Banjuraizah Johar
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Preferred name
Banjuraizah Johar
Official Name
Banjuraizah, Johar
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Scopus Author ID
36782257500
Researcher ID
ELA-9787-2022

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  • Publication
    Comparative study of different polyatomic ions of electrolytes on electricity generation and dye decolourization in photocatalytic fuel cell
    ( 2020-10-01)
    Ong Y.P.
    ;
    Ho Li Ngee
    ;
    Ong S.A.
    ;
    Banjuraizah Johar
    ;
    Ibrahim A.H.
    ;
    Lee S.L.
    ;
    Nordin N.
    Developing an effective interface interaction between photoanode and electrolyte is crucial for achieving superior photocatalytic fuel cell (PFC) performance. In this aspect, the contribution of the medium or electrolyte properties in the PFC system such as dye concentration, ionic nature and active radicals play a decisive role. Herein, we constructed a PFC with ZnO loaded nickel foam (ZnO/Ni) photoanode to study the influence of initial dye concentration, pH and supporting electrolytes of different polyatomic anions on the PFC performance. The optimum initial dye concentration and pH for the PFC with reactive red 120 as organic pollutants were found to be 30 mg L−1 and 7.5, respectively. The PFC performance can be synergistically enhanced by the addition of three types of polyatomic anions (Na3PO4, Na2SO4 and NaNO3) as supporting electrolytes. In turn, PO43- had the greatest influence on the reduction of internal resistance (highest short circuit current, Jsc) which corresponded to the conductivity of dye solution. Eventually, the higher charge of polyatomic ions could contribute to higher energy conversion efficiency in PFC. Nonetheless, SO42- anions favoured the cleavage of aromatic compounds by the advantage of recycling between SO42- and SO4[rad]- through hole scavenging activity. Comprehensively, our findings provided new insight into the selection of supporting electrolyte as well as the proposed mechanism of active radicals involved in PFC. Additionally, the ZnO/Ni photoanode demonstrated its excellent recyclability as it retained high PFC performance after five consecutive runs.
  • Publication
    The effect of treated flue gas desulfurization (FGD) sludge addition on the properties of non-stoichiometric cordierite
    ( 2025-01)
    Fatin Fatini Othman
    ;
    Banjuraizah Johar
    ;
    Khor Shing Fhan
    ;
    Suffi Irni Alias
    ;
    Nik Akmar Rejab
    This study examines the incorporation of treated Flue Gas Desulphurization (FGD) by-products from the glass industry in Malaysia into non-stoichiometric cordierite compositions, focusing on its effects on the physical, mechanical, and microstructural properties. New ceramic samples were developed using a blend of kaolin, silica, talc, and treated FGD sludge. The results indicate that increasing the amount of treated FGD sludge leads to desirable properties such as a low thermal coefficient of expansion (2.62 – 3.64 x 10-6/ ℃), reduced density, and decreased average flexural strength (34.43 – 54.69 MPa), along with an increase in average porosity (17.04 - 31.90 %). Notably, ceramics that were treated with 3 wt% FGD sludge crystallized α-cordierite at a lower sintering temperature (1250 ℃), whereas traditional solid-state reaction methods need higher temperatures (>1350 ℃) to make α-cordierite. Overall, replacing feldspar with treated FGD sludge in non-stoichiometric cordierite formulations presents a sustainable strategy for recycling industrial waste and reducing the need for natural resources. The resulting materials exhibit characteristics suitable for lightweight construction applications, such as commercial bricks, due to their light weight, adequate flexural strength, and appropriate porosity.
  • Publication
    Phase Analysis of Bio-Based Derived Tricalcium Disilicate From 2CaO:1SiO2 By X-ray Diffraction
    ( 2021-12-14)
    Siti Nur Hazwani Yunus
    ;
    Fhan K.S.
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Jakfar N.H.
