Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleat...Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleate (Span80) and polyoxyethylene sorbitan monooleate (Tween 80) were introduced to the terpolymerization system in an attemptto mitigate the gel effect. This enabled the preparation of high-performance amphoteric polyacrylamides, which werecharacterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The influences of the dispersanttype and content as well as the hydrophilic-lipophilic balance (HLB) on the gel effect were examined, and the mechanismunderlying the suppression of the gel effect was considered. The obtained results indicated that the gel effect can beeffectively mitigated using an aqueous adiabatic terpolymerization system containing mixed Span 80/Tween 80 dispersantsat various contents. In particular, mixed dispersant contents of 0.6%–0.8% with HLB values of 5.0–6.0 afforded the optimalperformance (e.g., high viscosity, fast aqueous dissolution time, and the like).展开更多
LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrotherma...LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrothermal method. The starting solution and the concentration of dispersant have significant influences on the morphology of LiCoPO4,and the electrochemical performance is improved via controlling the particle size and morphology by the hydrothermal method. The cell using smaller particle LiCoPO4 as cathode delivers a larger capacity and lower cell polarization.展开更多
Diesel engine technology innovation causes excessive soot accumulated in engine oil.Due to its detrimental effect on lubricant and diesel engine,improving the dispersibility of engine oil to restrain soot aggregation ...Diesel engine technology innovation causes excessive soot accumulated in engine oil.Due to its detrimental effect on lubricant and diesel engine,improving the dispersibility of engine oil to restrain soot aggregation efficiently is the key technique for formulations.In this study,the aggregation of soot and interaction between dispersant and soot were investigated by molecular dynamic simulation.It was found that the molecular interaction between the dispersant and the soot aggregation system had a significant influence on disrupting the soot aggregation.Bis-PIBSI was more beneficial to having more interaction sites with soot molecules,while the mono-PIBSI with a high proportion of polar groups had stronger interaction with soot molecules.According to the simulation result,suggestions for use of additives were proposed.Carbon black dispersancy test was exploited to verify the dispersion effect of different dispersants on carbon black.The results indicate that mono-PIBSI and bis-PIBSI added at suitable mixture ratio to lubricant could perform good dispersion ability.展开更多
The effects of sodium carboxymethyl cellulose and sodium citrate as dispersants on nano-ceramic aqueous suspension were examined by the measurements of ζ -potential and the sedimentation test. The results show that p...The effects of sodium carboxymethyl cellulose and sodium citrate as dispersants on nano-ceramic aqueous suspension were examined by the measurements of ζ -potential and the sedimentation test. The results show that proper addition of sodium carboxymethyl cellulose or sodium citrate into nano-ceramic coating, exhibits an enhanced dispersion and stability compared with the coating without dispersants. The negative ζ -potential of the particles in the nano-coating increases with the increase of pH value of the coating, and the curve of ζ -pH moves to lower pH range when the dispersants are added into the coating. To ensure that the coating has not only good stability and dispersibility but also no corrosivity to substrate alloy, adding 1.00% sodium citrate into coating with pH value of 7-8 is preferable to adding sodium carboxymethyl cellulose.展开更多
This work presents the influence of dispersants on coal-water slurry(CWS),which was prepared from the solid residue of plasma pyrolysis of coal.The effects of dispersant type,solid concentration,dispersant content,and...This work presents the influence of dispersants on coal-water slurry(CWS),which was prepared from the solid residue of plasma pyrolysis of coal.The effects of dispersant type,solid concentration,dispersant content,and temperature on the rheological properties of CWS are examined.A suitable empirical model regarding the relation between viscosity and temperature is proposed.Through the sedimentation experiment of CWS,dispersants are found to significantly promote the stability of CWS.展开更多
In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding syst...In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding system.The influence of three dispersants(citric acid,FS10 and urea)on the flow ability of colloidal alumina bonded corundum castables was researched to choose a suitable dispersant for solving the shaping problem.In order to further understand the influence of dispersants on the flow ability and the mechanism,the rheological property and Zeta potential value of the colloidal aluminadispersant system and the matrix-colloidal alumina-urea-water system were tested.The results show the castables added with the urea have the best flow ability,and the appropriate addition of the urea is 0.5%.展开更多
