Ho Li Ngee
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Preferred name
Ho Li Ngee
Official Name
Ho, Li Ngee
Alternative Name
Li Ngee, Ho
Ho, Li Ngee
Ngee, Ho Li
Ho, L. N.
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Scopus Author ID
57219028372
Researcher ID
DDY-6348-2022

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  • Publication
    The reaction of wastewater treatment and power generation of single chamber microbial fuel cell against substrate concentration and anode distributions
    ( 2020-12-01)
    Tan S.M.
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Yee Shian
    ;
    Thung W.E.
    ;
    Teoh T.P.
    This study demonstrated the effectiveness of single chamber up-flow membrane-less microbial fuel cell (UFML-MFC) in wastewater treatment concurrently with bioelectricity generation. The objectives of this study were to examine the effect of influent substrate concentration (0.405 g/L, 0.810 g/L, 1.215 g/L, 1.620 g/L), anode distributions (11 cm, 17 cm, 23 cm) and surface morphologies for biofilm formation on the performance of wastewater treatment and power generation. The optimum performance was obtained with substrate concentration of 0.810 g/L. The COD removal efficiency, output voltage, internal resistance, power density and current density obtained were 84.64%, 610 mV, 200 Î©, 162.59 mW/m2 and 468.74 mA/m2, respectively. The Coulombic Efficiency (CE), Normalized Energy Recovery (NERS and NERv) were 1.03%, 789.38 kWh/kg COD and 22.56 kWh/m3, respectively. The results also indicate that the output voltage and power generation obtained in a continuous up-flow MFC were higher with A3 (23 cm), which is of larger electrodes spacing followed by A2 (17 cm) and A1 (11 cm) caused by the enrichment of anaerobic microbial population at A1.
  • 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
    Enhanced photodegradation of phenol by ZnO nanoparticles synthesized through sol-gel method
    ( 2017-12-01)
    Nik Noor Athirah Nik Yusoff
    ;
    Ho Li Ngee
    ;
    Ong Soon An
    ;
    Wong Yee Shian
    ;
    Wan Fadhilah Khalik
    ;
    Fahmi Ridzwan
    Zinc oxide (ZnO) utilization in advanced oxidation process (AOP) via solar-photocatalytic process was a promising method for alternative treating wastewater containing phenol. The ZnO photocatalyst semiconductor was synthesized by sol-gel method. The morphology of the ZnO nanostructures was observed by using scanning electron microscope (SEM) and the crystallite phase of the ZnO was confirmed by x-ray diffraction (XRD). The objective of this study was to synthesis ZnO nanoparticles through a sol-gel method for application as a photocatalyst in the photodegradation of phenol under solar light irradiation. The photodegradation rate of phenol increased with the increasing of ZnO loading from 0.2 until 1.0 g. Only 2 h were required for synthesized ZnO to fully degrade the phenol. The synthesized ZnO are capable to totally degrade high initial concentration up until 45 mg L-1 within 6 h of reaction time. The photodegradation of phenol by ZnO are most favoured under the acidic condition (pH3) where the 100% removal achieved after 2 h of reaction. The mineralization of phenol was monitored through chemical oxygen demand (COD) reduction and 92.6% or removal was achieved. This study distinctly utilized natural sunlight as the sole sources of irradiation which safe, inexpensive; to initiate the photocatalyst for degradation of phenol.
  • Publication
    Comparison of Different Cathode Materials for Degradation of Reactive Red 120 and Electricity Generation in Photocatalytic Fuel Cell
    ( 2020-10-01)
    Mariaswamy A.J.
    ;
    Ong Soon An
    ;
    Abdul Latif Abdul Rani
    ;
    Ho Li Ngee
    In this study, a photocatalytic fuel cell (PFC) based on immobilized zinc oxide (ZnO) on carbon felt photoanode and activated carbon flakes as cathode was designed for the treatment of azo dye, reactive red 120 (RR120) containing wastewater and simultaneous electricity generation. Under light irradiation, generated electron-hole pairs at the photoanode travel via the external circuit to the cathode, thus generating electricity. This was the first attempt where activated carbon flakes were applied as cathode material in PFC. This study examined the influence of parameters such as light irradiation, cathode material, initial dye concentration, supporting electrolytes, pH and concentration of oxidizing agent and hydrogen peroxide (H2O2) on the efficiency of PFC to degrade azo dye of RR120 while generating electricity. Complete decolourization of up to 50 mg/L of RR120 dye was achieved but increased dye concentration significantly reduced the PFC efficiency. The PFC efficiency improved using an amalgamation of supporting electrolytes, pH and oxidizing agent at optimum levels, achieving total dye removal and producing a maximum power density of 18.58 mW/cm2.
