• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.837-841
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• 2003

Duplex microstructure of zirconia and alumina has been achieved via an organic-inorganic solution technique. Zirconium 2,4-pentanedionate, aluminum nitrate and polyethylene glycol were dissolved in ethyl alcohol without any precipitation. The organicinorganic precursor gels were turned to porous powders having volume expansion through explosive, exothermic reaction during drying process. The volume expansion was caused by abrupt decomposition of the organic groups in the gels during the vigorous exothermic reaction. The volume expanded, porous powders were crystallized and densified at 1500$^{\circ}C$ for 1 h. At the optimum amount of the PEG polymer, the metal cations were well dispersed in the solution and a homogeneous polymeric network was formed. The polymer content also affected on the specific surface area of the synthesized powder and the grain size of the sintered composite.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.265-271
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• 2002

Density, water resistance, Raman and infrared spectroscopy were used to investigate the change of structural characteristics with the composition of phosphate galss samples made by melting method. The structural abnormality of the density and water resistance were rapidly increased and shown near the 60mol% of $P_2O_5$. This result could be explained by the structural changes owing to the strong shrinkage of glass network by the coordination of DBO(Double-Bonded Oxygen) around $Mg^{2+}$ cations. In addition, it seems that the DBOs coordinating $Mg^{2+}$ cations lose its characteristics of double bonding and resonate with other NBOs(Non-Bonding Oxygen).

• Korean Journal of Materials Research
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• v.2 no.2
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• pp.151-156
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• 1992

Using $Ba(OH)_2{\cdot}8H_2O, \;Sr(OH)_2{\cdot}8H_2O$ and $Ti(i-OC_3H_7)_4$, fine $(Ba_{1-x}, \;Sr_{x})TiO_3$ powders were synthesized through sol-gel process. The particle size of the powders calcined at $700^{\cric}C$ proved to be 20-40nm by the observation of TEM micrographs and measurement of BET specific surface area. The analysis of XRD patterns showed that the phase of the powders was cubic, and it was identified with the lattice parameters determined through XRD patterns and the shift of (112) peaks that the solid solution powders were synthesized. It was expected through the analysis of relative ratio of cations and the uniformity of compositions in the powders examined by EDAX analysis and relative dielectric constant measurements for sintered body that the distribution of cations was uniform in particle unit.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.375-383
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• 1996

Effects of forest fire on soil nutrients in pine forests were studied in Dosong, Kangwon Province in Korea. Soil samples were collected from burned sites and unburned sites (control) at Kusungri, Sampori and Wunbongri. Soil pH in burned sites was higher than that in unburned sites. Soil organic matter did not differ significantly between the burned and unburned sites. Concentrations of available phosphorus in burned soils were about 3 times higher than those in unburned sites. Also, concentrations of ammonium nitrogen were markedly increased in burned sites contrary to those of nitrate nitrogen. Total nitrogen, however, showed no significant difference between the sites. Concentrations of cations, calcium and magnesium, in burned sites were also significantly increased. Thus, even though forest fire removed the aboveground biomass of pine forests, inorganic nutrients added from ash may play a great role for growth of sprouts and seedlings after forest fire.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1719-1723
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• 2002

1,5-diphenylcarbazone was immobilized on sodium dodecyl sulfate coated alumina. The alumina particle was effectively used for collection of mercury(II) and methylmercury cations at sub-ppb level. The adsorbed mercury was eluted with l mol $L^{-1}$ of hydrobromic acid solution. The mercury(II) was then directly measured by cold vapor atomic absorption spectrometry utilizing tin (II) chloride where as the total mercury was determined after the oxidation of methylmercury into the inorganic mercury. The methylmercury concentration was calculated by the difference between the value of total mercury and mercury (II). Mercury (II) and methylmercury cations were completely recovered from water with a preconcentration factor of 100 (for 1 L solution.) Relative standard deviation at Hg L ${\mu}gL^{-1}$ level 1.7%(n=8) and the limit of detection was 0.11 ${\mu}gL^{-1}$. The procedure was applied to spring water, well water and seawater and accuracy was assessed through recovery experiments.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.460-466
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• 2014

