The effect of anionic-nonionic mixed surfactant (SDBS-TX100) on the uptake of phenanthrene and pyrene by ryegrass in a hydroponic system was studied, and the influence factors including the com- positions and concentr...The effect of anionic-nonionic mixed surfactant (SDBS-TX100) on the uptake of phenanthrene and pyrene by ryegrass in a hydroponic system was studied, and the influence factors including the com- positions and concentrations of mixed surfactants and the compounds properties were also discussed. The results showed that SDBS-TX100 mixtures with certain compositions and concentrations could enhance the uptake of phenanthrene and pyrene by ryegrass, which could be attributed to the im- proved uptake capacity of ryegrass roots for phenanthrene and pyrene. SDBS-TX100 can enhance the uptake of phenanthrene and pyrene by ryegrass in a wider range of surfactant concentrations (0―0.8 mmol/L) in comparison with corresponding single surfactants, and the maximal contents of phenan- threne and pyrene in ryegrass roots were obtained with the concentrations of SDBS-TX100 around the corresponding critical micelle concentrations. The uptake of phenanthrene and pyrene by ryegrass increased with the increasing mole fraction of SDBS in mixed surfactant solutions, and SDBS-TX100 mixture with a mole ratio of SDBS to TX100 at 9:1 had the greatest capacity in enhancing the uptake of phenanthrene and pyrene, at which the corresponding maximal concentrations of phenanthrene and pyrene in ryegrass roots were 216 and 8.16 times those without surfactants, respectively. Results from this study indicate that the anionic-nonionic mixed surfactants (SDBS-TX100) would be a preferred selection for the application of surfactant-enhanced phytoremediation technology to contaminated soils.展开更多
A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,th...A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,the formation water and rock components in the Tahe Oilfield,the long-term thermal stability,salt tolerance and the ability to change the wettability,interfacial activity and oil washing efficiency of the mixed surfactant system were studied.The system contains the anionic surfactant SDB and another cationic surfactant SDY.When the total mass concentration of the SS solution is 0.15 wt%,m(SDB)/m(SDY)ratio is 1 to 1,and excellent efficiencies are achieved for oil washing for five kinds of Tahe Oilfield crude oils(more than 60%).In addition,after adding cationic surfactant,the adsorption capacity of the surfactant is further reduced,reaching 0.261 mg/g.The oil displacement experiments indicate that under a temperature of 150°C and a salinity of 24.6×104 mg/L,the SS system enhances the oil recovery by over 10%after water flooding.The SS anionic–cationic surfactant system is first presented in the open literature that can be successfully applied to obtain predictions of Tahe Oilfield carbonate reservoirs with a high temperature and high salinity.展开更多
A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system containe...A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.展开更多
Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant...Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.展开更多
Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding sy...Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.展开更多
In the presence of mixed micelle of a cationic and a nonionic surfactants,the reaction of scandium(Ⅲ) with phenylfluorone or its derivatives results in a very sensitive colouration:furthermore this chromophoric syste...In the presence of mixed micelle of a cationic and a nonionic surfactants,the reaction of scandium(Ⅲ) with phenylfluorone or its derivatives results in a very sensitive colouration:furthermore this chromophoric system tolerates the existence of a considerable amount of masking agents,so that many interfering ions can be masked and its selectivity would be further improved.After studying the optimum conditions and main charac- ters of some similar systems,the system of Sc(Ⅲ)—Orthonitrophenyuorone—Cetyltrimethylammonium Bromide(CTMAB)—Triton X-200 is chosen for the spectrophotometric determination of microamount of scandium.The proposed method shows not only high sensitivity(with a molar absorptivity of 2.12×1~sL mol^(-1)·cm^(-1))and selectivity,but also high tolerance of chromophoric conditions.Beer's law is obeyed over a range of 0～6.0 μg Sc/25ml.If the dual-wavelength method is applied,a much higher molar absorptivity o|' 3.04×10~5L·mol^(-1)·cm^(-1)than those of other systems ever reported in the literatures can be attained:more- over.its linear range is extended to 0～8.0 μg Sc/25ml and its reproducibility is also improved.展开更多
