Displaying publications 101 - 120 of 282 in total

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  1. Energy Band Gap Modulation in Nd-Doped BiFeO3/SrRuO3 Heteroepitaxy for Visible Light Photoelectrochemical Activity
    Tan KH, Chen YW, Van CN, Wang H, Chen JW, Lim FS, et al.
    ACS Appl Mater Interfaces, 2019 Jan 09;11(1):1655-1664.
    PMID: 30561192 DOI: 10.1021/acsami.8b17758
    The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer and thus altering the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principle calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
    Matched MeSH terms: Electrons
  2. Dry sliding wear behaviour of talc-reinforced UHMWPE composite for implant application
    Chang BP, Hazizan Md Akil, Ramdziah bt Md Nasir
    Sains Malaysiana, 2015;44:819-825.
    As of today, ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic material normally used as bearing
    components for human joint replacements. However, formation of wear debris from UHMWPE after certain service
    periods may cause adverse effects which remain as unresolved issues. In this study, mechanical and dry sliding wear
    properties of UHMWPE reinforced with different loading of talc particles were investigated. The wear test was carried
    out using Ducom TR-20 pin-on-disc tester at different pressure velocity (pv) factors under dry sliding conditions. The
    worn surfaces and transfer films of pure UHMWPE and talc/UHMWPE composites were observed under scanning electron
    microscope (SEM). The experimental results showed that the microhardness increased with the increase of talc loadings
    in UHMWPE. The 20 wt. % talc/UHMWPE composites showed a 17% increment in microhardness as compared with pure
    UHMWPE. The dry sliding wear behaviour of UHMWPE was also improved upon the reinforcement of talc. The wear rate
    of UHMWPE decreased after incorporation of talc particles. The coefficient of friction (COF) increased slightly under low
    pv conditions. At high pv conditions, the COF decreased in values with increasing talc loadings. The improvement in
    wear behaviour may be attributed to the increase in load-carrying capacity and surface hardness of the talc/UHMWPE
    composites. SEM micrographs on worn surfaces showed that plastic deformation and grooving wear were dominant for
    UHMWPE. The plastic deformation and grooving wear were reduced upon the reinforcement of talc particles. The talc/
    UHMWPE composites produced smoother and uniform transfer films as compared to pure UHMWPE.
    Matched MeSH terms: Electrons
  3. Growth and anatomical responses in xanthostemon chrysanthus as influenced by paclobutrazol and potassium nitrate
    Nazarudin MA, Tsan F, Adzmi Y, Normaniza O
    Sains Malaysiana, 2015;44:483-489.
    A study was conducted to determine the effects of a plant growth regulator (paclobutrazol, PBZ) and commercial
    fertilizer (Krista-K Plus) as a source of potassium nitrate (KNO3
    ) on the growth of Xanthostemon chrysantus. It was
    also attempted to investigate the anatomical changes in the leaf and stem after the treatment. Nine treatments, i.e.
    control (no PBZ and Krista-K Plus application), 0 PBZ gL-1 + 100 g Krista-K Plus, 0 PBZ gL-1 + 200 g Krista-K Plus,
    0.125 PBZ gL-1 + 0 g Krista-K Plus, 0.125 PBZ gL-1 + 100 g Krista-K Plus, 0.125 PBZ gL-1 + 200 g Krista-K Plus, 0.25
    PBZ gL-1 + 0 g Krista-K Plus, 0.25 PBZ gL-1 + 100 g Krista-K Plus and 0.25 PBZ gL-1 + 200 g Krista-K Plus, were
    tested. PBZ was soil drenched at the commencement of the study while Krista-K Plus was applied at three-month
    intervals. Plant growth performances such as tree height, diameter at breast height, canopy diameter and leaf area
    were recorded monthly throughout the study period. Stem and leaf samples were collected before the application
    of treatments and after six months of treatments for anatomical observation by using electron microscope. Plant
    height, diameter at breast height, crown diameter and leaf area were significantly reduced with the application of
    PBZ. Palisade parenchyma thickness was increased by 33.83% with 0.25 PBZ gL-1 + 200 g Krista-K Plus, while only
    2.44% increment recorded in the control tree. Xylem thickness in the stem was reduced by 21.81% after treated with
    the highest dosage of PBZ, while the control tree only had 1.78% increment. Spongy parenchyma thickness in the leaf
    was unaffected. However, palisade parenchyma was found the thickest after combined treatment with 0.25 PBZ gL-1
    + 200 g Krista-K Plus. Micrograph images of the cross-section of leaf lamina and stem showed that the cells were
    tightly arranged in response to the application of PBZ.
