• Environmental Engineering Research
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• v.17 no.2
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• pp.111-116
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• 2012

This study investigates the complete removal of nitrate and the recovery of valuable ammonium salt by the combination of nanoscale zero-valent iron (NZVI) and a membrane contactor system. The NZVI used for the experiments was prepared by chemical reduction without a stabilizing agent. The main end-product of nitrate reduction by NZVI was ammonia, and the solution pH was stably maintained around 10.5. Effective removal of ammonia was possible with the polytetrafluoroethylene membrane contactor system in all tested conditions. Among the various operation parameters including influent pH, concentration, temperature, and contact time, contact time and solution pH showed significant effects on the ammonia removal mechanism. Also, the osmotic distillation phenomena that deteriorate the mass transfer efficiency could be minimized by pre-heating the influent wastewater. The ammonia removal rate could be maximized by optimizing operation conditions and changing the membrane configuration. The combination of NZVI and the membrane contactor system could be a solution for nitrate removal and the recovery of valuable products.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.226-232
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• 1995

This study is a result of the experiments to determine the optimum conditions of salting of Chinese cabbages for making tasty Kimchi. For the experiments, various methods of salting of Baechu were set up and the best method of salting had prepared Kimchi to investigated the best salt kind. In the two best results by method of salting salt kind, were investigated for salting time of Kimchi. There were certain amounts of Kimchi had prepared for each case of the combinations of the three conditions. Every case of Kimchi was refrigerated and was evaluated by sensory tests. In the salt concentration, pH and acidity of the Kimchi were measured. The results are as follows; In three cases of Kimchi, for salt concentration, level of 2.4-3.0$^{\circ}$ was maintained in Kimchi solid from the beginning to the end, while it was high in the beginning and gradually lowered in Kimchi liquid. The level of pH in both solid and liquid of Kimchi quickly dropped at the beginning of fermentation period and turned slow as time passed. And the level of acidity was increased little bit in the beginning, but it suddenly multipied until the third day of preservation. Since then, it had increased gradually thereafter as it was before. This experiments show that Kimchi can be the best taste in the case of Chinese cabbage soak in brine- free natural salt are kept for five hours.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.2
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• pp.167-174
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• 1989

AS a part of investigation to use anchovy more effectively as food source, this work was undertaken the processing conditions of extracts from rapid fermented anchovy sauce. To prepare rapid fermented products, the chopped anchovy was mixed with 50% water (w/w), and then hydrolyzed by autolysis or addition of koji under different conditions of hydrolysis. The optimal conditions for hydrolysis of chopped anchovy were revealed $50^{\circ}C$, 6 hours, pH 8.0 by autolysis, and ,$50^{\circ}C$, 6 hours, pH 7.0 by addition of 10% koji, respectively. But, pH control was not much beneficial in increasing yield. The effect of soybean protein isolote for improvement of bitter taste was also tested. The reasonable amount of added soybean protein isolate was revealed 5% on the weight basis of the chopped anchovy. The reaction mixture hydrolyzed under optimal conditions were added with 1% onion powder (w/w), 1% garlic powder(w/w) and 1% red pepper powder(w/w) for masking fishy odor, inactivated for 20 min at $100^{\circ}C$, and then centrifuged for 20 min at 4,000 rpm. The supernatant liquor was filtrated and evaporated to 50%(v/v). finally, table salt was added for bateriostatic effect and characteristic taste of rapid fermented products. the reasonable amount of added table salt was reversed 15% on the volume basis of the evaporated liquor. The hydrolysis ratio of product made by addition of water, product made by addition of koji and water, and product made by addition of soybean protein isolate, koji and water hydrolyzed under optimal conditions were 58.4%, 82.1% and 86.2%, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.68-74
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• 1999

