• Korean Journal of Soil Science and Fertilizer
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• v.37 no.6
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• pp.371-377
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• 2004

Sulfate adsorption in forest soils is a process of sulfur dynamics playing an important role in plant uptake, cation movement, acid neutralization capacity and so on. The relationship between sulfate adsorption and some physicochemical properties of four forest soils was investigated. Extractable sulfate contents and sulfate adsorption capacity (SAC) in the forest soils varied much among study sites. Extractable sulfate contents were more in sub-surface soils with lower organic matter and greater Al and Fe oxides than in surface soils. The average contents of $Al_d$ and $Fe_d$ in the sub-surface soils were 8.49 and $12.45g\;kg^{-1}$, respectively. Soil pH, cation exchange capacity and clay content were positively correlated with the extractable sulfate contents and SAC. Organic carbon content, however, was negatively correlated with the extractable sulfate contents, implying the competitive adsorption of sulfate with soil organic matter. Considerably significant correlation was found between inorganic + amorphous Al and Fe oxides and the sulfate adsorption, but crystalline Al and other fractions of Fe oxide showed no correlation. Relatively close relationship between the adsorbed sulfates and soil pH, cation exchange capacity, or amorphous Al oxides indicates that the accelerated soil acidification may substantially reduce the potential for sulfate adsorption contributing to sulfur flux in forest ecosystems.

• Clean Technology
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• v.4 no.2
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• pp.11-22
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• 1998

The photo-sensitized oxidation of benzene in water was investigated under various reaction conditions using persulfate, sulfate, nitrate, nitrite and chloride ions as sensitizers. Persulfate ion was proved to be the most effective sensitizer, while sulfate and nitrite could not play any sensitizing role on the benzene photooxidation. When exited together with other ions, the nitrite ion inhibited the photooxidation of benzene by quenching the produced hydroxyl radicals.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1286-1293
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• 1998

${SO_4}^{2-}$ ions present in industrial waste water if combined with other metal ions in the water can cause serious scale problem in a transporting pipe. In this study therefore ${SO_4}^{2-}$ ions in an acidic solution have been removed by using surface active glasses. Glasses with various compositions of $SiO_2-Na_2O-B_2O_3-RO$ (R=Mg, Ca, Sr, Ba) system were reacted in a ${SO_4}^{2-}$ ion-containing solution with various pHs ranging from 1 to 4 for various time the reacted glass surfaces were analyzed by XRD and SEM and all ions in the reacted solution were also measured ${SO_4}^{2-}$ ions in the solution were combined with divalent ions leached out of glass and precipitated on the glass surface as sulfate crystals. In this was the surface ion could be removed from the acidic solution. The sulfate ion removal capacity is closely related to the solubility product con-stants of the newly formed sulfate crystals. Almost no sulfate crystal was formed on the MgO-containing glass while sulfate crystals were easily formed on the glass containing either SrO or BaO This indicates that those glasses have strong removal efficiency of ${SO_4}^{2-}$ ions from the solution.

• Clean Technology
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• v.4 no.2
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• pp.23-31
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• 1998

Photo-sensitized oxidation of benzene in aqueous solution was conducted with persulfate, nitrate, nitrite, sulfate and chloride as sensitizers.In the photo-sensitized oxidation of benzene persulfate, nitrate and nitrite could act as sensitizers, while no detectable effects could be observed with sulfate and chloride. With increasing nitrite concentration the photo-sensitized oxidation of benzene ran through a maximum value and decreased thereafter with increasing nitrite concentration. A build-up of nitrite ions seemed to scavenge hydroxyl radicals. When nitrite was present with other ions, nitrite inhibited the photo-sensitized oxidation of benzene. Phenol and biphenyl were identified as intermediate.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.877-891
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• 1998

This study was designed to observe the effects of various concentration of polyacrylic acid containing different concentration of sulfate ion on the crystal formation on the enamel surface. Experimental crystal growth solutions were made of $10\%,\;20\%,\;30\%\;and\;40\%$ polyacrylic acid(molecular weight,5,000) solutions which containing 0.1M, 0.2M, 0.3M, 0.5M, and 1.0M sulfate ion respectively. The extracted human first bicuspid enamel surface was contacted for n seconds with these solutions, washed for 15 seconds, dried, and then the crystal topography on the enamel surface was observed under the scanning electron microscope. The crystal topography were evaluated on the SEM photographs by degree of crystal coverage, crystal length, and consistency of crystal morphology, and conclusions were as the follows. 1. Polyacrylic acid solution etched slightly the enamel surface, and the difference of etching effect by its concentration was not observed. 2. The effect of concentration of polyacrylic acid on the crystal formation was less, especially that of $20\%\~40\%$ polyacrylic acid was almost not different. 3. Concentration of the sulfate ion was a determinant factor in precipitating crystals on the enamel. The experimental crystal growth solutions containing 0.1 M sulfate ion did not make crystal formation but those containing over 0.2 M sulfate ion did. 4. The degree of crystal coverage showed a tendency to increase and then decrease according to the concentration of sulfate ion in the $20\%-40\%$ polyacrylic acid. The experimental solutions containing 0.5 M sulfate ion showed the peak of degree of crystal coverage. 5. The crystal length showed a tendency to decrease by increment of sulfate ion in the polyacrylic acid solution. 6. There was a tendency to increase the frequency of random arragement of short crystals when increasing the concentration of sulfate ion in the polyacrylic acid solution. The lower concentration of sulfate ion in the polyacrylic acid solutions tended to make spherulitic arrangement of crystals, the higher concentration of sulfate ion, the more random arrangement of crystals. The experimental solutions containing 0.5M sulfate ion showed more spherulitic arrangement than random arrangement of crystals. 7. The best one of these experimental crystal growth solutions was $30\%$ polyacrylic acid solution containing 0.5M sulfate ion.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.708-717
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• 2002

