Removal of Strontium Ions from Aqueous Solutions

Abstract

A Zn(II)-based metal−organic framework (MOF) compound and MnO 2 were used to prepare ZnO x -MOF@MnO 2 composites for selective Sr 2+ removal in aqueous solutions. The ZnO x -MOF@MnO 2 composites were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and Brunauer−Emmett−Teller surface area analysis. The functional groups, morphologies, thermal stabilities, and specific surface areas of the composites were suitable for Sr 2+ adsorption. A maximum adsorption capacity of 147.094 mg g −1 was observed in batch adsorption experiments, and the sorption isotherms were fit well by the Freundlich model of multilayer adsorption. Adsorption reached equilibrium rapidly in kinetic experiments and followed the pseudo-secondorder kinetic model. The adsorption capacity of the ZnO x -MOF@MnO 2 composite with the highest MnO 2 content was high over a wide pH range, and the composite was highly selective toward Sr 2+ in solutions containing coexisting competing ions. Also, it has a good reusability for removing Sr 2+ .

Applications of Metal‐Organic Frameworks in Water Treatment: A Review

“…[74,124] Or various radioactive contaminants, found in wasters from nuclear power wastes and nuclear reactors, can easily diffuse into water resources and eventually be concentrated in human thyroid gland, increasing the risk of leukemia and death. [125,126] In addition, antibiotics widely used in the fields of pharmacy and clinical medicine will also cause ecological pollution. [127] The entry of antibiotics into soil and water environment may drive the bacteria to produce antibiotics-resistant genes and reduce the therapeutic outcomes of antibiotics and other drugs.…”

Fabrication of cellulosic paper containing zeolitic imidazolate framework and its application in removal of anionic dye from aqueous solution

“…Metal-organic frameworks (MOFs) have been studied and applicated extensively in the field of gas storage, separation, sensing, and catalysis due to their abundant nanopores (Kim et al 2017;Sun et al 2019;Demakov et al 2020;Pérez-Cejuela et al 2020). The composition of MOFs and other materials is a valuable approach to the development of new materials with better applicability considering the recycling and the improved properties of MOFs (Li et al 2017;Choi et al 2020). In particular, the growth of MOFs on the surface of different substrates can lead to the formation of membrane MOF materials, which are particularly valuable in separation techniques and catalysis (Guo et al 2010;Jiang et al 2013;So et al 2013;Lange and Obendorf 2015;Wang et al 2015;Matsumoto and Kitaoka 2016;Yu et al 2016;Rafti et al 2017).…”

Intensive adsorption of strontium ions by using the synthesized [Zn(bim)2(bdc)]n: Metal–organic framework in batch and fixed‐bed column experiments

“…They are assembled by metal ions and organic ligands. [ 11–13 ] Some features such as ultrahigh‐specific surface areas, mechanical stability, chemical tuneability and modularity, high porosity, and controllable pore size and shape are attributed to these adsorbents. [ 11 ] The design and synthesis of MOFs have attracted a great deal of attention, owing to their intriguing architectures in the synergetic coordination of metals with different ligands and multiple functions lining the cavities.…”

“…They estimated the high sorption capacity of 147.094 mg g −1 for Sr ions on Zn‐based MOF and concluded the selective removal of strontium ions from radioactive liquid waste. [ 12 ] The ability of porous adsorptive material such as MOF‐ZBB has not been investigated in strontium sorption from the aqueous solution. Thus, this would be the subject of this study.…”