• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.171-175
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• 1969

This study wa attempted to extract the Potash-Ammonia Fertilyzer in most satisfactory yield from the Uncalcinecl Domestic Alunite ore applying an optimal reaction conditions (Ammonia water concentration and applicable reaction pressure, etc.), it was found that almost all amount of $K_2SO_4$ was extracted in the forms of $K_2SO_4·(NH_4)_2SO_4$mixture under such conditions. The experimental data to note are as follows: 1. The optimal pressure applied to the reaction was 600 to 700 Psig. 2. The optimal concentration of Ammonia water was 7 Mol/L. 3. The reaction time needed was 3 hours. 4. The extraction rate and degree were not at variance with sorts and occurrences of Alunite ore.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.642-655
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• 2013

In this study, semi-continuous measurements of $PM_{2.5}$ mass, organic and elemental carbon (OC and EC), black carbon (BC), and ionic species concentrations were made for the period of April 03~13, 2012, at a South Area Supersite at Gwangju. Possible sources causing the high concentrations of major chemical species in $PM_{2.5}$ observed during a haze episode were investigated. The measurement results, along with meteorological parameters, gaseous pollutants data, air mass back trajectory analyses and PSCF (potential source contribution function) results, were used to study the haze episode. Substantial enhancements of OC, EC, BC, $K^+$, $SO{_4}^{2-}$, $NO{_3}{^-}$, $NH{_4}{^+}$, and CO concentrations were closely associated with air masses coming from regions of forest fires in southeastern China, suggesting likely an impact of the forest fires. Also the PSCF maps for EC, OC, $SO{_4}^{2-}$, and $K^+$ demonstrate further that the long-range transport of smoke plumes of forest fires detected over the southeastern China could be a possible source of haze phenomena observed at the site. Another possible source leading to haze formation was likely from photochemistry of precursor gases such as volatile organic compounds, $SO_2$, and $NO_2$, resulting in accumulation of secondary organic aerosol, $SO{_4}^{2-}$ and $NO{_3}{^-}$. Throughout the episode, local wind directions were between 200 and $230^{\circ}C$, where two industrial areas are situated, with moderate wind speeds of 3~5 m/s, resulting in highly elevated concentration of $SO_2$ with a maximum of 15 ppb. The $SO{_4}^{2-}$ peak occurring in the afternoon hours coincided with maximum ambient temperature ($24^{\circ}C$) and ozone concentration (~100 ppb), and were driven by photochemistry of $SO_2$. As a result, the pattern of $SO{_4}^{2-}$ variations in relation to wind direction, $SO_2$ and $O_3$ concentrations, and the strong correlation between $SO_2$ and $SO{_4}^{2-}$ ($R^2=0.76$) suggests that in addition to the impact of smoke plumes from forest fires in the southeastern China, local $SO_2$ emissions were likely an important source of $SO{_4}^{2-}$ leading to haze formation at the site.

• 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.

• Membrane and Water Treatment
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• v.3 no.1
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• pp.63-76
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• 2012

Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.313-319
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• 2007

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were $H_3PO_4,\;CaCl_2,H_3BO_3$, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, $1.1;NaNO_3,\;4.4;MgSO_4{\cdot}7H_2O,\;0.8;KCl,\;0.4;CaCl_2,\;0.27;H_3PO_4,\;1.0ml/l;\;and\;trace elements\;(mg/l):H_3BO_3,\;0.25;CuSO_4,\;0.6;MnSO_4,\;2.2;Na_{2}MoO_4,\;0.5;ZnSO_4,\;6.0;FeSO_4,\;8.0;CoCL_2,\;1.0;$ and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from $10{\times}\;to\;105{\times}$, which is ten times higher than the non-optimized rich medium.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.17-21
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• 2016

The corrosion behavior of aluminum alloys in the $H_2SO_4$ solution was investigated based on potentiodynamic techniques. Electrochemical properties, such as corrosion potential($E_c$), passive potential($E_p$), corrosion current density($I_c$), corrosion rate(mpy), of Al-Mg-Si, Al-Cu-Si and Al-Si alloys were characterized at room temperature. Passive aluminum oxide film, which including $Al_2(SO_4)_3$ and $3Al_2O_34SO_38H_2O$, were uniformly formed on the surface via the reaction of Al with $SO{_3}^{2-}$ or $SO{_4}^{2-}$ ions in the $H_2SO_4$ solution and the dependence of the corrosion behavior on the alloying element was discussed. The selective leaching of alloy element increased with increasing Cu content in the aluminum alloys.

