Li-ngee Ho - Academia.edu (original) (raw)

Papers by Li-ngee Ho

The objective of this study was to evaluate the performance of an upflow membrane-less microbial ... more The objective of this study was to evaluate the performance of an upflow membrane-less microbial fuel cell (UFML MFC) with various types of carbon material as cathodes in power output and chemical oxygen demand (COD) reduction. The UFML MFC was designed with carbon felt as anode material, and the bioreactor was filled with 0.6-cm diameter of gravel at the anode region. Carbon flake, Pt-loaded carbon paper, and carbon felt were used as cathode electrodes. The voltage output (power density) for the carbon flake cathode and Pt-loaded carbon paper cathode was 384± 16 mV (44.4±2.5 mW/m 2 ) and 399±9 mV (44.1± 3 mW/m 2 ), respectively. The percentage of COD reduction at the anode region and effluent was above 75 and 85 %, respectively, for all cathode materials. The coulombic efficiency was 15.95, 6.09, and 15.32 % for Ptloaded carbon paper, carbon felt, and carbon flake, respectively. The result suggests that power generation and COD reduction were influenced by the cathode material. Carbon flake can be considered as a costeffective cathode material in UFML MFC for future application in real biological wastewater treatment process.

Environmental science and pollution research international, Jan 17, 2016

This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in d... more This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24 h. The degradation and mineralization of RB5 with 0.1 M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523 mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05 mA cm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245 mW cm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6 mV and 0.055 mA cm(-2), r...

Journal of Cleaner Production, 2016

Water, Air, & Soil Pollution, 2016

Bioprocess and biosystems engineering, Jan 19, 2016

The main aim of this study is to investigate the performance of organic oxidation and denitrifica... more The main aim of this study is to investigate the performance of organic oxidation and denitrification of the system under long-term operation. The MFC reactor was operated in continuous mode for 180 days. Nitrate was successfully demonstrated as terminal electron acceptor, where nitrate was reduced at the cathode using electron provided by acetate oxidation at the anode. The removal efficiencies of chemical oxygen demand (COD) and nitrate were higher in the closed circuit system than in open circuit system. Both COD and nitrate reduction improved with the increase of organic loading and subsequently contributed to higher power output. The maximum nitrate removal efficiency was 88 ± 4 % (influent of 141 ± 14 mg/L). The internal resistant was 50 Ω, which was found to be low for a double chambered MFC. The maximum power density was 669 mW/m(3) with current density of 3487 mA/m(3).

Journal of Water Reuse and Desalination, 2015

Bioresource Technology, 2015

This study demonstrated a successful operation of up-flow constructed wetland-microbial fuel cell... more This study demonstrated a successful operation of up-flow constructed wetland-microbial fuel cell (UFCW-MFC) in wastewater treatment and energy recovery. The goals of this study were to investigate the effect of circuit connection, organic loading rates, and electrode spacing on the performance of wastewater treatment and bioelectricity generation. The average influent of COD, NO3(-) and NH4(+) were 624mg/L, 142mg/L, 40mg/L, respectively and their removal efficiencies (1day HRT) were 99%, 46%, and 96%, respectively. NO3(-) removal was relatively higher in the closed circuit system due to lower dissolved oxygen in the system. Despite larger electrode spacing, the voltage outputs from Anode 2 (A2) (30cm) and Anode 3 (A3) (45cm) were higher than from Anode 1 (A1) (15cm) as a result of insufficient fuel supply to A1. The maximum power density and Coulombic efficiency were obtained at A2, which were 93mW/m(3) and 1.42%, respectively.

