Browsing by Author "Abuzalat, Osama"

Now showing 1 - 7 of 7
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    Facile and rapid synthesis of functionalized Zr-BTC for the optical detection of the blistering agent simulant 2-chloroethyl ethyl sulfide (CEES)
    (Royal Society of Chemistry, 2021-02) Abuzalat, Osama; Homayoonnia, Setareh; Wong, Danny; Tantawy, Hesham R.; Kim, Seonghwan
    2-chloroethyl ethyl sulfide (CEES) is a simulant for the chemical warfare agent, bis(2-chloroethyl) sulfide, also known as mustard gas. Here, we demonstrate a facile and rapid method to synthesize a functionalized metal-organic framework (MOF) material for the detection of CEES in trace level. While Zr-BTC is synthesized, in-situ encapsulation of fluorescent material (Fluorescein) into Zr-BTC voids is performed with a simple solvothermal reaction. The produced F@Zr-BTC is used as a fluorescent probe for CEES detections. The synthesized material shows fluorescence quenching under illumination at excitation wavelength of 470 nm when the F@Zr-BTC is exposed to CEES. This sensing material shows the highest fluorescence quenching at an emission wavelength of 534 nm with CEES concentration as low as 50 ppb. Therefore, the demonstrated sensing method with F@Zr-BTC offers a fast and convenient protocol for selective and sensitive detection of CEES in practical applications.
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    ItemOpen Access
    Facile and rapid synthesis of functionalized Zr-BTC for the optical detection of the blistering agent simulant 2-chloroethyl ethyl sulfide (CEES)
    (Royal Society of Chemistry, 2021-02) Kim, Seonghwan; Abuzalat, Osama; Homayoonnia, Setareh; Wong, Danny; Tantawy, Hesham R
    2-chloroethyl ethyl sulfide (CEES) is a simulant for the chemical warfare agent, bis(2-chloroethyl) sulfide, also known as mustard gas. Here, we demonstrate a facile and rapid method to synthesize a functionalized metal-organic framework (MOF) material for the detection of CEES in trace level. While Zr-BTC is synthesized, in-situ encapsulation of fluorescent material (Fluorescein) into Zr-BTC voids is performed with a simple solvothermal reaction. The produced F@Zr-BTC is used as a fluorescent probe for CEES detections. The synthesized material shows fluorescence quenching under illumination at excitation wavelength of 470 nm when the F@Zr-BTC is exposed to CEES. This sensing material shows the highest fluorescence quenching at an emission wavelength of 534 nm with CEES concentration as low as 50 ppb. Therefore, the demonstrated sensing method with F@Zr-BTC offers a fast and convenient protocol for selective and sensitive detection of CEES in practical applications.
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    High-Performance, Room Temperature Hydrogen Sensing With a Cu-BTC/Polyaniline Nanocomposite Film on a Quartz Crystal Microbalance
    (2019-01) Abuzalat, Osama; Wong, Danny; Park, Simon S.; Kim, Seonghwan
    In this paper, we demonstrate a high-performance hydrogen sensor under ambient conditions by growing a Cu-BTC/polyaniline (PANI) nanocomposite film on a quartz crystal microbalance (QCM) using intense pulsed light. The QCM was first sputter coated with a 200-nm-thin layer of copper. The copper layer was then oxidized by sodium hydroxide and ammonium persulfate. A solution containing the organic ligand (BTC) and PANI was then dropped and dried on the copper hydroxide surface of a QCM with intense pulsed light which resulted in Cu-BTC/PANI nanocomposite film on a QCM. The gas sensing performance of the Cu-BTC film and Cu-BTC/PANI composite film was compared under ambient conditions. It was found selectivity and sensitivity of the Cu-BTC/PANI nanocomposite film to hydrogen were significantly improved. In addition, a fast response time (from 2 to 5 s), operation at room temperature even in the presence of high relative humidity (up to 60%), good repeatability were achieved with the Cu-BTC/PANI nanocomposite film-grown QCM sensor.
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    In situ encapsulation of ZrQ in UiO-66 (Zr-BDC) for pore size control to enhance detection of a nerve agent simulant dimethyl methyl phosphonate (DMMP)
    (Wiley, 2022-06-08) Wong, Danny; Kim, Seonghwan; Abuzalat, Osama
    Chemical warfare agents are toxic chemicals that require rapid, easy-to-use, sensitive, and selective sensors to countermeasure. Simulants, such as dimethyl methyl phosphonate (DMMP), are used to test the effectiveness of sensors toward nerve agents. Metal organic frameworks (MOFs) offer large surface area and selective accessibility to active sites making them appealing for chemical sensing applications. In this work, we propose a fast, facile, direct synthesis method for manufacturing fluorescent MOFs with high sensitivity and selectivity. Zr-BDC is synthesized with 1, 4-benzenedicarboxylic acid (BDC) as an organic ligand and zirconium (Zr) metal. Fluorescent materials are then encapsulated in a novel and rapid in situ approach with strong solvents. X-ray diffraction, UV–visible spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy are used to verify the successful formation of fluorescent MOFs. Compared to other methods, the gel synthesis method helps to control crystal growth leading to higher BET surface areas of ~1150 m2 g−1 for Zr-BDC and 850 m2 g−1 for ZrQ@Zr-BDC. Titration experiments show the sensitivity of the material to DMMP down to 8.3 nM with a highly linear response. Enhanced fluorescence and occupation of mesopores by ZrQ enable lower limit of detection than those of comparable works in literature. The encapsulation mechanism also prevents substantial defects that would otherwise lead to water adsorption.