    Matched MeSH terms: Electrons
  4. Low pressure DC-Plasma system for the modification of Polymeric Membrane surfaces
    Chalad Yuenyao, Thawat Chittrakarn, Yutthana Tirawanichakul, Hideki Nakajima
    Sains Malaysiana, 2017;46:783-793.
    The main objectives of this work were to develop a lab-scale direct current (DC) glow discharges plasma system for modification of organic and inorganic membranes. Characteristics of plasma system were presented under the discharge of five gases (Ar, N2, air, O2, and CO2). A Langmuir double probe was used for the evaluation of the electron temperature (Te) and electron density (ne) of plasmas. The current and voltage (I-V) characteristic curves were analyzed. Relationships between breakdown voltage (VB) of gases and products of gas pressure and inter-electrode gap (pd) were studied in form of Paschen curves. The results showed that Te of plasma in various gases was in the range of 4-13 eV, while the ne varied between 108 and 109 cm-3. The plasma generated at different gas pressure and applied voltage is in the normal and abnormal modes. Finally, the constructed DC-plasma system was utilized for modification of polymeric membrane surfaces. Treatment time, discharge power and type of gas were varied. The tailoring of membrane surfaces was analyzed through the water contact angle and percent-weight loss (PWL) measurements, DMTA, AFM, XPS and FTIR spectrum. It could be shown that DC-plasma from this system can be used to modify the surface of polymeric membranes.
    Matched MeSH terms: Electrons
  5. Fluorescence quenching reaction of chlorophyll a by tris(acetylacetonate)iron(iii) in various solvents
    Leesakul N, Masen D, Grampp G
    Sains Malaysiana, 2017;46:1369-1377.
    hlorophyll a is known as the prevailing light absorbing pigment giving a strong absorption and fluorescence emission in visible region. Quenching reactions of the chlorophyll a fluorescence by Fe(acac)3 were precisely investigated in various organic solvents which are benzene toluene, ethanol, methanol, dmf, dmso and acetonitrile. Electron transfer performance of chlorophyll a by Fe(acac)3 was investigated from oxidative quenching reaction. Herein, the simplified Rehm-Weller relationship was used to calculate the free energy change of the photo-induced electron transfer reaction. Emission intensity decreased when the concentration of Fe(acac)3 quencher was increased. Non-linear Stern-Volmer plots are found to be affected by inner filter effect more than the ground state complex formation. Rate of quenching reactions (kq) were determined from the Stern-Volmer equation with corrected inner filter effect. The rates of quenching reactions occurred faster in high viscous solvents.
    Matched MeSH terms: Electrons
  6. Facile synthesis of AgCl/BiYO3 composite for efficient photodegradation of RO16 under UV and visible light irradiation
    Sirimahachai R, Harome H, Wongnawa S
    Sains Malaysiana, 2017;46:1393-1399.
    AgCl/BiYO3
    composite was successfully synthesized via the aqueous precipitation method followed by calcination. The
    varied amount of AgCl (10, 20 and 30%) was mixed into BiYO3
    via sonochemical-assisted method. The structures and
    morphologies of the as-prepared AgCl/BiYO3
    composite were characterized by x-ray diffraction (XRD), scanning electron
    microscopy (SEM) and UV-vis diffused reflectance spectroscopy (UV-vis DRS). The optical absorption spectrum of AgCl/
    BiYO3
    composite showed strong absorption in visible region. The photocatalytic activity of AgCl/BiYO3
    composite was
    evaluated by the photodegradation of reactive orange16 (RO16), which was selected to represent the dye pollutants,
    under UV and visible light irradiation. The results indicated that 20% AgCl/BiYO3 photocatalyst was the most capable
    photocatalyst in this series in the degradation of RO16 under both UV and visible light illumination within 1 h. Moreover,
    the mechanism of photocatalytic degradation of AgCl/BiYO3
    was elucidated using three types of free radical scavengers.