    ;
    Cheng Ee Meng
    In this paper, tricalcium disilicate was formed from dicalcium silicate compound powder, synthesised via a mechanochemical technique using a stoichiometric 2CaO:1SiO2. Compound CaO and SiO2 were derived from the bio-waste of eggshell and rice husk at the calcination temperature of 900oC and 800oC, respectively. The dicalcium disilicate powder was sintered for 2 hours at different temperatures ranging from 1150oC to 1350oC. Using X-ray diffraction with Rietveld analysis, it was found that the amount of tricalcium disilicate with monoclinic (beta) crystal structure increases on sintering temperature at the expense of dicalcium silicate. The complete formation of single-phase tricalcium disilicate began at a sintering temperature of 1300oC. The effect of sintering temperatures on the crystallisation and phase transition of dicalcium silicate is reported. The size of crystallites depends on the sintering temperature. The finding of this study rebound to the benefit of society by reducing the risk-off pollution cause by accessive redundant bio-waste eggshell and rice husk and also reduced the amount of CaO and SiO2 used in the fabrication of Ca3Si2O7
  • Publication
    Impact of secondary phases content on the mechanical properties of cordierite
    ( 2017-01-01)
    Eing Kuan Kok
    ;
    Banjuraizah Johar
    ;
    Ho Li Ngee
    ;
    Zabar Yahidah
    The Cordierite ceramic body had been synthesized through conventional techniques solid state reaction by using non-stoichiometric composition (2.5 MgO. 1.8 Al2O3. 5 SiO2). The sintering temperature study was carried out by heat treated the samples at several degree of sintering temperature (1250 °C, 1275 °C, 1300 °C, 1325 °C, 1350 °C and 1375 °C). The qualitative and quantitative of crystalline phase analysis was accomplished by using X-ray Diffraction (XRD) technique and Rietveld structural refinement. The Scanning electron microscopy (SEM) was employed for morphology analysis. The mechanical properties of samples were determined by Vicker's Hardness test. Rietveld quantitative phase analysis results show that α phase Cordierite constitutes up to 96.4 wt% when the samples was sintered for 2 hours at sintering temperature of 1375 °C and obtained densified and orderly crystal structure arrangement in SEM micrograph except the mechanical strength. The sample obtained the uppermost α phase Cordierite content gained the lowest hardness values (4.0±0.8GPa). Conversely, the sample contains 90 wt% α-cordierite and 1.4 wt% magnesium titatnate achieve highest hardness which is about 4.9±0.79GPa.
  • Publication
    A highly sustainable hydrothermal synthesized MnO2 as cathodic catalyst in solar photocatalytic fuel cell
    ( 2021-01-01)
    Ong Y.P.
    ;
    Ho Li Ngee
    ;
    Ong Soon An
    ;
    Banjuraizah Johar
    ;
    Ibrahim A.H.
    ;
    Thor S.H.
    ;
    Yap K.L.
    A unidirectional flow solar photocatalytic fuel cell (PFC) was successfully developed for the first time to offer alternative for electricity generation and simultaneous wastewater treatment. This study was focused on the synthesis of α-, δ- and β-MnO2 by wet chemical hydrothermal method for application as the cathodic catalyst in PFC. The crystallographic evolution was performed by varying the ratios of KMnO4 to MnSO4. The mechanism of the PFC with the MnO2/C as cathode was also discussed. Results showed that the catalytic activity of MnO2/C cathode was mainly predominated by their crystallographic structures which included Mn–O bond strength and tunnel size, following order of α- > δ- > β-MnO2/C. Interestingly, it was discovered that the specific surface areas (SBET) of different crystal phases did not give an impact on the PFC performance. However, the Pmax could be significantly influenced by the micropore surface area (Smicro) in the comparison among α-MnO2. Furthermore, the morphological transformation carried out by altering the hydrothermal duration demonstrated that the nanowire α-M3(24 h)/C with 1:1 ratio of KMnO4 and MnSO4 yielded excellent PFC performance with a Pmax of 2.8680 μW cm−2 and the lowest Rint of 700 Ω.
