Siti Kartini Enche Ab Rahim
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Siti Kartini Enche Ab Rahim
Official Name
Siti Kartini, Enche Ab Rahim
Alternative Name
Rahim, S. K.Enche Ab
Enche Ab Rahim, S. K.
Rahim, Siti Kartini Enche Ab
Main Affiliation
Scopus Author ID
57115278300
Researcher ID
EJE-7983-2022

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  • Publication
    Facile synthesis of magnetophoretic augmented adsorbent for water remediation
    ( 2024-03)
    Chuan Chuan Lim
    ;
    Ng Qi Hwa
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Hoo Peng Yong
    ;
    Siew Hoong Shuit
    ;
    Sigit Tri Wicaksono
    In this new era of globalization, magnetic adsorbents have gained vast attention from researchers in wastewater treatment applications. In this study, sulphonated magnetic multi-walled carbon nanotubes (S-MMWCNTs) were used to remove methylene blue (MB) from an aqueous solution. The S-MMWCNTs are characterized by various analytical methods to investigate their adsorbent features. Adsorption behaviours of the as-prepared composites affected by solution pH and contact time were systematically studied and discussed. The adsorption kinetic data fit the pseudo-second-order kinetic model well. Moreover, the MB removal efficiency of S-MMWCNTs only drops slightly (~6.5%) after five consecutive adsorption cycles, showing their good stability and recyclability.
  • Publication
    The Effect of Infrared Drying on Orthosiphon Stamineus Leaves Quality
    ( 2021-01-01)
    Palanisamy V.V.
    ;
    Mohd Saifizi Saidon
    ;
    Norawanis Abdul Razak
    ;
    Ismail K.A.
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Sulong M.M.S.
    ;
    Alkhayyat A.
    ;
    Wan Azani Wan Mustafa
    ;
    Salah O.R.
    The dryer system is an important part of the drying of food and herbs, among other things. As a result, a special dryer is needed to keep the food or herbs fresh for as long as possible without killing the good nutrients. In this project, Orthosiphon stamineus herb will be used to dry using an Infrared dryer. Infrared drying involves transferring heat by radiation from a hot source to a lower-temperature substance that has to be heated or dried. The temperature of the heated element determines the peak wavelength of the radiation. The purpose of this project is to design an infrared dryer system and analyze the quality of the dried herb. The Orthosiphon Stamineus have been dried using a 200W Infrared dryer system at 60°C for 2hours. Total phenolic compounds and antioxidant capacity were determined using the Folin-Ciocalteu method and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay and evaluated using a UV/VIS Spectrophotometer, respectively. A moisture analyzer was used to look at the changes in moisture content, and a colorimeter was used to look at the colour changes. The result showed that drying O.stamineus under 60°C has significantly affected the herbal leaves quality in terms of moisture content, colour properties, Antioxidant capacity, and Total phenolic content.
  • Publication
    Plant-based calcium silicate from rice husk ash: A green adsorbent for free fatty acid recovery from waste frying oil
    ( 2024-02-29)
    Zainor Syahira Zainal
    ;
    Pengyong Hoo
    ;
    Abdul Latif Ahmad
    ;
    Ahmad Zuhairi Abdullah
    ;
    Qihwa Ng
    ;
    Siewhoong Shuit
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Andas J.
    Driven by the urgent need for a solution to tackle the surge of rice husk (RH) and waste frying oil (WFO) waste accumulation at a global scale, this report highlights the use of calcium silicates (CS) extracted from acid-pre-treated rice husk ash (RHA) for free fatty acid (FFA) removal from WFO as conventional RHA shows limited FFA adsorption performance. A novel alkaline earth silicate extraction method from acid-pre-treated RHA was outlined. The structural and behavioural attributes of the synthesised CS were identified through BET, SEM-EDS, and XRD analyses and compared to those of RHA. Notable morphology and structural modification were determined, including reducing specific surface areas, mitigating from amorphous to crystalline structure with regular geometric forms, and detecting Si–O–Ca functional groups exclusive to CS adsorbents. A comparison study showed superior lauric acid (LA) adsorption performance by CS absorbents over acid-pre-treated RHA, with a significant increase from 0.0831 ± 0.0004 mmol LA/g to 2.5808 ± 0.0011 mmol LA/g after 60 min. Recognised as the best-performing CS adsorbent, CS-1.0 was used for further investigations on the effect of dosage, LA concentration, and temperature for efficient LA adsorption, with up to 100% LA removal and 5.6712 ± 0.0016 mmol LA/g adsorption capacity. The adsorption isotherm and kinetic studies showed LA adsorption onto CS-1.0 followed Freundlich isotherm with KF = 0.0598 mmol(1-1/n) L(1/n) g−1 & Qe,cal = 3.1696 mmol g−1 and intraparticle diffusion model with kid = 0.1250 mmol g−1 min0.5 & Ci = 0.9625 mmol g−1, indicating rapid initial adsorption and involvement of carboxylate end of LA and the calcium ions on the CS-1.0 in the rate-limiting step. The high equilibrium adsorption capacity and LA adsorption rate indicated that the proposed CS-1.0 adsorbent has excellent potential to recover FFA from WFO effectively.
