Jeng Yih Law | Universiti Kuala Lumpur (original) (raw)

Papers by Jeng Yih Law

Journal of Water Process Engineering, 2020

Abstract Water pollution is a severe issue to the environment globally. The removal of the pollut... more Abstract Water pollution is a severe issue to the environment globally. The removal of the pollutant from the water sources are unavoidable and it can be achieved through new generation types of membrane, generally known as mixed-matrix membrane (MMM). However, the stability of single nanomaterials in mixed-matrix membrane remains as a major obstacle to obtain a stable membrane performance. Hence, the goal of the study is to investigate the effect of nanohybrid towards the enhancement of MMM followed by optimizing nanohybrid concentration that required to produce the desire membrane. First, graphene oxide (GO) and iron oxide decorated graphene oxide nanohybrid (Fe3O4/GO) were synthesized using modified Hummer’s method and co-precipitation in the presence of GO prior to the incorporation into polysulfone (PSf) matrix while the membranes were fabricated via phase inversion method. The optimal membrane, M5-0.6 (0.6 wt% Fe3O4/GO nanohybrid concentration) showed that, the hydrophilicity of the modified membrane increased by 11.42 % from 78.8° to 69.8° attributed to the presence of hydrophilic nanohybrid that favor the transport water molecules across the membrane. Associated with this, M5-0.6 membrane showed better permeation flux of 87.01 L/m2.h and Congo red rejection of 98 % as compared to neat membrane at 51.82 L/m2.h and 87 %. Additionally, the M5-0.6 membrane also experience better antifouling properties at high flux recovery ratio (FRR) of 95 % while the neat membrane showed lower FRR of 87 %. Besides, M5-0.6 membrane also showed better stability as indicated by the lower flux decline at 23 % as compare to neat membrane at 41 %.

Applied Biochemistry and Biotechnology, 2005

Proceedings of the 14th Asia Pacific Confederation of Chemical Engineering Congress, 2012

Proceedings of the 14th Asia Pacific Confederation of Chemical Engineering Congress, 2012

Journal of Membrane Science, 2019

In this study, osmotically driven forward osmosis (FO) was employed prior to crystallization proc... more In this study, osmotically driven forward osmosis (FO) was employed prior to crystallization process in the downstream recovery of bio-based succinic acid. The fermentation broth containing succinic acid was initially pretreated using activated carbon. Powdered activated carbon (PAC) showed its effectiveness for glucose, formic acid, and color removal while succinic acid concentration remained unaffected. The untreated and treated fermentation broths were then concentrated using the FO process. FO exhibited a remarkable enhancement of concentration factor (CF) by 3.9-fold for the treated broth, thus resulting in a final succinic acid concentration of 111.26 g/L. By contrast, higher flux loss and lower CF were observed for untreated broth, mainly due to the adverse effect of severe membrane fouling and cake layer formation. Succinic acid crystals were then successfully recovered from the FO-concentrated broth in the final crystallization step. The purity and yield of succinic acid crystals were 90.52% and 67.09%, respectively for treated broth. This work demonstrated the development of a feasible FO-crystallization process for the downstream recovery of bio-based succinic acid. The findings have important implications for practical applications of FO technology in the bioprocess industries.

Chinese Journal of Chemical Engineering, 2018

In this study, we investigated the essential role of feed solution pH so as to gain insights into... more In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis (FO) process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the pH-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution pH enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at pH above its pKa2 value. The rejection of succinate increased in the following order of chemical form: C2H4C2O4H2 < C2H4C2O4Hˉ < C2H4C2O42−. With real seawater as the draw solution, low to moderate water fluxes (< 4 L·m−2 ·h−1) were observed. The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at pH of approximately 6.90.

Journal of Industrial and Engineering Chemistry, 2017

This study investigated the use of multiple-solute salts as potential draw solution (DS) for forw... more This study investigated the use of multiple-solute salts as potential draw solution (DS) for forward osmosis (FO) process. The novel concept of applying readily available waste byproducts as DS is briefly described in this paper. Two organic salts (sodium acetate and sodium formate) were used as draw solutes. The results indicated that the water flux performance was consistent with the osmotic pressure of the DS and that the binary-solute DS (each with 0.5 M concentration) was capable of achieving comparable water flux compared to the 1.0 M single-solute DS. Considering the variation of byproduct concentration during fermentation, a newly developed ternary-solute DS is introduced by employing NaCl additive. The physicochemical properties including osmotic pressure and viscosity were calculated by OLI Stream Analyzer software. Coupling these organic salts with NaCl demonstrated improvement of the DS including osmotic pressure and water flux. Succinate rejections of greater than 99% were obtained indicating insignificant succinate loss to the DS compartment. Although an increase of the reverse chloride flux was observed at increasing NaCl additive concentration, the acetate and formate ions demonstrated reduction of specific reverse solute flux attributed to higher water flux shown by ternary-solute DS.