    The significant enhancement was attributed to the formation of AgCl/BiYO3
    heterojunction resulting in the low electronhole
    pair recombination rate.
    Matched MeSH terms: Electrons
  7. Molecular orbitals of delocalized electron clouds in neuronal domains
    Poznanski RR, Cacha LA, Latif AZA, Salleh SH, Ali J, Yupapin P, et al.
    Biosystems, 2019 Sep;183:103982.
    PMID: 31195028 DOI: 10.1016/j.biosystems.2019.103982
    We have further developed the two-brains hypothesis as a form of complementarity (or complementary relationship) of endogenously induced weak magnetic fields in the electromagnetic brain. The locally induced magnetic field between electron magnetic dipole moments of delocalized electron clouds in neuronal domains is complementary to the exogenous electromagnetic waves created by the oscillating molecular dipoles in the electro-ionic brain. In this paper, we mathematically model the operation of the electromagnetic grid, especially in regard to the functional role of atomic orbitals of dipole-bound delocalized electrons. A quantum molecular dynamic approach under quantum equilibrium conditions is taken to illustrate phase differences between quasi-free electrons tethered to an oscillating molecular core. We use a simplified version of the many-body problem to analytically solve the macro-quantum wave equation (equivalent to the Kohn-Sham equation). The resultant solution for the mechanical angular momentum can be used to approximate the molecular orbital of the dipole-bound delocalized electrons. In addition to non-adiabatic motion of the molecular core, 'guidance waves' may contribute to the delocalized macro-quantum wave functions in generating nonlocal phase correlations. The intrinsic magnetic properties of the origins of the endogenous electromagnetic field are considered to be a nested hierarchy of electromagnetic fields that may also include electromagnetic patterns in three-dimensional space. The coupling between the two-brains may involve an 'anticipatory affect' based on the conceptualization of anticipation as potentiality, arising either from the macro-quantum potential energy or from the electrostatic effects of residual charges in the quantum and classical subsystems of the two-brains that occurs through partitioning of the potential energy of the combined quantum molecular dynamic system.
    Matched MeSH terms: Electrons
  8. Experimental and DFT investigation on the influence of electron donour/acceptor on the hydrogen bonding interactions of 1-(1,3-benzothiazol-2-yl)-3-(r-benzoylthiourea)
    Wun FML, Muhd Hafizi Zainal, Syahidah Mohd Tahir, Ishak B. Ahmad, Mohammad B. Kassim
    Sains Malaysiana, 2018;47:923-929.
    The presence of two different chromophores in benzothiazole molecule namely benzothiazole and aromatic rings lead to
    interesting chemical and biological properties that attract more researches on the compounds. Three new benzothiazolylbenzoythiourea
    compounds namely 1-(1,3-benzothiazol-2-yl)-3-(benzoylthiourea) (BBT), 1-(1,3-benzothiazol-2-yl)-3-
    (4-chlorobenzoylthiourea) (BBT-4Cl) and 1-(1,3-benzothiazol-2-yl)-3-(4-methoxybenzoylthiourea) (BBT-4OCH3
    ) with
    different electron withdrawing substituents (R) at the para positions on the benzene ring of benzoylthiourea ring have
    been synthesized from the reaction of R-benzoyl isothiocyanate (R= H, Cl, and OCH3
    ) and 2-aminobenzothiazole. The
    compounds were characterized by spectroscopic techniques (infrared, 1
    H proton NMR and UV-Vis). The IR spectra showed
    the frequency signals of n (C=O), n (C=S), n (N-H) at 1664-1673, 1238-1249 and 3031-3055 cm-1, respectively. The 1
    H
    proton NMR spectra showed the presence of N-H amine and amide signals in the region of (12.14-12.35) and (14.17-14.43)
    ppm, respectively. The proton signals of the two benzothiazole and benzoylthiourea moieties appear at 7.08-8.16 ppm.