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    Rapid Fabrication of Metal–Organic Framework Films from Metal Substrates Using Intense Pulsed Light
    (2018-01) Yim, Changyong; Abuzalat, Osama; Elsayed, Mohamed; Park, Simon; Kim, Seonghwan
    In this article, we demonstrate an innovative approach for the fabrication of uniform metal–organic framework (MOF) films on Cu or Zn metal substrates by using intense pulsed light (IPL). The metal substrates are first treated with a strong oxidizing agent to convert the metal to the corresponding metal hydroxide, then MOF films are prepared by in situ growth over the metal hydroxide surface with an organic ligand by multiple IPL irradiations at room temperature and ambient conditions. The metal hydroxide absorbs the light from IPL, which discharges an excessive energy with relatively short pulse duration (milliseconds), then converts the light to thermal energy. Four well-known MOF compounds, Cu-BTC, Cu-BDC, ZIF-8, and MOF-5 film, are successfully synthesized and characterized by scanning electron microscopy and X-ray diffraction analysis. The effects of organic ligand concentration and IPL exposure time on MOF film synthesis are systematically investigated. The innovative fabrication method presented in this study offers many advantages such as short processing time, low cost process under ambient conditions, less use of consumable chemicals, and applicability to fabrication of other MOF films.
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    Sonochemical fabrication of Cu(II) and Zn(II) metal-organic framework films on metal substrates
    (2018-07) Abuzalat, Osama; Wong, Danny; Elsayed, Mohamed; Park, Simon; Kim, Seonghwan
    In this article, we demonstrate a rapid and facile method for in-situ growth of metal-organic framework (MOF) films on Cu or Zn metal substrates by sonochemical techniques. The substrates were first treated with a strong oxidizing agent to convert the metal to the corresponding metal hydroxide. Ultrasonic irradiation provided the energy to drive the reaction between the metal ion sources and organic ligands. Four MOF films (Cu-BTC, Cu-BDC, ZIF-8 and MOF-5) were successfully fabricated by this approach. The produced films were characterized by scanning electron microscopy and X-ray diffraction analysis. The effects of organic ligand concentration and ultrasonic irradiation time on MOF film synthesis were also systematically investigated. The rapid and facile fabrication method presented in this article could serve a new route to grow MOF films on various gas sensor surfaces. Of the MOF films, ZIF-8 film was tested as a potential methane sensor.
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    Synthesis and Characterization of Metal-Organic Frameworks Films and their Application as Chemical Sensors
    (2019-08-08) Abuzalat, Osama; Kim, Seonghwan; Park, Simon S.; Du, Ke; Li, Simon; Hill, Josephine M.; Chung, Hyun Joong
    Metal-organic frameworks (MOFs) are porous crystalline materials composed of metal ions and organic ligands. Recent research displays a growing interest in utilizing MOFs for the potential application of detecting trace gases. This is performed by designing a homogenous thin film of MOFs on a solid substrate attachment. Fabrication of MOFs into thin films present drawbacks, which include long processing times, poor homogeneity, and weak attachment to substrates. In this work, two new synthesis approaches have been developed to overcome the limitations mentioned. These methods of preparation were developed for Cu-BTC, Cu-BDC, ZIF-8 and MOF-5 films on a metal substrate. The metal substrates were chosen to act as a metal ion source by creating a metal hydroxide layer via oxidation, which facilitates the dissolution of metals ions to coordinate with the organic ligands. Intense pulsed light (IPL) and ultrasonic irradiations were used to overcome the activation energy required to initiate the chemical reaction. Both IPL and sonication methods showed good homogeneity, attachment and crystallinity. The IPL film crystal sizes are relatively smaller than the sonicated crystals, this can be contributed to the shorten reaction time of the IPL method (3 min). This study introduces a novel approach to processing MOF films for sensors applied to gas detection. Interestingly, a high-performance hydrogen sensor has been demonstrated by synthesizing a Cu-BTC/polyaniline (PANI) nanocomposite film on a quartz crystal microbalance (QCM) using the IPL method. The selectivity and sensitivity of hydrogen gas on the Cu-BTC film and Cu-BTC/PANI film were compared at room temperature. The Cu-BTC/PANI film showed significantly enhanced results compared to the Cu-BTC film. In addition, a 2 - 5 second response time was achieved while operating at room temperature, showing indifference to high relative humidity (ca. 60%). TiO2-SnO2/MWCNT doped with Cu-BTC was also fabricated using IPL technique for trace ammonia detection. The IPL contributed to the rapid processing time and the thermal conversion of anatase TiO2 to rutile TiO2. The functional film showed a limit of detection of 3.3 ppm. The sensor exhibits reversibility during cyclic testing and minimal drift suggesting that the reaction mechanism is primarily surface adsorption.