Phong Mai - Academia.edu (original) (raw)
Papers by Phong Mai
Materials Research-ibero-american Journal of Materials, 2021
The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction of poly(benzyl-L-glutamat... more The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction of poly(benzyl-L-glutamate) by the palladium/charcoal catalyst proved to be an effective method for obtaining polyglutamic acid pure and particularly exhibiting in the α-helix secondary structure. The structure of this synthetic polypeptide was assessed by infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, temperature-modulated differential scanning calorimetry and wideangle powder X-ray diffraction methods. The α-helical PG was, for the first time, combined with multi-walled carbon nanotubes (MWCNTs). The obtained PG was demonstrated to be a promising matrix to disperse MWCNTs, forming MWCNT/PG biocomposites.
Current Research in Food Science
Journal of the Brazilian Chemical Society, 2022
The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexy... more The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexyl)-2-(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EP4HP) and 4-(2-ethylhexyl)- 2,6-di(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EDP4HP) have been successfully synthesized via C–H direct arylation reaction. The structures of these conjugated molecules were determined via nuclear magnetic resonance and Fourier-transform infrared spectroscopy (FTIR). The optical properties of conjugated molecules were evaluated via ultraviolet visible (UV-Vis) and fluorescence spectroscopies. The conjugated molecules exhibited the efficient fluorescence quenching toward herbicide mesotrione as nitroaromatic pesticides that could be promising candidates as the chemosensor for tracing of nitroaromatic pesticides.
Chemical engineering transactions, 2020
High production costs are biggest obstacles for the commercialization of the lignocellulosic bioe... more High production costs are biggest obstacles for the commercialization of the lignocellulosic bioethanol. For an attempt to reduce the chemical consumption of the alkaline pretreatment process, the waste solution with high basicity was investigated to be re-used. In respect to the pretreatment efficiency, a minimum addition of NaOH was calculated and the calculation philosophy was presented. The efficiency is defined as the change in the ratio of lignin/cellulose, which leads to cellulose-enriched material after pretreatment. Rubber wood saw dust was employed as the lignocellulose biomass feedstock. HPLC was used to analyze the chemical contents of the starting and pretreated material samples instead of the poor evaluation of the pretreatment efficiency based on only mass loss as that done in the previous study. The experimental results showed that with an alkaline solution of NaOH 2.0 wt% treating the woody material for 24 hours, the cellulose content increased from 41.2 % to 53.52 ...
Science and Technology Development Journal, 2011
Recent years in Vietnam, diatomaceous earth has been attractive to researchers and manufacturers ... more Recent years in Vietnam, diatomaceous earth has been attractive to researchers and manufacturers due to its applications, particularly in the field of filter aid manufacture. In this study, diatomite from Dai Lao valley deposit (Bao Loc, Lam Dong province) was seclected for investigation of its possible application in preparation of filter aids. For this purpose, diatomite ore was characterized and treated in different acids in order to improve the material characteristics for filter aid manufacture. Chemical and physical properties of the raw and treated diatomite were determined using different instruments such as X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). The obtained results showed that Lam Dong diatomite has low SiO2 (52.9%) and high Fe2O3 content (5.32%). In order to enrich SiO2 and eliminate unnecessary components, different acids (6M H2SO4, 3.5M HCl and 5M HCl) were used. Among acids used, le...
Polímeros, 2021
The UV light-mediated metal-free polymerizations of 4-vinylpyridine (4VP) have been successfully ... more The UV light-mediated metal-free polymerizations of 4-vinylpyridine (4VP) have been successfully performed by using 10-(pyren-1-yl)-10H-phenothiazine (PPTh) and pyrene as photocatalysts. The preparation of narrow polydispersity poly (4-vinyl pyridine) (P4VP) with high conversions was enabled in both protic as well as unprotic reaction media at ambient temperature. Additionally, copolymerizations of 4VP with acrylate and methacrylate monomers were also demonstrated, affording metal-free copolymer products.
