• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.177-189
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• 2009

Iron (oxyhydr)oxides commonly form as secondary minerals of high reactivity and large surface area resulting from alteration and weathering of primary minerals, and they are efficient sorbents for inorganic and organic contaminants. Accordingly, they have a great potential in industrial applications and are also of substantial interest in environmental sciences. Goethite (${\alpha}$-FeOOH) is one of the most ubiquitous and stable forms of iron (oxyhydr)oxides in terrestrial soils, sediments, and ore deposits, as well as a common weathering product in rocks of all types. This study focused on adsorption reaction as a main mechanism in scavenging arsenic using goethite. Goethite was synthesized in the laboratory to get high purity, and a variety of mineralogical and physicochemical features of goethite were measured and related to adsorption characteristics of arsenic. To compare differences in adsorption reactions between arsenic species, in addition, a variety of experiments to acquire adsorption isotherm, adsorption edges, and adsorption kinetics were accomplished. The point of zero charge (PZC) of the laboratory-synthesized goethite was measured to be 7.6, which value seems to be relatively higher, compared to those of other iron (oxyhydr)oxides. Its specific surface area appeared to be $29.2\;m^2/g$ and it is relatively smaller than those of other (oxyhydr)oxides. As a result, it was speculated that goethite shows a smaller adsorption capacity. It is likely that the affinity of goethite is much more larger for As(III) (arsenite) than for As(V) (arsenate), because As(III) was observed to be much more adsorbed on goethite than As(V) in equivalent pH conditions. When the adsorption of each arsenic species onto goethite was characterized in various of pH, the adsorption of As(III) was largest in neutral pH range (7.0~9.0) and decreased in both acidic and alkaline pH conditions. In the case of As(V), the adsorption appeared to be highest in the lowest pH condition, and then decreased with an increase of pH. This peculiarity of arsenic adsorption onto goethite might be caused by macroscopic electrostatic interactions due to variation in chemical speciation of arsenic and surface charge of goethite, and also it is significantly affected by change in pH. Parabolic diffusion model was adequate to effectively evaluate arsenic adsorption on goethite, and the regression results show that the kinetic constant of As(V) is larger than that of As(III).

• Tuberculosis and Respiratory Diseases
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• v.50 no.2
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• pp.158-170
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• 2001

Background : Although an oxidants and antioxidants imbalance has been considered in the pathogenesis of chronic obstructive pulmonary disease (COPD), there is a paucity of reports focussing on the smoking-induced changes of oxidants and antioxidants in COPD. Method : The concentration of antioxidants (ascorbic acid, uric acid, retinol, and $\alpha$- & $\gamma$-tocopherol) was measured in the serum and induced sputum of 30 healthy controls and 34 stable COPD patients using high performance liquid chromatography (HPLC). The inhibition of lipid peroxidation as an index of antioxidant capacity was measured in the serum by a TBA assay. Results : The serum concentration of ascorbic acid, $\alpha$-tocopherol, and retinol were significantly lower in the patients with COPD than in healthy controls ($484.8{\pm}473.3$ vs $1497.8{\pm}819.2\;pmol/L$, $48.38{\pm}17.34$ vs $73.96{\pm}26.29\;pmol/L$, p<0.001, and $9.51{\pm}8.33$ vs $15.01{\pm}5.88\;pmol/L$, p<0.05, respectively, mean$\pm$SD). However, there were little differences in the ascorbic acid and uric acid concentrations in the induced sputum between the COPD patients and the controls. The induced sputum to serum ratio of ascorbic acid was significantly higher in COPD patients compared with healthy control (0.375 vs 0.085, p<0.05). In the normal controls, the serum ascorbic acid concentration was lower in smokers than in nonsmokers ($1073{\pm}536$ vs $1757{\pm}845\;pmol/L$, p<0.05), but the level was still higher than that of the COPD patients (p<0.05). The serum retinol levels were correlated with $FEV_1$ in COPD patients (r=0.58, p<0.05). The products of lipid peroxidation were increased in normal smokers and COPD compared with norma1 nonsmokers ($115.56{\pm}19.93$ vs $120.02{\pm}24.56$ vs $91.87{\pm}20.71\;{\mu}mol/{\mu}mol$ Pi of liposome, p<0.05). Conclusion : Cigarette smoking may induce the dep1etion of serum antioxidants and this depletion of antioxidants is suggested to play a role in the pathogenesis of COPD.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.359-370
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• 2009