    A theoretical study based on Density Functional Theory (DFT) and Time-Dependent (TD) DFT was conducted to optimize
    the geometrical structure and investigate the electronic properties of title compounds. The highest occupied molecular
    orbital (HOMO) was found on the benzothiazole moiety; while, the lowest-unoccupied molecular orbital (LUMO) was
    located at the benzoylthiourea fragment. The DFT optimized structures possessed an intramolecular hydrogen bonding
    and the types of para substituents used influenced the properties of hydrogen bonding.
    Matched MeSH terms: Electrons
  9. Fulltext Design, synthesis and biological profile of heterocyclic benzimidazole analogues as prospective antimicrobial and antiproliferative agents
    Tahlan S, Kumar S, Ramasamy K, Lim SM, Shah SAA, Mani V, et al.
    BMC Chem, 2019 Dec;13(1):50.
    PMID: 31384798 DOI: 10.1186/s13065-019-0567-x
    Background: Nitrogen containing heterocycles are widely used and investigated by pharmaceutical industry, as they are important in discovery and designing of new drug molecules. Drugs with a benzimidazole nucleus possess exclusive structural features and electron-rich atmosphere, which enable them to bind to a number of biologically important targets and result in a wide range of activities. This has served as the basis of the present study whereby new scaffolds with benzimidazole moiety were designed and synthesized.

    Methods: The structures of synthesized compounds were confirmed by physicochemical and spectral means. The synthesized compounds were screened for their antimicrobial and antiproliferative activities by tube dilution and Sulforhodamine B (SRB) assays, respectively.

    Results and conclusion: The in vitro biological screening results revealed that compound Z24 exhibited promising antimicrobial and anticancer activities which are comparable to standards.

    Matched MeSH terms: Electrons
  10. Fulltext Enhancing Photocurrent Performance Based on Photoanode Thickness and Surface Plasmon Resonance Using Ag-TiO2 Nanocomposites in Dye-Sensitized Solar Cells
    Lokman MQ, Shafie S, Shaban S, Ahmad F, Jaafar H, Mohd Rosnan R, et al.
    Materials (Basel), 2019 Jun 30;12(13).
    PMID: 31262020 DOI: 10.3390/ma12132111
    This study investigated the different thicknesses of TiO2 photoanode films and the effect of surface plasmon resonance (SPR) of Ag-TiO2 nanocomposites on the current-voltage (I-V) performance of dye-sensitized solar cells (DSSC). The TiO2 layer was deposited using the doctor blade technique and the thickness of the TiO2 films was controlled by using a different number of Scotch tape layers. The silver nanoparticles (AgNP) were synthesised using a chemical reduction method and the concentration of sodium citrate as a reducing agent was varied from 4 to 12 mM to study the effect of citrate ion on the size of the nanoparticles. Ag-TiO2 nanopowder was prepared by adding pure anatase TiO2 powder into AgNP colloidal solution. The mixture was left to dry for 24 h to obtain Ag-TiO2 powder for paste preparation. The three-layer Scotch tape, with thickness of 14.38 µm, achieved a high efficiency of 4.14%. This results showed that three layers was the optimal thickness to improve dye loading and to reduce the charge recombination rate. As for the Ag-TiO2 nanocomposites, 10 mM of AgNP, with a mean diameter of 65.23 nm and high efficiency of 6.92%, proved that SPR can enhance the absorption capability of dye and improve the photon-to-electron generation.
    Matched MeSH terms: Electrons
  11. Fulltext Texture Evolution in AA6082-T6 BFSW Welds: Optical Microscopy and EBSD Characterisation
    Tamadon A, Pons DJ, Clucas D, Sued K
    Materials (Basel), 2019 Oct 01;12(19).
