• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.246-252
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• 2015

In steel factory, hot roller cleaning process produces a lot of iron oxide particles called as mill scale. Major components of these particles are wustite (FeO), magnetite ($Fe_3O_4$), and hematite ($Fe_2O_3$). In this study, we tried to produce pure magnetite from the mill scale because of the largest phosphate adsorption capacity of the magnetite. The mill scale was treated with acid (HCl+$H_2O_2$), base (NaOH), and acid-base ($H_2SO_4$+NaOH). Batch adsorption tests showed the acid and/or base treatment could increase the phosphate adsorption capacity of the iron oxides from 0.28 to over 3.11 mgP/g. Magnetite, which could be obtained by acid and base treatment of the mill scale, showed the best adsorption capacity. From the kinetic analysis, both Freundlich and Langmuir isotherm well described the phosphate adsorption behavior of the magnetite. In Langmuir model, maximum phosphate adsorption capacity was found to be 5.1 mgP/g at $20^{\circ}C$.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.557-563
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• 2016

To improve the germination of Spiraea fritschiana seeds for mass propagation, we evaluated the effect of a range of temperatures, cold stratification periods, and gibberellic acid ($GA_3$) treatments on three germination characteristics. Final germination percentage (FGP) increased as the temperature for seed germination increased, up to $30^{\circ}C$, while the mean germination time (MGT) and the mean number of days to 30% germination ($T_{30}$) decreased when seeds were germinated at $25-30^{\circ}C$. The optimum germination temperature of S. fritschiana seeds is approximately $30^{\circ}C$ considering FGP, MGT, and $T_{30}$ together. FGP increased with the duration of cold stratification up to a period of 6 weeks, but declined after 8 weeks of cold stratification, as prolonged cold stratification can induce dormancy with a resultant decline in germination. Pretreatment with 6-8 weeks of cold stratification or soaking seeds in distilled water or $500mg{\cdot}L^{-1}$ $GA_3$ for 24 h accelerated and increased the germination of S. fritschiana seeds, regardless of temperature. However, further study might be required to evaluate the effect of $GA_3$ concentrations lower than $500mg{\cdot}L^{-1}$ on the promotion of germination in S. fritschiana seeds.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.241-247
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• 1991

The objective of this experiment was to study the effect of dextrin on vacuum frying dried carrots. The concentrations of dextrin solution were 0%, 10%, 20%, 30% and the criteria for quality evaluation were sorption characteristics, rehydration power, color and crispness differences. The sorption characteristics were evaluated by Peleg's equation. Rehydration, color and crispness were determined by rehydration percentage, colorimetry and sensory evaluation, respectively. The dextrin pretreatment of carrot resulted in the reduction of adsorption rate and the equilibrium moisture content of dried carrot at various range of relative humidities, and the adsorption rate of samples pretreated with aqueous dextrin solution at different temperatures($4^{\circ}C,\;20^{\circ}C,\;30^{\circ}C$) were in the following decreasing order : control>10% dextrin>20% dextrin>30% dextrin. As the concentration of dextrin solution and ambient temperature increased, BET monomolecular layer moisture content decreased significantly. In addition, as the concentration of dextrin solution increased, the crispness intensity increased and the color of sample treated with 20% dextrin solution was similar to that of raw carrot.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.57-65
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• 2005

This study suggested a new method for the solidification of molten salt waste generated from the electro-metallurgical process in the spent fuel treatment. Using binary material system, sodium silicate and phosphoric acid, metal chlorides were converted into metal phosphate in the micro-reaction module formed by SiO$_{2} particles. The volatile element in the reaction module would little vaporized below 1100$^{circ}$C After the gel product was mixed with borosilicate glass powder and thermally treated at 1000$^{circ}$C, li exists as Li$_{3}$PO$_4$ separated from glass phase and, Cs and Sr would be incorporated into an amorphous phase from XRD analysis. In case of the addition of ZrCl$_{4}$ to the binary system, the gel products were transformed into NZP structure considered as an prospective ceramic waste form after heat-treatment above 700 $^{circ}$C. From these results, the gel-route pretreatment can be considered as an effective approach to the solidincation of molten salt waste by the confirmed process or waste form and this also would be an alternative method on the ANL method using zeolites in USA by the confirmation of its chemical durability as an future work.