  • Publication
    Integrated photocatalytic and sequencing batch reactor (SBR) treatment system for degradation of phenol
    ( 2017-04-06)
    Nik Noor Athirah Nik Yusoff
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Yee Shian
    ;
    Wan Fadhilah Wan Mohd Khalik
    ;
    Lee Sin Li
    This study will examine the efficiency of the simultaneous photocatalytic and biodegradation process in the same treatment reactor. The sequencing batch reactor or also known as SBR is an effective wastewater treatment method that has been applied widely. SBR system has become an alternative method for industrial wastewater treatment with high concentration of chemical oxygen demand (COD), and phenolic compound. In order for the photocatalytic process to occur, ZnO nanoparticles immobilized onto sponge were introduced to the reactor. It was observed that the COD value were decreased, indicated that the simultaneous biodegradation and photodegradation process in functional. The effect of ZnO nanoparticles on the production and composition of extracellular polymeric substances (EPS) and the physiochemical stability of activated sludge in hybrid growth type SBR were monitored. The percentages of removal are varied with different concentration of ZnO nanoparticles. The highest COD removal recorded is 31.5% with concentration of ZnO 0.6 mg/L. With the present of the ZnO nanoparticles, the degradation of phenol was relatively better than combination of biological of photlysis and biological.
  • Publication
    Biotreatment of sulfonated dyestuffs with energy recovery in microbial fuel cell: Influencing parameters, kinetics, degradation pathways, mechanisms, and phytotoxicity assessment
    ( 2021-08-01)
    Tan S.M.
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Y.S.
    ;
    Che Zulzikrami Azner Abidin
    ;
    Thung W.E.
    ;
    Teoh T.P.
    Removal of recalcitrant sulfonated dyestuff intermediates from wastewater has been an urgent challenge for environmental technologies. In this regard, the biodegradations of monoazo Methyl Orange (MO) and diazo dyes Reactive Black 5 (RB5) towards wastewater treatment and bioelectricity generation in microbial fuel cell were investigated and compared through the studies on azo dye concentration, aeration, sampling points arrays, and electrode spacings. The degradation of diazo RB5 yielded higher chemical oxygen demand removal, decolourization efficiencies, and power generation over monoazo MO. The decolourization efficiency of RB5 (97.62%) increased with an increase of RB5 concentration (50 mg/L), suggesting that the system has the capability of removing higher RB5 concentration. However, contrary results were obtained with MO due to its toxicity. This study also demonstrated that the decolourization rate of diazo RB5 (0.1533 h-1) was ≈ 53% higher than monoazo MO (0.0727 h-1). The findings revealed that the degradation kinetic was remarkably influenced by the chemical structure of dye, where dye with more electron-withdrawing groups at para position are more susceptible to be reduced. Higher output voltage (568.59 mV) and power generation (108.87 mW/m2) were attained with RB5 due to electron donor availability and electron-shuttling characteristics of RB5 decolourized intermediates. Furthermore, detailed degradation pathways of MO and RB5 were presented based on the UV-vis and GC-MS results. The phytotoxicity assessment via Sorghum bicolor seeds had further verified the reduction in toxicity after the treatment of azo dyes.
  • Publication
    Influence of Amaranth dye concentration on the efficiency of hybrid system of photocatalytic fuel cell and Fenton process
    ( 2017-10-01)
    Noradiba Nordin
    ;
    Ho Li Ngee
    ;
    Ong Soon An
    ;
    Abdul Haqi Ibrahim
    ;
    Wong Yee Shian
    ;
    Sin Li Lee
    ;
    Oon Yoong Sin
    ;
    Oon Yoong Ling
    A novel sustainable hybrid system of photocatalytic fuel cell (PFC) and Fenton process is an alternative wastewater treatment technology for energy-saving and efficient treatment of organic pollutants. The electrons generated from PFC photoanode are used to produce H2O2 in the Fenton reactor and react with the in situ generation of Fe2+ from sacrificial iron for hydroxyl radical formation. In this study, the effect of different initial Amaranth dye concentrations on degradation and electricity generation were investigated. ZnO/Zn photoanode was prepared by anodizing method and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results revealed that the maximum power density (9.53 mW/m2) and current density (0.0178 mA/m2) were achieved at 10 mg/L of Amaranth. The correlation between dye degradation, voltage output, and kinetic photocatalytic degradation were also investigated and discussed.