Arsenic and heavy metals leached out as a result of oxidation of tailings exposed to the surface pose a serious environmental contamination of mine areas. This study investigated how arsenic behavior is controlled by a variety of processes, such as oxidation of sulfides and formation or alteration of secondary minerals, based on mineralogical methods. The study was carried out using the tailing samples obtained from Nakdong mine located in Jeongseongun, Gangwondo. After separating magnetic and non-magnetic minerals using pretreated tailing samples, each mineral sample was classified according to their colors and metallic lusters observed by the stereoscopic microscope. Subsequently, the mineralogical properties were determined using various instrumental analyses, such as x-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), and electron probe micro analyzer (EPMA). The literature review confirmed that various ore minerals were identified in the Nakdong ore deposits. In this study, however, there were observed a few original ore minerals as well as secondary and/or tertiary minerals newly formed as a result of weathering including oxidation. In particular, we did not recognize pyrrhotite which has been known to originally exist in a large abundance, but peculiarly colloform-type iron (oxy)hydroxides were identified, which indicates most of pyrrhotite has been altered by rapid weathering due to its large reactivity. In addition, a secondary scorodites filling the fissure of weathered primary arsenopyrites were identified, and it is speculated that arsenic is immobilized through such a alteration reaction. Also, we observed tertiary iron (oxy)hydroxides were formed as a result of re-alteration of secondary jarosites, and it suggests that the environment of tailing has been changed to high pH from low pH condition which was initiated and developed by oxidation reactions of diverse primary ore minerals. The environmental change is mainly attributed to interactions between secondary minerals and parental rocks around the mine. As a result, not only was the stability of secondary minerals declined, but tertiary minerals were newly formed. As such a process goes through, arsenic which was immobilized is likely to re-dissolve and disperse into surrounding environments.

• Clean Technology
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• v.11 no.3
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• pp.123-128
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• 2005

Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1064-1071
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• 2003

An investigation of various olive oils available in Korea was carried out to assess their quality properties such as color, oxidative stability, fatty acid composition, tocopherol content, sterol content and benzo(a)pyrene content. In color measurement, by using a Lovibond color scale and Hunter color difference meter, both a and b values of extra virgin olive oil were higher than those of pure olive oil by Tintometer (Lovibond PFX995). However, extra virgin olive oil showed higher a value and lower L value than pure olive oil by the Hunter color difference meter. In the rancimat test, the induction period of extra virgin olive oil $(38.03{\sim}8.47hr)$ was longer than that of pure olive oil $(32.40{\sim}9.94hr)$. In fatty acid composition, C18:1 $(72.01{\sim}78.53wt%)$ was present in the greatest amount, with lesser amounts of C18:2 $(4.88{\sim}10.36wt%)$ and C18:3 $(0.56{\sim}1.09wt%)$. The tocopherol content ranged from ${\alpha}-Toc\;4.09{\sim}13.89mg/100g$, ${\beta}-Toc\;0.57{\sim}1.34mg/100g$, and ${\gamma}-Toc$ $3.41{\sim}8.03mg/100g$, and ${\alpha}-tocopherol$ was found to be the main isomer in all oil samples. Therefore, there was little difference in the fatty acid composition and tocopherol content among the different types of olive oils. In sterol content, ${\beta}-sitosterol$ $(124.52{\sim}19.33mg/100g)$ and campesterol $(1.10{\sim}0.62mg/100g)$ of extra virgin olive oil were higher than that of pure olive oil $({\beta}-sitosterol\;92.68{\sim}17.44mg/100g,\;campesterol\;0.59{\sim}0.35mg/100g)$. Benzo(a)pyrene was found in almost all samples, with $0.287{\sim}0.106{\mu}g/kg$ in extra virgin olive oil and $1.204{\sim}2.130{\mu}g/kg$ in pure olive oil.

• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.51-57
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• 2002

The biological activities of immune modulating activities of the extracts from Echinacea purpurea, Chrysanthmum indicum L. and Circium japonicum var. ussuriense KITAMURA were compared. About 70% of the growth of human hepatocarcinoma and 80% of human gastric cancer cell was inhibited in adding 0.5mg/ml of the ethanol extracts of Echinacea purpurea, Chrysanthmum indicum L. and Circium japonicum var. ussuriense KITAMURA, respectively. The growth of human breast cancer cells was also inhibited in adding 0.5mg/ml of the extracts as well as 60% of the human cancer cells. It was proved that the growth of human normal lung cell, scored as 15% for the extracts. Overall selectivity of the extracts on several human cancer cell line was over 3, which is higher than those from the conventional herbs. The growth of both human immune B and T cells was enhanced up to 1.4 to 2.0 times by adding the extracts, compared to the controls. The secretion of tumor necrosis $factor-alpha(TNF-{\alpha})$ from T cell was also increased up to 94 pg/ml in adding the Echinacea purpurea ethanol extract (0.5mg/ml). Circium japonicum var. ethanol extract also increased up to about 96 pg/ml of interleukin-6(IL-6) from B cell.