The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds o...The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.展开更多
There are considerable amounts of off shore oil/gas fields in the South China Sea(SCS),and for potential oil spill events in this area,dispersants may provide a reliable large-scale response when the preferable option...There are considerable amounts of off shore oil/gas fields in the South China Sea(SCS),and for potential oil spill events in this area,dispersants may provide a reliable large-scale response when the preferable option of recapturing the oil cannot be achieved.In this paper,effect of chemical dispersants on underwater oil transport is investigated with an underwater oil spill model.Since the model is an adaption of an existing one,we first calibrate it by comparing the model result with echo-sounder data that were observed during the“DeepSpill”experiment with crude oil/LNG(liquefied natural gas)discharge.Then,with the hydrodynamic data provided by an operational forecasting system and the drilling data obtained from off shore platforms in the SCS,we apply the model to a hypothetical spill case,and examine the difference in oil distribution in water column caused by subsea dispersant application.The model results can provide valuable reference for contingency plan makers to make an efficient emergency response to potential underwater oil spill accidents in the SCS.展开更多
A controlled laboratory study was conducted to measure the dispersion effectiveness of Corexit 9500 on 23 different crude oils. This study was a part of a larger project initiated by the Bureau of Safety and Environme...A controlled laboratory study was conducted to measure the dispersion effectiveness of Corexit 9500 on 23 different crude oils. This study was a part of a larger project initiated by the Bureau of Safety and Environmental Enforcement (BSEE) testing 20 oils to compare the predictive value of laboratory dispersant effectiveness tests with their larger scale test conducted at Ohmsett, BSEE’s national oil spill response test facility located in Leonardo, NJ. The test used in this study was the Baffled Flask Test (BFT), which is planned for adoption as EPA’s official testing protocol for listing commercial dispersant products on the National Contingency Plan Product Schedule, replacing the current Swirling Flask Test (SFT) [1]. In addition, the results of 3 additional oils, the 2 used in the SFT and BFT as currently written plus another reference oil, are presented. The temperature used for the tests was 15°C, to match the temperature used at Ohmsett. The dispersion effectiveness ranged from 3.4% to 93%. The BFT is a laboratory test with results that are inversely correlated with oil viscosity and therefore has predictive value in the decision to use a dispersant in the event of a spill.展开更多
Dispersants, usually blending with several surfactants and a solvent, are used to enhance oil spill dispersion as small droplets in water column. Although there is growing acceptance of dispersants as a counter measur...Dispersants, usually blending with several surfactants and a solvent, are used to enhance oil spill dispersion as small droplets in water column. Although there is growing acceptance of dispersants as a counter measure to marine oil spills around the world, the two major issues with the dispersants are their toxicity to marine life and dispersion effectiveness (DE) for crude-oil, especially for heavy oil. To develop more efficient and less toxic dispersants, two kinds of sorbitol derivant nonionic surfactant (polysorbate 85 and sorbeth-40 tetraoleate), two kinds of glycolipid biosurfactants (rhamnolipid and sophorolipid) and less toxic solvent ethylene glycol butyl ether were chosen in this study, and two dispersant formulations were optimized by uniform design methods. Effects of dispersant-to-oil ratio, temperature, salinity and pH on the performance of the two optimized dispersants were investigated. The two dispersants had high dispersion effectiveness (DE) for heavy crude oil, while both dispersants keep high DE at the dispersant-to-oil ratio below 1:25 and the temperature above 5 ℃. In addition, the two dispersants also performed well in a wide range of salinity and pH values. Finally, toxicity tests revealed that the two dispersants showed low toxicity to two kinds of fish (Danio rerio and Microgobius gulosus).展开更多