Jurnal Teknologi, 2017

Forward osmosis (FO) technology has received increasing attention from many researchers since the... more Forward osmosis (FO) technology has received increasing attention from many researchers since the last decade. It is an osmotically driven membrane process in which water migrates across a semi-permeable membrane from a lower osmotic pressure feed solution to a higher osmotic pressure draw solution. FO technology is often applied as a hybrid system rather than a standalone process. The purpose of this paper is to review the different types of hybrid system configurations employing FO technology for the production of potable/pure water. The integration of FO technology with other processes which include reverse osmosis, crystallisation, membrane bioreactor, nanofiltration, and electrodialysis are presented and described in-depth. With the flourishing of various FO hybrid system configurations, it is believed that FO technology will play a vital role in the water processing industry.

Journal of Physical Science, 2017

Organic acids are important targeted chemicals in the renewable biorefinery industry. They are wi... more Organic acids are important targeted chemicals in the renewable biorefinery industry. They are widely used in various industries due to their variety of functionalities and less toxic properties. Conventionally, organic acids are produced through chemical processing using fossil raw materials. However, the biological production pathway has gained significant attention in recent years due to the growing environmental concern and movement towards green technology. To date, a variety of high-value organic acids such as succinic, lactic, butyric, acetic and fumaric acids have been produced via microbial fermentation. The primary challenge in the fermentative production of organic acids is the downstream recovery of the main products from the broth solution. Integration of membrane technology with other separation technologies in the downstream processing is deemed as a great opportunity for this purpose, for which membrane-based nanofiltration is seen as the potential technology. Nanofiltration offers several advantages such as great flexibility in the scale of production, high degree of separation and selectivity, and can be easily integrated with other separation units. This paper reviews the recovery of organic acids from fermentation broth using nanofiltration technologies, of which five types of organic acids are discussed in-depth. In particular, valuable findings concerning the effect of membrane properties, type of membrane used, and the effect of processing parameters on the organic acids recovery are highlighted in this paper.

CHEMICAL ENGINEERING TRANSACTIONS, 2017

The fermentative production of bio-based succinic acid is often accompanied by organic acid bypro... more The fermentative production of bio-based succinic acid is often accompanied by organic acid byproducts. In this study, the separation of succinate from organic acid salts (acetate and formate) using pressure-driven nanofiltration (NF) was studied. The performances of three nanofiltration membranes were compared and discussed. The influence of feed ratio on the succinate recovery was not significant given that succinate rejections of greater than 81.9 % were obtained in all cases. A comparison between monovalent rejection and divalent rejection suggests that the separation of multi-salt solution was influenced by the Donnan-steric effects. Taking into account the permeation fluxes and organic acid salt retentions, the NFW membrane manufactured by Synder Filtration was considered the most appropriate membrane for the separation of divalent succinate from other organic acid salts. This study strongly supports the use of NF technology for the downstream recovery of high valuable products.

Jurnal Teknologi, 2017

Osmotically-driven forward osmosis (FO) has gained significant attention in the last decade due t... more Osmotically-driven forward osmosis (FO) has gained significant attention in the last decade due to its potential application in various disciplines. Draw solution serves as the driving force in FO process for inducing water transport across the membrane. FO technology can be used to reject or concentrate high valuable products in the chemical and bioprocess industries which often encounter great challenge in terms of dilute product formation. In this study, commercial cellulose triacetate (CTA) flat sheet FO membrane was investigated using several types of inorganic draw solute. Pure water fluxes ranged from 5.20 to 6.30 L.m-2 .h-1 were achieved for selected draw solutes. The reverse solute leakage was shown by the increment of conductivity in the feed solution. Among the draw solutes, NaCl demonstrated highest reverse solute leakage (72.45 µS cm-1) attributed to its relatively smaller molecular size. The water fluxes at feed to draw solution volume ratios of 1:2 and 1:3 were found to be slightly lower than that to the volume ratios of 1:0.6 and 1:1. With respect to sodium succinate feed solution, MgCl2 was capable of generating higher osmotic pressure and thus higher water flux was observed compared to NaCl draw solute. Overall, the selected inorganic draw solutes demonstrated encouraging FO performances and could be used for concentrating sodium succinate solution.