Journal of Materials Science: Materials in Electronics, 2015

Desalination and Water Treatment, 2015

Electrically conductive adhesives (ECAs) have been investigated for the use in microelectronics p... more Electrically conductive adhesives (ECAs) have been investigated for the use in microelectronics packaging as a lead-free solder substrate. As metal filler in conductive adhesives, silver is the most commonly used due to its high conductivity and stability. However, the cost of conductive adhesives with silver fillers is much higher than conventional lead-free solders and silver has poor electro-migration performance. Copper is a promising candidate for conductive filler metal due to its low resistivity and low cost, but oxidation causes this metal to lose conductivity. In this study, ECAs using surface-modified copper fillers were developed. In particular, to overcome the problem associated with the oxidation of copper, copper nanoparticles were coated with organic substance from when nanoparticles were made. The organic-coated copper was tested as a filler metal. Especially the effect of organic layer on the electrical resistance just after curing and after high-temperature exposure was investigated. As a result, it was found that the electrical resistance of ICA with organic-coated copper filler was more stable than that of ICA with pure copper filler.

Bioresource Technology, 2015

Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the ... more Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the feasibility of the bioreactor for decolorization of Acid Orange 7 (AO7) and electricity generation simultaneously. The performance of UFML MFC was evaluated in terms of voltage output, chemical oxygen demand (COD) and color removal efficiency by varying the concentration of AO7 in synthetic wastewater. The results shown the voltage generation and COD removal efficiency decreased as the initial AO7 concentration increased; this indicates there is electron competition between anode and azo dye. Furthermore, there was a phenomenon of further decolorization at cathode region which indicates the oxygen and azo dye are both compete as electron acceptor. Based on the UV-visible spectra analysis, the breakdown of the azo bond and naphthalene compound in AO7 were confirmed. These findings show the capability of integrated UFML MFC in azo dye wastewater treatment and simultaneous electricity generation.

Journal of Materials Engineering and Performance, 2014

2013 14th International Conference on Electronic Packaging Technology, 2013

Journal of …, 2011

The objective of present study is to evaluate the using of constructed wetland under semi-batch o... more The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7) containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and the presence of Phragmites australis had a significant impact on the removal of organic matters, AO7, aromatic amines and NH 4 -N. The COD removal efficiency in the aerated and non-aerated wetland reactors was 95 and 62%, respectively. The NH 4 -N removal efficiency in the aerated wetland reactor (86%) was significantly higher than the nonaerated wetland reactor (14 %). All wetland reactors show high removal efficiency of AO7 (> 94%) but only the aerated wetland reactor perform better in the removal of aromatic amines.

Water, Air, & Soil Pollution, 2012

Water, Air, & Soil Pollution, 2012

Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewa... more Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)containing wastewater using granular activated carbon (GAC)-biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC-biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k 2 ) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC-biofilm SBR system.

Water, Air, & Soil Pollution, 2012

ABSTRACT The objective of this study was to investigate and compare the kinetic photocatalytic de... more ABSTRACT The objective of this study was to investigate and compare the kinetic photocatalytic degradation of mono azo dyes Acid Orange 7 (AO7) and Methyl Orange (MO) under solar light irradiation with titanium dioxide (TiO 2) as a photocatalyst. Several operational parameters affecting the photocatalytic degradation of dye were evaluated such as different azo dyes, initial dye concentration, TiO 2 dosage, with and without aeration and sunlight irradiation. The data obtained was well fitted with the Langmuir- Hinshelwood kinetic model. It was observed that the pseudo-first-order rate constants for AO7 were higher than MO in all cases, indicating that the photocatalytic degradation of AO7 was easier and more rapid than MO. The analysis of chemical oxygen demand and UV-Vis spectra shows the AO7 and MO not only being decolorized due to the breakdown of azo bond but also being mineralized if the azo dye solutions were continually exposed to solar light irradiation after the decolorization process.

