Heah Cheng Yong
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Preferred name
Heah Cheng Yong
Official Name
Heah, Cheng Yong
Alternative Name
Yong, Heah Cheng
Yong, H. C.
Heah, Cheng Yong
Heah, C. Y.
Cheng-Yong, Heah
Cheng Yong, Heah
Main Affiliation
Scopus Author ID
54402789500
Researcher ID
S-7139-2019

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Microstructural Analysis of Fly Ash-based Geopolymers with various Alkali Concentration

2019-08-14 , Hui-Teng N. , Heah Cheng Yong , Yun-Ming L. , Mohd. Mustafa Al Bakri Abdullah , Yong-Sing N.

In the present work, a comparative study on the effect of different concentration of sodium hydroxide (NaOH) on fly ash-based geopolymer was investigated. The geopolymer synthesis by mixing fly ash with alkali activator (a mixture of NaOH and sodium silicate) at solid/liquid ratio of 2.5. The NaOH were used 6M, 8M, 10M, 12M and 14M with constant sodium silicate/NaOH ratio of 2.5. The geopolymers were cured at room temperature (29°C) for 24 hours and 60°C in oven for another 24 hours. The testing and analysis of the fly ash-based geopolymers were performed after 28 days. The adequate Na+ ions and densified microstructure were observed at optimum 8M-NaOH-activated fly ash-based geopolymers.

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Properties of polyaniline/graphene oxide (PANI/GO) composites: effect of GO loading

2021-09-01 , Mutalib T.N.A.B.T.A. , Tan Soo Jin , Foo Kai Loong , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah

Polyaniline/graphene oxide (PANI/GO) composites at different wt% of GO were prepared via solution method. PANI was mixed with the GO synthesized from the improved Hummer’s method. The formation of GO was confirmed via Raman and C/O ratio. Based on the FT-IR, XRD and SEM results, it confirmed the presence of both PANI and GO characteristics at 10.9°, 25.8° and 27.8° and interactions between PANI and GO particles in PANI/GO composites at different GO loading. SEM micrographs showed a folding and wrinkled surface of GO due to the defect upon oxidation process. This means that the weak π–π interactions or the agglomeration of GO have caused PANI unable to attach on the large conjugated basal planes of GO sheets. The defective domains made GO as an insulator as it contained distortions and oxygen-containing functional groups and their local decoration. Low-conductivity domain had conquered most of the GO region which later reduced the pathway of the current flow; therefore, conductivity is affected. The wrinkled structure also resulted in the low conductivity as it weakens the interfacial interaction between PANI and GO and thus disrupted the electron movement in the composites. Due to this, the electrical conductivity reached up to 1.83 × 10−10 S/cm as the GO loading increased to 50 wt%.

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Discovering the roles of electrode distance and configuration in dye degradation and electricity generation in photocatalytic fuel cell integrated electro-Fenton process

2022-01-01 , Thor S.H. , Ho Li Ngee , Ong Soon An , Che Zulzikrami Azner Abidin , Heah Cheng Yong , Nordin N. , Ong Y.P. , Yap K.L.

Photocatalytic fuel cell (PFC) integrated electro-Fenton (EF) system (PFC-EF system) was considered as an eco-friendly approach for dye degradation and electricity generation simultaneously. The modification on configuration of PFC-EF system was aimed to improve the dye degradation and power output. Effect of electrode distance on the efficiency of PFC-EF system was investigated as it was a crucial factor in the mass transfer of ions in PFC-EF system. Closer electrode distance reduced the resistance flow of ions and enhanced the mass transfer of ions between the electrodes in both PFC and EF, eventually yielded higher concentration of reactive species for removal of dye. Four different electrode configurations by varying the number of cathodes in PFC and EF were investigated to discover the most efficient operating configuration for this PFC-EF system. The dye decolourization rate was evaluated and compared by using pseudo-first order and second order in both PFC and EF system, respectively. Results revealed that single cathode PFC-EF system was the most effective configuration in dye degradation while double cathodes PFC-EF system was the optimal configuration to be used for power output.