  • Publication
    Decolorization and mineralization of Amaranth dye using multiple zoned aerobic and anaerobic baffled constructed wetland
    ( 2017-08-03)
    Harvinder Kaur Lehl
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Yee Shian
    ;
    Farah Naemah Mohd Saad
    ;
    Oon Yoong Ling
    ;
    Oon Yoong Sin
    ;
    Thung Wei Eng
    ;
    Yong Chin Yii
    The objective of this study is to determine the reduction efficiency of Chemical Oxygen Demand (COD) as well as the removal of color and Amaranth dye metabolites by the Aerobic–anaerobic Baffled Constructed Wetland Reactor (ABCW). The ABCW reactor was planted with common reed (Phragmite australis) where the hydraulic retention time (HRT) was set to 1 day and was fed with synthetic wastewater with the addition of Amaranth dye. Supplementary aeration was supplied in designated compartments of the ABCW reactor to control the aerobic and anaerobic zones. After Amaranth dye addition the COD reduction efficiency dropped from 98 to 91% while the color removal efficiency was 100%. Degradation of azo bond in Amaranth dye is shown by the UV–Vis spectrum analysis which demonstrates partial degradation of Amaranth dye metabolites. The performance of the baffled unit is due to the longer pathway as there is the up-flow and down-flow condition sequentially, thus allowing more contact of the wastewater with the rhizomes and micro-aerobic zones.
  • Publication
    Polypropylene biofilm carrier and fabricated stainless steel mesh supporting activated carbon: Integrated configuration for performances enhancement of microbial fuel cell
    ( 2021-08-01)
    Tan S.M.
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Y.S.
    ;
    Che Zulzikrami Azner Abidin
    ;
    Thung W.E.
    ;
    Teoh T.P.
    The mass transfer resistance at the anode and the reduction of oxygen at the cathode are currently perceived as two major bottlenecks of microbial fuel cells. To overcome these issues, an integrated configuration was developed for performances enhancement on simultaneous bioelectricity generation and wastewater treatment in single chamber up-flow membrane-less microbial fuel cell (UFML-MFC). Polypropylene biofilm carriers were used as anodic packing materials and fabricated stainless steel mesh holder supporting activated carbon flakes (CF/SM) was employed as biocathode configuration in this study. The employments of polypropylene carriers and CF/SM enhanced not only the active surface area and microbial adhesion, but also the mass transfer of MFC system. The maximum output voltage, power and current generation achieved in this system were 615 mV, 162.59 mW/m2 and 468.74 mA/m2, respectively. In terms of wastewater treatment performance, UFML-MFC achieved 85.6% and 95.7% of COD and NH4+ removal, respectively. The COD reduction in closed circuit was 9.87% better than open circuit due to stimulation of electrochemical-active bacteria for electron transfer to the anode, which favoured organic matter degradation. The enrichment of electrogenic bacteria at A3, which was largest electrode spacing (23 cm) in the system resulted a higher voltage and power output compared to A1 (11 cm) and A2 (17 cm). Besides, the energy performances of this MFC system were also evaluated based on NERs (1.074 kWh/kg COD), NERv (22.86 Wh/m3) and CE (10.42%).
  • Publication
    Innovative baffled microbial fuel cells for azo dye degradation: Interactive mechanisms of electron transport and degradation pathway
    ( 2021-05-01)
    Oon Y.S.
    ;
    Ong Soon An
    ;
    Ho Li Ngee
    ;
    Wong Yee Shian
    ;
    Oon Y.L.
    ;
    Lehl H.K.
    ;
    Thung W.E.
    Two membrane-less baffled microbial fuel cells (BMFCs) were developed for non-dye (BMFC1) and dye degradation (BMFC2) investigations along with simultaneous bioelectricity generation. The influence of salinity, organic loading, circuit connection, aeration rate, dye concentration and addition of intermediates on BMFCs performances were evaluated systematically. The increase of salinity by 3-fold (0.39 g/L of NaCl) lowered the internal resistance of BMFC1 system by 38%–620 Ω, and the power density increased 49% to 10.55 ± 0.86 mW/m2. While the further increase of salinity (10-fold) adversely affected BMFC1. The power performance of BMFC1 improved with higher organic loading. Whereas, the increment in organic loading enhanced the decolourisation efficiency but deteriorated the power performance of BMFC2 ascribed to the competition between New Coccine (NC) molecules and anode for electrons. This finding corroborates that NC was a preferable electron acceptor than the anode. The addition of 50 mg/L NC increased the power density by 53% to 12.40 ± 1.60 mW/m2, which revealed that NC decolourised intermediates could act as the electron mediator, hence led to the increase of power performance. The electron-mediating mechanism of NC decolourised intermediate, 1-amino-2-naphthol-6,8-disulfonate as electron shuttle was unveiled. The in-depth understanding of the mechanisms involved in dye degradation in MFCs was presented, where a comprehensive degradation pathway of NC was proposed based on the intermediates identified via UV–Visible spectra, Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) and gas chromatograph-mass spectrometer (GC-MS) analyses.