Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the ...Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the catalyst design strategies for preparing the Ni supported on ZSM-5 zeolite catalysts to promote ESR.Specifically,two-dimensional ZSM-5 nanosheet and conventional ZSM-5 crystal were used as the catalyst carriers and two synthesis strategies,i.e.,in situ encapsulation and wet impregnation method,were employed to prepare the catalysts.Based on the comparative characterization of the catalysts and comparative catalytic assessments,it was found that the combination of the in situ encapsulation synthesis and the ZSM-5 nanosheet carrier was the effective strategy to develop catalysts for promoting H_(2) production via ESR due to the improved mass transfer(through the 2-D structure of ZSM-5 nanosheet)and formation of confined small Ni nanoparticles(resulted via the in situ encapsulation synthesis).In addition,the resulting ZSM-5 nanosheet supported Ni catalyst also showed high Ni dispersion and high accessibility to Ni sites by the reactants,being able to improve the activity and stability of catalysts and suppress metal sintering and coking during ESR at high reaction temperatures.Thus,the Ni supported on ZSM-5 nanosheet catalyst prepared by encapsulation showed the stable performance with~88% ethanol conversion and~65% H_(2) yield achieved during a 48-h longevity test at 550-C.展开更多
MgAl and MgMAl oxides（M = Co,Ni and Cu） with a Mg：M：Al molar ratio = 4：1：1 were synthesized from the calcination of their corresponding layered double hydroxide（LDHs） precursors.Their catalytic activities were...MgAl and MgMAl oxides（M = Co,Ni and Cu） with a Mg：M：Al molar ratio = 4：1：1 were synthesized from the calcination of their corresponding layered double hydroxide（LDHs） precursors.Their catalytic activities were examined for the oxidation of ethylbenzene using tert-butylhydroperoxide（TBHP） as an oxidant.The oxidized product was mainly acetophenone.The catalytic activities were in the order of MgCuAlMgNiAl～NiAl～MgCoAl～CoAlCuAlMgAl oxides.Reusability studies show that the catalysts are stable under the reaction conditions.展开更多
An organophosphorus-based diamine has been synthesized and used as a curing and flame retarding bifunctional agent for epoxy resins.This phosphorodiamidate functions not only as a crosslinking materials in the Epon 82...An organophosphorus-based diamine has been synthesized and used as a curing and flame retarding bifunctional agent for epoxy resins.This phosphorodiamidate functions not only as a crosslinking materials in the Epon 828 epoxy resin curing process but also as a fire retarding compound to produce thin films or composites upon curing.This phosphorus-containing reactive amine was synthesized via condensation of phenyphosphonic dichloride with ethylenediamine in the presence of sodium methoxide.The product was then purified and later characterized by NMR and FTIR spectroscopy as well as MALDI-TOF mass spectrometry.Kinetics studies of the curing reaction of the phosphorodiamidate were carried out in comparison with the non-phosphorus containing ethylenediamine reference crosslinking agent.Thermal stability of the cured epoxy ware investigated by thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).Moreover,flame retardant properties of the obtained materials was investigated by limiting oxygen index(LOI)measurements as well as the UL-40 method.The obtained results show that epoxy resin cured with phosphorodiamidate possesses higher thermostability compared to the epoxy cured with the regular ethylenediamine counterpart.This is evident by higher amount of char formed upon burning.More importantly,the LOI value of 27 was observed in the phosphorodiamidate-cured epoxy resin compared with LOI of 20 of the epoxy resin cured with ethylenediamine where no phosphorus was present.The UL-94 highest rating of V-0 materials was obtained with only about 2-3 wt%of the phosphorus element.The chemistry,curing kinetics,and thermal properties of these new epoxy formulations are discussed.展开更多
