The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Sebastiao Avelino - One of the best experts on this subject based on the ideXlab platform.
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equilibrium diagrams at 27 degree c of the water sodium tungstate Dodecylamine chloride system
Journal of Chemical & Engineering Data, 1993Co-Authors: A Dantas A Neto, T N De Castro Dantas, Marcia M L Duarte, Sebastiao AvelinoAbstract:Amines are usually used in extracting tungsten from scheelite. Dodecylamine chloride in kerosene and octanol was used as an extracting agent in order to establish the phase diagram at 27C for water + sodium tungstate + Dodecylamine chloride. Acetone was used to prevent emulsion formation. This procedure made it possible to achieve better partition coefficients; however, there appears to be a saturation region.
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Equilibrium diagrams at 27 [degree]C of the water + sodium tungstate + Dodecylamine chloride system
Journal of Chemical & Engineering Data, 1993Co-Authors: A. A. Dantas Neto, T N De Castro Dantas, Marcia M L Duarte, Sebastiao AvelinoAbstract:Amines are usually used in extracting tungsten from scheelite. Dodecylamine chloride in kerosene and octanol was used as an extracting agent in order to establish the phase diagram at 27C for water + sodium tungstate + Dodecylamine chloride. Acetone was used to prevent emulsion formation. This procedure made it possible to achieve better partition coefficients; however, there appears to be a saturation region.
Liang Shen - One of the best experts on this subject based on the ideXlab platform.
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the adsorption of Dodecylamine and oleic acid on kaolinite surfaces insights from dft calculation and experimental investigation
Applied Surface Science, 2019Co-Authors: Jun Chen, Fangqin Lu, Liang ShenAbstract:Abstract The interaction of hydrophobic modifiers with clay mineral surfaces plays an important role in the hydrophobic aggregation sedimentation for the treatment of clay-rich tailing. The adsorption of Dodecylamine and oleic acid on kaolinite was investigated at the atomic level by using density functional theory (DFT) calculation and compared with the experimental results of hydrophobic aggregation. The effect of molecular and ionic forms of modifiers as well as the (0 0 1) and (00-1) surfaces of kaolinite were examined. The polar head groups of Dodecylamine and oleic acid are adsorbed on the kaolinite surface mainly by hydrogen bonding and electrostatic attraction. The ionic and molecular forms are the preferred adsorption species of Dodecylamine and oleic acid, respectively. The adsorption ability of kaolinite (0 0 1) surface toward Dodecylamine and oleic acid is stronger than that of (00-1) surface. The adsorption energies of the complete oleic acid on kaolinite (00-1) surface are positive. In a large pH range, Dodecylamine is the preferred hydrophobic modifier of kaolinite relative to oleic acid.
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flotation of fine kaolinite using Dodecylamine chloride fatty acids mixture as collector
Powder Technology, 2017Co-Authors: Liang Shen, Huaifa WangAbstract:Abstract In order to improve the flotation recovery of fine kaolinite, mixed Dodecylamine chloride/fatty acid was used as collector in kaolinite flotation process. The performance of Dodecylamine chloride/fatty acid mixture collector on kaolinite flotation was investigated using flotation test and computational method. Surface tension measurement, contact angle measurement and image analysis were also used to study the flotation behavior of Dodecylamine chloride and mixture collectors. The flotation results showed that much higher kaolinite flotation recovery was obtained in the presence of Dodecylamine chloride/octanoic acid mixture compared with that in the presence of Dodecylamine chloride alone. Surface tension measurements indicated that the mixed Dodecylamine chloride/octanoic acid collector was more efficient at decreasing the air–water interfacial tension. Molecular dynamics simulation showed that the octanoic acid molecules were interleaved among Dodecylamine chloride ions and co-adsorbed at the kaolinite (001) surface. The relative concentration of water molecules near kaolinite (001) surface further decreased in the presence of Dodecylamine chloride/octanoic acid compared with that in the presence of Dodecylamine chloride alone, which indicated a much stronger hydrophobicity of the kaolinite (001) surface.