Experimental data are presented on the enhanced solubilities of fluorene (FLR) resulting from solubilization in aqueous solutions of two conventional surfactants: cationic cetyltrimethylammonium bromide (CTAB) , anion...Experimental data are presented on the enhanced solubilities of fluorene (FLR) resulting from solubilization in aqueous solutions of two conventional surfactants: cationic cetyltrimethylammonium bromide (CTAB) , anionic sodium dodecyl sulfate (SDS), nonioinic polyethylene glycol dodecyl ether (Brij35) and a cationic gemini bis (hexadecyldimethylammonium) pentane dibromide (G5). The critical micellar concentration of surfactants was determined by surface tension measurements and aqueous solubilities of fluorene compound in surfactant solutions were measured spectrophotometrically. Solubilization of PAH compound commenced at the surfactant critical micelle concentration and was proportional to the concentration of surfactant in micelle. The results of the mixed systems were analyzed with the help of regular solution theory, in which the deviation of CMCexp values for mixed surfactant systems from CMCideal was measured by evaluating the interaction parameter, βm. Negative values of βm were observed in all equimolar binary systems which show synergism in the mixed micelle. Attraction force between two oppositely charged head groups lead the strongest synergism effect between cationic gemini and anionic conventional surfactant. In addition to molar solubilization ratio (MSR) solubilization efficiency is also quantified in terms of micelle-water partition coefficient (Km).展开更多
The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammon...The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammonium bromide (CTAB) at molar fraction of AEO9, A EO9 α =0.5. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γCMC), maximum surface excess concentration (Γmax) and minimum area per molecule at the air/solution interface (Amin) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were determined. Mixtures of both AEO9/SDS and AEO9/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.展开更多
This study investigates the potential of enhancing oil recovery from a Middle East heavy oil field via hot water injection followed by injection of a chemical surfactant and/or a biosurfactant produced by a Bacillus s...This study investigates the potential of enhancing oil recovery from a Middle East heavy oil field via hot water injection followed by injection of a chemical surfactant and/or a biosurfactant produced by a Bacillus subtilis strain which was isolated from oil-contaminated soil.The results reveal that the biosurfactant and the chemical surfactant reduced the residual oil saturation after a hot water flood.Moreover,it was found that the performance of the biosurfactant increased by mixing it with the chemical surfactant.It is expected that the structure of the biosurfactant used in this study was changed when mixed with the chemical surfactant as a probable synergetic effect of biosurfactant-chemical surfactants was observed on enhancing oil recovery,when used as a mixture,rather than alone.This work proved that it is more feasible to inject the biosurfactant as a blend with the chemical surfactant,at the tertiary recovery stage.This might be attributed to the fact that in the secondary mode,improvement of the macroscopic sweep efficiency is important,whereas in the tertiary recovery mode,the microscopic sweep efficiency matters mainly and it is improved by the biosurfactantchemical surfactant mixture.Also as evidenced by this study,the biosurfactant worked better than the chemical surfactant in reducing the residual heavy oil saturation after a hot water flood.展开更多
Polyoxyethylene sorbitan monooleate(Tween-80) and oleic acid(OA) with different molar ratios were mixed and spread at air/water interface on subphases with varied pH values by using a Langmuir trough to investigate th...Polyoxyethylene sorbitan monooleate(Tween-80) and oleic acid(OA) with different molar ratios were mixed and spread at air/water interface on subphases with varied pH values by using a Langmuir trough to investigate the laws governing the performance of the two components.The surface excess free energy(△G_M^(exc)) of mixed monolayers with various mixed molar ratios at different pH values under the surface pressure of 10 mN/m was analyzed,for the compatibility evaluation of mixtures in the monolayer.The results indicated that Tween-80 and OA could be miscible in thermodynamics under almost all the conditions in the experiments,except when the molar ratios of OA were more than 0.5 on the alkaline subphase at pH 9.5.The better thermodynamic compatibility between OA and Tween-80 occurred as the surface pressure was 10 mN/m,when the molar ratios of OA were 0.7 and 0.1 respectively in our experiments.展开更多
The interaction of cationic gemini surfactants(alkanediyl-α,ω-bis(alkyl dimethylammonium bromide)) with an antipsychotic drug(chlorpromazine hydrochloride(CPZ)) has been investigated. Various micellar and interfacia...The interaction of cationic gemini surfactants(alkanediyl-α,ω-bis(alkyl dimethylammonium bromide)) with an antipsychotic drug(chlorpromazine hydrochloride(CPZ)) has been investigated. Various micellar and interfacial parameters have been deliberated by surface tension measurement to report the nature of interactions between drug and novel surfactant mixtures. The behavior of mixed systems, their compositions and activities of components have been analyzed in the light of Rubingh's theory. The results indicate synergism in the binary mixtures.The binding study between CPZ and surfactants has been done by spectroscopic techniques such as UV–visible and fluorescence. The results are discussed in the light of the use of gemini surfactants as promising drug delivery agents for phenothiazine drugs, and hence, improve their bioavailability.展开更多