Journal of Water Process Engineering, 2020

Abstract Water pollution is a severe issue to the environment globally. The removal of the pollut... more Abstract Water pollution is a severe issue to the environment globally. The removal of the pollutant from the water sources are unavoidable and it can be achieved through new generation types of membrane, generally known as mixed-matrix membrane (MMM). However, the stability of single nanomaterials in mixed-matrix membrane remains as a major obstacle to obtain a stable membrane performance. Hence, the goal of the study is to investigate the effect of nanohybrid towards the enhancement of MMM followed by optimizing nanohybrid concentration that required to produce the desire membrane. First, graphene oxide (GO) and iron oxide decorated graphene oxide nanohybrid (Fe3O4/GO) were synthesized using modified Hummer’s method and co-precipitation in the presence of GO prior to the incorporation into polysulfone (PSf) matrix while the membranes were fabricated via phase inversion method. The optimal membrane, M5-0.6 (0.6 wt% Fe3O4/GO nanohybrid concentration) showed that, the hydrophilicity of the modified membrane increased by 11.42 % from 78.8° to 69.8° attributed to the presence of hydrophilic nanohybrid that favor the transport water molecules across the membrane. Associated with this, M5-0.6 membrane showed better permeation flux of 87.01 L/m2.h and Congo red rejection of 98 % as compared to neat membrane at 51.82 L/m2.h and 87 %. Additionally, the M5-0.6 membrane also experience better antifouling properties at high flux recovery ratio (FRR) of 95 % while the neat membrane showed lower FRR of 87 %. Besides, M5-0.6 membrane also showed better stability as indicated by the lower flux decline at 23 % as compare to neat membrane at 41 %.

Applied Biochemistry and Biotechnology, 2005

Proceedings of the 14th Asia Pacific Confederation of Chemical Engineering Congress, 2012

Proceedings of the 14th Asia Pacific Confederation of Chemical Engineering Congress, 2012

Journal of Membrane Science, 2019

In this study, osmotically driven forward osmosis (FO) was employed prior to crystallization proc... more In this study, osmotically driven forward osmosis (FO) was employed prior to crystallization process in the downstream recovery of bio-based succinic acid. The fermentation broth containing succinic acid was initially pretreated using activated carbon. Powdered activated carbon (PAC) showed its effectiveness for glucose, formic acid, and color removal while succinic acid concentration remained unaffected. The untreated and treated fermentation broths were then concentrated using the FO process. FO exhibited a remarkable enhancement of concentration factor (CF) by 3.9-fold for the treated broth, thus resulting in a final succinic acid concentration of 111.26 g/L. By contrast, higher flux loss and lower CF were observed for untreated broth, mainly due to the adverse effect of severe membrane fouling and cake layer formation. Succinic acid crystals were then successfully recovered from the FO-concentrated broth in the final crystallization step. The purity and yield of succinic acid crystals were 90.52% and 67.09%, respectively for treated broth. This work demonstrated the development of a feasible FO-crystallization process for the downstream recovery of bio-based succinic acid. The findings have important implications for practical applications of FO technology in the bioprocess industries.

Chinese Journal of Chemical Engineering, 2018

In this study, we investigated the essential role of feed solution pH so as to gain insights into... more In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis (FO) process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the pH-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution pH enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at pH above its pKa2 value. The rejection of succinate increased in the following order of chemical form: C2H4C2O4H2 < C2H4C2O4Hˉ < C2H4C2O42−. With real seawater as the draw solution, low to moderate water fluxes (< 4 L·m−2 ·h−1) were observed. The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at pH of approximately 6.90.

Journal of Industrial and Engineering Chemistry, 2017

This study investigated the use of multiple-solute salts as potential draw solution (DS) for forw... more This study investigated the use of multiple-solute salts as potential draw solution (DS) for forward osmosis (FO) process. The novel concept of applying readily available waste byproducts as DS is briefly described in this paper. Two organic salts (sodium acetate and sodium formate) were used as draw solutes. The results indicated that the water flux performance was consistent with the osmotic pressure of the DS and that the binary-solute DS (each with 0.5 M concentration) was capable of achieving comparable water flux compared to the 1.0 M single-solute DS. Considering the variation of byproduct concentration during fermentation, a newly developed ternary-solute DS is introduced by employing NaCl additive. The physicochemical properties including osmotic pressure and viscosity were calculated by OLI Stream Analyzer software. Coupling these organic salts with NaCl demonstrated improvement of the DS including osmotic pressure and water flux. Succinate rejections of greater than 99% were obtained indicating insignificant succinate loss to the DS compartment. Although an increase of the reverse chloride flux was observed at increasing NaCl additive concentration, the acetate and formate ions demonstrated reduction of specific reverse solute flux attributed to higher water flux shown by ternary-solute DS.