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Flotation of fine kaolinite using Dodecylamine chloride/fatty acids mixture as collector
Powder Technology, 2017Co-Authors: Liang Shen, Huaifa WangAbstract:Abstract In order to improve the flotation recovery of fine kaolinite, mixed Dodecylamine chloride/fatty acid was used as collector in kaolinite flotation process. The performance of Dodecylamine chloride/fatty acid mixture collector on kaolinite flotation was investigated using flotation test and computational method. Surface tension measurement, contact angle measurement and image analysis were also used to study the flotation behavior of Dodecylamine chloride and mixture collectors. The flotation results showed that much higher kaolinite flotation recovery was obtained in the presence of Dodecylamine chloride/octanoic acid mixture compared with that in the presence of Dodecylamine chloride alone. Surface tension measurements indicated that the mixed Dodecylamine chloride/octanoic acid collector was more efficient at decreasing the air–water interfacial tension. Molecular dynamics simulation showed that the octanoic acid molecules were interleaved among Dodecylamine chloride ions and co-adsorbed at the kaolinite (001) surface. The relative concentration of water molecules near kaolinite (001) surface further decreased in the presence of Dodecylamine chloride/octanoic acid compared with that in the presence of Dodecylamine chloride alone, which indicated a much stronger hydrophobicity of the kaolinite (001) surface.
Zhenyu Chen - One of the best experts on this subject based on the ideXlab platform.
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INHIBITION EFFECT OF Dodecylamine ON CARBON STEEL CORROSION IN HYDROCHLORIC ACID SOLUTION
Surface Review and Letters, 2012Co-Authors: Zhenyu Chen, Ling HuangAbstract:Dodecylamine spontaneously adsorbs on carbon steel via its polar group (-NH2) in hydrochloric acid solution. Furthermore, it forms a monolayer film on carbon steel surface. The inhibition mechanism of Dodecylamine for carbon steel is geometric blocking effect. The adsorption of Dodecylamine on carbon steel surface follows Arrhenius equation. The adsorption slightly increases activated energy, but greatly reduces pre-exponential factor value. Atomic force microscopy force curves indicate that at the area without adsorbed Dodecylamine, no obvious adhere force occurs. At the area with adsorbed Dodecylamine, however, an average 1.3 nN adhere force is observed.
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Influence of sodium chromate and Dodecylamine on enhanced dissolution behavior of Cu—Ni alloy induced by AFM tip scratching
Journal of Materials Science, 2006Co-Authors: June Qu, Zhenyu ChenAbstract:The influence of two inhibitors sodium chromate and Dodecylamine on enhanced dissolution of Cu–Ni alloy initiated by atomic force microscopy (AFM) tip scratching in 1.5 M NaCl and 0.01 M HCl was investigated. The lateral force traces and force versus distance curves were measured by AFM in distilled water without or with inhibitors to investigate the influence of inhibitors on physical characters of sample surfaces. The results indicated that enhanced dissolution caused by AFM tip scratching was inhibited by adding sodium chromate or Dodecylamine into the corrosive solutions, but their inhibition mechanisms are different. The inhibition effect of sodium chromate is due to its oxidation ability to repair the destroyed protection film and the increase of rigidity of metal surface resulted from the formation of oxide film containing Cr elements. On the other hand, the inhibition effect of Dodecylamine is due to the organic adsorption film on metal surface to weaken the friction forces between the tip and the sample and to elevate the ionization energy of metal.
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The inhibition by Dodecylamine of enhanced dissolution of Cu-Ni alloy initiated by an AFM tip/surface interaction
Anti-corrosion Methods and Materials, 2005Co-Authors: Jun‐e Qu, Zhenyu ChenAbstract:Purpose – To investigate the influence of an organic corrosion inhibitor on the enhanced dissolution of metal, initiated by AFM tip scratching in corrosive media.Design/methodology/approach – The test solutions were 1.5 M NaCl and 0.01 M HCl. AFM tip scratching experiments were performed for Cu‐Ni alloys in solutions with or without 0.005 M Dodecylamine. AFM frictional loop tests were also performed to investigate the effect of Dodecylamine on the tip‐surface frictional interaction.Findings – Enhanced dissolution of Cu‐Ni alloy was observed as a result of AFM tip scratching both in NaCl and HCl solutions, and in HCl the effect was more severe than was the case in NaCl. Enhanced dissolution was inhibited markedly by adding 0.005 M Dodecylamine to the corrosive media. The results of frictional loop tests indicated that frictional interaction between the tip and the alloy surface was diminished by the adsorption of Dodecylamine on the sample surface. The weakening of tip‐surface frictional interaction and th...