    PMID: 31581446 DOI: 10.3390/ma12193215
    One of the difficulties with bobbin friction stir welding (BFSW) has been the visualisation of microstructure, particularly grain boundaries, and this is especially problematic for materials with fine grain structure, such as AA6082-T6 aluminium as here. Welds of this material were examined using optical microscopy (OM) and electron backscatter diffraction (EBSD). Results show that the grain structures that form depend on a complex set of factors. The motion of the pin and shoulder features transports material around the weld, which induces shear. The shear deformation around the pin is non-uniform with a thermal and strain gradient across the weld, and hence the dynamic recrystallisation (DRX) processes are also variable, giving a range of observed polycrystalline and grain boundary structures. Partial DRX was observed at both hourglass boundaries, and full DRX at mid-stirring zone. The grain boundary mapping showed the formation of low-angle grain boundaries (LAGBs) at regions of high shear as a consequence of thermomechanical nature of the process.
    Matched MeSH terms: Electrons
  12. Targeted Surface Doping with Reversible Local Environment Improves Oxygen Stability at the Electrochemical Interfaces of Nickel-Rich Cathode Materials
    Steiner JD, Cheng H, Walsh J, Zhang Y, Zydlewski B, Mu L, et al.
    ACS Appl Mater Interfaces, 2019 Oct 16;11(41):37885-37891.
    PMID: 31589393 DOI: 10.1021/acsami.9b14729
    Elemental doping represents a prominent strategy to improve interfacial chemistry in battery materials. Manipulating the dopant spatial distribution and understanding the dynamic evolution of the dopants at the atomic scale can inform better design of the doping chemistry for batteries. In this work, we create a targeted hierarchical distribution of Ti4+, a popular doping element for oxide cathode materials, in LiNi0.8Mn0.1Co0.1O2 primary particles. We apply multiscale synchrotron/electron spectroscopy and imaging techniques as well as theoretical calculations to investigate the dynamic evolution of the doping chemical environment. The Ti4+ dopant is fully incorporated into the TMO6 octahedral coordination and is targeted to be enriched at the surface. Ti4+ in the TMO6 octahedral coordination increases the TM-O bond length and reduces the covalency between (Ni, Mn, Co) and O. The excellent reversibility of Ti4+ chemical environment gives rise to superior oxygen reversibility at the cathode-electrolyte interphase and in the bulk particles, leading to improved stability in capacity, energy, and voltage. Our work directly probes the chemical environment of doping elements and helps rationalize the doping strategy for high-voltage layered cathodes.
    Matched MeSH terms: Electrons
  13. Electron flow of biological H2 production by sludge under simple thermal treatment: Kinetic study
    Amin MM, Taheri E, Bina B, van Ginkel SW, Ghasemian M, Puad NIM, et al.
    J Environ Manage, 2019 Nov 15;250:109461.
    PMID: 31499462 DOI: 10.1016/j.jenvman.2019.109461
    Mixed culture sludge has been widely used as a microbial consortium for biohydrogen production. Simple thermal treatment of sludge is usually required in order to eliminate any H2-consuming bacteria that would reduce H2 production. In this study, thermal treatment of sludge was carried out at various temperatures. Electron flow model was then applied in order to assess community structure in the sludge upon thermal treatment for biohydrogen production. Results show that the dominant electron sink was acetate (150-217 e- meq/mol glucose). The electron equivalent (e- eq) balances were within 0.8-18% for all experiments. Treatment at 100 °C attained the highest H2 yield of 3.44 mol H2/mol glucose from the stoichiometric reaction. As the treatment temperature increased from 80 to 100 °C, the computed acetyl-CoA and reduced form of ferredoxin (Fdred) concentrations increased from 13.01 to 17.34 e- eq (1.63-2.17 mol) and 1.34 to 4.18 e- eq (0.67-2.09 mol), respectively. The NADH2 balance error varied from 3 to 10% and the term e-(Fd↔NADH2) (m) in the NADH2 balance was NADH2 consumption (m = -1). The H2 production was mainly via the Fd:hydrogenase system and this is supported with a good NADH2 balance. Using the modified Gompertz model, the highest maximum H2 production potential was 1194 mL whereas the maximum rate of H2 production was 357 mL/h recorded at 100 °C of treatment.