This research studied the initiator efficiency for producing polymeric particles of poly(styrene-co-methyl methacrylate)copolymers by a Shirasu porous glass membrane(SPG)emulsification technique followed by suspension...This research studied the initiator efficiency for producing polymeric particles of poly(styrene-co-methyl methacrylate)copolymers by a Shirasu porous glass membrane(SPG)emulsification technique followed by suspension copolymerization.BPO,ADVN,and AIBN were used as initiators and we found that BPO is the most suitable initiator.Copolymers for various feed ratios of styrene/methyl methacrylate were thus synthesized by benzoyl peroxide,and their copolymer particle size,molecular weight distribution and pat-ride size distribution were characterized.Then n-BMA or 2-EHMA was added as the third monomer to decrease the terpolymer glass transition temperature.This article describes the preparation technique,recipes and polymerization conditions for producing both copolymer and terpolymer particles,particle size changes,the corresponding particle morphologies and glass transition temperatures.展开更多
The extraction of palladium from hydrochloric acid solutions into emulsion liquid membranes (ELMs) using LIX 984N-C as the extractant was investigated. The influential factors and the total capacities of palladium ext...The extraction of palladium from hydrochloric acid solutions into emulsion liquid membranes (ELMs) using LIX 984N-C as the extractant was investigated. The influential factors and the total capacities of palladium extraction were determined by a batch method. The behavior of palladium extraction by ELMs under the operational conditions-pH of the external feed phase, surfactant and extractant concentration, internal stripping phase concentration, treat ratio and agitation speed were reported. Using LIX 984N-C, palladium was effectively extracted from the external acidic chloride feed phase into the internal receiving phase of W/O emulsions. More than 92% of palladium could be extracted at a feed pH of 2 with 3% Span 80, 9% LIX 984N-C and 7M HCl at a stirring speed of 300 rpm.展开更多
A fast and sensitive method for the determination of thiol compounds including homocysteine, glutathione and N-aeetyl-l-cysteine using microchip capillary electrophoresis was proposed. The mierochip was made from an e...A fast and sensitive method for the determination of thiol compounds including homocysteine, glutathione and N-aeetyl-l-cysteine using microchip capillary electrophoresis was proposed. The mierochip was made from an elastomerie material-poly （dimethylsiloxane） （PDMS）. The microehip configureation consists of a top layer of PDMS containing of injection and separation channels, reservoirs and a gold microwire sealed with a bottom layer of PDMS. A gold microwire was used as the working electrode and platinum mierowire was used as counter electrode. The pulsed amperometric detection （PAD） was applied for determination of these thiol compounds. The experiments were carried out with 20 mM MES and 1 mM SDS buffer （pH 6.0）. In order to optimize the conditions, detection and separation potential, pH buffer, injection time, and PAD parameters were studied. Homocysteine, glutathione and N-aeetyl-L-cysteine can be separated and detected in less than 2 rain at the detection potential of ＋0.8 V, separation potential of ＋1200 V, and injection time of 20 s, with good reproducibility and sensitivity.展开更多
The three-dimensional computational fuid dynamics(3D-CFD)of a pulsating flow applied to the fluid catalytic cracking(FCC)reaction was investigated in the riser of a circulating fluidized bed reactor.The kinetic parame...The three-dimensional computational fuid dynamics(3D-CFD)of a pulsating flow applied to the fluid catalytic cracking(FCC)reaction was investigated in the riser of a circulating fluidized bed reactor.The kinetic parameters of the FCC and coke burning reactions for predicting the reactant conversion and product yield percentages were applied.To increase the reactant conversion level and product yield.the effect of the pulsating flow operating parameters was considered using a 2k statistical experimental design with four factors(amplitude,frequency,types of the waveform,and amplitude ratio).The 3DCFD simulation was successfully validated from the experimental literature data.The frequency and type of the waveform were found to be the significant operating parameters.The expression of the fitted regression model and response surface contour were derived and revealed that the pulsating flow provides a higher reactant conversion level and product yield percentages compared to a non-pulsating or steady flow.展开更多
The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis（FTS） without a reduction step. The effect of different citr...The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis（FTS） without a reduction step. The effect of different citric acid（CA）：iron nitrate（N） molar ratios and acid types on the FTS performance of catalysts were investigated. The CA：N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide（FexC）, which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA：N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA：N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst（CA：N molar ratio = 0.1） achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.展开更多
