• 한국가금학회지
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• 제43권2호
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• pp.55-61
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• 2016

With the aim of investigating the differences in the quality traits of breast meat between spent hen and broiler chicken, the physicochemical characteristics, fatty acid profile and sensory attributes of breast meat from the two chicken types were assessed. A higher protein content and a lower moisture content were found in breast of spent hen compared to that of commercial broilers (P<0.05). No significant differences in crude fat and ash contents were detected between commercial broilers and the older spent hens (P>0.05). Spent hens showed a significantly lower pH value than did commercial broilers. Spent hen meat had a higher $L^*$ value than broiler chicken meat did (P<0.05). However, $a^*$ and $b^*$ values of breast meat were similar between spent hens and commercial broilers. Water holding capacity values measured in the breast meat were comparable between the two types of chicken used in this study (P>0.05). However, spent hen meat showed a higher cooking loss value than did broiler meat (P<0.05). Total polyunsaturated fatty acid content was significantly higher in spent hen meat compared to broiler meat, in particular eicosapentaenoic acid and docosahexaenoic acid. Nevertheless, sensory characteristics of breast meat were comparable between spent hen and broiler chicken. This information can help consumers to understand better the nutritive value and important quality traits of breast meat from commercial broilers and spent hens.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.785-790
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• 2017

To collect zinc, Fe and Zn in spent pickling solution were extracted by using TBP (tributyl phosphate), and Zn was recovered from extracted solution to zinc oxalate particles by oxalic acid solution. The reusability of TBP solvent was also tested. The distribution coefficient of Zn was not affected by the concentration of Fe in spent pickling solution, almost constant with the values of 7.12~9.31 when extracted by TBP solvent. It was found that the extraction capacity of TBP solvent for Zn is higher than that for Fe. The extraction efficiency of Zn was higher than 95%, while most of Fe was left in aqueous phase. After the recovery, the used TBP solvent could be repeatedly reused for the extraction of Zn up to eight times. XRD analysis showed that zinc oxalate ($ZnC_2O_4$ $2H_2O$) was formed from the reaction of Zn-TBP and oxalic acid. From the results of SEM analysis, the formation of zinc oxalate particle was strongly affected by the concentration of oxalic acid. In summary, Zn in spent pickling solution was successfully separated and recovered with TBP solvent and oxalic acid solution, respectively.

• 생명과학회지
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• 제17권4호
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• pp.568-574
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• 2007

리그닌 분해 세균인 Pseudomonas sp. LG2는 lignocellulose 기질을 분해하여 APPL 화합물을 생성하는 균주이다. 이 균주를 BSG(brewer's spent grain)가 함유된 배지에서 배양한 배양액에서 APPL 화합물을 확인하였다. 세포외 조효소들의 유도에 관한 여러 가지 탄소원의 영향을 조사한 결과 glucose 배지에서는 xylanase의 효소활성만 확인 되었고 xylose, arabinose에서 배양한 조효소에서는 FAE 및 xylanase의 효소활성이 없었다. Oat spelt xylan, HBSG I(hydrolyzed brewer's spent grain I), HBSG II(hydrolyzed brewer's spent grain II) 및 AFBSG(autoclaved fraction from brewer's spent grain)를 탄소원으로 배양한 조효소에서는 FAE 및 xylanase의 효소활성이 확인됐다. Pseudomonas sp. LG2를 oat spelt xylan, HBSG I, HBSG II 및 AFBSG를 탄소원으로 사용하여 14일 동안 배양하면서 배양기간에 따른 세포외 효소들의 FAE와 xylanase 활성을 조사하였다. Xylanase의 최고 활성은 xylan을 탄소원으로 6일간 배양 했을때 5.3 U/mg으로 가장 높았으며, FAE의 최고 활성은 AFBSG를 탄소원으로 배양했을 때 배양 8일째 15.4 mU/mg으로 가장 높았다. Oat spelt xylan, HBSG I, HBSG II 및 AFBSG를 탄소원으로 사용하여 배양한 배지에 분리된 ferulic acid가 확인되었다. 세포외 효소의 FAE 활성은 methyl ferulic acid, methyl caffeic acid, methyl p-coumaric acid에 대해 esterase의 활성을 보였으나, methyl sinapinic acid, methyl vanillic acid 및 methyl gallic acid에 대해서는 esterase의 활성이 없었다.