The main objective of this study is to develop a new protocol for bench-scale dispersant effectiveness testing adapted for subsea dispersants injection (SSDI). The new approach includes turbulence conditions, dispersa...The main objective of this study is to develop a new protocol for bench-scale dispersant effectiveness testing adapted for subsea dispersants injection (SSDI). The new approach includes turbulence conditions, dispersant injection techniques and quantification of effectiveness, more representative for a SSDI operation. Results from the new system are compared to dispersant effectiveness measured with established laboratory methods, used for screening dispersants for surface application. The most significant result is that the dispersant ranking obtained with the new test relevant for subsea releases was very different compared to the ranking obtained by screening methods used for surface application of dispersants. This strongly indicates that existing standard methods for dispersant effectiveness testing designed for simulating conditions relevant for surface application of dispersants, are less relevant for SSDI effectiveness testing and justify the need for a more relevant method. Such a Dispersant Injection Effectiveness Test (DIET) is suggested and documented in this study.展开更多
A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS appl...A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS application performance investigation shows that the MAD dispersant has better abilities in reducing CWS viscosity and stabilizing the slurry than a commercial dispersant—sulfonated naphthalene-formaldehyde condensate(SNF). The physicochemical property investigation of the two tested dispersants shows that the adsorption amount of the MAD at coal-water interface is much larger than that of SNF, and the MAD has better wetting property than the SNF on the coal surface. It indicated that the excellent capabilities of MAD are related to the adsorption mode of standing upright on the coal surface. Based on the above, the mechanism of dispersion and stabilization of the CWS prepared from MAD dispersant is presented.展开更多
As the efficiency of dispersants with different origins is questionable for each typical oil sample,the present study provides a reproducible and reliable method for screening asphaltene dispersants for a typical asph...As the efficiency of dispersants with different origins is questionable for each typical oil sample,the present study provides a reproducible and reliable method for screening asphaltene dispersants for a typical asphaltenic crude oil.Four different asphaltene dispersants(polyisobutylene succinimide.polyisobutylene succinic ester,nonylphenol-formaldehyde resin modified by polyamines.and rapeseed oil amide) were prepared and their performance on two oils from an Iranian field under laboratory and reservoir conditions was studied.A thorough analysis including ash content and SARA tests was performed on the solid asphaltene particles to characterize the nature of deposits.Then a highly efficient carrier fluid,which is crucial when injecting dispersant into the wells,was selected from a variety of chemicals by comparing their solubility.In the next step,using an optical microscope,a viscometer,and a Turbiscan.the screening of dispersants under laboratory conditions was done on a mixture of dead oil and dispersant to evaluate the onset of asphaltene precipitation and its stability when titrating by a precipitant.Finally,two different mixtures of the efficient dispersants.live oil,and carrier fluid were used with the solid detection system(SDS) and the filtration method to examine their effects on the onset pressure of asphaltene precipitation and the asphaltene content of the crude oil under reservoir conditions.The results show that the combination of experimental methods used in this work could be consistently applied to screening asphaltene dispersants.Among the four different dispersants applied here,the dispersant based on nonylphenol-formaldehyde resin modified by polyamines showed the best performance on the available live oils.This chemical modified the onset pressure of asphaltene precipitation of light oil from 4300 psi to about 3600 psi and decreased the precipitated asphaltene of heavy oil by about 30%.展开更多
The effects of SN5040 and polyethylene glycol(PEG)individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy.The adsorp...The effects of SN5040 and polyethylene glycol(PEG)individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy.The adsorption mechanism of these dispersants was detected by zeta potential,isothermal absorption and FTIR analysis.It is found that SN5040 is superior for stabilizing nano-TiO2 in aqueous suspension to PEG in basic region,and the optimum mass fraction of SN5040 addition is 3%.In the case of NaCl addition,the optimum value increases with the increase of NaCl concentration in the solution.When the mixture of SN5040 and PEG is employed,the antagonism appears preponderant.When SN5040 and PEG are added sequentially,the synergistic reaction takes place.The synergistic reaction can be attributed to the mechanism that PEG adsorption decreases the electronic repulsion between SN5040 molecules,which results in the increase of SN5040 adsorption density.PEG is adsorbed by the interaction with the pre-adsorbed SN5040 layer.Furthermore,the modified inner wall latex paint with well dispersed nano-TiO2 suspension is endowed with excellent ultraviolet absorption and antibacterial properties.展开更多
