• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.144-149
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• 1999

The two distinct adsorption sites and transition between the under and over-potentially deposited hydrogen (UPD H and OPD H) on the polycrystalline iridium (poly-Ir) surface in the 0.2 M LiOH electrolyte have been studied using the phase-shift method. At the forward and backward scans, the UPD H peak occurs on the cyclic voltam-mogram. The transition region on the phase-shift profile or the Langmuir adsorption isotherm occurs at ca. -0.80 to -0.95 V vs. SCE. At the transition region (-0.80 to -0.95 V vs. SCE), the equilibrium constant (K) for H adsorption transits from $7.9\times10^{-2}\;to\;1.5\times10^{-4}$ and vice versa. Similarly, the standard free energy $({\Delta}G_{ads})$ of H adsorption transits from 6.3 to 21.8kJ/mol and vice versa. The UPD H and OPD H on the poly-Ir surface act as two distinguishable electroadsorbed H species. Both the UPD H peak and the transition region are attributed to the two distinct adsorption sites of the UPD H and OPD H on the poly-Ir surface.

• Resources Recycling
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• v.29 no.5
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• pp.38-47
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• 2020

In this study, factors affecting the adsorption reaction for the separation/recovery of V and W using Lewatit monoplus MP 600, a strong basic anion exchange resin, from the leachate obtained through the soda roasting-water leaching process from the spent SCR DeNO_X catalyst investigated and the adsorption mechanism was discussed based on the results. In the case of the mixed solution of V and W, both ions showed a high adsorption ratio at pH 2-6, but the adsorption of W was greatly reduced at pH 8. In the adsorption isothermal experiment, both V and W were fitted well at the Langmuir adsorption isotherm, and the reaction kinetics were fitted well at pseudo-second-order. As a result of conducting an adsorption experiment by adjusting the pH with H₂SO₄ to remove Si, which inhibits the adsorption of V and W from the leachate, the lowest W adsorption ratio was shown at pH 8.5. Desorption of W was hardly achieved in strongly acidic solutions, and desorption of V was well performed in both strongly acidic and strongly basic solutions.

• Journal of the Korean Ceramic Society
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• v.56 no.2
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• pp.146-152
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• 2019

In order to study the transport behavior of tripolyphosphate (TPP) in aqueous solutions, the adsorption process of TPP on synthetic goethite, which exists stably in supergene environment, has been systematically studied. The adsorption properties under different conditions (pH, electrolyte presence, and temperature) were investigated. The adsorption of TPP in the presence of humic acid (HA)/fulvic acid (FA) has also been discussed in this paper. The results indicated that the adsorption capacity quickly increased within the first hour and equilibrium was reached within 24 h. The adsorption capacity decreased from 1.98 to 0.27 mg·g^-1 upon increasing the pH from 8.5 to 11.0, whereas the adsorption of TPP on goethite hardly changed with increasing electrolyte concentration. The results of analysis of the kinetic and isothermal models showed that the adsorption was more in accord with the pseudo second-order equation and Freundlich model. The adsorption capacity decreased obviously regardless of the order of addition of TPP, HA, and goethite. Subsequent addition of FA led to a large increase in the adsorption capacity, which might be attributed to the adsorption ability of FA. According to the predictions of the kinetic and isothermal models and the spectroscopic evidence (X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM)), the adsorption mechanism may be mainly based on surface complexation and physical adsorption.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.301-306
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• 2004

Statement of problem. Fibronectin mediates its biological effects by binding to integrins on cell membranes through a consensus site including the Arg-Gly-Asp (RGD) sequence within tenth type III module. Purpose. The purpose of our study was to investigate the adsorption affinity of human recombinant fibronectin peptide (hFNIII 9-10) to titanium and to investigate the effect of the surrounding ionic composition on the adsorption process. Material and methods. As for evaluating the affinity of hFNIII 9-10 to Ti, titanium disks were incubated in 40, 80 and $120{\mu}g/ml$ hFNIII 9-10 solution at $37^{\circ}C$ overnight, repectively. As for evaluating the effect of surrounding ionic concentration, hFNIII 9-10 was dissolved in distilled water, phosphate buffered saline and RPMI 1640. Optical density (O.D.) was measured in ELISA reader. Results. The results were as follows; 1. The adsorption of hFNIII 9-10 showed significantly highest mean optical density (O.D.) value in $80{\mu}g/ml$. 2. The difference of ionic composition in DW, PBS and RPMI did not influence the adsorption amount of hFNIII 9-10.

• Carbon letters
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• v.2 no.2
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• pp.109-112
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• 2001

For the adsorption of ammonia, activated carbon fibers (ACFs) were subjected to sulfuric acid treatment in order to modify the surface functional groups. The surface acid and base value of ACFs were measured using titration and FT-IR spectrometry. SEM was used to investigate the surface morphology. Acid treatments by $H_3PO_4$, $H_2SO_4$, and $HNO_3$ were performed to increase the adsorption capacity of $NH_3$. As a result, Cellulose-based ACF has high adsorption capacity for ammonia. The ammonia removal efficiency of ACF was the maximum which was treated by 15 wt% sulfuric acid at $100^{\circ}C$ for 60 min. The average pore diameter little increased from $19{\AA}$ to $20.8{\AA}$ and the specific surface area of ACF considerably decreased and acid values increased by 15 wt% sulfuric acid treatment. Ammonia reacted with sulfonyl radicals. After adsorption of ammonia, white material was grown on the surface of ACF through the adsorption of ammonia and it was determined to ammonium sulfate.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.237-246
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• 1988

