• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.93-99
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• 2000

Treatment of shaving scrap, a chrome containing solid scrap generated by leather manufacturing process, has been so far depended on mainly incineration, soil landfill and ocean dumping, which give bad impact on environment and cause pollution. Shaving scrap generates from the mechanical work for controlling the final thickness of leather and its main components are collagen protein and pan of chromium compound. For the purpose of reusing this leather waste as resources, researches in connection with collagen fiber recovery, gelable protein recovery and liquid fertilizer is being speedily progressed. In the experiment, shaving scrap went through wet pulverizing treatment by physical and chemical methods. Then, making the leather sheet evenly, it is mixed with natural latex and every kind of binding materials in the container, and the mixtures were passed through experimental hydraulic press machine and applied to Fourdrinier machine respectively. Lastly, a test for fading out physical strength and properties of multiple-purpose of leather-like material was performed on a continuous leather sheet prepared by the experiment. In result, the physical strength and properties of leather-like material showed noticeable differences according to mixing ratio of binding materials, beating methods and the Ends of binding materials selected, and generally tear strength was the weakest property among others. Also, by the pilot scale experiment in sequence, it was possible to manufacture recycled goods made of soft and hard types of leather-like material with various performances.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.90-96
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• 1998

An experiment to make mixed juices carrying the freshness and other specific characteristics of vegetables and fruits which are useful for the prevention and treatment of various diseases was attempted on the emphases of pretreatment methods, combination of fruits and vegetables, and elimination of microorganisms. Blanch in boiling water prior to extraction for green vegetables, addition of ascorbic acid during extraction for tomatoes and apples, or addition of ascorbic acid after blanch in 3% acetic acid for carrots was effective to keep colors and suspended solids in liquid extract. On the basis of sensory evaluation the extracts from tomatoes, apples. carrots. mallows, watercreses+pine needles, Angelica keiskei Koiz, jujubes and lemons were selected and mixed at the ratio of 3 : 3 : 3 : 1/2 : 1/2 : 1/2 : 1/2 : 1/5. The mixed extracts were pasteurized for 15sec at $96^{\circ}C$ or filtered through a ultramembrane filter. While the centrifuge precipitation and retentates on the membrane filter were autoclaved and combined with ultrafiltrates. The mixed juices showed $pH\;4.07{\sim}4.10$ titratable acidity $66.35{\sim}84.08$, soluble solid $7{\sim}9^0Brix$, reducing sugar $5.42{\sim}6.97%$, glucose $1.96{\sim}2.30%$, fructose $3.46{\sim}4.14%$ and high content of K, Mg and Ca. Ultrafiltration showed better quality scores in color, juice. Peroxidase and microorganisms were inactivated by thermal treatment and ultrafiltration.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.830-834
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• 2003

The optimal condition for the production and extraction of monacolin K was reported. HPLC was used to determine monacolin K a kind of metabolite of Monascus from red-koji made of Monascus purpureus CBS 281.34. After culturing Monascus in solid and liquid media at $30^{\circ}C$ for 10 days, each of these were inoculated with soybean, wheat, barley, waxy rice, and rice and cultivated at $30^{\circ}C$ for 11 days. The production of monacolin K was the highest(0.35g/100g) when cultured with rice. The yield of monacolin K in red-koji increased with drying temperature and time according to the removal of water. Considering monacolin K content and the degree of death of Monascus, red-koji was dried at $80^{\circ}C$ for 60 min. Although monacolin K in red-koji was mostly extracted by 80% ethanol, there was no difference in monacolin K between shaking for 1 min and extraction for $0{\sim}24$ hr after sonication for 7 min. The extracted yield of monacolin K was the highest when the ratio of red-koji and 80% ethanol was 1:9. Moreover, the production of monacolin K appeared to be parallel with that of the pigment.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.626-633
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• 2017