The synthesis and properties of three kinds of hyper-dispersants are studied in this paper,which are non-terminated,carboxyl-terminated and polyethylene imine grafted poly(hydroxyl carboxylic acid) ester.The hyper-dis...The synthesis and properties of three kinds of hyper-dispersants are studied in this paper,which are non-terminated,carboxyl-terminated and polyethylene imine grafted poly(hydroxyl carboxylic acid) ester.The hyper-dispersants are synthesized by the materials of 12-hydroxy-stearic acid,stearic acid and polyethylene imine,which are used to improve the dispersion properties of nano titanium dioxide(nano-TiO2) in low-concentration resin solution system.The influences of hyper-dispersants on the viscosity and stability of the system are studied.It is found that polyethylene imine grafted hyper-dispersant has the best dispersion performance in nano-TiO2 dispersion system,and the optimal content of the hyper-dispersant is 4%.展开更多
In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flota...In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy(SEM), zeta-potential measurements, and X-ray photoelectron spectroscopy(XPS). The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid(less than 300 g/t) favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.展开更多
Dispersion behavior of ultra fine BaTiO_3 particles in the aqueous solution of ammonium citrate (NH_4-CA) or citric acid lanthanum chelate (NH_4-La-CA) was investigated. The dispersion property was characterized with ...Dispersion behavior of ultra fine BaTiO_3 particles in the aqueous solution of ammonium citrate (NH_4-CA) or citric acid lanthanum chelate (NH_4-La-CA) was investigated. The dispersion property was characterized with sedimentation value. It is easier to obtain well dispersed slurry with NH_4La-CA than NH_4-CA. In an attempt to better understand the role of citric acid radical, simulation of the dispersant adsorption on BaTiO_3 particle was performed with universal force field (UFF). It is demonstrated that the interaction between citric acid radical and BaTiO3 particle surface is a weak chemical adsorption. Trivalent citric acid radical is adsorbed on BaTiO3 particle surface with maximal adsorption energy. And, larger molecules of NH_4-La-CA formed by adding La3+ lead to better dispersion property than NH_4-CA.展开更多
Good fluidity(low viscosity) of highly concentrated kaolin is highly needed in paper-coating industry.We put forward an effective route to improve the viscosity concentration of Beihai kaolin slurries.The effects of v...Good fluidity(low viscosity) of highly concentrated kaolin is highly needed in paper-coating industry.We put forward an effective route to improve the viscosity concentration of Beihai kaolin slurries.The effects of various factors such as solid content,pH,dispersant content,and urea-intercalation on the viscosity of kaolin slurries were investigated.The results revealed that the viscosity of kaolin slurries significantly decreased with decreasing solid content or with increasing pH and dispersant content.It was worth noting that ureaintercalation was proven to be an efficient method for promoting the dispersion of highly concentrated kaolin as compared with adding dispersant.The intercalation ratio of urea-intercalated kaolin was increased from 17.36%with 2%of urea addition to 81.30%with 6%of urea addition.Meanwhile,the viscosity concentration of raw kaolin slurry was improved from 65.0%to 70.13%after the intercalation of urea with 6%addition,which was attributed to finer particle size,increased pH value and more negative charges of urea-intercalated kaolin.Therefore,the route is effective to improve the dispersion of highly concentrated kaolin for paper-coating.展开更多
A novel photosensitive copolymer P(SS-co-AA-g-GMA)(PSAG) was synthesized and utilized to noncovalently functionalize pristine single-walled carbon nanotubes(SCNTs). PSAG was highly effective for the solubilization of ...A novel photosensitive copolymer P(SS-co-AA-g-GMA)(PSAG) was synthesized and utilized to noncovalently functionalize pristine single-walled carbon nanotubes(SCNTs). PSAG was highly effective for the solubilization of SCNTs in water and validated by UV-vis absorption spectra experiments, resulting in homogeneous and stable PSAG-SCNT aqueous dispersion. The microstructure of SCNTs was observed through Raman spectroscopy and transmission electron microscopy. In addition, compared with the two common polymeric dispersants of Triton X-100 and PSS, PSAG demonstrated more effective performances for dispersing SCNTs under identical conditions. Furthermore, the photosensitive PSAG-SCNTs can be crosslinked after UV irradiation, leading to significant improvement in the water resistance of SCNT films. UV-cured films can be transferred to plastic wrap to form a flexible film with high electrical conductivity.展开更多
基金the Project of Science and Technology Program of Guangzhou City of China(Project Nol.201604020004)for the financial support to this research.