Denitrification of nitrate in groundwater using iron nanoparticles has received increasing interest in recent years.In order to fabricate iron nanoparticles with homoge-neously spherical shape and narrow size distribu...Denitrification of nitrate in groundwater using iron nanoparticles has received increasing interest in recent years.In order to fabricate iron nanoparticles with homoge-neously spherical shape and narrow size distribution,a simple and“green”method was developed to synthesize iron nano-particles.The conventional microemulsion methods were modified by applying Span 80 and Tween 60 as mixed sur-factants.The maximum content of water in the Water-in-oil(W/O)microemulsion and its appropriate forming conditions were found,and then the microemulsion system consisting of saturated Fe^(2+)solution was used to synthesizeα-Fe ultrafine particles by redox reaction.The nanoparticles were characterized by using powder X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that the average diameter of the particle is about 80-90 nm.The chemical activity of the obtained iron nanoparticles was studied by the denitrification experiment of nitrate.The results show that under the experimental conditions,iron removed most of the 80 mg/L nitrate within 30 min.The mass balance of nitrate reduction with nanoscale Fe indicates that endproducts are mainly ammonia.Two possible reaction pathways for nitrate reduction by nanoscale iron particles have been proposed in this work.展开更多
The rheological behavior of the aqueous solutions of mixed sulfate gemini surfactant with no spacer group, referred to as d-C12S, and dodecyltrimethylammonium bromide （C12TABr） at a total concentration of 100 mmol,L...The rheological behavior of the aqueous solutions of mixed sulfate gemini surfactant with no spacer group, referred to as d-C12S, and dodecyltrimethylammonium bromide （C12TABr） at a total concentration of 100 mmol,L-1 but different molar ratios of ClzTABr to d-C12S （a1） was investigated using steady rate and frequency sweep measurements. The wormlike micelles were formed over a narrow a1 range of 0.20-0.27. The viscoelastic solutions exhibited Maxwell fluid behavior. At the optimum molar ratio of 0.25, the zero-shear viscosity was as high as 600 paos and the length of the mixed wormlike micelle was about 0.45-0.85 pm. The present result provides an exam- ple to construct long wormlike micelles by anionic gemini surfactant.展开更多
Ni（II） ions were removed from aqueous waste using micellar enhanced ultrafiltration （MEUF） with a mixture of surfactants. The surfactant mixture was the nonionic surfactant Tween 80 （TW80） mixed with the anionic...Ni（II） ions were removed from aqueous waste using micellar enhanced ultrafiltration （MEUF） with a mixture of surfactants. The surfactant mixture was the nonionic surfactant Tween 80 （TW80） mixed with the anionic surfactant sodium dodecyl sulfate （SDS） in different molar ratios ranging from 0.1-1.5. The opera- tional variables of the MEUF process such as pH, applied pressure, surfactant to metal ion ratio and nonionic to ionic surfactant molar ratio （α） were evaluated. Rejection of Ni and TW80 was 99% and 98% respectively whereas that for SDS was 65%. The flux and all resistances （fouling resistance, resistance due to concentration polarization） were measured and calculated for entire range of α respectively. A calculated flux was found to be declined with time, which was mainly attributed to concentration polarization rather than resistance from membrane fouling.展开更多
Iron nanoparticles with dynamic light scattering median diameter around 10 nm have been prepared by thermal decomposition under a nitrogen atmosphere from diironnonacarbonyl (DINC) dissolved in n-butyl-3-methylimidazo...Iron nanoparticles with dynamic light scattering median diameter around 10 nm have been prepared by thermal decomposition under a nitrogen atmosphere from diironnonacarbonyl (DINC) dissolved in n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF). The effect of temperature changes in the range of 170<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C - 200<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C and changes in concentration of DINC in BMIMBF in the range of 0.1% - 0.9% on the properties of obtained iron nanoparticles has been investigated. The stable dispersion of iron nanoparticle in ethanol has been prepared after separation of nanoparticles from ionic liquid by centrifugation following by their re-dispersion in ethanol. The possibility of quantitative analysis of iron content in ethanol dispersion by deposition of ferromagnetic nanoparticles on the surface of plastic-protected neodymium magnet, dissolution of iron in hydrochloric acid and addition of ammonium thiocyanate solution following by spectrophotometric determination of iron cations at wavelength of 490 nm has been investigated. The feasibility of using the same approach in case of addition of ethanol dispersion of iron nanoparticles to the liquid animal feeds for evaluation of efficiency of their mixing has been discussed.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20737002 and 40571143)National Research and Development Program of China (Grant No. 2003CB415004)Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT 0536)
