• KSBB Journal
• /
• v.6 no.1
• /
• pp.105-109
• /
• 1991

In separating alkaline protease from the bacteria (Bacillus licheniformis) fermentation broth using reverse micelle, effects of various factors;ionic strength, pH and surfactant concentration, on separation efficiency were studied. KCl controls the ionic strength. The lower KCl concentration was in the feed solution, the more protein and activity was recovered. The higher KCl concentration was in the stripping solution, the more protein and activity was recovered. Using sodium-di-2-ethylhexyl sulfosuccinate(Aerosol-OT or AOT) as a surfactant, the higher AOT concentration in the solvent, the more activity and protein were recovered. 0.1N NaOH and IN HCl were used to adjust pH. Maximum recovery of protein mass and activity were obtained at feed solution of pH 5.3. Maximum activity was recovered at stripping solution of pH 7.5

• Elastomers and Composites
• /
• v.43 no.2
• /
• pp.88-103
• /
• 2008

This study was purposed to investigate the effects of surfactants and fillers on physical properties of hydrophilic polyvinylsiloxane dental impression materials (PVS). Incorporation of surfactants enhanced the hydrophilicity of the PVS, however, it induced increased viscosity and permanent deformation ratio, delayed setting, and decreased tensile strength. At high concentrations of surfactant, the tensile strength was observed to decrease significantly due to the internal pore formation. Especially, the hydrophilicity of the PVS was significantly enhanced with the addition of Silwet L-77. However, the viscosity, strain in compression, pore formation, and setting time increased whereas the elastic recovery rate and strength remarkably decreased. The PVS dental materials containing Span 20 showed the lowest degree of viscosity increase, delayed setting, pore formation, and hydrophilicity. The delayed setting, pore formation, and strength decrease caused by the incorporation of surfactant were improved by substituting the crystalline quartz filler with diatomaceous earth while the contact angle of PVS dental materials increased.

• KSBB Journal
• /
• v.14 no.6
• /
• pp.661-664
• /
• 1999

Proteins were extracted from an aqueous phase with reversed micelles. The effect of pH, and salt concentration on the solubilization of lysozyme in AOT/isooctane solution was studied to explore the potential for employing this solvent system in the large-scale recovery and concentration of proteins using liquid extraction. For pH values below the isoelectric point, pl of the protein, solubilization was high, probably owing to strong electrostatic interactions between the positively charged proteins and the anionic surfactant heads forming the inner micelle wall. At low ionic strength complete solubilization of the protein was observed. A pH higher than the pl of lysozyme and a salt concentration lower than that of the water pool were required for the recovery aqueous phase to ensure the back extraction of lysozyme from the AOT reversed micelles.

• Resources Recycling
• /
• v.20 no.4
• /
• pp.52-57
• /
• 2011

Present paper reports a new method to separate the electrolyte membranes and carbon paper without using ultrasonic waves and stirring. In this method, these were separated from fuel cell membrane-electrode assembly(MEA) using the distilled water, butanol and surfactant by dipping method without the dispersion of catalyst particles. Separated carbon paper catalysts and fuel cell Pt/C catalysts were heated in aqua regia at $80{\sim}85^{\circ}C$ and added to precipitant. After calcination, Pt metal was recovered which might be used in fabricating new fuel cells.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.4
• /
• pp.455-461
• /
• 2005

This study was designed to investigate the fundamental aspects of a possible recovery of phosphorus strategy from wastewater by using the zirconium mesoporous structured materials as a new type of ion exchangers. Zirconium mesoporous structure material was synthesized by hydro-thermal synthesis. The synthesized zirconium mesoporous structure was examined by X-ray diffraction (XRD) and Transmission electron micrograph (TEM). From the results of XRD and TEM, it was found out that hexagonal mesoporous structure, pore size was about $47{\AA}$, was synthesized. Experimental results showed that the complex of zirconium sulfate tetrahydrate and surfactant micelles had very high ability for capture of phosphorus. The amount of phosphate ions exchanged into the solid was as great as 3.4mmol/g-ZS. And the ion exchange reaction was occurred between $PO_4{^{3-}}$ and $SO_4{^{2-}}$ and also between $PO_4{^{3-}}$ and $OH^-$. Therefore, it is possible to get the higher removal efficiency than other ion exchange media and adsorbent.

• Mass Spectrometry Letters
• /
• v.3 no.3
• /
• pp.78-81
• /
• 2012

The hydrophobic hydrocarbon chain and the polar sulfate group confer surfactant properties and enable them to be used as anionic surfactants. Anionic surfactants (AS) are known for their adverse impact on environment, particularly on aquatic ecosystem. In the present study a fast, sensitive and selective method for the determination and subsequent quantification of six anionic surfactants was developed using hydrophilic interactive liquid chromatography (HILIC) coupled to a electrospray ionization (ESI) mass spectrometer (MS), in the concentration range 15-20 ${\mu}g/L$. The capability of the method was established using regression analysis and ANOVA. The method performance was evaluated by analyzing real time surface water spiked with 1-dodecyl hydrogen sulfate at 15 ${\mu}g/L$. Combined efficiency of solid phase extraction and MS detection established recovery of 89% in presence of natural matrix. These results point out that HILIC coupled to multistage MS procedures can be a powerful technique for environmental applications concerning the screening of polar contaminants.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.1
• /
• pp.32-37
• /
• 2006

