Now showing 1 - 10 of 44
  • Publication
    Mesoporous Structure of Doped and Undoped PEG on Ag/TiO2 Thin Film
    In this reaserch, photocatalyst silver titanium dioxide was doped and modified by Polyethylene Glycol (PEG). The purpose of the present study was to analyse the synthesized Ag/TiO2 thin film doped and undoped PEG. Ag/TiO2 thin films on silicon wafer have been prepared by sol-gel spin coating. The samples were characterized by Grazing Incidence X-ray diffraction (GIXRD), Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscope (AFM). The doped and undoped PEG Ag/TiO2 thin films showed a mesoporous TiO2 matrix which includes TiO2 crystallites of 10-20 nm in size and small Ag nanoparticles (white spots) with various sizes ranging from 10 to 30 nm. However, doped PEG Ag/TiO2 thin film showed the Ag nanoparticles became agglomerates but still remained roughly uniform on the surface.
  • Publication
    The production of Malaysia bamboo charcoal (Gigantochloa albociliata) as the potential absorbent
    Bamboo charcoal was successfully carbonized at 500 °C and 800 °C using Malaysia buluh madu (Gigantochloa albociliata). Structural analysis was done using Atomic Force Microscopy (AFM) in two different solvents; ethanol and DI water. The functional groups of bamboo charcoal were confirmed using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption property of bamboo charcoal solution was investigated at different concentrations of 0.2, 0.4 and 0.7 mg/mL, using methylene blue test and characterized using UV-Vis Spectroscopy. Based on the adsorption investigation, it shows that the adsorption was increased as the concentration increased. It was also shown that at higher temperature and longer duration time, the adsorption process is improved.
  • Publication
    Microstructural Analysis of Fly Ash-based Geopolymers with various Alkali Concentration
    ( 2019-08-14)
    Hui-Teng N.
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    Yun-Ming L.
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    Yong-Sing N.
    In the present work, a comparative study on the effect of different concentration of sodium hydroxide (NaOH) on fly ash-based geopolymer was investigated. The geopolymer synthesis by mixing fly ash with alkali activator (a mixture of NaOH and sodium silicate) at solid/liquid ratio of 2.5. The NaOH were used 6M, 8M, 10M, 12M and 14M with constant sodium silicate/NaOH ratio of 2.5. The geopolymers were cured at room temperature (29°C) for 24 hours and 60°C in oven for another 24 hours. The testing and analysis of the fly ash-based geopolymers were performed after 28 days. The adequate Na+ ions and densified microstructure were observed at optimum 8M-NaOH-activated fly ash-based geopolymers.
  • Publication
    Effect of Solid-To-Liquids and Na2SiO3-To-NaOH Ratio on Metakaolin Membrane Geopolymers
    ( 2022-01-01)
    Masdiyana Ibrahim
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    Sauffi A.S.
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    Vizureanu P.
    Geopolymer is synthesized by polycondensation of SiO4 and AlO4 aluminosilicate complexes, tetrahedral frames linked with shared sialate oxygen. This paper studies the effect of the solids-to-fluids (S/L) and Na2SiO3/NaOH proportions on the preparing of metakaolin inorganic membrane geopolymer. By consolidating a mixture of metakaolin with sodium hydroxide, sodium silicate and foaming agent, the geopolymer membrane was made in required shape about 1 cm and cured at 80°C for 24 hours. After the curing process, the properties of the samples were tested on days 7. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solution were utilized as an alkaline activator with a NaOH fixation fixed at 10 M. The geopolymer inorganic membrane tests were set up with various S/L proportions (0.8, 1.0, 1.2 and 1.4) and Na2SiO3/NaOH proportions (0.5, 1.0, 1.5, 2.0 and 2.5). Aluminium (Al) powder as a foaming agent was used to create bubbles in porous structure and provide details on the development of membrane geopolymers. This metakaolin membrane, based on the geopolymer, was synthesized by a suspension that depends on the fast cementing mechanism of high-temperature slurries. Porous geopolymeric circles provided a homogeneous composition and quantitative distribution of pores. The water absorption, density, impact toughness testing and microstructure analyses were studied. However, considering the promising results, an adjustment in the mix design of the metakaolin inorganic membrane geopolymer mixtures could increase their mechanical properties without negatively affecting the mechanical properties and porosity, making these sustainable materials a suitable alternative to traditional porous cement concrete.