The work described herein represents an efficient method in the deposition of poly(3-methylthiophene),P3MeTh,thin films utilizing a microwave plasma system in combination with a simultaneous doping with iodine.It was ...The work described herein represents an efficient method in the deposition of poly(3-methylthiophene),P3MeTh,thin films utilizing a microwave plasma system in combination with a simultaneous doping with iodine.It was envisaged that,an alternative poly(3-methylthiophene),P(3MeTh),with an electron donating methyl substituent,would reduce the degree of ring opening which reportedly occur to a certain extent during the plasma polymerization process of its parent compound polythiophene.An alkyl substituent would also increase the solubility of the materials.P(3MeTh)thin film deposition has been performed utilizing microwave-induced plasma polymerization in order to directly grow films on glass substrates.Moreover,simultaneous doping of the so-formed polymer with iodine has been carried out as opposed to the post-synthesis doping method.This is aimed to prolong electrical conducting lifetime of the materials.The synthesized films were characterized by attenuated total reflection fourier transform infrared(ATR FT-IR)spectroscopy and energy dispersive X-ray spectroscopy(EDS)to confirm the incorporation of iodine dopant into the films.Scanning electron microscopy showed uniformly deposited films.It has been observed that the electrical conductivity of the doped film is 2 orders of magnitude higher than the undoped counterpart.The doped fabricated films exhibited UV-vis spectra indicative of increased π-conjugation(536 nm).Furthermore,electrical conductivity of the in situ doped P(3MeTh)is more highly sustained over a longer period of time.展开更多
基金funding from the European Union's Horizon 2020 Research and Innovation Program(872102)P.S.thanks the Science Achievement Scholarship of Thailand(SAST)for her research secondment at The University of Manchester.Y.J.thanks the National Natural Science Foundation of China(22378407)for funding.
文摘Compared to reforming reactions using hydrocarbons,ethanol steam reforming(ESR)is a sustainable alternative for hydrogen(H_(2))production since ethanol can be produced sustainably using biomass.This work explores the catalyst design strategies for preparing the Ni supported on ZSM-5 zeolite catalysts to promote ESR.Specifically,two-dimensional ZSM-5 nanosheet and conventional ZSM-5 crystal were used as the catalyst carriers and two synthesis strategies,i.e.,in situ encapsulation and wet impregnation method,were employed to prepare the catalysts.Based on the comparative characterization of the catalysts and comparative catalytic assessments,it was found that the combination of the in situ encapsulation synthesis and the ZSM-5 nanosheet carrier was the effective strategy to develop catalysts for promoting H_(2) production via ESR due to the improved mass transfer(through the 2-D structure of ZSM-5 nanosheet)and formation of confined small Ni nanoparticles(resulted via the in situ encapsulation synthesis).In addition,the resulting ZSM-5 nanosheet supported Ni catalyst also showed high Ni dispersion and high accessibility to Ni sites by the reactants,being able to improve the activity and stability of catalysts and suppress metal sintering and coking during ESR at high reaction temperatures.Thus,the Ni supported on ZSM-5 nanosheet catalyst prepared by encapsulation showed the stable performance with~88% ethanol conversion and~65% H_(2) yield achieved during a 48-h longevity test at 550-C.
基金support from the research grant"The 90th Anniversary of Chulalongkorn University Fund" from the Graduate School,Chulalongkorn University
文摘MgAl and MgMAl oxides（M = Co,Ni and Cu） with a Mg：M：Al molar ratio = 4：1：1 were synthesized from the calcination of their corresponding layered double hydroxide（LDHs） precursors.Their catalytic activities were examined for the oxidation of ethylbenzene using tert-butylhydroperoxide（TBHP） as an oxidant.The oxidized product was mainly acetophenone.The catalytic activities were in the order of MgCuAlMgNiAl～NiAl～MgCoAl～CoAlCuAlMgAl oxides.Reusability studies show that the catalysts are stable under the reaction conditions.
