Now showing 1 - 3 of 3
  • Publication
    A Novel Tri-Functionality pH-Magnetic-Photocatalytic Hybrid Organic-Inorganic Polyoxometalates Augmented Microspheres for Polluted Water Treatment
    ( 2023-02-01)
    Yee L.Y.
    ;
    ; ; ;
    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.
    ;
    ; ;
    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
    Application of the novel pH-catalytic-magnetic tri-functionalities augmented bead for removal of organic dye pollutants
    ( 2021-11-01)
    Yee L.Y.
    ;
    Ng Q.H.
    ;
    Shuit S.H.
    ;
    ;
    Mohammad Nawi D.
    ;
    Low S.C.
    A tri-functionality magnetic nanoparticles (MNPs) are crucial for environmental remediation. This research focused on the synthesis of pH-catalytic-magnetic polymer beads for dye removal by using phase inversion technique. In 15 wt% of polyethersulfone (PES) polymer possessed the highest porosity (80%) was used in the synthesis of MNPs-PES beads. The methylene blue (MB) removal efficiency of MNPs-PES beads and PES beads was 72.94% and 62.67%, respectively. Similarly, the removal efficiency of methyl orange (MO) dye is higher for MNPs-PES beads (38.56%) compared to PES beads (34.16%). Besides, the removal efficiency for MB dye by MNPs-PES beads increased from 77.59% to 96.90% when solution pH increased from 3 to 9 while removal of MO dye increased from 61.14% to 74.35% when solution pH decreased from 9 to 3. Moreover, the removal efficiency for MB dye increased from 72.94% to 93.43% when H2O2 is added. Additionally, MNPs-PES beads were recollected successfully using external magnet. These indirectly proved that the MNPs-PES beads were responsive towards the tri-functionalities of pH-catalytic-magnetic. Lastly, the adsorption of MB dye onto MNPs-PES beads were fitted well to Langmuir isotherm model and pseudo-second-order model with both correlations R2 of more than 0.98.