  • Publication
    A Review of Geopolymer Based Metakaolin Membrane as an Effective Adsorbent for Waste Water Treatment.
    ( 2020-07-09)
    Ibrahim M.
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    Syauqi Sauffi A.
    Geopolymer-based products help eco-accommodating sources of materials such as metakaolin, slag or fly ash. This review explores the blend configuration to generate geopolymer-based metakaolin membrane metakaolin and to evaluate the impact of a range of geopolymer-based metakaolin sintering temperatures at a temperature of 50 °C, 60 °C, 70 °C and 80 °C. As the quick development of a modern culture contributes to a large increase in interest in water, adsorption is taken closer to examined waste water extraction of the adsorption and repulsion of a metakaolin membrane geopolymer. Membrane waste water treatment is chosen to explore simple and inorganic membrane preparation techniques that have long help lives and low production costs. Reviews for geopolymer-based metakaolin membrane were therefore synthesized via a suspension that depends on the quick solidification method of high temperature suspension geopolymer slurries that were used as an adsorbent for treating waste water. Porous geopolymeric spheres have developed a homogenous structure with the aid of electron microscopy and Brunauer Emmett Teller (BET) investigations.Since permeable materials are regularly adsorbents, this examination has analyzed the adsorption by membrane geopolymers of heavy metals. This finding will advance the formation of improved wastewater treatment systems and along these lines give an elective answer for ecological harm brought about by substantial metal contaminations. Along these lines, molar (SiO2/Na2O) ratio of metakaolin and sodium silicate are fundamental in assembling a sort of geopolymer-based inorganic membrane which does not require a high temperature sintering process. Adsorption and dismissal consolidated can be utilized for wastewater auxiliary electrical plating forms not exclusively to proficiently wipe out center and low groupings of overwhelming metals in wastewater yet in addition to wipe out little sub-atomic contaminants in wastewater.
  • Publication
    Interdigitated electrodes as impedance and capacitance biosensors: A review
    Interdigitated electrodes (IDEs) are made of two individually addressable interdigitated comb-like electrode structures. IDEs are one of the most favored transducers, widely utilized in technological applications especially in the field of biological and chemical sensors due to their inexpensive, ease of fabrication process and high sensitivity. In order to detect and analyze a biochemical molecule or analyte, the impedance and capacitance signal need to be obtained. This paper investigates the working principle and influencer of the impedance and capacitance biosensors. The impedance biosensor depends on the resistance and capacitance while the capacitance biosensor influenced by the dielectric permittivity. However, the geometry and structures of the interdigitated electrodes affect both impedance and capacitance biosensor. The details have been discussed in this paper.
  • Publication
    Effect of graphene oxide on microstructure and optical properties of TiO2 thin film
    ( 2019-01-01)
    Azani A.
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    Razak K.A.
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    Mohd Salleh M.A.A.
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    Abdul Razak M.F.S.
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    Ramli M.M.
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    Chobpattana V.
    GO/TiO2 thin films have been synthesized from titanium (IV) isopropoxide (TTIP) by a sol-gel method. The films were deposited onto a glass substrate using spin coating deposition technique then were subjected to annealed process at 350 °C. The different amount of graphene oxide (GO) was added into the parent solution of sol in order to investigate the microstructure, topography, optical band gap and photocatalytic activity of the thin films. The prepared thin films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), UV-VIS spectrophotometry and degradation of methylene blue (MB). AFM images reveal a rougher surface of GO/TiO2 thin film than bare TiO2 thin film due to GO particles. Moreover, the SEM images showed the formation of semispherical microstructure of bare TiO2 changes to some larger combined molecules with GO addition. The UV-Vis spectrophotometer results show that with optical direct energy gap decreases from 3.30 to 3.18 eV after GO addition due to the effect of high surface roughness and bigger grain size. Furthermore, the optical results also indicated that GO improved the optical properties of TiO2 in the visible range region.