Separation Science and Technology, 2013

Journal of Materials Science: Materials in Electronics, 2013

The objective of this study was to evaluate the performance of an upflow membrane-less microbial ... more The objective of this study was to evaluate the performance of an upflow membrane-less microbial fuel cell (UFML MFC) with various types of carbon material as cathodes in power output and chemical oxygen demand (COD) reduction. The UFML MFC was designed with carbon felt as anode material, and the bioreactor was filled with 0.6-cm diameter of gravel at the anode region. Carbon flake, Pt-loaded carbon paper, and carbon felt were used as cathode electrodes. The voltage output (power density) for the carbon flake cathode and Pt-loaded carbon paper cathode was 384± 16 mV (44.4±2.5 mW/m 2 ) and 399±9 mV (44.1± 3 mW/m 2 ), respectively. The percentage of COD reduction at the anode region and effluent was above 75 and 85 %, respectively, for all cathode materials. The coulombic efficiency was 15.95, 6.09, and 15.32 % for Ptloaded carbon paper, carbon felt, and carbon flake, respectively. The result suggests that power generation and COD reduction were influenced by the cathode material. Carbon flake can be considered as a costeffective cathode material in UFML MFC for future application in real biological wastewater treatment process.

Environmental science and pollution research international, Jan 17, 2016

This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in d... more This study investigated the effect of different supporting electrolyte (Na2SO4, MgSO4, NaCl) in degradation of Reactive Black 5 (RB5) and generation of electricity. Zinc oxide (ZnO) was immobilized onto carbon felt acted as photoanode, while Pt-coated carbon paper as photocathode was placed in a single chamber photocatalytic fuel cell, which then irradiated by UV lamp for 24 h. The degradation and mineralization of RB5 with 0.1 M NaCl rapidly decreased after 24-h irradiation time, followed by MgSO4, Na2SO4 and without electrolyte. The voltage outputs for Na2SO4, MgSO4 and NaCl were 908, 628 and 523 mV, respectively, after 24-h irradiation time; meanwhile, their short-circuit current density, J SC, was 1.3, 1.2 and 1.05 mA cm(-2), respectively. The power densities for Na2SO4, MgSO4 and NaCl were 0.335, 0.256 and 0.245 mW cm(-2), respectively. On the other hand, for without supporting electrolyte, the voltage output and short-circuit current density was 271.6 mV and 0.055 mA cm(-2), r...

Journal of Cleaner Production, 2016

Water, Air, & Soil Pollution, 2016

Bioprocess and biosystems engineering, Jan 19, 2016

The main aim of this study is to investigate the performance of organic oxidation and denitrifica... more The main aim of this study is to investigate the performance of organic oxidation and denitrification of the system under long-term operation. The MFC reactor was operated in continuous mode for 180 days. Nitrate was successfully demonstrated as terminal electron acceptor, where nitrate was reduced at the cathode using electron provided by acetate oxidation at the anode. The removal efficiencies of chemical oxygen demand (COD) and nitrate were higher in the closed circuit system than in open circuit system. Both COD and nitrate reduction improved with the increase of organic loading and subsequently contributed to higher power output. The maximum nitrate removal efficiency was 88 ± 4 % (influent of 141 ± 14 mg/L). The internal resistant was 50 Ω, which was found to be low for a double chambered MFC. The maximum power density was 669 mW/m(3) with current density of 3487 mA/m(3).

Journal of Water Reuse and Desalination, 2015

Bioresource Technology, 2015

This study demonstrated a successful operation of up-flow constructed wetland-microbial fuel cell... more This study demonstrated a successful operation of up-flow constructed wetland-microbial fuel cell (UFCW-MFC) in wastewater treatment and energy recovery. The goals of this study were to investigate the effect of circuit connection, organic loading rates, and electrode spacing on the performance of wastewater treatment and bioelectricity generation. The average influent of COD, NO3(-) and NH4(+) were 624mg/L, 142mg/L, 40mg/L, respectively and their removal efficiencies (1day HRT) were 99%, 46%, and 96%, respectively. NO3(-) removal was relatively higher in the closed circuit system due to lower dissolved oxygen in the system. Despite larger electrode spacing, the voltage outputs from Anode 2 (A2) (30cm) and Anode 3 (A3) (45cm) were higher than from Anode 1 (A1) (15cm) as a result of insufficient fuel supply to A1. The maximum power density and Coulombic efficiency were obtained at A2, which were 93mW/m(3) and 1.42%, respectively.