The present study investigated the effect of a water-washing process, which is part of the acid hydrometallurgical process for recovery of high purity of zinc, on the removal of alkali metals and chlorides (Na, K, Ca, Cl) from Electric arc furnace dust (EAFD). Two EAFD samples with different properties were characterized by particle size, XRD and element analysis, and their washing efficiencies (%) on alkali metals and chlorides were compared according to pH, washing time, liquid to solid (L/S) ratio and number of washings. The results show that the alkali metals and chlorides could be effectively removed by the washing (at L/S ration of 3 for more than 30 min., pH 10~11) while minimizing loss of zinc (<0.1%), in which the washing efficiency was Na-78%, K-76%, Cl >99%, respectively. Na and K could be removed up to 97% and 89% respectively by 3 times of repeated washings. With increased sample volume (10 times) of the mixed (1:1, w/w) sample with two types of EAFD, it was confirmed that the pH(10~11) can be used as the main process control parameter for the washing of the alkali metals regardless of EAFD properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.649-653
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• 1999

A magnetic fluid separation technology was confirmed to be very effective to remove the suspended solids (SS) from aquacultural recirculating water, In this study, the effects of operating variables on the characteristics of SS removal were investigated through the test runs using magnetite of 2 $\mu$m mean diameter as magnetic powder. Magnetic flocculation here formed by adsorbing fine magnetites on the surface of suspended solid was observed. The strength of magnet was of significance in determining the SS removal efficiency as well as the capacity of the equipment. In addition, the SS removal efficiency decreased with an increase in the superficial liquid velocity, but the effect became negligible when the mass ratio of magnetite to the suspended solids was higher than 1.0.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.517-520
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• 2006

The leaching behaviors of zinc and manganese oxides of spent alkaline manganeses battery in sulfuric acid solution by using $H_{2}O_{2}$ as a reducing agent were investigated according to the concentration of $H_{2}SO_{4}$, temperature, reaction time, and the amount of $H_{2}O_{2}$. The experimental results of zinc and manganeses dissolution rates obtained without a reducing agent at 100 g/L solid/liquid ratio, 3.0 M $H_{2}SO_{4}$, $60^{\circ}C$ and 200 r.p.m. were 97.7% and 43.5%, respectively. On the other hand, zinc and manganeses dissolution rates obtained by adding 30 mL reducing agent at $60^{\circ}C$ were 99.6% and 97.1%, respectively. The addition of the reducing agent increased the leaching of manganese by two-fold compared to the absence of a reducing agent. In case of adding over 30 mL $H_{2}O_{2}$, however, the leaching rates of zinc and manganeses were independent of reducing agent amounts.

• Clean Technology
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• v.23 no.2
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• pp.158-162
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• 2017

$FeCl_3$ solution has been used as an etchant for metal etching such as Fe, Cu, Al and Ni. In the etching process, $Fe^{3+}$ is reduced to $Fe^{2+}$ and the etching efficiency is decreased. Waste $FeCl_3$ etchant has environmental, economic problems and thus the regeneration of the etching solution has been required. In this study, HCl was mixed with the $FeCl_2$ solution and then, $H_2O_2$, $NaClO_3$ were added into the mixed solution to oxidize the $Fe^{2+}$. During the oxidation process, oxidation-reduction potential (ORP) was measured and the relationship between ORP and oxidation ratio was investigated. The ORP is increased with increasing the concentration of $H_2O_2$ and $NaClO_3$, and then the ORP is decreased with oxidation progress. Such a behavior was in good agreement with Nernst's equation. Also, the oxidation efficiency was about 99% when a sufficient amount of HCl and $H_2O_2$, $NaClO_3$ were added.