Jurnal Teknologi, 2017

Forward osmosis (FO) technology has received increasing attention from many researchers since the... more Forward osmosis (FO) technology has received increasing attention from many researchers since the last decade. It is an osmotically driven membrane process in which water migrates across a semi-permeable membrane from a lower osmotic pressure feed solution to a higher osmotic pressure draw solution. FO technology is often applied as a hybrid system rather than a standalone process. The purpose of this paper is to review the different types of hybrid system configurations employing FO technology for the production of potable/pure water. The integration of FO technology with other processes which include reverse osmosis, crystallisation, membrane bioreactor, nanofiltration, and electrodialysis are presented and described in-depth. With the flourishing of various FO hybrid system configurations, it is believed that FO technology will play a vital role in the water processing industry.

Journal of Physical Science, 2017

Organic acids are important targeted chemicals in the renewable biorefinery industry. They are wi... more Organic acids are important targeted chemicals in the renewable biorefinery industry. They are widely used in various industries due to their variety of functionalities and less toxic properties. Conventionally, organic acids are produced through chemical processing using fossil raw materials. However, the biological production pathway has gained significant attention in recent years due to the growing environmental concern and movement towards green technology. To date, a variety of high-value organic acids such as succinic, lactic, butyric, acetic and fumaric acids have been produced via microbial fermentation. The primary challenge in the fermentative production of organic acids is the downstream recovery of the main products from the broth solution. Integration of membrane technology with other separation technologies in the downstream processing is deemed as a great opportunity for this purpose, for which membrane-based nanofiltration is seen as the potential technology. Nanofiltration offers several advantages such as great flexibility in the scale of production, high degree of separation and selectivity, and can be easily integrated with other separation units. This paper reviews the recovery of organic acids from fermentation broth using nanofiltration technologies, of which five types of organic acids are discussed in-depth. In particular, valuable findings concerning the effect of membrane properties, type of membrane used, and the effect of processing parameters on the organic acids recovery are highlighted in this paper.

CHEMICAL ENGINEERING TRANSACTIONS, 2017

The fermentative production of bio-based succinic acid is often accompanied by organic acid bypro... more The fermentative production of bio-based succinic acid is often accompanied by organic acid byproducts. In this study, the separation of succinate from organic acid salts (acetate and formate) using pressure-driven nanofiltration (NF) was studied. The performances of three nanofiltration membranes were compared and discussed. The influence of feed ratio on the succinate recovery was not significant given that succinate rejections of greater than 81.9 % were obtained in all cases. A comparison between monovalent rejection and divalent rejection suggests that the separation of multi-salt solution was influenced by the Donnan-steric effects. Taking into account the permeation fluxes and organic acid salt retentions, the NFW membrane manufactured by Synder Filtration was considered the most appropriate membrane for the separation of divalent succinate from other organic acid salts. This study strongly supports the use of NF technology for the downstream recovery of high valuable products.

Jurnal Teknologi, 2017

Osmotically-driven forward osmosis (FO) has gained significant attention in the last decade due t... more Osmotically-driven forward osmosis (FO) has gained significant attention in the last decade due to its potential application in various disciplines. Draw solution serves as the driving force in FO process for inducing water transport across the membrane. FO technology can be used to reject or concentrate high valuable products in the chemical and bioprocess industries which often encounter great challenge in terms of dilute product formation. In this study, commercial cellulose triacetate (CTA) flat sheet FO membrane was investigated using several types of inorganic draw solute. Pure water fluxes ranged from 5.20 to 6.30 L.m-2 .h-1 were achieved for selected draw solutes. The reverse solute leakage was shown by the increment of conductivity in the feed solution. Among the draw solutes, NaCl demonstrated highest reverse solute leakage (72.45 µS cm-1) attributed to its relatively smaller molecular size. The water fluxes at feed to draw solution volume ratios of 1:2 and 1:3 were found to be slightly lower than that to the volume ratios of 1:0.6 and 1:1. With respect to sodium succinate feed solution, MgCl2 was capable of generating higher osmotic pressure and thus higher water flux was observed compared to NaCl draw solute. Overall, the selected inorganic draw solutes demonstrated encouraging FO performances and could be used for concentrating sodium succinate solution.