文摘The effect of anionic-nonionic mixed surfactant (SDBS-TX100) on the uptake of phenanthrene and pyrene by ryegrass in a hydroponic system was studied, and the influence factors including the com- positions and concentrations of mixed surfactants and the compounds properties were also discussed. The results showed that SDBS-TX100 mixtures with certain compositions and concentrations could enhance the uptake of phenanthrene and pyrene by ryegrass, which could be attributed to the im- proved uptake capacity of ryegrass roots for phenanthrene and pyrene. SDBS-TX100 can enhance the uptake of phenanthrene and pyrene by ryegrass in a wider range of surfactant concentrations (0―0.8 mmol/L) in comparison with corresponding single surfactants, and the maximal contents of phenan- threne and pyrene in ryegrass roots were obtained with the concentrations of SDBS-TX100 around the corresponding critical micelle concentrations. The uptake of phenanthrene and pyrene by ryegrass increased with the increasing mole fraction of SDBS in mixed surfactant solutions, and SDBS-TX100 mixture with a mole ratio of SDBS to TX100 at 9:1 had the greatest capacity in enhancing the uptake of phenanthrene and pyrene, at which the corresponding maximal concentrations of phenanthrene and pyrene in ryegrass roots were 216 and 8.16 times those without surfactants, respectively. Results from this study indicate that the anionic-nonionic mixed surfactants (SDBS-TX100) would be a preferred selection for the application of surfactant-enhanced phytoremediation technology to contaminated soils.
基金The support from the China National High Technology Research and Development Program(No.2013AA064301)the National Natural Science Foundation of China(51274210)the Research Start-up Fund of Karamay Campus of China University of Petroleum-Beijing(XQZX20200013)is greatly appreciated.
文摘A new temperature-resistant and salt-tolerant mixed surfactant system(referred to as the SS system)for enhancing oil recovery at the Tahe Oilfield(Xinjiang,China)was evaluated.Based on the analysis of the crude oil,the formation water and rock components in the Tahe Oilfield,the long-term thermal stability,salt tolerance and the ability to change the wettability,interfacial activity and oil washing efficiency of the mixed surfactant system were studied.The system contains the anionic surfactant SDB and another cationic surfactant SDY.When the total mass concentration of the SS solution is 0.15 wt%,m(SDB)/m(SDY)ratio is 1 to 1,and excellent efficiencies are achieved for oil washing for five kinds of Tahe Oilfield crude oils(more than 60%).In addition,after adding cationic surfactant,the adsorption capacity of the surfactant is further reduced,reaching 0.261 mg/g.The oil displacement experiments indicate that under a temperature of 150°C and a salinity of 24.6×104 mg/L,the SS system enhances the oil recovery by over 10%after water flooding.The SS anionic–cationic surfactant system is first presented in the open literature that can be successfully applied to obtain predictions of Tahe Oilfield carbonate reservoirs with a high temperature and high salinity.
文摘A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.
基金financially supported by National Natural Science Foundation of China(No.22302229)Beijing Municipal Excellent Talent Training Funds Youth Advanced Individual Project(No.2018000020124G163)。
文摘Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.
文摘Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.
文摘In the presence of mixed micelle of a cationic and a nonionic surfactants,the reaction of scandium(Ⅲ) with phenylfluorone or its derivatives results in a very sensitive colouration:furthermore this chromophoric system tolerates the existence of a considerable amount of masking agents,so that many interfering ions can be masked and its selectivity would be further improved.After studying the optimum conditions and main charac- ters of some similar systems,the system of Sc(Ⅲ)—Orthonitrophenyuorone—Cetyltrimethylammonium Bromide(CTMAB)—Triton X-200 is chosen for the spectrophotometric determination of microamount of scandium.The proposed method shows not only high sensitivity(with a molar absorptivity of 2.12×1~sL mol^(-1)·cm^(-1))and selectivity,but also high tolerance of chromophoric conditions.Beer's law is obeyed over a range of 0～6.0 μg Sc/25ml.If the dual-wavelength method is applied,a much higher molar absorptivity o|' 3.04×10~5L·mol^(-1)·cm^(-1)than those of other systems ever reported in the literatures can be attained:more- over.its linear range is extended to 0～8.0 μg Sc/25ml and its reproducibility is also improved.