  • Publication
    Studies on Antifouling Characteristic of the Magnetic Field Induced-PES-Fe3O4 Membrane for Water Remediation
    ( 2022-01-01)
    Tan N.N.
    ;
    Ng Qi Hwa
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Heah C.W.
    ;
    Chew T.L.
    ;
    Hoo Peng Yong
    ;
    Sigit T.W.
    In this study Fe3 O4-polyethersulfone (PES) membranes were prepared in the present of a magnetic field or without a magnetic field by using the phase inversion process. A comparison of membrane properties was investigated. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) were used to determine the morphology and chemical composition of the prepared membranes. Furthermore, the fouling analysis of the non-magnetized and magnetized Fe3 O4-PES membranes were also conducted through the filtration study. The pure water flux of membranes increased from 158.49±11.96 L/m2·hr (neat PES) to 187.06±6.54 L/m2·hr (magnetized Fe3 O4-PES). These results showed that the magnetized Fe3 O4-PES membrane not only had the high pure water flux but also had a high HA rejection and good antifouling ability. As such, magnetized Fe3 O4-PES membrane had excellent comprehensive properties which could use for water remediation.
  • Publication
    Characterization and Kinetic Studies on Photocatalytic Degradation of Phenol in Aqueous Solution
    ( 2020-12-18)
    Azaliah Azhari E.N.
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Duke A.
    ;
    Hoo Peng Yong
    Recently, many researchers tend to study the performance of hybrid polyoxometalates (HPOM) as photocatalyst due to its greater performance in photocatalytic degradation. The process that based on the light enhanced generation of reactive OH radical that plays an important role in order to convert organic compound completely into water, CO2 and inorganic compounds. In this research, the photocatalytic degradation of phenol was studied using HPOM as photocatalyst. The HPOM was synthesized and used to study its effect on photocatalytic degradation of phenol. The synthesized HPOM were characterized using SEM and FTIR. It was found that the surface morphology of the synthesized HPOM le displayed an irregular spherical-like shape, granular structure with different size and least distribution of non-agglomerated rod-like nanoparticles. The present of WO6 octahedral and PO4 octahedral indicated that Keggin type structure of synthesized hybrid polyoxometalates. The kinetics of photocatalytic degradation of phenol via hybrid polyoxometalates follows pseudo first order kinetic reaction.
  • Publication
    Removal of methylene blue using magnetic multi-walled carbon nanotubes: process optimization study
    ( 2020-12-18)
    Lim C.C.
    ;
    Shuit S.H.
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Hoo Peng Yong
    ;
    Ng Qi Hwa
    Adsorption is the most common methods used in industry for the removal of dye. In this study, magnetic multi-walled carbon nanotubes (MMWCNTs) was served as adsorbent for the removal of methylene blue (MB). Statistical optimization of the MB removal efficiency via response surface methodology coupled with central composite design was performed and reported. It was observed that all three experimental parameters: adsorption temperature (25-50 C), MB concentration (10-50 ppm) and MMWCNTs dosage (0.01-0.05 g/20mL) were significant in the removal of MB. The optimized conditions of 99.21 % MB removal efficiency can be achieved at adsorption temperature of 38 C, MB concentration of 23 ppm and MMWCNTs dosage of 0.033 g/20mL. The verification of the prediction was performed with 3 repeated experiments and the results were found to be in good agreement with the experimental data with only 0.21 % error.
  • Publication
    Synthesis and Characterisation of Self-Cleaning TiO2/PES Mixed Matrix Membranes in the Removal of Humic Acid
    ( 2023-04-01)
    Poon Y.K.
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Ng Qi Hwa
    ;
    Hoo Peng Yong
    ;
    Abdullah N.Y.
    ;
    Amira Mohd Nasib
    ;
    Abdullah N.S.
    Membrane application is widespread in water filtration to remove natural organic matter (NOM), especially humic acid. However, there is a significant concern in membrane filtration, which is fouling, which will cause a reduction in the membrane life span, a high energy requirement, and a loss in product quality. Therefore, the effect of a TiO2/PES mixed matrix membrane on different concentrations of TiO2 photocatalyst and different durations of UV irradiation was studied in removing humic acid to determine the anti-fouling and self-cleaning effects. The TiO2 photocatalyst and TiO2/PES mixed matrix membrane synthesised were characterised using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray powder diffraction (XRD), scanning electron microscope (SEM), contact angle, and porosity. The performances of TiO2/PES membranes of 0 wt.%, 1 wt.%, 3 wt.%, and 5 wt.% were evaluated via a cross-flow filtration system regarding anti-fouling and self-cleaning effects. After that, all the membranes were irradiated under UV for either 2, 10, or 20 min. A TiO2/PES mixed matrix membrane of 3 wt.% was proved to have the best anti-fouling and self-cleaning effect with improved hydrophilicity. The optimum duration for UV irradiation of the TiO2/PES mixed matrix membrane was 20 min. Furthermore, the fouling behaviour of mixed matrix membranes was fitted to the intermediate blocking model. Adding TiO2 photocatalyst into the PES membrane enhanced the anti-fouling and self-cleaning properties.