The higher bacterial numbers on clay than on sand were caused by different environmental factors. Such factors affecting the adsorption of E. coli ATCC 11775 in the sediment as follows; optimal pH range for the adsorption of E. coli ATCC 11775 was pH 7.5-pH 9.5. E. coli ATCC 11775 were shown maxima in the salinity of 18.$75%_{o}$ on sand type sediment and $12.5%_{o}$ on clay type sediment. Bacteria attached better to clay typed sediment than to sand typed sediment when organic substance was eliminated. Beef extract of 0.5%-1% concentration was found to promote the attachment of E. coli ATCC 11775 effectively. Peptone of 0.5% was enganced the attachment on the clay, and peptone of 1.3%-5%, on the sand. E. coli ATCC 11775 was found to adsorb onto benthonite with the highest efficiency and on celite with the lowest efficiency. Efficiency of adsorption by inorganic ions was shown due to higher values of ion. Adsorption was achieved in the order of $Al^{3+}, Ca^{2+}, Na^{+}$.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.333-338
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• 2002

In this work, the characterization of adsorption of Cu, Zn and Cd on granular activated carbon in water has been studied. The factors that affect adsorption in boundary between activated carbon and wastewater are concentration, temperature, contact time, pH and so on. As the result of this study, the maximum adsorption amount of Cu occurred near pH 7, while that of Zn and Cd was near pH 9.6 and 10, respectively. As contact time and temperature are transformed, such factors as optimum contact time and temperature are taken into consideration in an adsorptive process of heavy metal because an adsorption and a reducing process occur. In isotherm of Freundlich, 1/n values of Cu, Cd capacity were between 0.16 and 0.5.

• Macromolecular Research
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• v.11 no.5
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• pp.347-351
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• 2003

The hydrophobic ligand-containing hollow polypropylene (PP) membranes were synthesized by the mutual radiation induced graft copolymerization with glycidylmethacrylate (GMA) onto hollow PP membrane followed by the subsequent functionalization with L-phenylalanine. FT-IR, elemental analysis and UV spectroscopy were utilized to characterize copolymer composition, and degree of grafting, functionalization conversion and ${\gamma}$-globulins adsorption. The degree of grafting on the PP surface increased with the reaction time and total dose of E-beam. In the subsquent functionalization, the amount of L-phenylalanine increased with the increase in the degree of grafting and the degree of conversion was about 30%. The ${\gamma}$-globulins adsorption experiments showed that adsorption capacity had a maximum value at pH 8. The ${\gamma}$-globulins adsorption capacity in the basic pH region was higher than in the acidic pH region.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.77-86
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• 1995

Lead(II) removal efficiency by natural kaolinite was investigated through laboratory experiments. This study was conducted in two phases-sorption and desorption. In the adsorption study, the influence of sorption kinetics and sorption isotherm and various parameters such as pH, temperature, coexisting other heavy metal ions on the lead adsorption was investigated. And desorption study was carried out in order to find the re-usability of kaolinite as an adsorbent. The results of the study are as follows. 1. Sorption kinetics was investigated under the condition of 2.5 mg/l adsorbent concentration, pH 6.5$\pm$0.05, temperature $30\pm 0.5\circ$C, initial lead(II) concentration 25 mg/l. Adsorption rate was initially rapid and the extent of adsorption arrived at adsorption equilibrium with 73% adsorption efficiency in an hour. 2. The sorption isotherm experiment was made with different initial lead(II) concentration. A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the sorption intensity (1/n) was 0.47 and the measure of sorption (k) was 2.44. So, it was concluded that sorption of lead(II) by kaolinite is effective. 3. The effect of pH on lead(II) sorption by kaolinite shows that at a pH of 3, only 6% of the total lead(II) was adsorbed and at a pH 9, 97% of the lead(II) was removed. And the effect of temperature on lead(II) sorption by kaolinite shows that as the temperature increased, the amount of lead(II) sorption per unit weight of kaolinite increased. But the effect was minor (p<0.05). 4. Sorption isotherm of lead coexisting cadmium (II) or zinc (II) was lower than that of lead itself. It was caused by the result of competitive sorption to adsorption site. And there was no difference between the sorption isotherm of cadmium and zinc. 5. In desorption studies, only 5.12% desorption took place in distilled water, while 52.08% in 0.1 N hydrochloric acid. Consequently used kaolinite could be regenerated by hydrochoric acid.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.579-585
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• 2005

Cheap and environmental sound biosorbent was made for the adsorption of arsenate using an waste activated sludge. The biosorbents were methylated in 9hours and 24 hours respectively for the better adsorption of arsenate. The amount adsorbed of arsenate(V) increased with increasing methylation time. The specific arsenate adsorption was 0.06mmol As(V)/g biomass when the biosorbent was methylated in 24 hours. The methylated biosorbents were also studied with pH 5, 7 and 9. The pH of the solution affect the amount of adsorption of arsenate of the biosorbent even though it was methylated. The specific arsenate adsorption of the biosorbent at pH 5 was best and it was three times greater than the amount of arsenate adsorbed at pH 9.