文摘Gelation adversely affects the aqueous adiabatic terpolymerization of acrylamide (AM), sodium acrylate (NaAA),and 2-methacryloyloxyethyl trimethylammonium chloride (DMC). Here, the mixed dispersants sorbitan monooleate (Span80) and polyoxyethylene sorbitan monooleate (Tween 80) were introduced to the terpolymerization system in an attemptto mitigate the gel effect. This enabled the preparation of high-performance amphoteric polyacrylamides, which werecharacterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The influences of the dispersanttype and content as well as the hydrophilic-lipophilic balance (HLB) on the gel effect were examined, and the mechanismunderlying the suppression of the gel effect was considered. The obtained results indicated that the gel effect can beeffectively mitigated using an aqueous adiabatic terpolymerization system containing mixed Span 80/Tween 80 dispersantsat various contents. In particular, mixed dispersant contents of 0.6%–0.8% with HLB values of 5.0–6.0 afforded the optimalperformance (e.g., high viscosity, fast aqueous dissolution time, and the like).
文摘LiCoPO4 micron-rods with an average diameter of about 500 nm and length of about 5 μm were synthesized by dispersant-aided hydrothermal method. Poly(n-vinylpyrrolidone) (PVP) was used as dispersant in the hydrothermal method. The starting solution and the concentration of dispersant have significant influences on the morphology of LiCoPO4,and the electrochemical performance is improved via controlling the particle size and morphology by the hydrothermal method. The cell using smaller particle LiCoPO4 as cathode delivers a larger capacity and lower cell polarization.
基金We gratefully acknowledge the support from the China Petrochemical Corporation funding(Sinopec Group,No.117022)on this work.
文摘Diesel engine technology innovation causes excessive soot accumulated in engine oil.Due to its detrimental effect on lubricant and diesel engine,improving the dispersibility of engine oil to restrain soot aggregation efficiently is the key technique for formulations.In this study,the aggregation of soot and interaction between dispersant and soot were investigated by molecular dynamic simulation.It was found that the molecular interaction between the dispersant and the soot aggregation system had a significant influence on disrupting the soot aggregation.Bis-PIBSI was more beneficial to having more interaction sites with soot molecules,while the mono-PIBSI with a high proportion of polar groups had stronger interaction with soot molecules.According to the simulation result,suggestions for use of additives were proposed.Carbon black dispersancy test was exploited to verify the dispersion effect of different dispersants on carbon black.The results indicate that mono-PIBSI and bis-PIBSI added at suitable mixture ratio to lubricant could perform good dispersion ability.
文摘The effects of sodium carboxymethyl cellulose and sodium citrate as dispersants on nano-ceramic aqueous suspension were examined by the measurements of ζ -potential and the sedimentation test. The results show that proper addition of sodium carboxymethyl cellulose or sodium citrate into nano-ceramic coating, exhibits an enhanced dispersion and stability compared with the coating without dispersants. The negative ζ -potential of the particles in the nano-coating increases with the increase of pH value of the coating, and the curve of ζ -pH moves to lower pH range when the dispersants are added into the coating. To ensure that the coating has not only good stability and dispersibility but also no corrosivity to substrate alloy, adding 1.00% sodium citrate into coating with pH value of 7-8 is preferable to adding sodium carboxymethyl cellulose.
基金the financial support from the National Key Research and Development Program of China(2016YFB0301800)the National Natural Science Foundation of China(21606104).
文摘This work presents the influence of dispersants on coal-water slurry(CWS),which was prepared from the solid residue of plasma pyrolysis of coal.The effects of dispersant type,solid concentration,dispersant content,and temperature on the rheological properties of CWS are examined.A suitable empirical model regarding the relation between viscosity and temperature is proposed.Through the sedimentation experiment of CWS,dispersants are found to significantly promote the stability of CWS.