  • Publication
    A Novel Tri-Functionality pH-Magnetic-Photocatalytic Hybrid Organic-Inorganic Polyoxometalates Augmented Microspheres for Polluted Water Treatment
    ( 2023-02-01)
    Yee L.Y.
    ;
    Ng Qi Hwa
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Hoo Peng Yong
    ;
    Chang P.T.
    ;
    Ahmad A.L.
    ;
    Low S.C.
    ;
    Shuit S.H.
    The severe water pollution from effluent dyes threatens human health. This study created pH-magnetic-photocatalytic polymer microspheres to conveniently separate the photocatalyst nanoparticles from the treated water by applying an external magnetic field. While fabricating magnetic nanoparticles’ (MNPs) microspheres, incorporating 0.5 wt.% iron oxide (Fe3O4) showed the best magnetophoretic separation ability, as all the MNPs microspheres were attracted toward the external magnet. Subsequently, hybrid organic–inorganic polyoxometalates (HPOM), a self-synthesized photocatalyst, were linked with the functionalized magnetic nanoparticles (f-MNPs) to prepare augmented magnetic-photocatalytic microspheres. The photodegradation dye removal efficiency of the augmented magnetic-photocatalytic microspheres (f-MNPs-HPOM) was then compared with that of the commercial titanium dioxide (TiO2) photocatalyst (f-MNPs-TiO2). Results showed that f-MNPs-HPOM microspheres with 74 ± 0.7% photocatalytic removal efficiency better degraded methylene orange (MO) than f-MNPs-TiO2 (70 ± 0.8%) at an unadjusted pH under UV-light irradiation for 90 min. The excellent performance was mainly attributed to the lower band-gap energy of HPOM (2.65 eV), which required lower energy to be photoactivated under UV light. The f-MNPs-HPOM microspheres demonstrated excellent reusability and stability in the photo-decolorization of MO, as the microspheres retained nearly the same removal percentage throughout the three continuous cycles. The degradation rate was also found to follow the pseudo-first-order kinetics. Furthermore, f-MNPs-HPOM microspheres were pH-responsive in the photodegradation of MO and methylene blue (MB) at pH 3 (acidic) and pH 9 (alkaline). Overall, it was demonstrated that using HPOM photocatalysts in the preparation of magnetic-photocatalytic microspheres resulted in better dye degradation than TiO2 photocatalysts.
  • Publication
    Integrating advanced Keggin-structure polyoxometalate into polymeric membrane to enhance photocatalytic self-cleaning and antifouling functionalities
    ( 2022-04-01)
    Koo D.C.H.
    ;
    Tan N.N.
    ;
    Ng Qi Hwa
    ;
    Siti Kartini Enche Ab Rahim
    ;
    Low S.C.
    ;
    Yeo R.Y.Z.
    The high photocatalytic activity of environmentally benign Keggin-type polyoxometalate (POM) was introduced into polyethersulfone (PES) membrane to promote membrane anti-fouling and self-cleaning functionality. Neat PES and POM/PES hybrid membranes were synthesized via phase inversion method. X-ray diffraction (XRD) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy proved the success of synthesizing Keggin-type POM. The traits of the membranes were evaluated using scanning electron microscopy (SEM), ATR-FTIR, contact angle measurement, porosity and porometer. The hydrophilicity of all the POM/PES hybrid membranes was enhanced and resulted in the reduction of contact angle of the membrane (52.21±0.1101°, 45.11±0.6657° and 50.30±0.1054°) for 0.025, 0.05 and 0.1 wt% POM/PES hybrid membranes, respectively, compared to that of the neat PES membrane (57.30±0.0817°). Additionally, all the POM/PES hybrid membranes showed excellent anti-fouling and self-cleaning characteristics as compared to that of the neat PES membrane. 0.05 wt% POM/PES hybrid membrane outstood all the other membranes, which marks the HA rejection at 77.12% and was able to achieve flux recovery ratio (FRR) of 111.34% with temporal superhydrophilicity effect in just merely 150 seconds at 254 nm UV irradiation.
  • Publication
    Photocatalytic Degradation of Methylene Blue Using Polyoxometalate as Photocatalyst
    ( 2023-06-09)
    Siti Kartini Enche Ab Rahim
    ;
    Azahri E.N.A.
    ;
    Hoo Peng Yong
    ;
    Ng Qi Hwa
    ;
    Abdullah N.S.
    Polyoxometalates (POM), Na2C6H4NO2. [PW12O40] have been synthesized under hydrothermal conditions and characterized. The SEM result indicates that morphology of photocatalyst was homogeneous. The performance of POM was then tested on photocatalytic degradation of methylene blue at different operating conditions. The degradation of methylene blue was dependent on several parameters, such as its initial concentration, HPOM loading and temperature. Langmuir–Hinshelwood model is usually used to describe the kinetics of this photocatalytic process. It was found that rate constant, kapp decreased with increasing initial concentrations of methylene blue. However, as increases in HPOM loading improved methylene blue degradation. The activation energy obtained was low due to this photocatalytic process being less dependent on temperature.