The optimum conditions for selective .elimination of salt from tuna boiled extract (TBE) by electrodialysis were determined. The desalination conditions of TBE were determined at various pH's, concentrations and volumes of TBE. The ion-exchange membrane with a molecular weight cut off 100Da was used for desalting of TBE. The desalination times on $1\%$ and $10\%$ of TBE concentrations were 40 min and 240 min, respectively. The electrodialysis process could removed above $95\%$ of the initial salt content in $1\%$ and $10\%$ of TBE concentrations. The desalination of TBE at pH 4.0 was $14\%$ higher than that at pH 9.0 The amount of water transferred by the electrodialysis was determined. The electrodialysis process could remove above $90\%$ of the initial salt content in $5\%$ TBE for 80 min. The initial volume and the permeate did not have significant effects on desalination time and ratio. The key parameters for the desalination of TBE were pH and concentration of TBA.

• Journal of the Korean Society of Food Culture
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• v.27 no.2
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• pp.211-224
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• 2012

Eggplant pickles were classified into three groups based on salt concentration (1, 3, 5%) and three groups based on drying time (30, 60 and 120 minutes), followed by storage at $5^{\circ}C$ for 28 days. Raw eggplant contains 94.82% water content. The increase in salt concentration and drying time caused a decrease in the moisture content. Compared to the 0.27% ash content of raw eggplant, the ash content of eggplant pickles increased noticeably with increasing salt concentration due to penetration into the eggplant pickles. pH values decreased significantly as the levels of salt concentration and dying time increased (p<0.05). In terms of storage time, pH values decreased from 21 days. The variation in salinity increased significantly as the concentration of salt increased. Compared to normal pickles salted at 5.39% salinity, eggplant pickles constituted 0.27~0.77% (1%), 0.40~1.14% (3%), and 0.47~11.20% (5%) 'low-salinity' eggplant pickles. Reducing-sugar content differed on the dates of 7, 14 and 21 in drying time and at 3% salinity. Hardness differed at 30, 60, and 120M on the 28th and 1, 5% salt concentration. Resilience differed according to drying time and from dates of 0 to 14th. The number of total microbes decreased at low salinity. In terms of storage time, the number of microbes tended to decrease after the 21st. In the consumer preference test, lightness of 5%-30M was the highest value.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.146-155
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• 1983

Fundamental study was carried out to elucidate the mechanisms of biological degradation of dyestuff in environments. A few bacterial strains which were capable of degrading amarnath were obtained from soil through an extensive screening program and identified by microbiolological properties. Conditions for bacterial growth and amaranth degradation were characterized and optimized, and the degradation products were identified. The results were as follows. 1. The most active strain A12-1 to be capable of degradation of amaranth was identified as Pseudomonas sp. 2. Optimal conditions for growth of the strain A12-1 were:$35^{\circ}C$ and pH 7.5, and growth was markedly increaesd by aeration. 3. Degradation of amaranth by the strain was accessed under similiar conditions for growth, however significantly inhibited when the culture was aerated. 4. Both bacterial growth and amaranth degradation were gradually decreased with increased concentration of amaranth in the culture. 5. Reaction of the crude enzyme from the strain A12-1 was optimal at $35^{\circ}C$ and pH 7.5 for degrading amaranth. 6. Sodium naphthionate and R-amino salt were found to be the products of amaranth degradation by the strain A12-1.

• Macromolecular Research
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• v.13 no.1
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• pp.45-53
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• 2005

In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacryl­amide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N'-methylenebis­acrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g­PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-poly­methacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the Alg-g-PMAM or the H-Alg-g-PMAM was characterized by FTIR spectroscopy. The effects of the grafting variables (i.e., concentration of MBA, MAM, and APS) and the alkaline hydrolysis conditions (i.e., NaOH concentration, hydrolysis time, and temperature) were optimized systematically to achieve a hydrogel having the maximum swelling capacity. Measurements of the absorbency in various aqueous salt solutions indicated that the swelling capacity decreased upon increasing the ionic strength of the swelling medium. This behavior could be attributed to a charge screening effect for monovalent cations, as well as ionic cross-linking for multivalent cations. Because of the high swelling capacity in salt solutions, however, the hydrogels might be considered as anti-salt superabsorbents. The swelling behavior of the superabsorbing hydrogels was also measured in solutions having values of pH ranging from 1 to 13. Furthermore, the pH reversibility and on/off switching behavior, measured at pH 2.0 and 8.0, suggested that the synthesized hydrogels were excellent candidates for the controlled delivery of bioactive agents. Finally, we performed preliminary investigations of the swelling kinetics of the synthesized hydrogels at various particle sizes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.829-835
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• 2016