文摘In order to make corundum castables satisfy more severe service conditions in high temperature industries,colloidal alumina due to the same main component with corundum castables was introduced for a pure binding system.The influence of three dispersants(citric acid,FS10 and urea)on the flow ability of colloidal alumina bonded corundum castables was researched to choose a suitable dispersant for solving the shaping problem.In order to further understand the influence of dispersants on the flow ability and the mechanism,the rheological property and Zeta potential value of the colloidal aluminadispersant system and the matrix-colloidal alumina-urea-water system were tested.The results show the castables added with the urea have the best flow ability,and the appropriate addition of the urea is 0.5%.
文摘The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.
基金Supported by the National Natural Science Foundation of China(Nos.41806111,41790473)the Open Foundation of Key Laboratory of Marine Spill Oil Identifi cation and Damage Assessment Technology,State Oceanic Administration(No.201608)+3 种基金the National Key Research and Development Plan(No.2016YFC1402304)the NSFC Innovative Group Grant(No.41421005)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1606402)the High Performance Computing Center at the Institute of Oceanology,Chinese Academy of Sciences。
文摘There are considerable amounts of off shore oil/gas fields in the South China Sea(SCS),and for potential oil spill events in this area,dispersants may provide a reliable large-scale response when the preferable option of recapturing the oil cannot be achieved.In this paper,effect of chemical dispersants on underwater oil transport is investigated with an underwater oil spill model.Since the model is an adaption of an existing one,we first calibrate it by comparing the model result with echo-sounder data that were observed during the“DeepSpill”experiment with crude oil/LNG(liquefied natural gas)discharge.Then,with the hydrodynamic data provided by an operational forecasting system and the drilling data obtained from off shore platforms in the SCS,we apply the model to a hypothetical spill case,and examine the difference in oil distribution in water column caused by subsea dispersant application.The model results can provide valuable reference for contingency plan makers to make an efficient emergency response to potential underwater oil spill accidents in the SCS.
文摘A controlled laboratory study was conducted to measure the dispersion effectiveness of Corexit 9500 on 23 different crude oils. This study was a part of a larger project initiated by the Bureau of Safety and Environmental Enforcement (BSEE) testing 20 oils to compare the predictive value of laboratory dispersant effectiveness tests with their larger scale test conducted at Ohmsett, BSEE’s national oil spill response test facility located in Leonardo, NJ. The test used in this study was the Baffled Flask Test (BFT), which is planned for adoption as EPA’s official testing protocol for listing commercial dispersant products on the National Contingency Plan Product Schedule, replacing the current Swirling Flask Test (SFT) [1]. In addition, the results of 3 additional oils, the 2 used in the SFT and BFT as currently written plus another reference oil, are presented. The temperature used for the tests was 15°C, to match the temperature used at Ohmsett. The dispersion effectiveness ranged from 3.4% to 93%. The BFT is a laboratory test with results that are inversely correlated with oil viscosity and therefore has predictive value in the decision to use a dispersant in the event of a spill.
文摘Dispersants, usually blending with several surfactants and a solvent, are used to enhance oil spill dispersion as small droplets in water column. Although there is growing acceptance of dispersants as a counter measure to marine oil spills around the world, the two major issues with the dispersants are their toxicity to marine life and dispersion effectiveness (DE) for crude-oil, especially for heavy oil. To develop more efficient and less toxic dispersants, two kinds of sorbitol derivant nonionic surfactant (polysorbate 85 and sorbeth-40 tetraoleate), two kinds of glycolipid biosurfactants (rhamnolipid and sophorolipid) and less toxic solvent ethylene glycol butyl ether were chosen in this study, and two dispersant formulations were optimized by uniform design methods. Effects of dispersant-to-oil ratio, temperature, salinity and pH on the performance of the two optimized dispersants were investigated. The two dispersants had high dispersion effectiveness (DE) for heavy crude oil, while both dispersants keep high DE at the dispersant-to-oil ratio below 1:25 and the temperature above 5 ℃. In addition, the two dispersants also performed well in a wide range of salinity and pH values. Finally, toxicity tests revealed that the two dispersants showed low toxicity to two kinds of fish (Danio rerio and Microgobius gulosus).