    Matched MeSH terms: Electrons
  14. Fulltext Two-Dimensional, Hierarchical Ag-Doped TiO2 Nanocatalysts: Effect of the Metal Oxidation State on the Photocatalytic Properties
    Md Saad SK, Ali Umar A, Ali Umar MI, Tomitori M, Abd Rahman MY, Mat Salleh M, et al.
    ACS Omega, 2018 Mar 31;3(3):2579-2587.
    PMID: 31458546 DOI: 10.1021/acsomega.8b00109
    This paper reports the synthesis of two-dimensional, hierarchical, porous, and (001)-faceted metal (Ag, Zn, and Al)-doped TiO2 nanostructures (TNSs) and the study of their photocatalytic activity. Two-dimensional metal-doped TNSs were synthesized using the hydrolysis of ammonium hexafluorotitanate in the presence of hexamethylenetetramine and metal precursors. Typical morphology of metal-doped TNSs is a hierarchical nanosheet that is composed of randomly stacked nanocubes (dimensions of up to 5 μm and 200 nm in edge length and thickness, respectively) and has dominant (001) facets exposed. Raman analysis and X-ray photoelectron spectroscopy results indicated that the Ag doping, compared to Zn and Al, much improves the crystallinity degree and at the same time dramatically lowers the valence state binding energy of the TNS and provides an additional dopant oxidation state into the system for an enhanced electron-transfer process and surface reaction. These are assumed to enhance the photocatalytic of the TNS. In a model of photocatalytic reaction, that is, rhodamine B degradation, the AgTNS demonstrates a high photocatalytic activity by converting approximately 91% of rhodamine B within only 120 min, equivalent to a rate constant of 0.018 m-1 and ToN and ToF of 94 and 1.57 min-1, respectively, or 91.1 mmol mg-1 W-1 degradation when normalized to used light source intensity, which is approximately 2 times higher than the pristine TNS and several order higher when compared to Zn- and Al-doped TNSs. Improvement of the crystallinity degree, decrease in the defect density and the photogenerated electron and hole recombination, and increase of the oxygen vacancy in the AgTNS are found to be the key factors for the enhancement of the photocatalytic properties. This work provides a straightforward strategy for the preparation of high-energy (001) faceted, two-dimensional, hierarchical, and porous Ag-doped TNSs for potential use in photocatalysis and photoelectrochemical application.
    Matched MeSH terms: Electrons
  15. Fulltext Scalable Mesoporous Platinum Diselenide Nanosheet Synthesis in Water
    Ali Umar A, Md Saad SK, Mat Salleh M
    ACS Omega, 2017 Jul 31;2(7):3325-3332.
    PMID: 31457657 DOI: 10.1021/acsomega.7b00580
    Newly discovered two-dimensional (2D) atomic crystals (nanosheet) of platinum diselenide (PtSe2) have progressively attracted attention due to their expected high performance in catalysis, sensing, electronics, and optoelectronics applications. Further extraordinary physicochemical properties are expected if these nanosheets of platinum diselenide can possess mesoporosity as this may enable a high range of molecular adsorption, enhancing their functionalities in catalysis, batteries, supercapacitors, and sensing. Here, we present for the first time a straightforward, aqueous-phase synthetic strategy for the preparation of scalable nanosheets of platinum diselenide with mesoporous structure via a surfactant-templated self-assembly followed by a thermal annealing phase-transformation process. We used hexamethylenetetramine as a hexagonal honeycomb (sp2-sp3 orbital) scaffold for assembling the Pt and Se organic complexes to form the nanosheet structure, which is stable, preserving the 2D structure and mesoporosity during a thermal annealing at 500 °C. Density functional theory analysis then indicated that the mesoporous nanosheets of platinum diselenide exhibit a high free-energy and large density of π electrons crossing the Fermi level, inferring a high-catalytic performance. This effortless strategy is currently being extended to the synthesis of other transition metal dichalcogenides, including the preparation of multi-metal atomic dichalcogenide nanosheets, for a wide variety of scientific and technological applications.
