• Resources Recycling
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• v.31 no.5
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• pp.34-41
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• 2022

Smelting reduction of spent lithium-ion batteries results in metallic alloys, slag, and dust containing Li(I). Precipitation of Li₂CO₃ was performed using the synthetic leachate of the dust. Herein, the effects of the precipitant and addition of non-aqueous solvents on the precipitation of Li(I) were investigated. Na₂CO₃ was a more effective precipitating agent than (NH₄)₂CO₃ owing to the hydrolysis reaction of dissolved ammonium and carbonate. The addition of acetone or ethanol improved the Li(I) precipitation percentage for both the precipitants. When using (NH₄)₂CO₃, the Li(I) precipitation percentage increased at a solution pH of 12. Under the same conditions, the Li(I) precipitation percentage using Na₂CO₃ was much higher than that using (NH₄)₂CO₃.

• Journal of People, Plants, and Environment
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• v.23 no.4
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• pp.445-453
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• 2020

Background and objective: Calcium chloride (CaCl₂) and sodium chloride (NaCl) are commonly used as a deicing agent in South Korea and penetrate the soil on the roadside, causing damage to plants. This study was conducted to investigate the salinity reduction effect of Pennisetum alopecuroides and the chemical characteristics of soil leachate. Methods: The plants were treated with five different concentrations of CaCl₂ (0, 1, 2, 5, and 10g·L^-1) and were grouped into the Cont., C1, C2, C5, and C10 groups. CaCl₂ of 200 m·L^-1 was sprayed to each plant once every two weeks. The growth of P. alopecuroides (plant height, leaf length, leaf width and the number of leaves) was measured. The level of EC and pH, and exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) in the leachate of soil was monitored. Results: The pH of soil leachate decreased as the CaCl₂ concentration increased, and the EC increased significantly. The content of K⁺ did not change significantly until the concentration of CaCl₂ reached 5 g·L^-1, but the content of Ca²⁺, Na⁺, and Mg²⁺ significantly increased. The plant height, leaf length, and leaf width of P. alopecuroides showed the highest value in CaCl₂ 1 g·L^-1 followed by CaCl₂ 2 g·L^-1 and the control group. Root fresh weight was the highest in CaCl₂ 2 g·L^-1. On the other hand, there was no change in the shoot fresh weight, dry weight and root dry weight, and P. alopecuroides growth inhibition at the concentration of 5 g·L^-1 or higher in the plant height and leaf length. Conclusion: P. alopecuroides is relatively highly salt-tolerant and can improve the salt damaged soil by lowering the content of the salt-based exchangeable K⁺ ions.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.419-429
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• 2022

Water accounts for the largest proportion of body weight and is an essential element for the physiological functioning of the human body. According to 2013-2017 Korea National Health and Nutrition Examination Survey (KNHANES) data, the average water intake of Koreans was 2,167.3 mL/day and 62% of them did not meet the Dietary Reference Intakes for Koreans (KDRIs) for water. However, the consumption of beverages is continuously increasing. KDRIs sets the adequate intake (AI) for water, but tolerable upper intake level (UL) and chronic disease risk reduction intake (CDRR) are not provided. Compared to 2015, the AI of total water from both food and fluids in the 2020 KDRIs slightly increased or decreased according to age. The AI for children 1-2 years old, boys 6-8 years and 9-11 years old, and girls 6-8 years old decreased by 100 mL/day, while that of boys 12-14 years old increased by 100 mL/day. The AI of total water was the sum of the water intake from food and fluids reported by the KNHANES, with an extra milk intake of 200 mL/day. Therefore, it is not appropriate to use the AI of total water intakes for the reference of beverage intakes. It is preferable to consume water or milk rather than beverages containing sugar and others including caffeine, sodium, etc. when drinking fluid water. We suggest the following improvements in the future KDRIs for water: improving the adequacy of the water content ratio of Korean conventional foods, supplementing the fluid water intake survey, reflecting the current water intake status by life cycle, setting KDRIs for water for the elderly considering the physiological changes, health status and dietary habits, and promotion of research on the relationship between water intake and health for Koreans.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.95-102
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• 2023

Despite the easing of social distancing, demand for non-face-to-face services continues to rise. Recently, the EU is pursuing a comprehensive plastic use reduction by expanding the scope of plastic use regulations for packaging plastics according to the New Cyclical Economy Action Plan(NCEAP). In response to this trend, the packaging industry is moving away from conventional non-degradable/petroleum-based plastics and conducting research on packaging materials using biodegradable plastics such as PLA(Poly Lactic Acid), PBAT(Poly Butylene Adipate-co-butylene Terephthalate). On the other hand, ginkgo leaves occur in large quantities in Korea and act as a cause of slip accidents and flooding. In this study, a method to utilize ginkgo biloba leaf as a new alternative biomass resource was proposed by producing lactic acid through pretreatment, enzymatic saccharification, and fermentation processes. For the efficiency of lactic acid production, a comparative analysis of lignin content from before and after browning was performed. In addition, the degree of glucan extraction was evaluated by applying a pretreatment method using three catalysts: hot water, sulfuric acid, and sodium hydroxide. It is difficult to expect high production of lactic acid with single process. Therefore, an integrated process operation using both the pretreated hydrolyzate and the residual solid enzymatic saccharification solution must necessarily be applied.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.296-296
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• 2022