• Journal of the Mineralogical Society of Korea
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• v.2 no.2
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• pp.81-89
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• 1989

Alunite occurs as massive, cavity-filling and veinlets in the Cretaceous Hwangsan Formation in the Sungsan mine, Korea. It is a hydrothermal alteration product of rhyolitic tuffs, and associated with dickite, quartz and barite. The average chemical formula of alunite in the mine is $(K_{0.93}Na_{0.07})_{1.00}Al_{3.00}(SO_4)_{2.00}(OH)_6$. Atomic percentage of Na substituting for K in A site of the alunite structure varies from 5.9 to 9.2. Unit-cell volume and c dimension decrease with increasing Na atomic percentage. On the basis of thermal and high temperature XRD analyses, the decomposition of alunite into $KAl(SO_4)_2$ and $NaAl(SO_4)_2$ concomitant with the liberation of structural water (12.86%) occurs at about $550^{\circ}C$. The reconstruction of $KAl(SO_4)_2$ and $NaAl(SO_4)_2$ to $Al_2(SO_4)_3$, arcanite and thenardite, and the crystallization of ${\gamma}-Al_2O_3$ take place at about $720^{\circ}C$. The destruction of $Al_2(SO_4)_3$ structure takes place at about $760^{\circ}C$ removing 3/4 of total $SO_3$ (27.32%).

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1265-1272
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• 2007

A solid acid catalyst, NiSO4/CeO2-ZrO2 was prepared simply by promoting ZrO2 with CeO2 and supporting nickel sulfate on CeO2-ZrO2. The support of NiSO4 on ZrO2 shifted the phase transition of ZrO2 from amorphous to tetragonal to higher temperatures because of the interaction between NiSO4 and ZrO2. The surface area of 10-NiSO4/1-CeO2-ZrO2 promoted with CeO2 and calcined at 600 oC was very high (83 m2/g) compared to that of unpromoted 10-NiSO4/ZrO2 (45 m2/g). This high surface area of 10-NiSO4/1-CeO2-ZrO2 was due to the promoting effect of CeO2 which makes zirconia a stable tetragonal phase as confirmed by XRD. The role of CeO2 was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity of the sample, and high thermal stability of the surface sulfate species. 10-NiSO4/1- CeO2-ZrO2 containing 1 mol% CeO2 and 10 wt% NiSO4, and calcined at 600 oC exhibited maximum catalytic activities for both reactions, 2-propanol dehydration and cumene dealkylation.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.327-332
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• 1987

Soil samples were collected from the paddy soils growing two crops of rice and garlic in Kyung-pook province. To obtain the basic information on the application of S-fertilizer in the garlic field, the adsorption and release amount of $SO_4{^{-2}}$ in subsoil samples were determined. The ranges of $SO_4{^{-2}}$ contents in surface and sub-soil were 59-117 and 34-102 ppm, respectively. The amount of $SO_4{^{-2}}$ adsorbed by soil samples was found to be more at lower pH and higher concentration of $SO_4{^{-2}}$. The $SO_4{^{-2}}$ adsorption constants in Freundlich equation tended to be higher at lower pH. It is apparent that most of $SO_4{^{-2}}$ was released in the first extraction. However, the lower the pH of extracted solution, the more the $SO_4{^{-2}}$ contents was released by distilled water.

• Polymer(Korea)
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• v.38 no.1
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• pp.103-107
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• 2014

Poly(acrylonitrile-butadiene-styrene) (ABS) composite sheets containing titanium dioxide ($TiO_2$), barium sulfate ($BaSO_4$), calcium carbonate ($CaCO_3$) were prepared by using a co-rotating twin screw extruder, and the reflectance and flexural modulus of the composite sheets were measured. The fillers were well dispersed in ABS matrix. The reflectance of composite sheet was increased with increasing $TiO_2$ and $BaSO_4$ content. Sheet having $TiO_2$ 20 wt% composition, with 5~20 wt% $BaSO_4$ resulted in more than 95% of reflectance. The flexural modulus of composite sheet was increased from 1864 MPa for $ABS/TiO_2/BaSO_4$ 85/10/5 (w/w/w) to 3134 MPa for $ABS/TiO_2/BaSO_4$ 55/20/25 (w/w/w).