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71.
N. Muthukumar S. Maruthamuthu A. Ilangovan N. Palaniswamy 《Surface and interface analysis : SIA》2007,39(6):533-541
Biodegradation occurs in the diesel/water interface in petroleum product pipelines. The microbial contamination can result in inhibitor/fuel degradation, leading to unacceptable levels of turbidity, filter plugging, storage tank corrosion and stored product souring. Therefore, selection of the biocide/inhibitor plays an important role in the transportation of petroleum products through pipelines. Three biocides (cationic and nonionic) were employed to study the biodegradation in a diesel‐water interface. The biocidal efficiency against degradation of diesel was examined by employing Fourier‐transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and gas chromatography mass spectrometry (GC‐MS) techniques. Bronopol (2‐bromo‐2‐nitro‐propane‐1, 3‐diol) was found to have higher bactericidal efficiency than N‐cetyl‐N,N, N‐trimethyl ammonium bromide (CTAB) and cetyl pyridinum bromide (CPB). But the cationic biocides (CTAB and CPB) showed good biocidal efficiency at the interface. The data are explained in terms of a model that postulates the formation of a ‘micelle’ at the diesel‐water interface. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
72.
Rupert B. Hurley 《Journal of separation science》1980,3(3):147-148
This paper describes a design for an all-glass GC/MS interface. The design has advantages due to low dead volume, lack of column effluent adsorption and degradation, simple interface production and installation, and ease of column mounting/dismounting. 相似文献
73.
《Electroanalysis》2006,18(7):649-654
For the first time, the voltammetry of an ensemble of immobilized benzonitrile microdroplets containing 5,10,15,20‐tetraphenyl‐21H,23H‐porphine iron (III) chloride, TPPFeCl immobilized at platinum electrodes immersed in various aqueous electrolytes has been explored. The reduction of TPPFeCl was observed with the voltammetric response seen to be highly dependent on the nature of ions in the surrounding aqueous phase. Unlike voltammetry in purely homogeneous solution the nature of the aqueous electrolyte can influence the voltammetry in the droplet phase. The electrochemical reduction of TPPFeCl contained within tetrabutylammonium chloride (TBACl) supported benzonitrile (PhCN) microdroplets immersed into an aqueous solution of TBACl was first studied. During TPPFeCl reduction the resulting [TPPFeCl]? species is stabilized due to the excess of chloride anions inside the oil droplet. Voltammograms of homogeneous solutions of PhCN supported with TBACl show similar chemically reversible process which is also attributed to the stable [TPPFeCl]? species. This anion stabilization was not observed when the oil droplets were supported with tetrabutylammonium perchlorate (TBAP) or when the PhCN solution bathing the microdroplet ensemble was supported with TBAP resulting in a chemically irreversible process. The voltammetry of unsupported droplets immobilized on a platinum electrode immersed in different aqueous electrolytes was also explored and the fate of the [TPPFeCl]? species formed considered during the reduction sweep. Similarities and difference to voltammetry in purely homogeneous media are noted and the use of droplet voltammetry provides complimentary information. 相似文献
74.
Crystal growth of calcium oxalate (CaC2O4) in bulk aqueous solution, reverse microemulsion of p-octyl polyethylene glycol phenylether (OP)/iso-octyl alcohol (IOA)/cydohexane/water and above microemulsions containing different kinds of amino acids, such as aspartic acid (Asp), tyrosine (Tyr) and tryptophan (Trp) were studied. The results indicated that different crystallization types of the crystals, which were calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD) and calcium oxalate trihydrate (COT), existed in bulk aqueous solution. But CaC2O4 growth mainly paralleled with (1 01) plane of COM in reverse microemulsion because of the induction of surfactant at water/oil interface. After adding amino acids into microemulsions, the growth of CaC2O4 crystals mainly influenced by the varieties of amino acids and the pH values of the amino acid aqueous solution. When pH values of the solutions was higher than isoelectric points of amino acids, CaC2O4 crystal paralleled with (1 01) plane of COM more easily with the addition of Trp, Tyr, Asp in turn; however, when pH of the solutions was lower than isoelectric points of Trp, CaC2O4 crystal growth paralleled with (020) face of COM. It is obviously that amino acids, pH values of the solutions and surfactant played important roles in the process of crystal growth of CaC2O4 in the microemulsions. The formation mechanism of CaC2O4 was also discussed in different microemulsions at last. 相似文献
75.
《Surface and interface analysis : SIA》2005,37(10):773-781
The formation of a passivation film (solid electrolyte interphase, SEI) at the surface of the negative electrode of full LiCoO2/graphite lithium‐ion cells using LiPF6 (1M ) in carbonate solvents as electrolyte was investigated by means of x‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The analyses were carried out at different potentials of the first and the fifth cycles, showing the potential‐dependent character of the surface‐film species formation. These species were mainly identified as Li2CO3 up to 3.8 V and LiF up to 4.2 V. This study shows the formation of the SEI during charging and its partial dissolution during discharge. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
76.