  • Publication
    Dielectric properties of Nephelium Lappaceum tropical wood
    ( 2020-03-25)
    Khor Shing Fhan
    ;
    Cheng Ee Meng
    ;
    Banjuraizah Johar
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Zaizul M.A.
    ;
    Wan Azani Wan Mustafa
    ;
    Nik Noriman Zulkepli
    ;
    Dahham O.S.
    Dielectric properties of rambutan wood (Nephelium Lappaceum) were investigated in three anisotropic directions, namely miters-cut, cross-cut, and rib-cut. Dielectric constants and dielectric loss factors were measured at ambient temperatures by using an impedance analyzer. The dielectric constant decreased as frequency increased from 4 to 1 MHz. Among the wood specimens, the rib-cut direction has the lowest dielectric constant, while the cross-cut direction has the highest value. A dielectric dispersion occurred within frequencies 100 Hz to 10 kHz, which corresponding to a relaxation peak as observed on dielectric loss factor spectra. The relaxation peak value of the dielectric loss factors shifted towards higher frequencies in the sequence of rib-cut, miters-cut, and cross-cut specimen. Above 500 Hz, the cross-cut specimen has the highest value conductivity than others. Generally, these variations were subjected to the anatomical structure in the wood, such as parenchyma, ray cell, vessel cell, and fiber cell.
  • Publication
    Effect of alteration ratios of magnesia and alumina in non-stoichiometric cordierite composition formulations (2.(8-n)MgO.1.(5+n)Al2O3.5SiO2) on phase transformation and crystallization
    ( 2017-01-01)
    Eing Kuan Kok
    ;
    Banjuraizah Johar
    ;
    Ho Li Ngee
    ;
    Zabar Yahidah
    This study focus on synthesis of α-phase cordierite using different non-stoichiometric cordierite composition through solid state reaction by adjusting the ratio of magnesia, MgO and alumina, Al2O3 in the cordierite composition formulation respectively. The qualitative and quantitative of phase analysis was carried out by X-ray diffractive (XRD) technique and Rietveld structural refinement method. Differential thermal analysis (DTA) was employed to investigate the crystallization behavior of various cordierite formulations as the function of temperature. The scanning electron microscopy (SEM) was also performed. Cordierite with formulation of 2.5 MgO1.8Al2O3.5SiO2 constitutes up to 96.4 wt% when the samples was sintered for 2 h at the optimal temperature of 1375 °C. The SEM micrograph revealed that the approaching single α-Cordierite sample obtained densified body with well alignment of crystal structure.
  • Publication
    The Microstructural and Bioactivity Behavior of Magnesium Alloy Filled with Bioglass for Biomedical Application
    ( 2022-01-24)
    Nur Maizatul Shima Adzali
    ;
    Dahlan N.F.
    ;
    Banjuraizah Johar
    ;
    Baharom N.A.
    Magnesium alloy have known as degradable implant material due to biodegradable properties. However, by developed Mg alloy matrix composites containing a bioceramic will produced more biodegradable and does not need second surgical to remove the implants in body. Powder metallurgy route was used to fabricate the AZ91/BG composite by mixing, compacting and sintering. Mg alloy (AZ91) was reinforced with 0, 3, 6, and 9 wt% of bioglass (BG) before compact and sintered at 400°C for 2 hours. The Vickers hardness, scanning electron microscope, and x-ray diffraction are used to investigate the effect of BG particles addition on the mechanical properties and microstructure of the composite AZ91/BG. Bioactivity behaviour was studied by immersion test of AZ91/BG composite into phosphate buffered saline (PBS) solution for 72 hours. The results showed that as the addition of BG increases from 3 to 9 wt%, the hardness of AZ91/BG decrease from 43.3HV to 27.9HV. The result also showed the formation of protective layers or apatite layer on the surface of AZ91/BG composite after immersed in PBS solution for 72 hours. Phase analysis by XRD shows the presence of peak Ca10(OH)2(PO4)6 as the BG increased from 3 to 9 wt%. As a conclusion, AZ91/3BG shows the optimum composite for biomedical application based on its properties and bioactivity behaviour.