    Matched MeSH terms: Electrons
  16. Enhanced visible-light driven multi-photoredox Cr(VI) and p-cresol by Si and Zr interplay in fibrous silica-zirconia
    Aziz FFA, Jalil AA, Hassan NS, Hitam CNC, Rahman AFA, Fauzi AA
    J Hazard Mater, 2021 Jan 05;401:123277.
    PMID: 33113710 DOI: 10.1016/j.jhazmat.2020.123277
    Multiple contaminants including heavy metals and phenolic compounds are normally co-exist in wastewater, which caused the treatment process is rather complicated. Herein, the synergistic photoredox of Cr(VI) and p-cresol (pC) by innovative fibrous silica zirconia (FSZr) photocatalyst was reported. The high surface area of FSZr comprised of microspheres with a bicontinuous concentric lamella structure morphology consisted of silica, while its core consisted of ZrO2 structure. The rearrangement of FSZr framework increased the crystallinity, formed Si-O-Zr bonds and narrowed the band gap of ZrO2 for enhanced of photoredox of Cr(VI) and pC. Compared to the reaction, the photoredox efficiency of FSZr for removing Cr(VI) and pC in simultaneous system was found to be 96 % and 59 %, respectively which are higher than that in its single system owing to the efficient electron-hole charge separation. Phenolic compound with high degree of electron donating group gave beneficial effect to photoreduction of Cr(VI). Consequently, a proposed mechanism involving multi-photoredox pathway were proposed based on photoredox reaction and scavengers studies. FSZr sustained the simultaneous photoredox activities after five runs demonstrating its possibility to be use in the wastewater treatment of various pollutants.
    Matched MeSH terms: Electrons
  17. Fulltext Synthesis of Porous Proton Ion Conducting Solid Polymer Blend Electrolytes Based on PVA: CS Polymers: Structural, Morphological and Electrochemical Properties
    M Nofal M, Aziz SB, Hadi JM, Abdulwahid RT, Dannoun EMA, Marif AS, et al.
    Materials (Basel), 2020 Oct 30;13(21).
    PMID: 33143345 DOI: 10.3390/ma13214890
    In this study, porous cationic hydrogen (H+) conducting polymer blend electrolytes with an amorphous structure were prepared using a casting technique. Poly(vinyl alcohol) (PVA), chitosan (CS), and NH4SCN were used as raw materials. The peak broadening and drop in intensity of the X-ray diffraction (XRD) pattern of the electrolyte systems established the growth of the amorphous phase. The porous structure is associated with the amorphous nature, which was visualized through the field-emission scanning electron microscope (FESEM) images. The enhancement of DC ionic conductivity with increasing salt content was observed up to 40 wt.% of the added salt. The dielectric and electric modulus results were helpful in understanding the ionic conductivity behavior. The transfer number measurement (TNM) technique was used to determine the ion (tion) and electron (telec) transference numbers. The high electrochemical stability up to 2.25 V was recorded using the linear sweep voltammetry (LSV) technique.
    Matched MeSH terms: Electrons
  18. Taguchi design-assisted immobilization of Candida rugosa lipase onto a ternary alginate/nanocellulose/montmorillonite composite: Physicochemical characterization, thermal stability and reusability studies
    Mohd Hussin FNN, Attan N, Wahab RA
    Enzyme Microb Technol, 2020 May;136:109506.