文摘The main objective of this study is to develop a new protocol for bench-scale dispersant effectiveness testing adapted for subsea dispersants injection (SSDI). The new approach includes turbulence conditions, dispersant injection techniques and quantification of effectiveness, more representative for a SSDI operation. Results from the new system are compared to dispersant effectiveness measured with established laboratory methods, used for screening dispersants for surface application. The most significant result is that the dispersant ranking obtained with the new test relevant for subsea releases was very different compared to the ranking obtained by screening methods used for surface application of dispersants. This strongly indicates that existing standard methods for dispersant effectiveness testing designed for simulating conditions relevant for surface application of dispersants, are less relevant for SSDI effectiveness testing and justify the need for a more relevant method. Such a Dispersant Injection Effectiveness Test (DIET) is suggested and documented in this study.
基金the financial supports provided by the National Natural Science Foundation of China (No. 21176148) the Scientific Subject Foundation of the Education Department of Shaanxi Provincial Government of China (No. 11JK0562)
文摘A rosin derivative and maleopimaric acid diethanolamide(MAD), was synthesized, characterized by FTIR and1 H NMR, and applied as dispersant for the coal-water slurry(CWS) prepared from Chinese Shenfu coal. The CWS application performance investigation shows that the MAD dispersant has better abilities in reducing CWS viscosity and stabilizing the slurry than a commercial dispersant—sulfonated naphthalene-formaldehyde condensate(SNF). The physicochemical property investigation of the two tested dispersants shows that the adsorption amount of the MAD at coal-water interface is much larger than that of SNF, and the MAD has better wetting property than the SNF on the coal surface. It indicated that the excellent capabilities of MAD are related to the adsorption mode of standing upright on the coal surface. Based on the above, the mechanism of dispersion and stabilization of the CWS prepared from MAD dispersant is presented.
文摘As the efficiency of dispersants with different origins is questionable for each typical oil sample,the present study provides a reproducible and reliable method for screening asphaltene dispersants for a typical asphaltenic crude oil.Four different asphaltene dispersants(polyisobutylene succinimide.polyisobutylene succinic ester,nonylphenol-formaldehyde resin modified by polyamines.and rapeseed oil amide) were prepared and their performance on two oils from an Iranian field under laboratory and reservoir conditions was studied.A thorough analysis including ash content and SARA tests was performed on the solid asphaltene particles to characterize the nature of deposits.Then a highly efficient carrier fluid,which is crucial when injecting dispersant into the wells,was selected from a variety of chemicals by comparing their solubility.In the next step,using an optical microscope,a viscometer,and a Turbiscan.the screening of dispersants under laboratory conditions was done on a mixture of dead oil and dispersant to evaluate the onset of asphaltene precipitation and its stability when titrating by a precipitant.Finally,two different mixtures of the efficient dispersants.live oil,and carrier fluid were used with the solid detection system(SDS) and the filtration method to examine their effects on the onset pressure of asphaltene precipitation and the asphaltene content of the crude oil under reservoir conditions.The results show that the combination of experimental methods used in this work could be consistently applied to screening asphaltene dispersants.Among the four different dispersants applied here,the dispersant based on nonylphenol-formaldehyde resin modified by polyamines showed the best performance on the available live oils.This chemical modified the onset pressure of asphaltene precipitation of light oil from 4300 psi to about 3600 psi and decreased the precipitated asphaltene of heavy oil by about 30%.
基金Project(04GK2007) supported by Hunan Industrial Key Project of Science and Technology
文摘The effects of SN5040 and polyethylene glycol(PEG)individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy.The adsorption mechanism of these dispersants was detected by zeta potential,isothermal absorption and FTIR analysis.It is found that SN5040 is superior for stabilizing nano-TiO2 in aqueous suspension to PEG in basic region,and the optimum mass fraction of SN5040 addition is 3%.In the case of NaCl addition,the optimum value increases with the increase of NaCl concentration in the solution.When the mixture of SN5040 and PEG is employed,the antagonism appears preponderant.When SN5040 and PEG are added sequentially,the synergistic reaction takes place.The synergistic reaction can be attributed to the mechanism that PEG adsorption decreases the electronic repulsion between SN5040 molecules,which results in the increase of SN5040 adsorption density.PEG is adsorbed by the interaction with the pre-adsorbed SN5040 layer.Furthermore,the modified inner wall latex paint with well dispersed nano-TiO2 suspension is endowed with excellent ultraviolet absorption and antibacterial properties.
