• Korea-Australia Rheology Journal
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• v.15 no.4
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• pp.179-185
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• 2003

Associating polymers act as flocculants in colloidal suspensions, because the hydrophobic groups (hydrophobes) can adsorb onto particle surfaces and create intermolecular cross-linking. The steady-shear viscosity and dynamic viscoelasticity were measured for suspensions flocculated by multichain bridging of associating polymers. The effects of surfactant on the suspension rheology are studied in relation to the bridging conformation. The surfactant molecule behaves as a displacer and the polymer chains are forced to desorb from the particle surfaces. The overall effect of surfactant is the reduction of suspension viscosity. However, the additions of a small amount of surfactant to suspensions, in which the degree of bridging is low, cause a viscosity increase, although the number of chains forming one bridge is decreased by the forced desorption of associating polymer. Since the polymer chains desorbed from one bridge can form another bridge between bare particles, the bridging density over the system is increased. Therefore, the surfactant adsorption leads to a viscosity increase. The surfactant influences the viscosity in two opposing ways depending on the degree of bridging.

• Geotechnical Engineering
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• v.13 no.2
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• pp.55-64
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• 1997

Laboratory tests were performed to desorb organic contaminants spiked onto soil particles by using surfactants. Nonionic and anionic surfactants were tested as potential desorbing solvents for extracting quinoline and 2-napthol adsorbed on soil particles. Ahionisc stirfactant remediated approximately 80% and 90% of quinoline and 2-napthol respectively and appeared to be more effective than nonionic surfactant in remediating those compounds, Comparison between simple deionized water washing of the organic contaminated soil and a given surfactant technique evaluated the improvement by the application of a Burfactant to the promotion of desorption.

• Journal of the Korean Ceramic Society
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• v.17 no.3
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• pp.145-150
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• 1980

This paper deals with the clay-bonded silicon carbide refractory saggars in terms of its oxidation resistance. Oxidation is one of the major causes of failure in silicon carbide refractory saggars during its services. Various anti-oxidation additives are coated on or added into silicon carbide refractories and their effects are studied while other conditions are equal. Several conclusions can be derived for optimum anti-oxidation additive as: 1. The additive should wet each silicon carbide grain completely during its firing. 2. The additive should have high viscosity at temperatures around $1, 350^{\circ}C$ where most silicon carbide refractory saggars are being used. 3. The additive should have ability to absorb or desorb oxygen depending on the local atmosphere inside of saggar during it service. 4. The addition should be kept as minimum as possible to prevent any "sweating" or "bloating" phenomena.ing" phenomena.mena.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.29-34
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• 2002

The microphase adsorption - spectral correction (MPASC) technique was described and applied to study the interaction of fluorescein isothiocyanate (FITC) with cetyl trimethylammonium bromide (CTAB). The synergism mechanism of micelle was analyzed and discussed. The aggregation of FITC on CTAB obeys the Langmuir monolayer adsorption. Results showed that the monomer and micellar aggregate is $FITC-CTAB_3$ and $(FITC-CTAB_3)_{29}$, respectively at pH 9.62. The adsorption constant of the CTAB-FITC aggregate was determined to be $2.10{\times}10^5$. Interestingly, it was observed for the addition of an anionic surfactant to desorb FITC from its CTAB aggregate and this has been applied to the quantitative determination of trace amounts of anionic detergent (AD) in sewage.

• Carbon letters
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• v.11 no.1
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• pp.13-21
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• 2010

Coconut shell activated carbon (CSAC) was investigated for its ability in the removal of two neutral chlorinated organic compounds, namely trichloroethylene (TCE) and dichloromethane (DCM) from aqueous solution using a packed bed column. The efficiency of the prepared activated carbon was also compared with a commercial activated carbon (CAC). The important design parameters such as flow rate and bed height were studied. In all the cases the lowest flow rate (5 mL/min) and the highest bed height (25 cm) resulted in maximum uptake and per cent removal. The experimental data were analysed using bed depth service time model (BDST) and Thomas model. The regeneration experiments including about five adsorption-desorption cycles were conducted. The suitable elutant selected from batch regeneration experiments (25% isopropyl alcohol) was used to desorb the loaded activated carbon in each cycle.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2338-2340
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• 2009

