• Resources Recycling
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• v.28 no.5
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• pp.60-67
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• 2019

A valuable metal recovery from waste resources such as spent rechargeable secondary batteries is of critical issues because of a sharp increase in the amount of waste resources. In this context, it is necessary to research not only recycling waste lithium-ion batteries (LIBs), but also reusing valuable metals (e.g., Li, Co, Ni, Mn etc.) recovered from waste LIBs. In particular, the lithium hydroxide ($LiOH{\cdot}xH_2O$), which is of precursors that can be prepared by the recovery of Li in waste LIBs, can be reused as a catalyst, a carbon dioxide absorbent, and again as a precursor for cathode materials of LIB. However, most studies of recycling the waste LIBs have been focused on the preparation of lithium carbonate with a recovery of Li. Herein, we show the preparation of high purity lithium hydroxide powder along with the precipitation process, and the systematic study to find an optimum condition is also carried out. The lithium carbonate, which is recovered from waste LIBs, was used as starting materials for synthesis of lithium hydroxide. The optimum precipitation conditions for the preparation of LiOH were found as follows: based on stirring, reaction temperature $90^{\circ}C$, reaction time 3 hr, precursor ratio 1:1. To synthesize uniform and high purity lithium hydroxide, 2-step precipitation process was additionally performed, and consequently, high purity $LiOH{\cdot}xH_2O$ powder was obtained.

• Journal of Life Science
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• v.29 no.8
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• pp.861-870
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• 2019

This study was undertaken to establish optimum medium compositions for cost-effective mannitol production by Leuconostoc mesenteroides SRCM201425 isolated from kimchi. L. mesenteroides SRCM21425 from kimchi was selected for efficient mannitol production based on fructose analysis and identified by its 16S rRNA gene sequence, as well as by carbohydrate fermentation pattern analysis. To enhance mannitol production by L. mesenteroides SRCM201425, the effects of carbon, nitrogen, and mineral sources on mannitol production were first determined using Plackett-Burman design (PBD). The effects of 11 variables on mannitol production were investigated of which three variables, fructose, sucrose, and peptone, were selected. In the second step, each concentration of fructose, sucrose, and peptone was optimized using a central composite design (CCD) and response surface analysis. The predicted concentrations of fructose, sucrose, and peptone were 38.68 g/l, 30 g/l, and 39.67 g/l, respectively. The mathematical response model was reliable, with a coefficient of determination of $R^2=0.9185$. Mannitol production increased 20-fold as compared with the MRS medium, corresponding to a mannitol yield 97.46% when compared to MRS supplemented with 100 g/l of fructose in flask system. Furthermore, the production in the optimized medium was cost-effective. The findings of this study can be expected to be useful in biological production for catalytic hydrogenation causing byproduct and additional production costs.

• Analytical Science and Technology
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• v.16 no.4
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• pp.292-298
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• 2003

In this study, the photooxidation and ozonation of humic acid (HA) in aqueous solution were conducted and the treated HA samples at different reaction time were analyzed using ultrafiltration techniques to evaluate the change of their molecular size distributions with its DOC removal. Molecular size distribution of untreated HA showed 41.5% in higher molecular size fractions (>30,000 daltons) and 15.2% in much smaller molecular size fraction (<500 daltons). As UV irradiation time was increased, it was observed that the degradation of the large molecules of the fraction of >30,000 daltons into much smaller molecules was increased. In UV system, the HA molecules of the fraction of <500 daltons became significantly more and its percentage was increased from 35.3% (UV only irradiation) to 58.9% ($UV/TiO_2$) and 87.8% ($UV/H_2O_2$) in the presence of the photocatalysis. Otherwise, ozonation of HA produced mainly the fraction of medium molecular size ranging from 3,000 to 30,000 daltons with much lower portion (<~7%) in the fraction of <500 daltons. In ozone only system, the fraction of 30,000~10,000 daltons occupied in 41.5% at 60 min of ozonation time. In $O_3/H_2O_2$ system, the fraction of 30,000~10,000 daltons and 10,000~3,000 daltons occupied in 38.9% and 36.2% respectively. Based on these results, we suggested applicable treatment process which could be combined with $UV/H_2O_2$, $UV/TiO_2$ and $O_3$, $O_3/H_2O_2$ system for more effective removal of humic acid in water treatment.

• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.324-333
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• 2001

Purpose: $^{123}I$-labeled fatty acids have been used in the evaluation of regional myocardial energy metabolism. This study aimed to evaluate the usefulness of $^{123}I$-BMIPP as a liposarcoma-imaging agent. Materials and Methods: We compared in vitro uptakes between liposarcoma(SW872) and glioma(9L) cell lines, and examined biodistribution and in vivo images of $^{123}I$-BMIPP in liposarcoma-bearing nude mice. Cold-BMIPP was labeled with $^{123}I\;using\;Cu^{2+}$ as catalyst. After purification by Sep-pak, radiochemical purity was determined by TLC. We compared cellular uptake between glioma and liposarcoma after incubation of 5, 10, 15, 30, 60, 120, and 180 mins with culture medium containing $^{123}I$-BMIPP. The difference in biodistribution was determined between non-feeding (water only) group for 18 hr and feeding group in normal mice (n=6/group) at 0.5, 2, and 24 hr. In liposarcoma-hearing nude mice model, liposarcoma, SW872, ceil lines were injected subcutaneously into the felt thigh of nude mice. The biodistribution of $^{123}I$-BMIPP was evaluated at 0.5, 2, and 24 hr (n:5 / group) and in vivo Image of $^{123}I$-BMIPP was obtained with gamma camera at 2 and 24 hr in liposarcoma-hearing nude mice. Results: Radiolabeling yield and radiochemical purity were 95% and above 99%, respectively. SW872 cell line showed more increased uptake than 9L with 1.5 times at 180 mins. The clearance of $^{123}I$-BMIPP in various tissues was more delayed in the non-feeding group than in the feeding group, especially at delayed time (24 hr) in normal mice, and the major excreting organ was the gastrointestinal tract. In liposarcoma-bearing nude mice, tumor/blood ratio of $^{123}I$-BMIPP was 0.94, 0.75, and 1.38 and tumor/muscle ratio was 0.66, 1.53, and 1.11 at 0.5, 2, and 24hr, respectively. $^{123}I$-BMIPP was selectively localized in liposarcoma at 24 hr image. Conclusions: These results suggest that $^{123}I$-BMIPP can be used as a liposarcoma-imaging agent.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.340-360
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• 2010

The depletion of fossil fuels, ecological problems associated with $CO_2$ emissions climate change, growing world population, and future energy supplies are forcing the development of alternative resources for energy (heat and electricity), transport fuels and chemicals: the replacement of fossil resources with $CO_2$ neutral biomass. Several options exist to cover energy supplies of the future, including solar, wind, and water power; however, chemical carbon source can get from biomass only. When used in combination with environmental friend production and processing technology, the use of biomass can be seen as a sustainable alternative to conventional chemical feedstocks. The biorefinery concept is analogous to today's petroleum refinery, which produce multiple fuels and chemical products from petroleum. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and value-added chemicals from biomass. Biorefinery is the co-production of a spectrum of bio-based products (food, feed, materials, and chemicals) and energy (fuels, power, and heat) from biomass [definition IEA Bioenergy Task 42]. By producing multiple products, a biorefinery takes advantage of the various components in biomass and their intermediates therefore maximizing the value derived from the biomass feedstocks. A biorefinery could, for example, produce one or several low-volume, but high-value, chemical or nutraceutical products and a low-value, but high-volume liquid transportation fuel such as biodiesel or bioethanol. Future biorefinery may play a major role in producing chemicals and materials as a bridge between agriculture and chemistry that are traditionally produced from petroleum. Industrial biotechnology is expected to significantly complement or replace the current petroleum-based industry and to play an important role.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.262-273
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• 2010

In the enzymatic hydrolysis of rice straw and wood meals using extra-cellular enzymes from Fomitopsis palustris, key factors which enhanced the sugar conversion yield were investigated in this work, such as enzyme production and enzyme reaction conditions, surfactant effects, and the surface structure of substrates. F. palustris cultured with softwood mixture produced 12.0 U/$m{\ell}$ for endo-${\beta}$-1,4-gulcanase (EG), 116.68 U/$m{\ell}$ for ${\beta}$-glucosidase (BGL), 18.82 U/$m{\ell}$ for cellobiohydrolase (CBH), and 13.33 U/$m{\ell}$ for ${\beta}$-xylosidase (BXL). These levels of BGL, CBH, and BXL activities were two to four folds more than enzyme activities of F. palustris cultured with rice straw. The optimum reaction conditions of cellulase-RS which produced by F. palustris with rice straw and cellulase-SW which produced by F. palustris with softwood mixture were pH 5.0 at $45^{\circ}C$ and pH 5.0 at $50^{\circ}C$, respectively. The sugar conversion yield of cellulase-SW had the highest value of $40.6{\pm}0.6%$ within 72 h when rice straw was used as substrate. By adding 0.1% Tween 20 (w/w-substrate), the sugar conversion yield of rice straw was increased to 44%, which was about four fifths sugar conversion yield of commercial enzyme, Celluclast 1.5L (Novozyme A/S). A low crystallinity and an intensive fibril surface observed by the scanning electron microscope may explain the high sugar conversion yield of rice straw.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.364-370
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• 1994