This study was investigated to compare the milling and physicochemical characteristics of six Korean wheat cultivars (Keumkang, KK; Jokyung, JK; Goso, GS; Joongmo2008, JM; Baekkang, BK; Saekeumkang, SKK) and five foreign wheat classes (Australian standard white wheat, ASW; Australian hard, AH; US northern spring, NS; US hard red winter, HRW; Soft wheat, SW). Korea and foreign wheat grains were milled using a Buhler MLU-202. Flour moisture, ash, protein, gluten, sedimentation, particle size, solvent retention capacity (SRC) and dough properties of flour were analyzed. Results showed that the hard wheats had a greater total flour yield and reduction fraction yield than the soft wheats regardless of the country. However, there were in the milling characteristics between the US and Korean soft wheats. GS, a soft wheat in Korea, had the lowest flour yield (59.6%) and the highest bran fraction yield (21.4%). The particle sizes of flour by milling fraction were B1>B2>B3 for the largest, and the R1〈R2〈R3 for the smallest. Particle size, ash, protein contents and the values of lactic acid SRC showed highly correlated with flour yield. The gluten-performance-index (GPI) is the ratio of the lactic acid SRC value to the sum of sodium carbonate and sucrose SRC values, and it has been used as a quality indicator for overall performance potential of flour. GPI values differed depending on the wheat variety or class, JM (0.82) was the highest value, and SKK (0.56) and SW (0.59) were low. The curve pattern of the Mixolab result also gives a quality indication of the flour sample. JM and NS flour had similar pattern at water absorption and gluten strength parameters and BK and HRW had similar viscosity patterns. These results will enable further study for blending Korean wheat cultivar to improve the flour quality.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.39.1-39.23
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• 2023

Objectives: This study aimed to investigate the effectiveness of different topical/systemic agents in reducing the damage caused by bleaching gel to pulp tissue or cells. Materials and Methods: Electronic searches were performed in July 2023. In vivo and in vitro studies evaluating the effects of different topical or systemic agents on pulp inflammation or cytotoxicity after exposure to bleaching agents were included. The risk of bias was assessed. Results: Out of 1,112 articles, 27 were included. Nine animal studies evaluated remineralizing/anti-inflammatories agents in rat molars subjected to bleaching with 35%-38% hydrogen peroxide (HP). Five of these studies demonstrated a significant reduction in inflammation caused by HP when combined with bioglass or MI Paste Plus (GC America), or following KF-desensitizing or Otosporin treatment (n = 3). However, orally administered drugs did not reduce pulp inflammation (n = 4). Cytotoxicity (n = 17) was primarily assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on human dental pulp cells and mouse dental papilla Cell-23 cells. Certain substances, including sodium ascorbate, butein, manganese chloride, and peroxidase, were found to reduce cytotoxicity, particularly when applied prior to bleaching. The risk of bias was high in animal studies and low in laboratory studies. Conclusions: Few in vivo studies have evaluated agents to reduce the damage caused by bleaching gel to pulp tissue. Within the limitations of these studies, it was found that topical agents were effective in reducing pulp inflammation in animals and cytotoxicity. Further analyses with human pulp are required to substantiate these findings.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.524-533
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• 2008

Industrial wastewater generated in the electroplating and metal finishing industries typically contain toxic free and complex metal cyanide with various heavy metals. Alkaline chlorination, the normal treatment method destroys only free cyanide, not complex metal cyanide. A novel treatment method has been developed which destroys both free and complex metal cyanide as compared with Practical Plant(I). Prior to the removal of complex metal cyanide by Fe/Zn coprecipitation and removal of others(Cu, Ni), Chromium is reduced from the hexavalent to the trivalent form by Sodium bisulfite(NaHSO$_3$), followed by alkaline-chlorination for the cyanide destruction. The maximum removal efficiency of chromium by reduction was found to be 99.92% under pH 2.0, ORP 250 mV for 0.5 hours. The removal efficiency of complex metal cyanide was max. 98.24%(residual CN: 4.50 mg/L) in pH 9.5, 240 rpm with 3.0 $\times$ 10$^{-4}$ mol of FeSO$_4$/ZnCl$_2$ for 0.5 hours. The removal efficiency of Cu, Ni using both hydroxide and sulfide precipitation was found to be max. 99.9% as Cu in 3.0 mol of Na$_2$S and 93.86% as Ni in 4.0 mol of Na$_2$S under pH 9.0$\sim$10.0, 240 rpm for 0.5 hours. The concentration of residual CN by alkaline-chlorination was 0.21 mg/L(removal efficiencies: 95.33%) under the following conditions; 1st Oxidation : pH 10.0, ORP 350 mV, reaction time 0.5 hours, 2nd Oxidation : pH 8.0, ORP 650 mV, reaction time 0.5 hours. It is important to note that the removal of free and complex metal cyanide from the electroplating wastewater should be employed by chromium reduction, Fe/Zn coprecipitation and, sulfide precipitation, followed by alkaline-chlorination for the Korean permissible limit of wastewater discharge, where the better results could be found as compared to the preceding paper as indicated in practical treatment(I).