Ionic palladium(II) complex containing a long aliphatic chain, [(tmeda)$PdL]_2(PF_6)_4$ (tmeda = N,N,N',N'-tetramethylethylenediamine; L = decylmethylbis(m-pyridyl)silane) allowed to form a puckered submicrosphere morphology without any template or additive. The puckered spheres reversibly adsorb and desorb dioxane molecules. Coligand and cosolvent effects on the formation of submicrospherical morphology were observed.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.748-752
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• 2001

Alkanethiols (CH3(CH2)n-1SH) based self-assembled monolayers (SAMs) on the clean copper surfaces have been examined for n = 4, 8, and 16. Using X-ray photoelectron spectroscopy (XPS) and contact angle analysis, it is found that alkanethiolate monolayers similar to those on gold are formed on clean copper surfaces. The monolayers are stable in air up to about 140 $^{\circ}C.$ Above 160 $^{\circ}C$ the monolayers begin to desorb through the oxidation reaction of the thiolate to sulfonate, with the alkyl chains remaining intact. Following this desorption step, the copper surface has begun to oxidize to CuO at about 180 $^{\circ}C$.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.180-186
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• 2009

To meet the NOx limit without a penalty of fuel consumption, urea SCR system is currently regarded as promising NOx reduction technology for diesel engines. SCR system has to achieve maximal NOx conversion in combination with minimal $NH_3$ slip. In this study, as a basic research to develop an algorithm for urea injection control, the characteristics of engine out NOx emission and behavior of NOx reduction during steady-state and transient conditions were investigated using 2L DI diesel engine. Test results show that on increasing the catalyst temperature the variations in the outlet NOx concentration are faster and maximal allowable $NH_3$ storage exponentially decreases. For change from a low to high engine load, it can be seen that a few seconds after load-step is required to reach full NOx conversion and the adsorbed amount of $NH_3$ at lower temperature desorb during the next temperature increase, causing $NH_3$ slip. Engine out NOx emission needs to be corrected because NOx emissions just after step load is lower than that of steay state condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.115-115
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• 2015

Many efforts have been devoted on chemical modification of graphene layer to modulate its electrical properties. In the previous report, laser irradiation on the CYTOP (Amorphous Fluoropolymer) covered graphene layer induces chemical modification wherein carbon fluoride is formed on the graphene surface. This results in the insulating I-V characteristics, which have been attracting much research interests on it. However, the direct analytical evidence of the fluoride formation on graphene surface is not yet studied. In this work we investigated what happened on the CYTOP/graphene interface during photon irradiation using spatially resolved photoemission spectroscopy method. It is found that the soft x-ray (614 eV) induces desorption of fluoride atoms from the CYTOP and change di-fluoride form to mono-fluoride. As the photo-induced fluorine desorption is continue strong dipole field generated by initial di-fluoride forms is gradually decreased, resulting in the overall binding energy shift of the C 1s core levels. Both photo-modified CYTOP and CYTOP starts to desorb above $286^{\circ}C$ (~ 0.047 eV), which means that no strong chemical interaction between CYTOP and graphene is established.

• Journal of Environmental Science International
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• v.5 no.3
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• pp.317-327
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• 1996

This study was performed to develop the biological treatment technology of wastewater polluted with heavy metals. Zinc-tolerant microorganism, such as Pseudomonas chlororaphis which possessed the ability to accumulate zinc, was isolated from industrial wastewaters polluted with various heavy metals. The characteristics of zinc accumulation in the cells, recovery of the zinc from the cells accumulating zinc, were investigated. Removal rate of zinc from the solution containing 100 mall of Zinc by zinc-tolerant microorganism was more than 90% at 48 hours after inoiulation of the microorganisms. A large number of the electron-dense granules were found mainly on thIn cell wall and membrane fractions, when determined by transmission electron microscope. Energy dispersive X- ray spectroscopy revealed that the electron-dense granules were zinc complex with the substances binding Heavy metals. The zinc accumulated into cells was not desorbed by distilled water, but more than 80% of the zinc accumulated was desorbed by 0.1M-EDTA. The residues of the cells after combustion at 55$0^{\circ}C$ amounted to about 21% of the dry weight of the cells. EDS analysis showed that the residues were comparatively pure zinc compounds containing more than 79% of zinc.