Clean Technologies and Environmental Policy, 2021
The Scientific World Journal, 2021
Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese tradit... more Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese traditional remedies due to its potential value for health. In this study, polysaccharides were extracted from G. lucidum using ultrasound-assisted enzymatic extraction method. The response surface methodology and Box–Behnken design were employed to investigate the effects of pH, extraction temperature, extraction time, and ultrasonic power on the content of polysaccharides. Based on ultraviolet-visible spectroscopy analysis, the highest content of polysaccharides in the extract was 32.08 mg/g under optimum experimental parameters including enzyme concentration of 3%, pH of 5.5, extraction temperature of 45°C, extraction time of 30 min, and ultrasonic power of 480 W. The Fourier-transform infrared spectroscopy was also used to identify the functional groups in the extracts. The molecular weights of polysaccharides were determined by gel permeation chromatography. The obtained extract was then ...
New Journal of Chemistry, 2020
Red muad and rice husk ash were treated without neutralization by acid to produce a support mater... more Red muad and rice husk ash were treated without neutralization by acid to produce a support material (RR).
Biomass [Working Title], 2020
Gasification is an indirect combustion of solid and liquid biomass by converting them to combusti... more Gasification is an indirect combustion of solid and liquid biomass by converting them to combustive syngas. Gasification is an alternative process for the traditional combustion, in which the emission of dust and toxic gases can be minimized. In this chapter, a comparison of these two biomass-to-heat conversion processes applied on biomass is presented in term of environmental impacts and technological benefits with a hope to provide readers a basic view of choices. Gasification is classified as in term of gasification agents, non-catalytic and catalytic process, and plasma assisted process. Popular types of gasification equipment, aka gasifiers, are introduced with working principles, through which the advantages and weakness of technology are briefly discussed.
IOP Conference Series: Materials Science and Engineering, 2020
This work is to implement a working model of an integrated process for bioethanol in the process ... more This work is to implement a working model of an integrated process for bioethanol in the process simulation based on rigorous model using the Aspen HYSYS simulation software. As a case study, the simulation is applied to design a pilot plant that converts rice straw into ethanol. The model is based on the process for biochemical conversion of lignocellulosic biomass (rice straw) to ethanol, proposed by the pilot plant of producing bio-ethanol with capacity of 152 kg rice straw/batch. The plant for manufacturing bio-ethanol with rice straw as raw materials comprises basically three units: Pretreatment of rice straw by alkaline treatment; Simultaneous saccharification fermentation (SSF) of rice straw to produce bio-ethanol and the unit for separation and purification of bio-ethanol mixture from simultaneous and fermentation unit. Modeling of rice straw feedstock as a solid material in Aspen HYSYS, including the creation of necessary hypothetical components. Investigate and analyze the...
Polymer, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
![Research paper thumbnail of Direct (hetero)arylation polymerization for the synthesis of donor–acceptor conjugated polymers based on N ‐benzoyldithieno [3,2‐b:2′,3′‐d]pyrrole and diketopyrrolopyrrole toward organic photovoltaic cell application](https://attachments.academia-assets.com/99910400/thumbnails/1.jpg)
](Polymer International, 2019
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as
MATEC Web of Conferences, 2019
Alkaline pretreatment has been known as the most popular method to process lignocellulosic materi... more Alkaline pretreatment has been known as the most popular method to process lignocellulosic materials for bioethanol production due to its simplicity and high efficiency. However, the waste water of the process has a very high basicity, which requires neutralization with acids upon further disposal. In this study, rubber wood saw dust (Hevea brasiliensis) was employed as lignocellulosic material and its pretreatment was inspected with both diluted H2SO4 and NaOH in different combination ways. Hereby, acid was used not only for waste water neutralization but also to contribute to lignin removal. Analysis results showed that an aqueous solution of 2.0 - 2.5 wt.% H2SO4 can be used to treat the biomass followed by alkaline pretreatment. By this so-called combo-pretreatment technique, cellulose was well preserved without significant hydrolysis while the final pretreatment efficiency was up to 63.0%, compared to 48.2% of using only the alkaline solution and 13.7% of using only the acidic s...