Durability is a major concern in the design and construction of concrete structures which are located in the sea environments. In particular, the combined action of chlorides, sulfates, and carbonation nay influence greatly the deterioration behavior of concrete structures. The purpose of the present study is to explore the diffusion characteristics of chloride ions in concrete structures under combined deterioration conditions. The present test results indicate that the chloride penetration into concrete structures is more pronounced under combined attacks of chlorides, sulfates and carbonation. The diffusion coefficients and surface chloride contents were found to increase under combined multiple deterioration conditions. The present study provides quantitatively the penetration and diffusion characteristics of chloride ions in concrete structures under various deterioration conditions. The results of present study may be efficiently used for the realistic design of concrete structures under combined deterioration conditions.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.55-61
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• 1998

This experiment was conducted to evaluate the effects of sulfate ion concentration in nutrient solution on the growth and qualify of Mongolian wormwood (Artemisia mongolica var. tenuifolia). Sulfate ion concentration was treated 0, 0.5, 1, 2 and 3mM using the modified nutrient solution composition for herb plants developed by European Vegetable R & D Center in Belgium. The growth of Mongolian wormwood was good at 3mM treatment and dry weight was best at 3mM treatment, Chlorophyll content increased with sulfate ion concentration. Mineral content did not show any significant difference among treatments. But Ca content in tissue markedly decreased at 3mM treatment. Sulfate ion uptake increased in proportion to sulfate ion concentration in nutreint solution, the higher sulfate ion concentration, the more uptake of sulfate ion by plant. At 1mM sulfate ion treatment, essential oil content was best, but the higher sulfate ion concentration resulted in decrease of essential oil content.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.361-367
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• 1983

The selective separation and the quantitative recovery of uranium from Korean monazite sand have been studied by anion-exchange chromatography. It has been shown that method of anion-exchange chromatography under controlled conditions of elution can be applied to the production of relatively high purity of Uranium Oxide from monazite sand. Under the optimum separation conditions, the recoveries from standard sample were up to 99.3% as $U_3O_8$ on sulfate form anion resin bed and 99.2% as $U_2O_3{\cdot}P_2O_7$ on phosphate form anion resin bed. The possibility of recovering uranium from the monazite sulfate solution using a strong base anion exchange resin-Amberlite IRA-900. Uranium was successfully recovered about 92 percent. Phosphate ion did not seem to interfere with the process.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.173-182
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• 2003

Recently, the durability of concrete structures has received great attention as the number of sea-side structures, such as new airport, bridges, and nuclear power plants, increases continuously. In this regards, many studies have been done on the chloride attack in concrete structures. However, those studies were confined mostly to the single deterioration due to chloride only, although actual environment is rather of combined type. The purpose of the present study is, therefore, to explore the effects of combined deterioration due to chlorides and sulfates in concrete structures. To this end, comprehensive experimental program has been set up to observe the chloride penetration behavior for various test series. The test results indicate that the chloride penetration is more pronounced for the case of combined attack than the case of single chloride attack. The surface chloride content is found to increase with time and the diffusion coefficient for chloride is found to decrease with time. The prediction equations for surface chloride content and diffusion coefficient were proposed according to test results. The equations for chloride penetration considering the time-dependent diffusion coefficients and surface chlorides were also suggested. The present study allows more realistic assessment of durability for such concrete structures which are subjected to combined attacks of chlorides and high concentration sulfates but the future studies for combined environment will assure the precise assessment.

• Membrane Journal
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• v.23 no.1
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• pp.92-99
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• 2013

In this study the nanofiltration (NF) membrane treatment of a sulfuric acid waste solutions containing copper ion ($Cu^{+2}$) discharging from the etching processes of the printed circuit board (PCB) manufacturing industry has been studied for the recycling of acid etching solution. SelRO MPS-34 4040 NF membrane from Koch company was tested to obtain the basic NF data for recycling of etching solution and separation efficiency (total rejection) of copper ion. NF experiments were carried out with a dead-end membrane filtration laboratory system. The pure water flux was increased with the increasing storage time in sulfuric acid solution and lowering pH of acid solution because of the enhancement of NF membrane damage by sulfuric acid. The permeate flux of acid solution was decreased with the increasing copper ion concentration. Total rejection of copper ion was decreased with the increasing storage time in sulfuric acid solution and copper ion concentration, and lowering the pH of acid solution. The total rejection of copper ion was decreased from initial 37% to 15% minimum value.