• Korean journal of food and cookery science
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• v.11 no.1
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• pp.37-43
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• 1995

Effect of the pretreatment with acetic acid(0.01%, 0.05%, 0.1%) on the fermentation of Chinese cabbage Kimchi, and differences in the degree of maturity between Chinese cabbage blades and midribs were observed. To estimate the degree of maturity, correlation analysis was used with several variables such as pH, titratable acidity, volatile acidity, ascorbic acid content, resazurin test value and pH/acidity ratio. Based on the pH and titratable acidity, the degree of maturity of Chinese cabbage midribs fermented at 10$^{\circ}C$ until the optimum stage of fermentation increased more rapidly than those of the blades. The stage of maturity of Kimchi pretreated with 0.01% acetic acid were slightly prolonged, compared to those pretreated with acetic acid at the higher levels. The pH of Chinese cabbage midribs and blades pretreated with acetic acid was lower than those of control between 2nd and l0th day of fermentation. The volatile acidity of Chinese cabbage midribs and blades increased proportionally with the concentration of acetic acid. The ascorbic acid contents of Chinese cabbage midribs showed higher than those of Chinese cabbage blades. During the fermentation, the higher concentration of acetic acid was used, the less ascorbic acid content was remained. The pH/acidity ratio, volatile acidity, ascorbic acid content and resazurin test value of Chinese cabbage midribs and blades during Kimchi fermentation at 10$^{\circ}C$ showed good correlations with the pH and titratable acidity.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.865-872
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• 2009

Continuous operation of aerobic sludge digestion reactor was attempted for 279 days. Anaerobic digester sludge, the target material of the experiment, was pretreated by sodium hydroxide at $40^{\circ}C$ for 120 minutes, and the pretreated sludge was fed to 5 L CSTR (continuous stirred tank reactor). Reactor performance was affected by properties of input sludge and HRT (hydraulic retention time). 6 days of HRT showed best and stable performance, and under this condition, removal rates of $NH_3$-N, SCOD, TKN, TCOD, SS, and VSS were 97.4%, 81.7%, 68.7%, 61.4%, 50.6%, and 47.0%, respectively. 73.9% of SS in anaerobic digester sludge was reduced by pretreatment and aerobic digestion. Effluent sludge had low soluble COD of 350 mg/L. This implied the sludge was stabilized and suitable for use as liquid fertilizer. Nitrification took place when HRT was higher than 4 days. $NO_3$-N concentration was as high as 658 mg/L while $NH_3$-N was as low as 20 mg/L.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.537-541
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• 2005

A bubbling fluidized bed reactor was used to study $CO_2$ capture from flue gas using a sodium-based dry regenerable sorbent, sorbA which was manufactured by Korea Electric Power Research Institute. A dry sorbent, sorbA, consists of $Na_2CO_3$ for absorption and supporters for mechanical strength. $CO_2$ capture was effective in the lower temperature range of $50-70^{\circ}C$, while regeneration occurred in the range of $120-300^{\circ}C$. To increase initial $CO_2$ removal, some amount of steam was absorbed in the sorbents before injecting simulated flue gas. It was possible to remove most $CO_2$ for 1-2 minutes at $50^{\circ}C$ and residence time of 2 seconds with steam pretreatment. Little or no reduction in initial reaction rate and capture capacity was observed in multicycle tests. The carbonated and regenerated sorbent samples were analyzed by NMR to confirm the extent of reaction. The results obtained in this study can be used as basic data for the scale-up design and operation of the $CO_2$ capture process with two fluidized bed reactors.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.384-388
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• 1996

