Wan Khairunnisa Wan Ramli
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Preferred name
Wan Khairunnisa Wan Ramli
Official Name
Wan Khairunnisa, Wan Ramli
Alternative Name
Ramli, W. K. W.
Ramli, Wan K. W.
Ramli, Wan Khairuzzaman Wan
Ramli, W. K. Wan
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Scopus Author ID
18435070700
Researcher ID
DNN-0208-2022

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  • Publication
    Enhancing carbon monoxide oxidation of Cobalt-Nickel containing a-deficient Perovskites through exsolution agents and reduction-oxidation pretreatment
    (Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS), 2025-04)
    Lew Guo Liang
    ;
    Wan Khairunnisa Wan Ramli
    ;
    Naimah Ibrahim
    ;
    Sureena Abdullah
    In this work, different types of exsolution agents and pretreatment processes, comprising reduction-oxidation (RO) components, were introduced to modulate the exsolution process of A-deficient perovskites, La₀.7Ce₀.₁Co₀.₃Ni₀.₁Ti₀.6O₃. The catalysts were assessed using field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM/EDS), X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Their carbon monoxide (CO) oxidation activity was also compared. The results showed that the catalytic activity degraded at 520°C when hydrogen (E-H) was used as the exsolution agent. When RO components were introduced as exsolution agents (E-CO/O₂) or in the pretreatment (RO2% and RO18%), the deactivation at high temperatures was mitigated. The results of this study showed that RO18% was favourably pretreated with RO components, recording the highest CO conversion of 60.57% at 520°C and across all temperatures with no degradation at high temperature. It also recorded the lowest activation energy of 14.449 kJ/mol. The EDS, XRD, and XPS analyses of the catalyst demonstrated that the active sites for this reaction are primarily Co₂+ with Ni serving as the anchor between the metals and perovskites support. A high amount of lattice oxygen (O₂) with higher binding energy and chemisorbed O2 species also influenced the improved catalytic activity, attracting CO for reaction, reacting with the available surface O₂ and the faster replenishment of O₂ vacancies by the absorbed and bulk O2 lattice. These findings highlight the prospects of CO and O₂ inclusion in pretreatment for perovskite catalyst as options to reduce metal agglomeration and further improve CO oxidation activity.
  • Publication
    Fe₃O₄-Doped polysulfane membrane for enhanced adsorption of copper from aqueos solution
    ( 2024-01-01)
    Wan Khairunnisa Wan Ramli
    ;
    Nur Maisyatul Syalina Abdul Wahab
    ;
    Siti Khalijah Mahmad Rozi
    ;
    Syumayyah Rasis
    ;
    Gavin Chew Tiong Chuen
    ;
    Lew Guo Liang
    Water pollution, especially from industrial wastewater has become one of the major global environmental problems. As the result of rapid industrialization, the expansion of industries such as the electroplating industry has resulted in an increase in heavy metals effluent, especially copper, in the wastewater, and this poses detrimental effects on the biodiversity and environment. The abatement of copper pollution has received widespread attention, and continuous research advancement has been observed in adsorption and membrane technology. Nanofiltration membranes with nanopores recorded higher suitability to remove ions but at the expense of membrane fouling as a result of the formation of contaminants on the surface layer that blocks the diffusion of contaminants into the membrane substructure. This research highlights the incorporation of Fe3O4 nanoparticles into the polysulfone (PSf) membrane matrix as an adsorptive membrane and their possible adsorption mechanism towards Cu, which can manifest the combined characteristics of both removal techniques. Fe3O4 nanoparticles were synthesized using the co-precipitation method. Fe3O4-doped PSf membranes were then synthesized with various concentrations of Fe via the Non-solvent Induced Phase Separation (NIPS) technique. The physicochemical properties of the Fe nanoparticles and the membranes were evaluated using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), water contact angle and porosity testing. Crystal phase analysis confirmed the formation of magnetite Fe3O4 in a cubic structure. Agglomerations of Fe NPs on the membrane surface were observed for membranes with lower Fe concentrations, suggesting the possibility of poor blending and this contributed to the lower adsorption capability of these membranes. Membranes with 2 wt.% Fe concentration (Fe-2.0) exhibited the highest Cu(II) ions adsorption capacity of 637 mg/g, which is trifold of those recorded for pristine PSF membrane (Fe-0.0). The adsorption data of Cu adsorption were best fitted into the Temkin isotherm and pseudo-second-order models, suggesting an adsorption mechanism involving an exothermic chemical interaction between Cu ions and the Fe3O4 NPs within the membrane. This research confirms the potential of incorporating Fe3O4 in the PSf membrane backbone to enhance Cu removal as an adsorptive membrane, even at lower NP concentrations.
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