Joseph M. Levy Athos C. Rosselli David S. Boyer Kathryn Cross 《Journal of separation science》1990,13(6):418-421
The usefulness and ease of utilizing supercritical fluid extraction (SFE) directly coupled to capillary gas chromatography (GC) as quantitative or qualitative analytical problem-solving tools will be demonstrated. As an alternative to conventional liquid solvent extractions, SFE presents itself as a means to achieve high extraction efficiencies of different compounds in complex solid matrices in very rapid tims frames. Moreover, SFE has an additional advantage of being able to achieve distinct extraction selectivities as a function of the solubilizing power of the supercritical fluid extracting phase. For on-line SFE/GC, the extraction effluent is directly transferred to the analytical chromatograph. On-line SFE/GC involves the decompression of pressurized extraction effluent directly into a heated, unmodified capillary split injection port of the GC. In this respect, SFE introduction into GC can be used as an alternative means of GC injection, comparable to such modes of injection as pyrolysis and thermal desorption. This paper will show applications of SFE/GC where mass spectrometric detection together with flame ionization detection was used for component identification from environmental, tobacco, and petroleum matrices. 相似文献
77.
应用扫描电化学显微镜研究了室温离子液体(Omim·Tf2N)与1,2-二氯乙烷(DCE)混合溶液/水界面上的电子转移反应. 在保持共同离子(Tf2N-)的浓度比恒定及异相电子转移反应由界面电势差所决定的条件下, 研究了离子液体和DCE混合溶液中二茂铁(Fc)与水相中亚铁氰化钾[K4Fe(CN)6]之间异相电子转移反应. 探讨了混合溶液中离子液体的体积分数(xRTIL)的变化对混合溶液/水界面上电子转移反应的影响. 结果表明, 随着xRTIL的减小(从1减小到0.1), Fc在混合溶液中的扩散系数单调递增(从2.730×10-7 cm2·s-1增加到9.131×10-6 cm2·s-1); 而异相电子转移反应速率常数(k)则先逐渐减小(从8.0 mol-1·cm·s-1减小到0.32 mol-1·cm·s-1), 之后又略有增大(从0.32 mol-1·cm·s-1增大到0.48 mol-1·cm·s-1). 对这种现象可能的原因进行了较详细探讨. 相似文献
78.
Adam Sokoowski Jan Chlebicki Kazimiera A. Wilk 《Colloids and surfaces. A, Physicochemical and engineering aspects》1993,80(2-3):243-249
The surface tension isotherms for pure oligooxypropylenated piperidine and morpholine at the aqueous solution—air interface were determined and interpreted. The surface excess concentration, Γ, the surface area per molecule, A, and the standard free energy of adsorption, ΔG°, were calculated according to a new empirical adsorption equation. The standard free energy contribution for the oxypropylene group (PO) in morpholine derivatives,ΔG° (PO) = −3.34 kJ mol−1, is substantially lower than that for the PO group located in the piperidine derivatives, i.e. ΔG° (PO)= −3.12 kJ mol−1. 相似文献
79.
Dynamic surface elasticity of polymer solutions 总被引:1,自引:0,他引:1
B. A. Noskov 《Colloid and polymer science》1995,273(3):263-270
The surfaces of surfactant solutions exhibit viscoelastic dilational behavior which may be investigated by modern optical and mechanical methods. The present study focuses on the dynamic dilational properties of the polymer solution — gas interface. Linear flexible polymer chains at the surface are considered as consisting of trains, lying on the surface, and loops and tails that protrude into the liquid. The Rouse model is used to describe the inner dynamics of the trains, whereas their motion relative to their neighbors on the surface can be described with the help of the reptation conception. An expression for the complex dynamic dilational surface elasticity has been derived. Although, in general, the relaxation of the surface tension is characterized by an infinite series of relaxation times, it is shown that for many systems the dynamics of the surface layer can be described approximately by only two main relaxation times. The dispersion equation, which was obtained earlier for solutions of conventional surfactants, is shown to be fulfilled for polymer solutions also. 相似文献
80.
Mori Toshiyuki Drennan John Wang Yarong Li Ji-Guang Ikegami Takayasu 《Journal of Thermal Analysis and Calorimetry》2002,70(2):309-319
Doped ceria (CeO2) compounds are fluorite type oxides that show oxygen ionic conductivity higher than yttria stabilized zirconia, in oxidizing
atmosphere. In order to improve the conductivity, the effective index was suggested to maximize the oxygen ionic conductivity
in doped CeO2 based oxides. In addition, the true microstructure of doped CeO2 was observed at atomic scale for conclusion of conduction mechanism. Doped CeO2 had small domains (10-50 nm) with ordered structure in a grain. It is found that the electrolytic properties strongly depended
on the nano-structural feature at atomic scale in doped CeO2 electrolyte.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献