    PMID: 32331714 DOI: 10.1016/j.enzmictec.2019.109506
    Biomass from oil palm frond leaves (OPFL) is an excellent reservoir of lignocellulosic material which full potential remains untapped. This study aimed to statistically optimize the covalent immobilization of Candida rugosa lipase (CRL) onto a ternary support comprised of OPFL derived nanocellulose (NC) and montmorillonite (MMT) in alginate (ALG) (CRL-ALG/NC/MMT). The coarser topology and the presence of characteristic spherical globules in the field emission scanning electron micrographs and atomic force micrographs, respectively, supported the existence of CRL on ALG/NC/MMT. In addition, amide peaks at 3478 and 1640 cm-1 in the fourier transform infrared spectra affirmed that CRL was covalently bonded to ALG/NC/MMT. The optimized Taguchi Design-assisted immobilization of CRL onto ALG/NC/MMT (7 h of immobilization, 35℃, pH 5, 7 mg/mL protein loading) gave a production yield of 92.89 % of ethyl levulinate (EL), as proven by gas chromatography-mass spectrometric ([M] +m/z 144, C7H12O3), FTIR and nuclear magnetic resonance (CAS-539-88-8) data. A higher optimal reaction temperature (50℃) and the reusability of CRL-ALG/NC/MMT for up to 9 esterification cycles substantiated the appreciable structural rigidification of the biocatalyst by ALG/NC/MMT, which improved the catalytic activity and thermal stability of the lipase.
    Matched MeSH terms: Electrons
  19. Electrochemical Long Period Fiber Grating Sensing for Electroactive Species
    Okazaki T, Orii T, Tan SY, Watanabe T, Taguchi A, Rahman FA, et al.
    Anal Chem, 2020 07 21;92(14):9714-9721.
    PMID: 32551577 DOI: 10.1021/acs.analchem.0c01062
    We present an electrochemical long period fiber grating (LPFG) sensor for electroactive species with an optically transparent electrode. The sensor was fabricated by coating indium tin oxide onto the surface of LPFG using a polygonal barrel-sputtering method. LPFG was produced by an electric arc-induced technique. The sensing is based on change in the detection of electron density on the electrode surface during potential application and its reduction by electrochemical redox of analytes. Four typical electroactive species of methylene blue, hexaammineruthenium(III), ferrocyanide, and ferrocenedimethanol were used to investigate the sensor performance. The concentrations of analytes were determined by the modulation of the potential as the change in transmittance around the resonance band of LPFG. The sensitivity of the sensor, particularly to methylene blue, was high, and the sensor responded to a wide concentration range of 0.001 mM to 1 mM.
    Matched MeSH terms: Electrons
  20. Coordination polymer-derived cobalt-embedded and N/S-doped carbon nanosheet with a hexagonal core-shell nanostructure as an efficient catalyst for activation of oxone in water
    Tuan DD, Oh WD, Ghanbari F, Lisak G, Tong S, Andrew Lin KY
    J Colloid Interface Sci, 2020 Nov 01;579:109-118.
    PMID: 32574728 DOI: 10.1016/j.jcis.2020.05.033
    As sulfate-radical (SR)-based advanced oxidation processes are increasingly implemented, Oxone has been frequently-used for generation of SR. While Co3O4 nanoparticle (NP) has been widely-accepted as a promising catalyst for activating Oxone, Co3O4 NPs tend to aggregate in water, losing their reactivity. Thus, many attempts have immobilized Co3O4 NPs on supports, especially carbonaceous substrates, because combination of Co NPs with carbon substrates offers synergistic effects for boosting catalytic activities. Moreover, carbon substrates doped with hetero-atoms (N and S) further increase electron transfer and reactivity. Therefore, it is even promising to immobilize Co NPs onto N/S-doped carbon (NSC) to form Co-embedded NSC (denoted as CoNSC) for enhancing Oxone activation. In this study, a convenient and facile technique is proposed to prepare such a CoNSC via a simple carbonization treatment of a coordination polymer of Co and trithiocyanuric acid (TTCA). The resulting CoNSC exhibits the sheet-like hexagonal morphology with the core-shell configuration, and Co NPs are well-embedded into the N/S-doped carbonaceous matrix, making it an advantageous heterogeneous catalyst for Oxone activation. As Azorubine S (ARS) decolorization is employed as a model reaction of Oxone activation, CoNSC exhibits a higher catalytic activity than pristine Co3O4 and NSC for Oxone activation to decolorize ARS. In comparison to the other reported catalysts, CoNSC also possesses a much lower Ea for ARS decolorization. CoNSC can be also reusable and stable for Oxone activation over multiple cycles without loss of catalytic activity. These features validate that CoNSC is a promising and useful Co-based catalyst for Oxone activation.
    Matched MeSH terms: Electrons
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