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Sintered and unsintered pressed fly ash geopolymer: A comprehensive study on structural transformation in nitric and sulfuric acid

2024-09-15 , Shee-Ween O. , Heah Cheng Yong , Liew Yun Ming , Ho Li Ngee , Wei-Hao L. , Mohd. Mustafa Al Bakri Abdullah , Wei-Ken P. , Yong-Jie H. , Pin-Hsun L.

Acidic attacks contribute to the degradation of cementitious materials, diminishing the structural service life and increasing the requirement for maintenance of the structure. To address the limited understanding of the impact of the sintering process on the acid resistance of pressed geopolymer, an investigation and comparison of the acid resistance of room-cured (RPG) and sintered (SPG) pressed geopolymer was performed. Specimens were immersed in 3 % and 8 % nitric (HNO3) and sulfuric (H2SO4) acids for 7 and 28 days. Despite the higher sorptivity, SPG demonstrated better mechanical strength retention than that of RPG. Specifically, the compressive strength of SPG after 3 % of HNO3 immersion for 28 days increased (+14.2 %), surpassing the control specimen, while RPG experienced a 14.5 % strength drop. The strength increment in SPG was due to the further geopolymerization during acid immersion. In RPG, a new crystalline phase of NaNO3 was observed after immersion in 8 % HNO3 for 28 days. In contrast, SPG showed no evidence of NaNO3 formation, indicating lower reactivity with HNO3 compared to RPG. Additionally, both RPG and SPG exhibited gypsum formation after immersion in H2SO4. The presence of gypsum induced crack formation in RPG, whereas SPG, with its intensive cross-linked structure, effectively compensated for gypsum expansion, preventing crack formation. This finding is crucial for practical applications where exposure to aggressive acids is a concern, as it provides a method to enhance the acid resistance of geopolymer structures.

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Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer

2022-01-01 , Wan-En O. , Yun-Ming L. , Heah Cheng Yong , Ho Li Ngee , Mohd. Mustafa Al Bakri Abdullah , Shee-Ween O. , Sandu A.V.

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.

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A sustainable photocatalytic fuel cell integrated photo-electro-Fenton hybrid system using KOH activated carbon felt cathodes for enhanced Amaranth degradation and electricity generation

2022-07-01 , Thor S.H. , Ho Li Ngee , Ong Soon An , Che Zulzikrami Azner Abidin , Heah Cheng Yong , Ong Y.P. , Yap K.L.

Photo-electro-Fenton (PEF) process was integrated with photocatalytic fuel cell (PFC) through the connection of electrodes and the cathodes were responsible for the acceptance of electrons. In this study, potassium hydroxide (KOH) was used to activate the carbon felt (CF) to improve the oxygen reduction reaction reactivity on cathodes for effective PFC integrated PEF hybrid system (PFC-PEF system) in Amaranth removal and electricity generation simultaneously. The results revealed that KOH activated CF cathodes had improved the electro-generation of hydrogen peroxide in both PFC and PEF and contributed to decolourisation efficiencies of 99.25% (PFC) and 96.10% (PEF). The maximum power density (4.218 μW cm−2) achieved by KOH activated CF cathode was 22% higher than that of pristine CF. The results revealed that air flow rate of 1000 mL min−1 favoured the generation of more reactive species for effective Amaranth degradation under the dissolved oxygen enrichment condition. The highest decolourisation rates were respectively achieved in PFC (0.5965 h−1) and PEF (0.2919 L mg−1 h−1) at air flow rate of 1000 mL min−1.

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Titanium Dioxide Loaded Reduced Graphene Oxide Nanocomposite Film as Counter Electrodes for Dye-Sensitized Solar Cells