The purpose of this study is to evaluate the clinical application of the no carrier added $[^{51}Cr]Cr(III)$-EDTA complexes, produced at Korea Cancer Center Hospital. The $[^{51}Cr]Cr(III)$-EDTA complexes, usefut for measurement of GFR were prepared at room temperature in the presence of bicarbonate catalysts. The radiochemical purity of $[^{51}Cr]Cr(III)$-EDTA was over 99% by paper electrophoresis. The time activity curves were obtained by counting the blood samples from 5 volunteers and counting the head and neck regions with whole body counter after injection of the $^{51}Cr$-EDTA, respectively. After the nonlinear regression, the area under curve was obtained. The plasma clearance of the $^{51}Cr$-EDTA was calculated with injected dose/AUC. The clearance rate calculated with the head and neck counting data was in good agreement with the result from the plasma sample radioactivity at 1-3 hrs after injection. From this result, the counting of head and neck region and the nonlinear regression by 2-compartment model could be applied for the measurement of the clearance rate. Using MIRD system, the absorbed radiation dose was calculated by residence $time{\times}S$. The absorbed whole body radiation dose was negligibly small.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.124-130
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• 2003

Effect of Korean red ginseng (KRG) on the level of serum and liver lipids and lipid peroxidation was investigated in the rats fed high fat diet. Content of serum total cholesterol was significantly decreased (P<0.05) in KRG I group and KRG II group. Content of HDL-cholesterol was significantly increased by 69.75% and 39.15% in KRG I and KRG II group compared to control group, respectively. Atherogenic index (hi) was also significantly decreased by 74.76% and 37.38% in KRG I and KRG II groups compared to control group, respectively. Serum triglyceride content was significantly decreased (p<0.05) in only KRG II group. Antioxidative activity of KRG on the lipid peroxidation of serum and tissues in rats was also studied in vivo by measuring the formation of thiobarbituric acid reactive substances (TBARS). Contents of TBARS in the serum of both KRG groups were significantly decreased (p<0.05) and that of nonheme iron in serum was significantly increased (p<0.05) in a dose-dependent manner, which suggested that lipid peroxidation contents are inversely correlated with serum nonheme iron content. Content of TBARS in liver was significantly decreased (p<0.05) in KRG I and KRG II groups, without any influence in other tissues. Content of TBIARS in liver microsomal fractions stimulated by Fe$^{2+}$/ascorbate was significantly decreased (p<0.05) in KRG I and KRG II groups, whereas this observation did not occur in liver mitochondrial fractions. When the effect of KRG on TBARS content in the liver fractions of homogenates, microsomes, and mitochodria stimulated by Fe$^{2+}$/ascorbate was tested in vitro experimental model, TBARS of liver three fractions was significantly decreased at 6 mg/mL KRG compared with those of control. These results suggested that KRG powder have hypocholesterolemic effect as well as antioxidative effect in the serum and liver of the rats fed high fat diet.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.139-147
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• 2021

Livestock manure is used as an organic fertilizer to replace chemical fertilizers after sufficient fermentation in an aerobic bioreactor. On the other hand, liquid manure disposal problems occur repeatedly because soil spraying is restricted during the summer when the crops are growing. To use liquid fertilizer (LF) as an additional nutrient source for crops, it is necessary to reduce the amount of suspended solids (SS) in the liquid fertilizer and secure stability problems against pathogenic microorganisms. This study examined the effects of the simultaneous SS removal and E.coli sterilization in the LF using the microbubble (MB) generator (FeMgO catalyst insertion). The remaining SS were further removed using the integrated microbubble and microfilter system. During the floating process in the MB device, the SS were removed by 57.9%, and the coliform group was not detected (16,200→0 MPN/100 mL). By optimizing the HRT of the integrated system, the removal efficiency of the SS was improved by 92.9% under the 0.1h of HRT condition. After checking the properties of the treated LF, 64.5%, 70.1%, 54.9%, and 51.5% of the TCOD, SCOD, PO4-P, and TN, respectively, were removed. The treated effluent from such an integrated system has a lower SS content than that of the existing LF and does not contain coliforms; therefore, it can be used directly as an additional fertilizer.