文摘Experimental data are presented on the enhanced solubilities of fluorene (FLR) resulting from solubilization in aqueous solutions of two conventional surfactants: cationic cetyltrimethylammonium bromide (CTAB) , anionic sodium dodecyl sulfate (SDS), nonioinic polyethylene glycol dodecyl ether (Brij35) and a cationic gemini bis (hexadecyldimethylammonium) pentane dibromide (G5). The critical micellar concentration of surfactants was determined by surface tension measurements and aqueous solubilities of fluorene compound in surfactant solutions were measured spectrophotometrically. Solubilization of PAH compound commenced at the surfactant critical micelle concentration and was proportional to the concentration of surfactant in micelle. The results of the mixed systems were analyzed with the help of regular solution theory, in which the deviation of CMCexp values for mixed surfactant systems from CMCideal was measured by evaluating the interaction parameter, βm. Negative values of βm were observed in all equimolar binary systems which show synergism in the mixed micelle. Attraction force between two oppositely charged head groups lead the strongest synergism effect between cationic gemini and anionic conventional surfactant. In addition to molar solubilization ratio (MSR) solubilization efficiency is also quantified in terms of micelle-water partition coefficient (Km).
基金Project (No. 2004C31058) supported by the National NaturalScience Foundation of China
文摘The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammonium bromide (CTAB) at molar fraction of AEO9, A EO9 α =0.5. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γCMC), maximum surface excess concentration (Γmax) and minimum area per molecule at the air/solution interface (Amin) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were determined. Mixtures of both AEO9/SDS and AEO9/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.
基金Majesty Research Fund (SR/SCI/BIOL/08/01),Sultan Qaboos University,Oman and the Petroleum Development of Oman (CR/SCI/BIOL/07/02) for the research grants
文摘This study investigates the potential of enhancing oil recovery from a Middle East heavy oil field via hot water injection followed by injection of a chemical surfactant and/or a biosurfactant produced by a Bacillus subtilis strain which was isolated from oil-contaminated soil.The results reveal that the biosurfactant and the chemical surfactant reduced the residual oil saturation after a hot water flood.Moreover,it was found that the performance of the biosurfactant increased by mixing it with the chemical surfactant.It is expected that the structure of the biosurfactant used in this study was changed when mixed with the chemical surfactant as a probable synergetic effect of biosurfactant-chemical surfactants was observed on enhancing oil recovery,when used as a mixture,rather than alone.This work proved that it is more feasible to inject the biosurfactant as a blend with the chemical surfactant,at the tertiary recovery stage.This might be attributed to the fact that in the secondary mode,improvement of the macroscopic sweep efficiency is important,whereas in the tertiary recovery mode,the microscopic sweep efficiency matters mainly and it is improved by the biosurfactantchemical surfactant mixture.Also as evidenced by this study,the biosurfactant worked better than the chemical surfactant in reducing the residual heavy oil saturation after a hot water flood.
文摘Polyoxyethylene sorbitan monooleate(Tween-80) and oleic acid(OA) with different molar ratios were mixed and spread at air/water interface on subphases with varied pH values by using a Langmuir trough to investigate the laws governing the performance of the two components.The surface excess free energy(△G_M^(exc)) of mixed monolayers with various mixed molar ratios at different pH values under the surface pressure of 10 mN/m was analyzed,for the compatibility evaluation of mixtures in the monolayer.The results indicated that Tween-80 and OA could be miscible in thermodynamics under almost all the conditions in the experiments,except when the molar ratios of OA were more than 0.5 on the alkaline subphase at pH 9.5.The better thermodynamic compatibility between OA and Tween-80 occurred as the surface pressure was 10 mN/m,when the molar ratios of OA were 0.7 and 0.1 respectively in our experiments.
基金Chemistry Department and Centre of Excellence for Advanced Materials Research, King Abdulaziz University
文摘The interaction of cationic gemini surfactants(alkanediyl-α,ω-bis(alkyl dimethylammonium bromide)) with an antipsychotic drug(chlorpromazine hydrochloride(CPZ)) has been investigated. Various micellar and interfacial parameters have been deliberated by surface tension measurement to report the nature of interactions between drug and novel surfactant mixtures. The behavior of mixed systems, their compositions and activities of components have been analyzed in the light of Rubingh's theory. The results indicate synergism in the binary mixtures.The binding study between CPZ and surfactants has been done by spectroscopic techniques such as UV–visible and fluorescence. The results are discussed in the light of the use of gemini surfactants as promising drug delivery agents for phenothiazine drugs, and hence, improve their bioavailability.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20477019)the Tianjin Natural Science Foundation of China(Grant No.07JCZDJC01800).