2021-12-21 , Low F.W. , Heah Cheng Yong , Liew Yun Ming , Md. Aminul Islam

The demands on conventional fossil fuels are increasing especially developing countries. The growth of population among countries also put a lot of pressure on coil consumption and resulted effect of greenhouse. These phenomena will dramatically increase the global warming and pollutes the nature of earth. For the worse, it would forming some erratic patterns like flood, draughts, wildfire, and so on. Therefore, renewable solar energy is the key target to reduce the fossil fuel consumption, minimize global warming issues, and involuntary minimizes the erratic weather patterns. Dye-sensitized solar cell (DSSCs) is one of the promising prospects for efficient renewable resources. Most of the researchers were tried to use platinum as counter electrode to perform the photovoltaic studies. However, the platinum material will made higher for the entire fabrication cost. Recently, we demonstrated a counter electrode in DSSCs system using the low-cost titanium dioxide (TiO2) decorated reduced graphene oxide (rGO) nanocomposite film. The TiO2-rGO nanocomposite (TiO2-rGO NC) as counter electrode is addressed to minimize electron losses and hence rapid the rate of dye regeneration at ground state. Practically, TiO2-rGO NC synthesized via one-step hydrothermal method. The crystallinity, functional groups, element composition, and morphology of TiO2-rGO NC were comprehensively studied. One-step hydrothermal method revealed that Ti particles (∼60 nm) have capable bonded with rGO thin film, as agreement with XRD and FTIR results. In DSSCs photovoltaic performance, the optimized power conversion energy (PCE) of TiO2-rGO NC as counter electrode achieved a 2.90%, which achieved a desire performance as comparable with rGO and TiO2. In this work, the low-cost TiO2-rGO NC as counter electrode with suppressed recombination in DSSCs is studied.

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Functionalized Carbon Nanotube-Modified ELISA for Early Detection of Heart Attack

2023-12-01 , Chow E.M.Y. , Foo Kai Loong , Subash Chandra Bose Gopinath , Tan Soo Jin , Kashif M. , Heah Cheng Yong , Liew Yun Ming

A warning issue of heart attacks in young adults needs immediate attention lately. Enzyme-linked immunosorbent assay (ELISA) is an easy and commonly used method for detecting early stages of heart attack. Cardiac troponin I (cTnI) is a responsible biomarker for acute myocardial infarction. However, the conventional ELISA system was only able to detect at 100 pM of cTnI. To improve the system, enhancements were introduced through the integration of functionalized carbon nanotube (fCNT) to amplify cTnI detection signals. By utilizing the advantage of fCNT, a noticeable improvement in results can be obtained. The detection limit was lowered down to an impressive 10 pM. Furthermore, the change of absorbance increased from 31.90% for conventional ELISA surge to 98.61 for modified ELISA system. This three-fold increase in sensitivity shows remarkable improvement through the introduction of fCNT in modified ELISA technique.

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Comparative mechanical and microstructural properties of high calcium fly ash one-part geopolymers activated with Na2SiO3-anhydrous and NaAlO2

2021-11-01 , Ooi Wan-En , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Li L.Y. , Ho Li Ngee , Foo Kai Loong , Ong Shee-Ween , Ng Hui-Teng , Ng Yong-Sing , Nur Ain Jaya

This paper investigates the effect of varying solid alkali activators on the fresh and hardened properties and microstructural changes of one-part geopolymers (OPGs). Single and binary solid alkali activators were used to activate high calcium fly ash. The alkali activators were either solely sodium metasilicate (Na2SiO3) or a combination of sodium aluminate (NaAlO2) and sodium metasilicate (Na2SiO3). The OPG activated with anhydrous Na2SiO3 achieved an excellent 28-day compressive strength of 83.6 MPa while OPG activated with NaAlO2 and Na2SiO3 attained a compressive strength of 45.1 MPa. The Na2SiO3-activated OPG demonstrated better fluidity than the OPG activated with NaAlO2 and Na2SiO3 due to the thixotropic behaviour caused by the NaAlO2. The Na2SiO3-activated OPG consisted of sodium-calcium aluminium silicate hydrate ((N,C)-A-S-H) gel phase, while the OPG activated with NaAlO2 and Na2SiO3 comprised of the coexistence of sodium aluminium silicate hydrate (N-A-S-H) and calcium aluminium silicate hydrate (C-A-S-H) gel phases. Regardless of the distinctive properties, the OPGs are adequate for building materials applications.

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Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer

2022-01-01 , Ooi Wan En , Liew Yun Ming , Heah Cheng Yong , Ho Li Ngee , Mohd. Mustafa Al Bakri Abdullah , Ong Shee Ween , Sandu A.V.

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.

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