• Journal of Plant Biology
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• v.28 no.1
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• pp.69-77
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• 1985

The degree of The degree of The degree of ${Zn}^{2+}$ effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested.${Zn}^{2+}$treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal ${Zn}^{2+}$level (10$^{-6}$ M). The other was that the different concentrations of ${Zn}^{2+}$was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of ${Zn}^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of ${Zn}^{2+}$concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of ${Zn}^{2+}$in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, ${Zn}^{2+}$(2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested. Z $n^{2+}$ treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal Z $n^{2+}$ level (10$^{-6}$ M). The other was that the different concentrations of Z $n^{2+}$ was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of Z $n^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of Z $n^{2+}$ concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of Z $n^{2+}$ in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, Z $n^{2+}$ (2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.effect on the photosynthetic electron transport and photophosphorylation activities in barley chloroplasts has been tested. Z $n^{2+}$ treatment was done in the 2 ways. One was that it was added into the chloroplasts suspensions isolated from the plants grown under the normal Z $n^{2+}$ level (10$^{-6}$ M). The other was that the different concentrations of Z $n^{2+}$ was applied in each growth medium. Then, it was not added into the chloroplasts suspensions isolated from the plants. PS II activity in both way of the treatments was more severely inhibited than PS I by the increment of Z $n^{2+}$ concentration. The photophosphorylation activity measured by pH measurement was gradually decreased with the increase of Z $n^{2+}$ concentration in both ways, too. However, it was shown that M $n^{2+}$ could be near fully overcome the inhibitory effect of Z $n^{2+}$ in PS II, and $Mg^{2+}$ could also reduce the Z $n^{2+}$ inhibition in the photophosphorylation. In the low concentrations of $Mg^{2+}$ (3 to 5$\times$10$^{-3}$ M) in the suspension, Z $n^{2+}$ (2$\times$10$^{-5}$ M) could increase the activity of photophosphorylation. As compares to other cations, Z $n^{2+}$ caused less inhibitory effect on the photophosphorylation activity than Cu, Cd, but more than Pb and Ni. It may be assumed that a complex from reaction of Z $n^{2+}$ and mercaptoethanol was produced and it could reduce the stability of CPI band during SDS-PAGE.ld reduce the stability of CPI band during SDS-PAGE.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.95-104
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• 2005

Effects of the aluminum melting temperature, melting time and a kind of flux agents on the distribution of surrogate nuclide were investigated in the electric furnace at the aluminum melting including surrogate radionuclides(Co, Cs, Sr) in order to establish the fundamental research of the melting technology for the metallic wastes from the decommissioning of the TRIGA research reactor. It was verified that the fluidity of aluminum melt was increased by adding flux agent but it was slightly varied according to the sort of flux agents. The results of the XRD analysis showed that the surrogate nuclides move into the slag phase and then they were combined with aluminum oxide to form more stable compound. The weight of the slag generated from aluminum melting test increased with increasing melting temperature and melting time and the increase rate of the slag depended on the kind of flux agents added in the aluminum waste. The concentration of the cobalt in the ingot phase decreased with increasing reaction temperature but it increased in the slag phase up to 90$\%$according to the experimental conditions. The volatile nuclides such as Cs and Sr considerably transferred from the ingot phase to the slag and dust phase.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.395-399
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• 2011

Material of the gasket for lithium ion battery requires the chemical resistance, the electrical insulting property, the compression set, the anti-contamination level and the low temperature resistance. We compounded ethylene propylene diene monomer (EPDM), which showed widely different solubility parameter index, with adjusting the amount of metal oxide as an activator. We did long-term test and compression set against an electrolyte with consideration for operating conditions in lithium-ion battery. In these tests, we checked the physical, chemical characteristics and the effect to lithium ion battery with different kinds of activators. In case of rubber with ZnO as an activator, through 1000 h depositing test in propylene carbonate which is one of representative solvents, we could get the satisfying characteristics and result. However, $Zn^{2+}$ had eluted in the ion elution test. So, ZnO should be limited in EPDM compound for the gasket material in lithium-ion battery.

• Microbiology and Biotechnology Letters
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• v.40 no.1
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• pp.43-49
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• 2012

In this study, we investigated the antibacterial activity and stability of a cream containing Hippophae rhamnoides leaf extract. The MIC values of ethyl acetate fraction from an H. rhamnoides leaf on Escherichia coli, Pityrosporum ovale, Propionibacterium acnes and Staphylococcus aureus were 0.5%, 0.25%, 0.25% and 0.06%, respectively. Stability evaluations, pH, viscosity and absorbance of the cream containing 0.25% ethyl acetate fraction of H. rhamnoides, were performed. The cream was measured under 4 different temperature conditions under sunlight at 2-week intervals for 12 weeks. The viscosity and pH were measured by a comparison of the experimental cream with a similar control cream. The H. rhamnoides extract was found to have contributed to the stability of the emulsion product via a protective effect in maintaining the viscosity of the cream against sunlight. The absorbance variations of the experimental cream at 270 nm were, under sunlight; $45^{\circ}C$, $37^{\circ}C$, $25^{\circ}C$, and $4^{\circ}C$. In addition, any change in color or smell was not observed through the 12 weeks of the experimental period. These results indicated that the cream containing 0.25% ethyl acetate fraction of H. rhamnoides leaf extract was stable. Accordingly, this suggests that further study is needed to provide additional information for manufacturers, who are seeking the application of the extract to improve anti-oxidant and antibacterial activities and the stability of cosmetic products.