文摘An organophosphorus-based diamine has been synthesized and used as a curing and flame retarding bifunctional agent for epoxy resins.This phosphorodiamidate functions not only as a crosslinking materials in the Epon 828 epoxy resin curing process but also as a fire retarding compound to produce thin films or composites upon curing.This phosphorus-containing reactive amine was synthesized via condensation of phenyphosphonic dichloride with ethylenediamine in the presence of sodium methoxide.The product was then purified and later characterized by NMR and FTIR spectroscopy as well as MALDI-TOF mass spectrometry.Kinetics studies of the curing reaction of the phosphorodiamidate were carried out in comparison with the non-phosphorus containing ethylenediamine reference crosslinking agent.Thermal stability of the cured epoxy ware investigated by thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).Moreover,flame retardant properties of the obtained materials was investigated by limiting oxygen index(LOI)measurements as well as the UL-40 method.The obtained results show that epoxy resin cured with phosphorodiamidate possesses higher thermostability compared to the epoxy cured with the regular ethylenediamine counterpart.This is evident by higher amount of char formed upon burning.More importantly,the LOI value of 27 was observed in the phosphorodiamidate-cured epoxy resin compared with LOI of 20 of the epoxy resin cured with ethylenediamine where no phosphorus was present.The UL-94 highest rating of V-0 materials was obtained with only about 2-3 wt%of the phosphorus element.The chemistry,curing kinetics,and thermal properties of these new epoxy formulations are discussed.
文摘This research studied the initiator efficiency for producing polymeric particles of poly(styrene-co-methyl methacrylate)copolymers by a Shirasu porous glass membrane(SPG)emulsification technique followed by suspension copolymerization.BPO,ADVN,and AIBN were used as initiators and we found that BPO is the most suitable initiator.Copolymers for various feed ratios of styrene/methyl methacrylate were thus synthesized by benzoyl peroxide,and their copolymer particle size,molecular weight distribution and pat-ride size distribution were characterized.Then n-BMA or 2-EHMA was added as the third monomer to decrease the terpolymer glass transition temperature.This article describes the preparation technique,recipes and polymerization conditions for producing both copolymer and terpolymer particles,particle size changes,the corresponding particle morphologies and glass transition temperatures.
文摘The extraction of palladium from hydrochloric acid solutions into emulsion liquid membranes (ELMs) using LIX 984N-C as the extractant was investigated. The influential factors and the total capacities of palladium extraction were determined by a batch method. The behavior of palladium extraction by ELMs under the operational conditions-pH of the external feed phase, surfactant and extractant concentration, internal stripping phase concentration, treat ratio and agitation speed were reported. Using LIX 984N-C, palladium was effectively extracted from the external acidic chloride feed phase into the internal receiving phase of W/O emulsions. More than 92% of palladium could be extracted at a feed pH of 2 with 3% Span 80, 9% LIX 984N-C and 7M HCl at a stirring speed of 300 rpm.
基金National Nanotechnology Center (NANOTEC) through grant No. NH-B-22-FN-10-50-06,Asian Development Bank (ADB),Graduate Thesis Grant and Chulalongkorn University for financial support
文摘A fast and sensitive method for the determination of thiol compounds including homocysteine, glutathione and N-aeetyl-l-cysteine using microchip capillary electrophoresis was proposed. The mierochip was made from an elastomerie material-poly （dimethylsiloxane） （PDMS）. The microehip configureation consists of a top layer of PDMS containing of injection and separation channels, reservoirs and a gold microwire sealed with a bottom layer of PDMS. A gold microwire was used as the working electrode and platinum mierowire was used as counter electrode. The pulsed amperometric detection （PAD） was applied for determination of these thiol compounds. The experiments were carried out with 20 mM MES and 1 mM SDS buffer （pH 6.0）. In order to optimize the conditions, detection and separation potential, pH buffer, injection time, and PAD parameters were studied. Homocysteine, glutathione and N-aeetyl-L-cysteine can be separated and detected in less than 2 rain at the detection potential of ＋0.8 V, separation potential of ＋1200 V, and injection time of 20 s, with good reproducibility and sensitivity.