基金supported by the Shanghai Leading Academic Disciplines (Grant No.T0105)the Key Laboratory of Science & Technology of Eco-Textile (Donghua University), Ministry of Education of China
文摘The synthesis and properties of three kinds of hyper-dispersants are studied in this paper,which are non-terminated,carboxyl-terminated and polyethylene imine grafted poly(hydroxyl carboxylic acid) ester.The hyper-dispersants are synthesized by the materials of 12-hydroxy-stearic acid,stearic acid and polyethylene imine,which are used to improve the dispersion properties of nano titanium dioxide(nano-TiO2) in low-concentration resin solution system.The influences of hyper-dispersants on the viscosity and stability of the system are studied.It is found that polyethylene imine grafted hyper-dispersant has the best dispersion performance in nano-TiO2 dispersion system,and the optimal content of the hyper-dispersant is 4%.
基金financially supported by the National Natural Science Foundation of China(Nos.51374079 and 51604130)the Talent Cultivation Foundation of Kunming University of Science and Technology(No.KKSY201521031)the Foundation of Yunnan Educational Committee,China(No.2015Y067)
文摘In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy(SEM), zeta-potential measurements, and X-ray photoelectron spectroscopy(XPS). The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid(less than 300 g/t) favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.
基金Project(020951) supported by Natural Science Fundation of Guangdong Province, China
文摘Dispersion behavior of ultra fine BaTiO_3 particles in the aqueous solution of ammonium citrate (NH_4-CA) or citric acid lanthanum chelate (NH_4-La-CA) was investigated. The dispersion property was characterized with sedimentation value. It is easier to obtain well dispersed slurry with NH_4La-CA than NH_4-CA. In an attempt to better understand the role of citric acid radical, simulation of the dispersant adsorption on BaTiO_3 particle was performed with universal force field (UFF). It is demonstrated that the interaction between citric acid radical and BaTiO3 particle surface is a weak chemical adsorption. Trivalent citric acid radical is adsorbed on BaTiO3 particle surface with maximal adsorption energy. And, larger molecules of NH_4-La-CA formed by adding La3+ lead to better dispersion property than NH_4-CA.
基金Funded by Chinese Ministry of Land and Resources(No.201311024)
文摘Good fluidity(low viscosity) of highly concentrated kaolin is highly needed in paper-coating industry.We put forward an effective route to improve the viscosity concentration of Beihai kaolin slurries.The effects of various factors such as solid content,pH,dispersant content,and urea-intercalation on the viscosity of kaolin slurries were investigated.The results revealed that the viscosity of kaolin slurries significantly decreased with decreasing solid content or with increasing pH and dispersant content.It was worth noting that ureaintercalation was proven to be an efficient method for promoting the dispersion of highly concentrated kaolin as compared with adding dispersant.The intercalation ratio of urea-intercalated kaolin was increased from 17.36%with 2%of urea addition to 81.30%with 6%of urea addition.Meanwhile,the viscosity concentration of raw kaolin slurry was improved from 65.0%to 70.13%after the intercalation of urea with 6%addition,which was attributed to finer particle size,increased pH value and more negative charges of urea-intercalated kaolin.Therefore,the route is effective to improve the dispersion of highly concentrated kaolin for paper-coating.
基金Funded by the National Natural Science Foundation of China(No.51403082)
文摘A novel photosensitive copolymer P(SS-co-AA-g-GMA)(PSAG) was synthesized and utilized to noncovalently functionalize pristine single-walled carbon nanotubes(SCNTs). PSAG was highly effective for the solubilization of SCNTs in water and validated by UV-vis absorption spectra experiments, resulting in homogeneous and stable PSAG-SCNT aqueous dispersion. The microstructure of SCNTs was observed through Raman spectroscopy and transmission electron microscopy. In addition, compared with the two common polymeric dispersants of Triton X-100 and PSS, PSAG demonstrated more effective performances for dispersing SCNTs under identical conditions. Furthermore, the photosensitive PSAG-SCNTs can be crosslinked after UV irradiation, leading to significant improvement in the water resistance of SCNT films. UV-cured films can be transferred to plastic wrap to form a flexible film with high electrical conductivity.