• Journal of Nutrition and Health
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• v.56 no.5
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• pp.537-553
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• 2023

Purpose: The purpose of this study was to evaluate the nutritional quality of complementary baby food products sold in Korea according to the baby food stages and food composition. Methods: A total of 1,587 complementary food products sold online and offline between March and December 2021 were investigated. They ranged from liquid meals to solid rice for babies aged 5 to 36 months. Results: The number of intakes per packaged volume was 2.8 in Stage 1, 1.9 in Stage 2, 1.4 in Stage 3, and 1.1 in Stage 4 (p < 0.0001). The dietary variety scores (DVS) of the complementary baby food products were 3.4 in Stage 1, 5.5 in Stage 2, 7.1 in Stage 3, and 9.7 in Stage 4 (p < 0.0001) and showed a significant increase in the later stages. The Korean dietary diversity score (KDDS) significantly increased from 2.3 in Stage 1, to 2.8 in Stage 2, 3.0 in Stage 3, and 3.4 in Stage 4 (p < 0.0001). The higher the baby food stage, the higher the proportion of grains/meat/vegetable ingredients. The ratio of protein intake to Adequate Intake (AI) or Recommended Nutrition Intake (RNI) was higher in products with a KDDS of 3 points or more, or in products with 2 points or fewer in Stages 1 and 2 (p < 0.0001, respectively). The ratio of protein intake to RNI increased as the KDDS score increased in Stages 3 and 4 (p < 0.0001, respectively). For all stages of baby foods, the ratio of protein intake to AI or RNI was high in products that included the meat group (beans, nuts, meat, eggs, fish, and shellfish) (p < 0.0001, respectively). Conclusion: Continuous research and nutritional evaluation are required for establishing nutrient content standards for commercially available baby foods, considering breast milk intake.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.128-133
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• 2024

Using the freezing removal method, we investigated residual pesticides in 50 grape seed oils distributed in Gyeonggi Province, South Korea. The fat was mixed with acetonitrile and then frozen at ≤-20℃ for 24 h. Fats and oils were removed by separating those in solid state and the extract acetonitrile in liquid state. Ten residual pesticides were detected 161 times in 49 of 50 cases. The detected pesticides were boscalid, cyclufenamide, deltamethrin, difenoconazole, fluxapyroxad, fenpyrazamine, kresoxim-methyl, piperonyl butoxide, tebuconazole, and trifluoxysorbin. Boscalid, a fungicide, was most frequently detected (44 times), followed by fluxapiroxad (35 times). The detection range was 0.01-1.10 mg/kg, which was within the legal limit of residual pesticide for grapes. The recovery rate of the detected pesticides was 72.6-129.8% and the ratio of estimated daily intake/acceptable daily intake was calculated to determine the risk of the detected pesticides, which was <0.0028%. This indicated that the risk caused by pesticide residues in grape seed oil is at a safe level.

• Resources Recycling
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• v.28 no.6
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• pp.79-86
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• 2019

Recently, the use of lithium ion battery(LIB) has increased. As a result, the price of lithium and the amount spent lithium on ion battery has increased. For this reason, research on recycling lithium in waste LIBs has been conducted1). In this study, the effect of roasting for the selective lithium leaching from the spent LIBs is studied. Chemical transformation is required for selective lithium leaching in NCM LiNi_xCo_yMn_zO₂) of the spent LIBs. The carbon in the waste EV cell powder reacts with the oxygen of the oxide at high temperature. After roasting at 550 ~ 850 ℃ in the Air/N₂ atmosphere, the chemical transformation is analysed by XRD. The heat treated powders are leached at a ratio of 1:10 in D.I water for ICP analysis. As a result of XRD analysis, Li₂CO₃ peak is observed at 700 ℃. After the heat treatment at 850 ℃, a peak of Li₂O was confirmed because Li₂CO₃ is decomposed into Li₂O and CO₂ over 723 ℃. The produced Li₂O reacted with Al at high temperature to form LiAlO₂, which does not leach in D.I water, leading to a decrease in lithium leaching ratio. As a result of lithium leaching in water after heat treatment, lithium leaching ratio was the highest after heat treatment at 700 ℃. After the solid-liquid separation, over 45 % of lithium leaching was confirmed by ICP analysis. After evaporation of the leached solution, peak of Li₂CO₃ was detected by XRD.