文摘Denitrification of nitrate in groundwater using iron nanoparticles has received increasing interest in recent years.In order to fabricate iron nanoparticles with homoge-neously spherical shape and narrow size distribution,a simple and“green”method was developed to synthesize iron nano-particles.The conventional microemulsion methods were modified by applying Span 80 and Tween 60 as mixed sur-factants.The maximum content of water in the Water-in-oil(W/O)microemulsion and its appropriate forming conditions were found,and then the microemulsion system consisting of saturated Fe^(2+)solution was used to synthesizeα-Fe ultrafine particles by redox reaction.The nanoparticles were characterized by using powder X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that the average diameter of the particle is about 80-90 nm.The chemical activity of the obtained iron nanoparticles was studied by the denitrification experiment of nitrate.The results show that under the experimental conditions,iron removed most of the 80 mg/L nitrate within 30 min.The mass balance of nitrate reduction with nanoscale Fe indicates that endproducts are mainly ammonia.Two possible reaction pathways for nitrate reduction by nanoscale iron particles have been proposed in this work.
基金Project supported by the Fundamental Research Funds for the Central Universities （No. JUSRP111A06）, the National Natural Science Foundation of China （Nos. 20673021, 20873024 and 21073081）, the Professional Foundation of Fuzhou University （No. XRC-0639）, and the Fujian Provincial Natural Science Foundation of China （No. 2010J01038）.
文摘The rheological behavior of the aqueous solutions of mixed sulfate gemini surfactant with no spacer group, referred to as d-C12S, and dodecyltrimethylammonium bromide （C12TABr） at a total concentration of 100 mmol,L-1 but different molar ratios of ClzTABr to d-C12S （a1） was investigated using steady rate and frequency sweep measurements. The wormlike micelles were formed over a narrow a1 range of 0.20-0.27. The viscoelastic solutions exhibited Maxwell fluid behavior. At the optimum molar ratio of 0.25, the zero-shear viscosity was as high as 600 paos and the length of the mixed wormlike micelle was about 0.45-0.85 pm. The present result provides an exam- ple to construct long wormlike micelles by anionic gemini surfactant.
文摘Ni（II） ions were removed from aqueous waste using micellar enhanced ultrafiltration （MEUF） with a mixture of surfactants. The surfactant mixture was the nonionic surfactant Tween 80 （TW80） mixed with the anionic surfactant sodium dodecyl sulfate （SDS） in different molar ratios ranging from 0.1-1.5. The opera- tional variables of the MEUF process such as pH, applied pressure, surfactant to metal ion ratio and nonionic to ionic surfactant molar ratio （α） were evaluated. Rejection of Ni and TW80 was 99% and 98% respectively whereas that for SDS was 65%. The flux and all resistances （fouling resistance, resistance due to concentration polarization） were measured and calculated for entire range of α respectively. A calculated flux was found to be declined with time, which was mainly attributed to concentration polarization rather than resistance from membrane fouling.
文摘Iron nanoparticles with dynamic light scattering median diameter around 10 nm have been prepared by thermal decomposition under a nitrogen atmosphere from diironnonacarbonyl (DINC) dissolved in n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF). The effect of temperature changes in the range of 170<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C - 200<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span>C and changes in concentration of DINC in BMIMBF in the range of 0.1% - 0.9% on the properties of obtained iron nanoparticles has been investigated. The stable dispersion of iron nanoparticle in ethanol has been prepared after separation of nanoparticles from ionic liquid by centrifugation following by their re-dispersion in ethanol. The possibility of quantitative analysis of iron content in ethanol dispersion by deposition of ferromagnetic nanoparticles on the surface of plastic-protected neodymium magnet, dissolution of iron in hydrochloric acid and addition of ammonium thiocyanate solution following by spectrophotometric determination of iron cations at wavelength of 490 nm has been investigated. The feasibility of using the same approach in case of addition of ethanol dispersion of iron nanoparticles to the liquid animal feeds for evaluation of efficiency of their mixing has been discussed.