  • Publication
    Formation of bio-based derived dicalcium silicate ceramics via mechanochemical treatment: physical, XRD, SEM and FTIR analyses
    ( 2023-07)
    Siti Nur Hazwani Yunus
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Nur Hazlinda Jakfar
    ;
    Cheng Ee Meng
    ;
    Emma Ziezie Mohd Tarmizi
    ;
    Zainal Abidin Talib
    Beta-dicalcium silicate plays an important role in modern technology, but its tendency for polymorphic transformation results in the dusting phenomenon, is a major challenge. Therefore, mechanochemical treatment is used to reduce the particle size to retain the stability of the polymorph. In this study, pure dicalcium silicate ceramics of β-monoclinic structure with P 121/c1 space group were synthesized using calcium oxide and silicate powders derived from calcined eggshells and rice husks, respectively. The powders were mixed in a 2:1 molar ratio by mechanochemical treatment and heat-treated in the air at temperatures ranging from 900°C to 1100°C for 2 h. The results reveal that pure betadicalcium silicate formed at 1100°C without adding stabilizers. The properties of the pristine and sintered bodies were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM revealed that the grain and pore sizes increase with rising sintering temperatures. FTIR spectra indicate the existence of Si-O bonds in -4 4 SiO tetrahedrons on all the samples. The sample sintered at 1000°C attains the lowest bulk density (1.2463 g/cm3), whereas the apparent porosity is the highest (62.5%). The reason for this trend is due to the decomposition of carbonate into CO2 gas. The densification onset for the sample sintered at 1100°C as the bulk density rises and grain size achieves 6.06 μm. This study further explains the effect of sintering temperatures on the physical, structural, and morphological properties of Ca2SiO4 which would also be useful for further optimization of its use.
  • Publication
    Effect of sintering temperature on dielectric and electrical properties of bio-waste derived beta-dicalcium silicate
    ( 2023-11-01)
    Mohd Yunus S.N.H.
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Jakfar N.H.
    ;
    Cheng Ee Meng
    ;
    Mohd Tarmizi E.Z.
    ;
    Talib Z.A.
    Beta-dicalcium silicate ceramics were synthesized by mechanochemical-assisted solid-state reaction route using rice husks and chicken eggshells as silica and calcium oxide sources. The ceramics were sintered at 900, 1000, and 1100 °C for 2 h in air. The effect of sintering temperature on these ceramics' morphological, breakdown strength, dielectric, and electrical properties was investigated. It was found that the ceramic sintered at the optimized temperature of 1100 °C formed the pure β-dicalcium silicate (β-Ca2SiO4). Scanning electron micrographs showed that with the increase in sintering temperature, the average grain size and pore size of the sintered ceramics increased while the grain boundary density decreased, which promoted the breakdown path and resulted in a decrease in breakdown strength. The dielectric behavior examined from 25 to 300 °C and in a frequency range of 4–5 MHz found that the dielectric constant and loss tangent decreased with increasing frequency. Nyquist plot of impedance confirmed a non-Debye type relaxation, and grain and grain boundary contributions were revealed from equivalent circuit fitting. Variations of impedance spectroscopy reflect the positive and negative temperature coefficient of resistance behavior for these ceramics. Electric modulus spectra revealed that with the sintering temperature increase, the samples' conductivity activation energies increased from 0.35 to 0.46 eV. All the sintered samples attained low dielectric loss (0.004 < tanδ < 0.1) above 103 Hz, which makes them suitable materials for capacitor application.
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