In this study, we have purified and characterized the membrane bound nitrate reductase obtained from the denitrifying bacteria, Ochrobactrum anthropi SY509, which was isolated from soil samples. O. anthropi SY509 can grow in minimal medium using nitrate as a nitrogen source. We achieved an overall purification rate of 15-fold from the protein extracted from the membrane fraction, with a recovery of approximately 12% of activity. The enzyme exhibited its highest level of activity at pH 5.5, and the activity was increased up to $70^{\circ}C$. Periplasmic and cytochromic proteins, including nitrite and nitrous oxide reductase, were excluded during centrifugation and were verified using enzyme essay. Reduced methyl viologen was determined to be the most efficient electron donor among a variety of anionic and cationic dyestuffs, which could be also used as an electron donor with dimethyl dithionite. The effects of purification and storage conditions on the stability of enzyme were also investigated. The activity of the membranebound nitrate reductase was stably maintained for over 2 weeks in solution. To maintain the stability of enzyme, the cell was disrupted using sonication at low temperatures, and enzyme was extracted by hot water without any surfactant. The purified enzyme was stored in solution with no salt to prevent any significant losses in activity levels.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.10
• /
• pp.1381-1391
• /
• 2002

The solvent sublation using ion pairs of metal-2-naphthoate(2-HNph) and tetrabutyl ammonium ($TBA^+$) ion has been studied for the concentration and determination of ultra trace Bi(III), In(III) and Tl(Ⅲ) ions in water samples. The partition coefficients ($K_p$) and the extraction percentages of 2-HNph and the ion pairs to methyl isobutyl ketone (MIBK) were obtained as basic data. After the ion pair $TBA^+$·M$(Nph)_4^-$ was formed in water samples, the analytes were concentrated by the solvent sublation and the elements were determined by GF-AAS. The pH of the sample solution, the amount of the ligand and counter ion added and stirring time were optimized for the efficient formation of the ion pair. The type and amount of optimum surfactant, bubbling time with nitrogen and the type of solvent were investigated for the solvent sublation as well. 10.0 mL of 0.1 M 2-HNph and 2.0 mL of 0.1 M $TBA^+$ were added to a 1.0 L sample solution at pH 5.0. After 2.0 mL of 0.2%(w/v) Triton X-100 was added, the ion pairs were extracted into 20.0 mL MIBK in a flotation cell by bubbling. The analytes were determined by a calibration curve method with measured absorbances in MIBK, and the recovery was 80-120%.

• Journal of the Korean institute of surface engineering
• /
• v.37 no.6
• /
• pp.344-349
• /
• 2004

Emulsions were formed through putting small quantity of nickel electroplating solution into supercritical carbon dioxide, and then electroplating in the $sc-CO_2$ emulsions was conducted. It is an environmental-friendly technology that can solve the treatment of a large quantity of toxic plating wastewater, which is a big problem in the existing wet plating, and also can reduce secondary waste generation fundamentally. Supercritical carbon dioxide emulsions enhanced by ultrasonic horn were formed by non-ionic surfactant and nickel solution. Plating condition within emulsions was set up as 120bar and $55^{\circ}C$ through measurement of electrical conductivity following the pressure change. Experiments were conducted respectively against supercritical carbon dioxide emulsions electroplating and general chemical electroplating, and then their results were compared and analyzed. As the experiment result utilizing emulsions, plating surface was formed very evenly even with a small quantity of electroplating solution, and fine particles were plated compactly without any pinhole or crack due to hydrogenation, which occurs in general electroplating. Used electroplating solution can be reused through recovery process. Therefore, this technology will be able to be applied as new clean technology in electro-plating.

• ALGAE
• /
• v.21 no.2
• /
• pp.245-251
• /
• 2006

Diurnal and age-related changes in air pressure were measured in air bladders of Ascophyllum nodosum from the Atlantic coast of Nova Scotia. Exterior and interior bladder volumes vary significantly with 4 and 6 y bladders being about 40% larger than 2 y bladders (p < 0.01). Freshly collected bladders yielded a mean pressure of 40.8 ± 6.5 cm H2O. Overnight (20 h) dark treatment at 15°C generated pressure reductions by 80% in 2 y bladders but only by about 30% in 4 and 6 y bladders. Furthermore, in 2 y bladders 8 out of 11 bladders were reduced to atmospheric pressure. Pressure losses were inversely related to pressure recovery after 2.5 h in natural daylight, but after 5 h in daylight there was no significant difference in pressure within the age groups. Even under 25% of full illumination, bladders inflated to full pressure after 5 h. The results show that differences in bladder age and bladder wall thickness have roles in diurnal patterns of bladder inflation and deflation. These results confirm that bladder inflation is based on photosynthetic O2 production and not on partial pressures of O2 in the surrounding medium as was suggested for Sargassum. Chemical analyses of fluid recovered after the interior of bladders were washed with saline showed no evidence for the occurrence of surfactant that might be responsible for maintaining the air-liquid interface.