To evaluate wood charcoal as raw material for mineral water production, dissolution of inorganic ions from charcoal to water, pH and adsorption ability of chlorine in water were investigated as main variables. More potassium ion was dissolved in water as higher temperature manufactured charcoal but other ions showed no difference with different charcoal making temperatures. Highest dissolved cation was potassium followed by calcium and sodium. Among wood species, charcoal from Quercus variabilis and Platanus occidentalis showed significantly higher potassium content in water than that of larch, red pine and white pine. Other cations had similar pattern to the potassium but their difference was not apparent as much as potassium. pH value of water treated with charcoal was higher for wood charcoals from Platanus occidentalis (pH 8.5) and Quercus variabilis (pH 8.4) which contained higher inorganic cations. In chlorine removal in water by charcoal, all wood charcoals showed greater chlorine removal than that of the control, but softwood charcoals resulted in higher removal than those of hardwoods. There was no significant difference in the dissolution of cations and pHs between particle charcoal and whole charcoal. With easy of control, whole charcoal is better for mineral water making raw material than particle charcoal does.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.205-210
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• 1983

The determination of charge density and charge distribution in montmorillonite are discussed. The method is based on cation exchange of the inorganic interlayer cations against decylammonium ion and molecular intercalation of n-alcanol. The results obtained from Yougil-bentonite show that charge density of 0.37 per unit formula and cation exchange capacity of 102.5 meq/100g.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.349-352
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• 1988

[(Benzene)Mn$(CO)_3$]$^+$ reacts with NaP(O) (OR)$_2$ (R = Me, Et, Ph) to give the phosphonate compound 1. Compound 1 reacts with R'Li (R = Me, Ph, $^nBu, ^tBu$) to yield the isomerized compound 2 and the alkylated compound 3. [(Toluene)Mn$(CO)_3$]$^+$ reacts with NaP(O)$(OMe)_2$ to give the phosphonate complexes 1-A and 1-B. Treatment of 1-A with $^tBuLi$ in THF affords complexes 3-A and 3-B with the later major. With 1-B only the complex 3-C is formed. [(Anisole)Mn$(CO)_3$]$^+$ reacts with NaP(O)$(OMe)_2$ to give the phosphate complex 1-C, which on treatment with $^tBuLi$ and then $H_2O$ yields compound 3-D. After demetallation of compound 3-D, meta-tertbutyl-anisole is obtained in a reasonable yield.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.23-29
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• 2003

Setschenow constants of six alkali and alkaline earth metal-based electrolytes (i.e., NaCl, KCl, CaCl$_2$, K$_2$SO$_4$, Na$_2$SO$_4$, NaClO$_4$) for three polycyclic aromatic hydrocarbons (PAHs) (i.e., naphthalene, pyrene, and perylene) were investigated to evaluate the influence of a variety of inorganic salts on the aqueous solubility of PAHs. Inorganic salts showed a wide range of K$\_$s/ values (L/mol), ranging from 0.1108 (NaClO$_4$) to 0.6680 (Na$_2$SO$_4$) for naphthalene, 0.1071 (NaClO$_4$) to 0.7355 (Na$_2$SO$_4$) for pyrene, and 0.1526 (NaClO$_4$) to 0.8136 (Na$_2$SO$_4$) for perylene. In general, the salting out effect of metal cations decreased in the order of Ca$\^$2+/>Na$\^$+/>K$\^$+/. The effect of SO$_4$$\^$2-/>Cl$\^$-/>ClO4$\^$-/ was observed for anions of inorganic salts. The K$\_$s/ values decreased in the order of perylene>pyrene>naphthalene for K$_2$SO$_4$. However, the order of decreasing salting out effect for NaCl, KCl, CaCl$_2$, and NaClO$_4$ was perylene>naphthalene>pyrene. Hydration free energy of the 1:1 and 2:1 alkali and alkaline earth metal-based inorganic salts solution was observed to have a meaningful correlation with Setschenow constants. Thermodynamic interactions between PAH molecules and salt solution can be of importance in determining the magnitude of salting out effect for PAHs at a given salt solution.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.