IFAC-PapersOnLine, 2015
This paper further explores the link between irreversible thermodynamics and system theory, and i... more This paper further explores the link between irreversible thermodynamics and system theory, and its use for port-based modeling for reaction systems. More specifically we show here that a pseudo Hamiltonian representation with R(x) > 0 can be obtained by considering the Brayton-Moser formulation via a unified potential function that verifies a thermodynamic evolution criterion. As a consequence, it gives additional degrees of freedom (i.e. to construct alternate pseudo Hamiltonian models with new passive outputs) usable for further studies on the control design. A representative example of irreversible processes via the non isothermal continuous stirred tank reactor model is used to illustrate the theoretical developments.
Desalination, 2014
ABSTRACT In this study, fouling behavior of alginic acid onto four types of hand-cast and one com... more ABSTRACT In this study, fouling behavior of alginic acid onto four types of hand-cast and one commercially-available seawater reverse osmosis membranes was investigated. Hand-cast membranes included a polyamide thin film composite and a zeolite-polyamide thin film nanocomposite, as well as poly(vinyl alcohol) coated versions of both. Flux decline due to fouling and the structural features of the fouling layers formed during seawater desalination experiments were analyzed using classic Kozeny–Carman cake filtration theory along with a more recently developed crossflow model. Initial rates of flux decline correlated strongly with membrane permeability and root-mean-squared roughness and moderately with alginate–membrane interfacial free energy. The porosity (i.e., hydraulic resistance) of the fouling layers correlated strongly with deionized water contact angle and moderately with surface area difference of the membranes. The contact angle of the membranes also heavily impacted the fouling layer mass and thickness. Membranes with high permeability, strong alginate–membrane interfacial energy of adhesion, and hydrophobic surfaces had the highest propensity for fouling by low porosity, high specific resistance cake layers. Results indicate that reverse osmosis membranes should be produced with hydrophilic, smooth, and large peak-to-peak surfaces in order to reduce flux decline due to cake layer formation.
Materials Research-ibero-american Journal of Materials, 2021
The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction of poly(benzyl-L-glutamat... more The synthesis of poly(L-glutamic acid) (PG) was investigated. Reduction of poly(benzyl-L-glutamate) by the palladium/charcoal catalyst proved to be an effective method for obtaining polyglutamic acid pure and particularly exhibiting in the α-helix secondary structure. The structure of this synthetic polypeptide was assessed by infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, temperature-modulated differential scanning calorimetry and wideangle powder X-ray diffraction methods. The α-helical PG was, for the first time, combined with multi-walled carbon nanotubes (MWCNTs). The obtained PG was demonstrated to be a promising matrix to disperse MWCNTs, forming MWCNT/PG biocomposites.
Current Research in Food Science
Journal of the Brazilian Chemical Society, 2022
The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexy... more The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexyl)-2-(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EP4HP) and 4-(2-ethylhexyl)- 2,6-di(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EDP4HP) have been successfully synthesized via C–H direct arylation reaction. The structures of these conjugated molecules were determined via nuclear magnetic resonance and Fourier-transform infrared spectroscopy (FTIR). The optical properties of conjugated molecules were evaluated via ultraviolet visible (UV-Vis) and fluorescence spectroscopies. The conjugated molecules exhibited the efficient fluorescence quenching toward herbicide mesotrione as nitroaromatic pesticides that could be promising candidates as the chemosensor for tracing of nitroaromatic pesticides.