文摘The three-dimensional computational fuid dynamics(3D-CFD)of a pulsating flow applied to the fluid catalytic cracking(FCC)reaction was investigated in the riser of a circulating fluidized bed reactor.The kinetic parameters of the FCC and coke burning reactions for predicting the reactant conversion and product yield percentages were applied.To increase the reactant conversion level and product yield.the effect of the pulsating flow operating parameters was considered using a 2k statistical experimental design with four factors(amplitude,frequency,types of the waveform,and amplitude ratio).The 3DCFD simulation was successfully validated from the experimental literature data.The frequency and type of the waveform were found to be the significant operating parameters.The expression of the fitted regression model and response surface contour were derived and revealed that the pulsating flow provides a higher reactant conversion level and product yield percentages compared to a non-pulsating or steady flow.
基金financial support to the Overseas Academic Presentation Scholarship for Graduate Students, Graduate School, Chulalongkorn University
文摘The purpose of this study was to prepare iron-based catalysts supported on silica by autocombustion method for directly using for Fischer-Tropsch synthesis（FTS） without a reduction step. The effect of different citric acid（CA）：iron nitrate（N） molar ratios and acid types on the FTS performance of catalysts were investigated. The CA：N molar ratios had an important influence on the formation of iron active phases and FTS activity. The iron carbide（FexC）, which is known to be one of the iron active phases, was demonstrated by the X-ray diffraction and X-ray photoelectron spectroscopy. Increasing the CA：N molar ratios up to 0.1 increased CO conversion of catalyst to 86.5%, which was then decreased markedly at higher CA：N molar ratios. An excess of CA resulted in carbon residues covering the catalyst surface and declined FTS activity. The optimal catalyst（CA：N molar ratio = 0.1） achieved the highest CO conversion when compared with other autocombustion catalysts as well as reference catalyst prepared by impregnation method, followed by a reduction step. The autocombustion method had the advantage to synthesize more efficient catalysts without a reduction step. More interestingly, iron-based FTS catalysts need induction duration at the initial stage of FTS reaction even after reduction, because metallic iron species need time to be transformed to FexC. But here, even if without reduction, FexC was formed directly by autocombustion and induction period was eliminated during FTS reaction.
文摘The work described herein represents an efficient method in the deposition of poly(3-methylthiophene),P3MeTh,thin films utilizing a microwave plasma system in combination with a simultaneous doping with iodine.It was envisaged that,an alternative poly(3-methylthiophene),P(3MeTh),with an electron donating methyl substituent,would reduce the degree of ring opening which reportedly occur to a certain extent during the plasma polymerization process of its parent compound polythiophene.An alkyl substituent would also increase the solubility of the materials.P(3MeTh)thin film deposition has been performed utilizing microwave-induced plasma polymerization in order to directly grow films on glass substrates.Moreover,simultaneous doping of the so-formed polymer with iodine has been carried out as opposed to the post-synthesis doping method.This is aimed to prolong electrical conducting lifetime of the materials.The synthesized films were characterized by attenuated total reflection fourier transform infrared(ATR FT-IR)spectroscopy and energy dispersive X-ray spectroscopy(EDS)to confirm the incorporation of iodine dopant into the films.Scanning electron microscopy showed uniformly deposited films.It has been observed that the electrical conductivity of the doped film is 2 orders of magnitude higher than the undoped counterpart.The doped fabricated films exhibited UV-vis spectra indicative of increased π-conjugation(536 nm).Furthermore,electrical conductivity of the in situ doped P(3MeTh)is more highly sustained over a longer period of time.