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.48-59
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• 2018

This study was conducted to suggest the effective management and recycling processes of coffee waste, which can be easily obtained from coffee shops and coffee-related products industries. Prior to the fabrication of pellets, the potential of coffee waste as a raw material of pellet was investigated through the examination of its chemical compositions and fuel characteristics. Major gradient included in coffee waste was holocellulose, followed by fat/oil and protein. Coffee waste contained a small quantity of ash (0.7%), such as calcium, sodium, potassium and magnesium. Interestingly, coffee waste was easily dried probably due to its porous structure. Pellets fabricated with coffee waste and larch sawdust showed good fuel characteristics, such as moisture content, ash content, density and durability. The pellets exceed greatly the minimum requirements of $1^{st}$-grade wood pellet standard designated by National Institute of Forest Science (NIFOS). Particularly, the high calorific value of coffee waste showed the potential as a raw material of pellet. However, owing to high nitrogen and sulfur contents, coffee waste is like to be used as a raw material of wood pellet for combined heat and power plants equipped with a reduction system of $NO_x$ and $SO_x$ gases. On the other hand, 91 wt% larch sawdust and 9 wt% coffee waste are required to fabricate the $1^{st}$-grade wood pellets designated by NIFOS. Pellets fabricated with the conditions are estimated to have nitrogen content of 0.298% and sulfur content of 0.03%. Lastly, if amounts of coffee waste and sawdust in the production of wood pellets are adequately adjusted according to its purchasing price, the manufacturing cost of pellet can effectively be reduced. In addition, it is expected tp prepare the effective recycling process of waste and to relieve the environmental burden with the reduction of waste from the commercialization of coffee waste/larch pellets.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1830-1841
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• 2012

We investigated the changes in microbial and physicochemical characteristics of the raw materials of Saengsk (brown rice, barley, carrot, potato, Angelica utilis Makino and kale) during storage after treatment with slightly acidic electrolyzed water (SAEW). To confirm the antimicrobial effects of the treatment washing solutions as well as the physicochemical changes in chromaticity, we stored the raw materials of Saengsik for 5, 10, 15, 20, 25 and 30 days at storage temperatures of 4, 10, 15, 20, 25 and $30^{\circ}C$ in a shelf-life study. The effects of microbial inhibition were higher in carrot treated with SAEW than in that treated with NaOCl, as indicated by a 1.75 log CFU/g reduction. Moreover, a 1.54 log CFU/g reduction of total coliforms was achieved in brown rice in response to SAEW treatment, which was higher than NaOCl treatment at all storage temperatures and periods. The lightness, redness and yellowness values of the raw materials of Saengsik were not significantly affected by SAEW treatments, except for Angelica utilis Makino and kale, whereas SAEW treatment resulted in decreased chromaticity values when compared to the NaOCl treatment. Overall, there was a significant difference (p<0.05) between the efficacy of the SAEW and NaOCl treatments. These results indicate that washing with SAEW is an effective method to reduce the microorganisms and enhance the shelf-life of raw materials of Saengsik; therefore, it can be effectively used to sanitize ingredients of Saengik without affecting the other properties during storage.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.238-244
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• 2009

Food allergy is a serious nutritional problem in both children and adults. Therefore, food allergenicity reduction methods are greatly needed. The allergenicity is altered by various manufacturing processes, and the digestibility of food proteins can be affected by food processing. This study was conducted to investigate the effect of in-vitro digestibility on the allergenicity of autoclaved market pork sausages using pepsin (30min) and trypsin (5, 30, 60, 90, and 120min). The binding ability of the porcine serum albumin (PSA) from sausages A and B significantly decreased by about 30 and 23%, respectively, after autoclave treatment (121; 5, 10, and 30 min). After the pepsin and trypsin treatments, the binding ability of products A and B at 30 min decreased. These competitive indirect enzyme-linked immunosorbent assay (ci-ELISA) results corresponded well with the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting results. The results demonstrated that the allergenicity of pork sausages considerably decreased after autoclave treatment, and were also maintained or decreased after enzyme treatment. Accordingly, autoclave treatment represents a promising processing technology for the reduction of the allergenicity of diverse food products.