Chemical engineering transactions, 2020
High production costs are biggest obstacles for the commercialization of the lignocellulosic bioe... more High production costs are biggest obstacles for the commercialization of the lignocellulosic bioethanol. For an attempt to reduce the chemical consumption of the alkaline pretreatment process, the waste solution with high basicity was investigated to be re-used. In respect to the pretreatment efficiency, a minimum addition of NaOH was calculated and the calculation philosophy was presented. The efficiency is defined as the change in the ratio of lignin/cellulose, which leads to cellulose-enriched material after pretreatment. Rubber wood saw dust was employed as the lignocellulose biomass feedstock. HPLC was used to analyze the chemical contents of the starting and pretreated material samples instead of the poor evaluation of the pretreatment efficiency based on only mass loss as that done in the previous study. The experimental results showed that with an alkaline solution of NaOH 2.0 wt% treating the woody material for 24 hours, the cellulose content increased from 41.2 % to 53.52 ...
Science and Technology Development Journal, 2011
Recent years in Vietnam, diatomaceous earth has been attractive to researchers and manufacturers ... more Recent years in Vietnam, diatomaceous earth has been attractive to researchers and manufacturers due to its applications, particularly in the field of filter aid manufacture. In this study, diatomite from Dai Lao valley deposit (Bao Loc, Lam Dong province) was seclected for investigation of its possible application in preparation of filter aids. For this purpose, diatomite ore was characterized and treated in different acids in order to improve the material characteristics for filter aid manufacture. Chemical and physical properties of the raw and treated diatomite were determined using different instruments such as X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). The obtained results showed that Lam Dong diatomite has low SiO2 (52.9%) and high Fe2O3 content (5.32%). In order to enrich SiO2 and eliminate unnecessary components, different acids (6M H2SO4, 3.5M HCl and 5M HCl) were used. Among acids used, le...
Polímeros, 2021
The UV light-mediated metal-free polymerizations of 4-vinylpyridine (4VP) have been successfully ... more The UV light-mediated metal-free polymerizations of 4-vinylpyridine (4VP) have been successfully performed by using 10-(pyren-1-yl)-10H-phenothiazine (PPTh) and pyrene as photocatalysts. The preparation of narrow polydispersity poly (4-vinyl pyridine) (P4VP) with high conversions was enabled in both protic as well as unprotic reaction media at ambient temperature. Additionally, copolymerizations of 4VP with acrylate and methacrylate monomers were also demonstrated, affording metal-free copolymer products.
Clean Technologies and Environmental Policy, 2021
The Scientific World Journal, 2021
Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese tradit... more Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese traditional remedies due to its potential value for health. In this study, polysaccharides were extracted from G. lucidum using ultrasound-assisted enzymatic extraction method. The response surface methodology and Box–Behnken design were employed to investigate the effects of pH, extraction temperature, extraction time, and ultrasonic power on the content of polysaccharides. Based on ultraviolet-visible spectroscopy analysis, the highest content of polysaccharides in the extract was 32.08 mg/g under optimum experimental parameters including enzyme concentration of 3%, pH of 5.5, extraction temperature of 45°C, extraction time of 30 min, and ultrasonic power of 480 W. The Fourier-transform infrared spectroscopy was also used to identify the functional groups in the extracts. The molecular weights of polysaccharides were determined by gel permeation chromatography. The obtained extract was then ...
New Journal of Chemistry, 2020
Red muad and rice husk ash were treated without neutralization by acid to produce a support mater... more Red muad and rice husk ash were treated without neutralization by acid to produce a support material (RR).
Biomass [Working Title], 2020
Gasification is an indirect combustion of solid and liquid biomass by converting them to combusti... more Gasification is an indirect combustion of solid and liquid biomass by converting them to combustive syngas. Gasification is an alternative process for the traditional combustion, in which the emission of dust and toxic gases can be minimized. In this chapter, a comparison of these two biomass-to-heat conversion processes applied on biomass is presented in term of environmental impacts and technological benefits with a hope to provide readers a basic view of choices. Gasification is classified as in term of gasification agents, non-catalytic and catalytic process, and plasma assisted process. Popular types of gasification equipment, aka gasifiers, are introduced with working principles, through which the advantages and weakness of technology are briefly discussed.