Journal of Materials Science: Materials in Electronics, 2015

Desalination and Water Treatment, 2015

Electrically conductive adhesives (ECAs) have been investigated for the use in microelectronics p... more Electrically conductive adhesives (ECAs) have been investigated for the use in microelectronics packaging as a lead-free solder substrate. As metal filler in conductive adhesives, silver is the most commonly used due to its high conductivity and stability. However, the cost of conductive adhesives with silver fillers is much higher than conventional lead-free solders and silver has poor electro-migration performance. Copper is a promising candidate for conductive filler metal due to its low resistivity and low cost, but oxidation causes this metal to lose conductivity. In this study, ECAs using surface-modified copper fillers were developed. In particular, to overcome the problem associated with the oxidation of copper, copper nanoparticles were coated with organic substance from when nanoparticles were made. The organic-coated copper was tested as a filler metal. Especially the effect of organic layer on the electrical resistance just after curing and after high-temperature exposure was investigated. As a result, it was found that the electrical resistance of ICA with organic-coated copper filler was more stable than that of ICA with pure copper filler.

Bioresource Technology, 2015

Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the ... more Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the feasibility of the bioreactor for decolorization of Acid Orange 7 (AO7) and electricity generation simultaneously. The performance of UFML MFC was evaluated in terms of voltage output, chemical oxygen demand (COD) and color removal efficiency by varying the concentration of AO7 in synthetic wastewater. The results shown the voltage generation and COD removal efficiency decreased as the initial AO7 concentration increased; this indicates there is electron competition between anode and azo dye. Furthermore, there was a phenomenon of further decolorization at cathode region which indicates the oxygen and azo dye are both compete as electron acceptor. Based on the UV-visible spectra analysis, the breakdown of the azo bond and naphthalene compound in AO7 were confirmed. These findings show the capability of integrated UFML MFC in azo dye wastewater treatment and simultaneous electricity generation.

Journal of Materials Engineering and Performance, 2014

2013 14th International Conference on Electronic Packaging Technology, 2013

Journal of …, 2011

The objective of present study is to evaluate the using of constructed wetland under semi-batch o... more The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7) containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and the presence of Phragmites australis had a significant impact on the removal of organic matters, AO7, aromatic amines and NH 4 -N. The COD removal efficiency in the aerated and non-aerated wetland reactors was 95 and 62%, respectively. The NH 4 -N removal efficiency in the aerated wetland reactor (86%) was significantly higher than the nonaerated wetland reactor (14 %). All wetland reactors show high removal efficiency of AO7 (> 94%) but only the aerated wetland reactor perform better in the removal of aromatic amines.

Water, Air, & Soil Pollution, 2012

Water, Air, & Soil Pollution, 2012

Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewa... more Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)containing wastewater using granular activated carbon (GAC)-biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC-biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k 2 ) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC-biofilm SBR system.

Water, Air, & Soil Pollution, 2012

ABSTRACT The objective of this study was to investigate and compare the kinetic photocatalytic de... more ABSTRACT The objective of this study was to investigate and compare the kinetic photocatalytic degradation of mono azo dyes Acid Orange 7 (AO7) and Methyl Orange (MO) under solar light irradiation with titanium dioxide (TiO 2) as a photocatalyst. Several operational parameters affecting the photocatalytic degradation of dye were evaluated such as different azo dyes, initial dye concentration, TiO 2 dosage, with and without aeration and sunlight irradiation. The data obtained was well fitted with the Langmuir- Hinshelwood kinetic model. It was observed that the pseudo-first-order rate constants for AO7 were higher than MO in all cases, indicating that the photocatalytic degradation of AO7 was easier and more rapid than MO. The analysis of chemical oxygen demand and UV-Vis spectra shows the AO7 and MO not only being decolorized due to the breakdown of azo bond but also being mineralized if the azo dye solutions were continually exposed to solar light irradiation after the decolorization process.

Separation Science and Technology, 2013

Journal of Materials Science: Materials in Electronics, 2013