This research was conducted to investigate the effective methods for browning inhibition on yam (Dioscorea aimadeimo) during dehydration by physical and chemical pretreatments. Moisture, crude protein, crude fiber and N-free extract contents of yam were 81.17%, 1.43%, 0.29% and 15.81%, respectively. Yams were sliced to 0.5 cm thickness and placed to single and poly layer in plastic tray, and then changes of their weights were measured during air dehydration at $50^{\circ}C,\;65^{\circ}C,\;and\;80^{\circ}C$. The dehydration time reaching to optimum moisture level for the pulverization of the yam slices were 10, 6, 3 hours(single layered) and 12, 7, 5 hours(multi layered) at the respective temperature. To inhibit browning at $80^{\circ}C$ air dehydration, water and steam blanching, microwave treatment effects were investigated on yam slices for 30 sec. and 60 sec. Steam blanching for 30 sec. was comparatively effective to inhibit browning of yam slices. Yam slices were immersed in single and combined browning inhibitor solutions and evaluated for browing degree during dehydration by the values of Hunter L, a, b and ${\Delta}E$. The most effective pretreatment to inhibit browning of yam slices was immersion In the solution containing 500 ppm of citric acid and 1000 ppm of cysteine for 1 min.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2004.10a
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• pp.67-72
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml $h^{-1}\;m^{-2}\;atm^{-1}$ at $5^{\circ}C\;and\;99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%\;CO_2+1\;or\;20\%\;O_2,\;8\%\;CO_2+1\;or\;20\%\;O_2,\;or\;12\%\;CO_2+20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2+1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. When stored at $20^{\circ}C$, slices from light-red tomato fruit grown with black polyethylene or hairy vetch mulches both showed a rapid increase in electrolyte leakage beginning 6 hours after slicing. However, slices from tomato fruit grown using the hairy vetch mulch tended to have lower electrolyte leakage than those grown with black polyethylene mulch. These results suggest that tomato fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch. Also, use of the disease forecasting model Tom-Cast, which can result in lower fungicide application than is currently used commercially, resulted in high quality fruit for fresh-cut processing. Experiments were conducted to determine if ethylene influences chilling injury, as measured by percentage of slices exhibiting water-soaked areas in fresh-cut tomato slices of 'Mountain Pride' and 'Sunbeam' tomato (Lycopersicon esculentum Mill.). Ethylene concentration in containers without ventilation significantly increased during storage at $5^{\circ}C$, whereas little or no accumulation of ethylene occurred in containers with one or six perforations. Chilling injury was greatest for slices in containers with six perforations, compared to slices in containers with one perforation, and was over 13-fold greater than that of slices in control containers with no perforations. An experiment was also performed to investigate the effectiveness of including an ethylene absorbent pad in containers on subsequent ethylene accumulation and chilling injury. While ethylene in the no-pad controls increased continually during storage of both 'Mountain Pride' and 'Sunbeam' tomatoes at $5^{\circ}C$ under modified atmosphere conditions, no increase in accumulation of ethylene was observed in containers containing ethylene absorbent pads throughout storage. The ethylene absorbent pad treatment resulted in a significantly higher percentage of chilling injury compared with the no-pad control. In studies aimed at inhibiting ethylene production using AVG during storage of slices, the concentration of ethylene in control containers (no AVG) remained at elevated levels throughout storage, compared to containers with slices treated with AVG. Chilling injury in slices treated with AVG was 5-fold greater than that of controls. Further, we tested the effect of ethylene pretreatment of slices on subsequent slice shelf-life and quality. In slices treated with ethylene (0, 0.1, 1, or $10\;{mu}L\;L^{-1}$) immediately after slicing, ethylene production in non-treated controls was greater than that of all other ethylene pre-treatments. However, pretreatment of slices 3 days after slicing resulted in a different pattern of ethylene production during storage. Ihe rate of ethylene production by slices treated with 1 L $L^{-1}$ ethylene 3 days after slicing was greater during storage than any of the other ethylene treatments. With slices pre-treated with ethylene, both immediately and 3 days after slicing, the rate of ethylene production tended to show an negative correlation with chilling injury. Chemical name used: 1-aminoethoxyvinylglycine (AVG).

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.51-55
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• 1997

To utilize the alkaline protease produced by Halomonas sp. ES-10 as an enzyme detergent, the crude enzyme was obtained by methanol precipitation and lyophilization. And it was processed to coated enzyme.The best mixing ratio of components such as coated enzyme, builders, actives, fillers and adjuvants on detergency was examined, and temperature and pH influencing detergency were also tested. Detergency test 0.15% detergent solution was carried out on EMPA test cloth #116 with shaking(90 rpm) for 10 min after 30 min of pretreatment. The detergent which contained coated-enzyme 1%, Zeolite 4A 20%, Tween 80 1. 5%, sodium borate 30%, sodium meta silicate 7.5% and water 40% showed about 90% of washing efficiency at 40$\circ $C and pH 10.0.