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adsorption behavior of Dodecylamine on copper nickel alloy surface in nacl solutions studied by electrochemical methods and afm
Materials Chemistry and Physics, 2005Co-Authors: June Qu, Zhenyu ChenAbstract:Abstract The adsorption behavior of Dodecylamine on a copper–nickel alloy in 0.2 M NaCl solutions was studied by electrochemical methods and atomic force microscopy (AFM). The polarization curves showed that Dodecylamine had both cathodic and anodic inhibition action, but was mainly a cathodic-type inhibitor. The results of electrochemical impedance spectroscopy (EIS) and in situ AFM phase images indicated that as the inhibitor concentration increased from 0.0005 to 0.005 M, the monolayer adsorbed film of inhibitor tended to become more ordered and denser so that corrosion inhibition efficiency tended to increase. Differential capacity curve experiments indicated that the adsorbed Dodecylamine film changed the structure of the double-electric layer and made the potential of zero charge (PZC) shift to the positive direction. AFM force curve measurements were also performed and showed that as a result of the adsorption of Dodecylamine on copper–nickel alloy surface, adhesive forces between the tip and the sample surface were detected and the long-range electrostatic repulsive forces between the tip and the sample surface were decreased.
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Adsorption behavior of Dodecylamine on copper–nickel alloy surface in NaCl solutions studied by electrochemical methods and AFM
Materials Chemistry and Physics, 2005Co-Authors: June Qu, Zhenyu ChenAbstract:Abstract The adsorption behavior of Dodecylamine on a copper–nickel alloy in 0.2 M NaCl solutions was studied by electrochemical methods and atomic force microscopy (AFM). The polarization curves showed that Dodecylamine had both cathodic and anodic inhibition action, but was mainly a cathodic-type inhibitor. The results of electrochemical impedance spectroscopy (EIS) and in situ AFM phase images indicated that as the inhibitor concentration increased from 0.0005 to 0.005 M, the monolayer adsorbed film of inhibitor tended to become more ordered and denser so that corrosion inhibition efficiency tended to increase. Differential capacity curve experiments indicated that the adsorbed Dodecylamine film changed the structure of the double-electric layer and made the potential of zero charge (PZC) shift to the positive direction. AFM force curve measurements were also performed and showed that as a result of the adsorption of Dodecylamine on copper–nickel alloy surface, adhesive forces between the tip and the sample surface were detected and the long-range electrostatic repulsive forces between the tip and the sample surface were decreased.
Peter Setlow - One of the best experts on this subject based on the ideXlab platform.
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isolation and characterization of bacillus subtilis spores that are superdormant for germination with Dodecylamine or ca2 dipicolinic acid
Journal of Applied Microbiology, 2013Co-Authors: Abigail Perezvaldespino, Sonali Ghosh, E P Cammett, L Kong, Yongqing Li, Peter SetlowAbstract:Aims To isolate and characterize spores superdormant (SD) for germination with either Ca2+-dipicolinic acid (CaDPA) or Dodecylamine. Methods and Results Bacillus subtilis spores were germinated three times with either CaDPA or Dodecylamine and germinated spores removed after each germination treatment, yielding 0·9% (CaDPA-SD spores) or 0·4% (Dodecylamine-SD spores) of initial dormant spores. Compared to dormant spores, CaDPA-SD spores germinated poorly with CaDPA and better with Dodecylamine and nutrient germinants, although release of DPA from individual CaDPA-SD spores was slow during nutrient germination, and this germination was strongly inhibited by TbCl3. The CaDPA-SD spores were sensitive to hypochlorite and had elevated levels of nutrient germinant receptors (GRs) relative to levels in dormant spores. Dodecylamine-SD spores' germination with Dodecylamine and nutrients was similar to that of dormant spores, their germination with Ca-DPA was slower than that of dormant spores, and these SD spores' GR levels were lower than in dormant spores. However, Dodecylamine-SD spores were not sensitive to hypochlorite, and the nutrient germination of these SD spores was only partially inhibited by TbCl3. Conclusions CaDPA-SD spores appear to have a coat defect and accompanying low levels of the cortex-lytic enzyme CwlJ. The defect in Dodecylamine-SD spores, however, is not clear. Significance and Impact of the Study The results suggest that triggering germination by non-GR-dependent germinants is a potential strategy for efficient spore inactivation.
