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        검색결과 8

        2.
        2023.11 구독 인증기관·개인회원 무료
        Bisphenol-A, also known as BPA, is commonly used as a building block for epoxy and polycarbonate plastics. However, it has been recently identified as a major source of water pollution due to its release into the water from plastic products. BPA-based resins can also contaminate the water with high concentrations of BPA, which can enter the water bodies through production units and wastewater discharge. Photocatalysis, particularly the photo-Fenton process, is an effective method for wastewater treatment and degrading pollutants. Titanium dioxide (TiO2) is usually chosen based on its high photocatalytic properties and high performance. However, its wide band gap energy is a major issue for the photocatalytic process. This means that the catalyst can only exhibit high photocatalytic performance under UV-light irradiation and usually requires an acidic pH, which limits its use. In order to address the aforementioned issues, a visible-light photoactive photo-Fenton reaction has been successfully developed to degrade bisphenol A at natural pH using H2O2. The process was highly efficient, achieving complete degradation of phenol in just three hours of visible light irradiation with Cu-MOF. This environmentally friendly Fenton process has the advantage of occurring at natural pH levels with the presence of H2O2, providing a new perspective for efficient degradation. The photocatalyst was characterized using single X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), and UV–vis diffuse reflectance spectroscopy (DRS).
        3.
        2023.05 구독 인증기관·개인회원 무료
        The removal of aqueous pollutants, including dye molecules from wastewater remains one of the pressing problems in the world. Because of chemical stability and conjugated structure, dye molecules cannot be easy decomposed by heat with oxidizing reagents such as H2O2 and light. The most common representative of widespread organic pollutant is methylene blue (MB) with molecular formula C16H18ClN3S, which is important colorant and used in various chemical and biological production industries and causes serious environment problems. Porous materials, including MOFs (metal-organic frameworks) have been applied for efficient MB photocatalytic degradation. However, one of the main barriers to using most MOFs to break down aromatic organics is wide band gap energy, which means that the catalyst can exhibit high photocatalytic performance only under UVlight irradiation. Moreover, most MOFs usually show the poor water stability of frameworks, which tend to dissolve in water with total destruction. In this work we report about two new copper based MOFs with high photocatalytic properties for efficient MB degradation from wastewater under UV-light and natural sunlight. Time, required for 100% MB degradation, equals 7 minutes under UV (source 4 W 254 nm VL-4.LC UV-lamp) and 60 minutes under natural sunlight irradiation in the presence of H2O2. Crystal structure information is provided using single crystal X-ray diffraction data. The composition and comparative characteristics of MOFs are given using powder X-ray diffraction, UV–visible diffuse reflectance spectroscopy, UVvisible spectroscopy and Fourier-transform infrared spectroscopy.
        4.
        2022.10 구독 인증기관·개인회원 무료
        Hydrogen-bonded organic frameworks (HOFs) are a new type of porous crystalline material that are constructed by intermolecular hydrogen bonding of organic building blocks to form twodimensional (2D) and three-dimensional (3D) crystalline networks. High-quality HOF single crystals are easily grown for direct superstructure analysis using single crystal X-ray diffraction, which is essential for revealing the relationship between structure and properties. The unique advantages of HOF, such as high crystallinity, porosity and fast regeneration, have allowed it to be used in a variety of applications including catalysis and gas separation. Squaric acid (SQA) is a non-carboxylic, organic acid with proton donor and acceptor ability which is known to take on a variety of coordination modes with metal ions. Pyrazine is a six-membered aromatic heterocycle bearing two nitrogen atoms, which has sp2 hybridized C atoms with C-H hydrogen bonds. This work describes the synthesis and structural characteristics of HOF based on squaric acid and pyrazine. Based on single crystal X-ray diffraction data, this MOF crystallizes in the triclinic P-1 space group. Each asymmetric unit is composed of H2SQ and pyrazine. All squaric acid molecules share one H atom with the N atom of pyrazine molecules. The layer distance between nearby O atoms from squaric acid in different layers equals 5.29 Å. Also, our HOF showed high adsorption capacity the during experiments. The composition and comparative characteristics of HOF are given using SCXRD, PXRD, SEM and UV-vis.
        5.
        2022.05 구독 인증기관·개인회원 무료
        Efficient capture and storage of radioactive iodine (consisting of two isotopes: 129I and 131I), produced or released from nuclear activities, are of paramount importance for sustainable development of nuclear energy due to their volatility and long half-life. Therefore, it is very important to develop new adsorbents for efficient utilization of radioactive iodine from nuclear waste. Various methods and materials are used for I2 capturing and removing, including MOFs due to their high porosity and fast adsorption kinetics, which are rightfully considered effective sorbents for removing I2. Metal–organic frameworks (MOFs) are porous crystalline materials which have diverse pore geometry and unique physicochemical properties, have attracted enormous attention for use in gas storage, separation and catalysis. The ability of MOFs to adsorb volatile products at room temperature can significantly improve the cost-effectiveness of the utilization process. This work describes the synthesis and characterization of three new metal-organic frameworks based on pyrazine (pyz), 44’bipyridine (bpy), 1,2 -bis(4 - pyridyl) – ethane (bpe) and copper (II) hexafluorozironate, as potential adsorbents for I2 capture. All of these three MOFs exhibit a two - dimensional (2D) crystal structure consisting from infinity non-crossing linear chains. The crystal structure of [Cu(pyz)2(ZrF6)2(H2O)2], [Cu(bpy)4(H2O)2ZrF6] and [Cu(bpe)4(H2O)2ZrF6] were characterized using powder X-ray diffraction (PXRD), single crystal X-ray diffraction (SC-XRD). Comparative characteristics of synthesized MOFs, including Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were also performed. The I2 sorption experiments were examined by UV-vis spectroscopy.