IOP Conference Series: Materials Science and Engineering, 2020
This work is to implement a working model of an integrated process for bioethanol in the process ... more This work is to implement a working model of an integrated process for bioethanol in the process simulation based on rigorous model using the Aspen HYSYS simulation software. As a case study, the simulation is applied to design a pilot plant that converts rice straw into ethanol. The model is based on the process for biochemical conversion of lignocellulosic biomass (rice straw) to ethanol, proposed by the pilot plant of producing bio-ethanol with capacity of 152 kg rice straw/batch. The plant for manufacturing bio-ethanol with rice straw as raw materials comprises basically three units: Pretreatment of rice straw by alkaline treatment; Simultaneous saccharification fermentation (SSF) of rice straw to produce bio-ethanol and the unit for separation and purification of bio-ethanol mixture from simultaneous and fermentation unit. Modeling of rice straw feedstock as a solid material in Aspen HYSYS, including the creation of necessary hypothetical components. Investigate and analyze the...
Polymer, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Polymer International, 2019
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as
MATEC Web of Conferences, 2019
Alkaline pretreatment has been known as the most popular method to process lignocellulosic materi... more Alkaline pretreatment has been known as the most popular method to process lignocellulosic materials for bioethanol production due to its simplicity and high efficiency. However, the waste water of the process has a very high basicity, which requires neutralization with acids upon further disposal. In this study, rubber wood saw dust (Hevea brasiliensis) was employed as lignocellulosic material and its pretreatment was inspected with both diluted H2SO4 and NaOH in different combination ways. Hereby, acid was used not only for waste water neutralization but also to contribute to lignin removal. Analysis results showed that an aqueous solution of 2.0 - 2.5 wt.% H2SO4 can be used to treat the biomass followed by alkaline pretreatment. By this so-called combo-pretreatment technique, cellulose was well preserved without significant hydrolysis while the final pretreatment efficiency was up to 63.0%, compared to 48.2% of using only the alkaline solution and 13.7% of using only the acidic s...
IFAC-PapersOnLine, 2015
This paper further explores the link between irreversible thermodynamics and system theory, and i... more This paper further explores the link between irreversible thermodynamics and system theory, and its use for port-based modeling for reaction systems. More specifically we show here that a pseudo Hamiltonian representation with R(x) > 0 can be obtained by considering the Brayton-Moser formulation via a unified potential function that verifies a thermodynamic evolution criterion. As a consequence, it gives additional degrees of freedom (i.e. to construct alternate pseudo Hamiltonian models with new passive outputs) usable for further studies on the control design. A representative example of irreversible processes via the non isothermal continuous stirred tank reactor model is used to illustrate the theoretical developments.
Desalination, 2014
ABSTRACT In this study, fouling behavior of alginic acid onto four types of hand-cast and one com... more ABSTRACT In this study, fouling behavior of alginic acid onto four types of hand-cast and one commercially-available seawater reverse osmosis membranes was investigated. Hand-cast membranes included a polyamide thin film composite and a zeolite-polyamide thin film nanocomposite, as well as poly(vinyl alcohol) coated versions of both. Flux decline due to fouling and the structural features of the fouling layers formed during seawater desalination experiments were analyzed using classic Kozeny–Carman cake filtration theory along with a more recently developed crossflow model. Initial rates of flux decline correlated strongly with membrane permeability and root-mean-squared roughness and moderately with alginate–membrane interfacial free energy. The porosity (i.e., hydraulic resistance) of the fouling layers correlated strongly with deionized water contact angle and moderately with surface area difference of the membranes. The contact angle of the membranes also heavily impacted the fouling layer mass and thickness. Membranes with high permeability, strong alginate–membrane interfacial energy of adhesion, and hydrophobic surfaces had the highest propensity for fouling by low porosity, high specific resistance cake layers. Results indicate that reverse osmosis membranes should be produced with hydrophilic, smooth, and large peak-to-peak surfaces in order to reduce flux decline due to cake layer formation.