  • Publication
    Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer
    ( 2022-01-01)
    Wan-En O.
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    Yun-Ming L.
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    Shee-Ween O.
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    Sandu A.V.
    The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.
  • Publication
    A study of two dimensional metal carbide MXene Ti3C2 synthesis, characterization conductivity and radiation properties
    ( 2019-01-01)
    Rasid Z.A.M.
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    Omar M.F.
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    Saidi S.A.
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    Sandu A.V.
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    Since the discovery of exceptional properties of graphene, a lot of researchers focused on the discovery of another nobel two-dimensional (2D) materials. Recently, an elegant exfoliation approaches was proposed as a method to synthesis a new family of transitional 2D metal carbide or nitrades of MXene from a layered MAX phase. A layered MAX phase of Ti3AlC2 was synthesized through pressureless sintering (PLS) the initial powder of 3TiH2/1.1Al/2C without preliminary dehydrogenation under argon atmosphere at 1350°C. An elegant exfoliation approach was used to eliminates Al from its precursor to form a layered-structure of Ti3C2. In this study, thermal conductivity of MAX phase and MXene were studied using absolute axial heat flow method to measure the abilities sample to conduct heat and the data was collected using Picolog 1216 Data Logger. Electrical conductivity of these two materials was also compared by using two-point probe, due to its simplicity. Radiation properties of 2D MXene Ti3C2 was studied by using an established radon monitor, placed in closed, fabricated container. Morphological and structural properties of this 2D material were also studied using an established FESEM and XRD apparatus. SEM images shows two types of morphology which is a layer of Ti3C2 and the agglomerates Al2O3 with graphite. XRD pattern reveals three phases in this material which is a rhombohedral Al2O3, rhombohedral graphite and rhombohedral Ti3C2 phases, respectively. Thermal and electrical conductivity of MXene were proven higher than MAX phase. Radon concentration for this material for five consecutive days explains the radiation level of this material which is under the suggestion value from US Environmental Protection Agency (EPA). From this finding, it is can conveniently say that the MXene material can be promising material for electronic application.
  • Publication
    Surface Modification of GO/TiO2 Thin Film by Sodium Dodecyl Sulphate for Photocatalytic Applications
    Photocatalyst material titanium dioxide (TiO2) and graphene oxide (GO) were used to improve the self-cleaning properties of thin films. The sol–gel spin-coating method was successfully used to synthesize GO/TiO2 thin films. Surface modification was applied to optimize the self-cleaning capabilities by adding several concentrations of sodium dodecyl sulfate (SDS) (0.1 w/v%, 0.2 w/v%, 0.3 w/v%, 0.4 w/v%, and 0.5 w/v%) to the parent solution. The synthesized thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, UV-visible spectroscopy, water contact angle analysis, and photocatalytic analysis. The AFM and SEM images revealed that as the SDS amount increased, the particles became less agglomerated, and the roughness of the surface reduced from 2.54 × 102 nm to 0.83 × 102 nm. The wettability analysis showed that when SDS increased to 0.4 w/v%, the water contact angle dropped to 15.30°, implying that the thin film exhibits hydrophilic qualities. A decrease in the GO/TiO2 band gap was obtained linearly with the increase in SDS addition from 3.17 eV to 2.75 eV. Finally, the improvement of the surface coating and reduction of the band gap enhanced the photocatalytic activity, which degraded 78.97% of methylene blue, which was obtained by 0.4SDS.
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