An excess in the nutrients such as nitrogen and phosphate leads to a phenomenon called eutrophication. In order to avoid this, numerous methods have been used to remove excess nutrients in the water. In this study, the use of a chemical method was assessed through the formation of magnesium ammonium phosphate. The difference in the removal efficiency of seawater and sea salt solution as primary sources of $Mg^{2+}$ ions and $Ca^{2+}$ ions for the formation of magnesium ammonium phosphate (MAP) and hydroxyapatite (HAP) respectively, were observed, taking into account the changes in pH and concentration. The results showed that seawater removed about 90 % phosphate and less than 50 % ammonia in sewage water condition, whereas the sea salt solution removed almost 90 % phosphate and 70 % ammonia in solution at pH 9 and 10 mM concentration of sea salt which further increases as the optimum ${Mg/PO_4}^{3-}$, ${NH_4}^+$ ratio reaches 2. The difference in the removal efficiency of seawater and sea salt was due to the fact that the set-ups were prepared in different conditions. This study suggests that both seawater and sea salt can be used to remove nutrients from the water. The relatively higher removal of phosphate can be explained by the formation of HAP from free $Ca^{2+}$ ions initially present in seawater and sea salt solution.

• The Journal of Engineering Geology
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• v.3 no.2
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• pp.191-201
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• 1993

Reduction is one of the important mechanisrns in decreasing the amount of Cr(VI) in wastewater and this reaction is quite dependent on pH and temperature. Either soil organic materials, or a high inorganic salt concentration with elevated temperature and low pH will provide a good condition for the reduction of Cr(VI) to Cr(III) in deep well injection zones. Chromate reduction by soil organic materials and chloride ion in various environment conditions is investigated. Aquifer and aquitard formation samples have been obtained from a deep well in St. Bernard Parish, and St. Charles Parish, LA, U.S.A., respectively. For this study, pH ranging from -0.81 to 2.0, temperature $50^{\circ}C{\;}and{\;}70^{\circ}C$, and cliloride concentration 0 M, 0.26 M and 0.52 M are used to represent the actual conditions in deep well injection zones.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.62-68
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• 1998

To develop methods to produce low salt fermented squid with rich flavor and acceptable shelf life, the optimum processing conditions such as water activity of raw material, amounts of NaCl, papain and gucose were investigated. Water activity of squid meat was adjusted to 0.94 (raw meat), 0.90 and 0.88 by cold air blast and each was salted with 3, 5, or 7% NaCl followed by fermenting at $10^{\circ}C$ for 6 weeks. Amino nitrogen was increased rapidly with high water activity and low NaCl concentration. As a result of organoleptic evaluation it was concluded that optimum conditions were to adjust water activity of raw material to 0.90 and to salt with 5% NaCl. When squid meat adjusting water activity to 0.90 was treated with 0.05, 0.1 and 0.5% papain and fermented at $10^{\circ}C$ for 6 weeks, SDS-PAGE pattern showed rapid breakdown of myofibrilar protein with increasing amounts of papain but the treatment with 0.1% enzyme was best organoleptically. pH values of squid meat added with 1 and 2% glucose were maintained lower than control (glucose 0%) but there were no significant differences between the two glucose treatments. Therefore, it was thought that adding of glucose might be extended shelf life of fermented squid with low salt concentration.