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Isolation and characterization of Bacillus subtilis spores that are superdormant for germination with Dodecylamine or Ca2+‐dipicolinic acid
Journal of Applied Microbiology, 2013Co-Authors: Abigail Perez-valdespino, Sonali Ghosh, E P Cammett, L Kong, Yongqing Li, Peter SetlowAbstract:Aims To isolate and characterize spores superdormant (SD) for germination with either Ca2+-dipicolinic acid (CaDPA) or Dodecylamine. Methods and Results Bacillus subtilis spores were germinated three times with either CaDPA or Dodecylamine and germinated spores removed after each germination treatment, yielding 0·9% (CaDPA-SD spores) or 0·4% (Dodecylamine-SD spores) of initial dormant spores. Compared to dormant spores, CaDPA-SD spores germinated poorly with CaDPA and better with Dodecylamine and nutrient germinants, although release of DPA from individual CaDPA-SD spores was slow during nutrient germination, and this germination was strongly inhibited by TbCl3. The CaDPA-SD spores were sensitive to hypochlorite and had elevated levels of nutrient germinant receptors (GRs) relative to levels in dormant spores. Dodecylamine-SD spores' germination with Dodecylamine and nutrients was similar to that of dormant spores, their germination with Ca-DPA was slower than that of dormant spores, and these SD spores' GR levels were lower than in dormant spores. However, Dodecylamine-SD spores were not sensitive to hypochlorite, and the nutrient germination of these SD spores was only partially inhibited by TbCl3. Conclusions CaDPA-SD spores appear to have a coat defect and accompanying low levels of the cortex-lytic enzyme CwlJ. The defect in Dodecylamine-SD spores, however, is not clear. Significance and Impact of the Study The results suggest that triggering germination by non-GR-dependent germinants is a potential strategy for efficient spore inactivation.
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germination of spores of bacillus subtilis with Dodecylamine
Journal of Applied Microbiology, 2003Co-Authors: Barbara Setlow, Anne E Cowan, Peter SetlowAbstract:Aims: To determine the properties of Bacillus subtilis spores germinated with the alkylamine Dodecylamine, and the mechanism of Dodecylamine-induced spore germination. Methods and Results: Spores of B. subtilis prepared in liquid medium were germinated efficiently by Dodecylamine, while spores prepared on solid medium germinated more poorly with this agent. Dodecylamine germination of spores was accompanied by release of almost all spore dipicolinic acid (DPA), degradation of the spore's peptidoglycan cortex, release of the spore's pool of free adenine nucleotides and the killing of the spores. The Dodecylamine-germinated spores did not initiate metabolism, did not degrade their pool of small, acid-soluble spore proteins efficiently and had a significantly lower level of core water than did spores germinated by nutrients. As measured by DPA release, Dodecylamine readily induced germination of B. subtilis spores that: (a) were decoated, (b) lacked all the receptors for nutrient germinants, (c) lacked both the lytic enzymes either of which is essential for cortex degradation, or (d) had a cortex that could not be attacked by the spore's cortex-lytic enzymes. The DNA in Dodecylamine-germinated wild-type spores was readily stained, while the DNA in Dodecylamine-germinated spores of strains that were incapable of spore cortex degradation was not. These latter germinated spores also did not release their pool of free adenine nucleotides. Conclusions: These results indicate that: (a) the spore preparation method is very important in determining the rate of spore germination with Dodecylamine, (b) wild-type spores germinated by Dodecylamine progress only part way through the germination process, (c) Dodecylamine may trigger spore germination by a novel mechanism involving the activation of neither the spore's nutrient germinant receptors nor the cortex-lytic enzymes, and (d) Dodecylamine may trigger spore germination by directly or indirectly activating release of DPA from the spore core, through the opening of channels for DPA in the spore's inner membrane. Significance and Impact of the Study: These results provide new insight into the mechanism of spore germination with the cationic surfactant Dodecylamine, and also into the mechanism of spore germination in general. New knowledge of mechanisms to stimulate spore germination may have applied utility, as germinated spores are much more sensitive to processing treatments than are dormant spores.
A Dantas A Neto - One of the best experts on this subject based on the ideXlab platform.
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equilibrium diagrams at 27 degree c of the water sodium tungstate Dodecylamine chloride system
Journal of Chemical & Engineering Data, 1993Co-Authors: A Dantas A Neto, T N De Castro Dantas, Marcia M L Duarte, Sebastiao AvelinoAbstract:Amines are usually used in extracting tungsten from scheelite. Dodecylamine chloride in kerosene and octanol was used as an extracting agent in order to establish the phase diagram at 27C for water + sodium tungstate + Dodecylamine chloride. Acetone was used to prevent emulsion formation. This procedure made it possible to achieve better partition coefficients; however, there appears to be a saturation region.