• 자원리싸이클링
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• 제28권6호
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• pp.36-45
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• 2019

석유화학공정에서 발생하는 폐촉매는 바나듐, 몰리브덴, 니켈, 코발트와 같은 희유금속을 함유하고 있다. 유기산에 의한 상기 금속의 침출에 대해 연구하였다. 본 논문에서 사용한 유기산에 의한 금속의 침출률은 옥살산 > 타르타르산 > 구연산 > 말레산 > 오스코브르산 순서이었다. 상기 유기산은 바나듐과 몰리브덴의 침출에 선택성이 있으며 옥살산에 의한 침출률이 가장 높았다. 옥살산의 농도, 반응온도, 광액밀도, 교반속도를 변화시켜 옥살산에 의한 바나듐의 최적침출조건을 얻었다. 옥살산에 의한 바나듐의 침출에 대한 속도식을 조사한 결과 Avrami식과 잘 맞았으며 활성화에너지는 8.76 kJ/mol로 물질전달에 의해 침출반응이 율속되었다.

• Bulletin of the Korean Chemical Society
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• 제20권1호
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• pp.59-64
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• 1999

Based on the study of hydrolysis behaviour of U(Ⅵ) ion and major fission product metal ions such as Cs(Ⅰ), Ce(Ⅲ), Nd(Ⅲ), Mo(Ⅵ), Ru(Ⅱ), and ZR(Ⅳ) in the titration media, the performance of noncomplexing-alkalimetric titration method for the determination of free acid in the presence of these metal ions was investigated and its results were compared to those from the completing methods. The free acidities could be determined as low as 0.05 meq in uranium solutions in which the molar ratio of U(Ⅵ)/H+ was less than 5, when the end-point of titration was estimated by Gran plot. The biases in the determinations were less than 1% and about +3% respectively for 0.4 meq and 0.05 meq of free acid at the U(Vl)/H+ molar ratio of up to 5. Applicability of this method to the determination of free acid in spent fuel solutions was confirmed by the analysis of nitric acid content in simulated spent fuel solutions and in a real spent fuel solution.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.270-274
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• 2001

With Increasing importance of electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. These spent baths contain iron and zinc as impurities, organic acids as complexing reagents, and phosphonate ions as oxidized species of tile reducing reagent. as well as several grams per liter of nickel. The spent baths are currently treated by conventional precipitation method. but a mettled with no sludge generation is desired. This work aims at establishing a recycling process of nickel from tile spent baths using solvent extraction. Extraction behaviors of nickel. iron. and zinc in various 쇼pes of real spent baths are investigated as a function of pH using LIX841, di (2-ethylhexyl)phosphoric acid (D2EHPA), and PC88A as tile extractants. Nickel is extracted by LIX84I at the equilibrium pH of more than 6 with high efficiency. For the weakly acid baths. iron and zinc are extracted by D2EHPA or PC88A without adjusting the pH of the baths leaving nickel in the aqueous phase. Stripping of nickel from LIX84I with sulfuric acid is also investigated. It is shown that concentrated nickel sulfate solution (> 100 ㎏-Ni/㎥) is obtained. This solution can be reused in the electroless plating process. Based on these findings, flow sheets for recovering nickel from the spent baths are proposed.

• 자원리싸이클링
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• 제7권5호
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• pp.46-51
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• 1998

질산계 에칭폐액으로부터 질산과 유가금속을 분리하여 재활용하기 위하여 용매추출법을 이용하여 질산성분을 회수하기 위한 기초 연구를 수행하였다. 주요 실험내용으로는 추출제의 종류와 농도에 따라 질산의 추출거동을 조사하였고, 질산의 추출시 구리, 납, 철, 주석 등의 금속이온들과의 분리성을 고찰하였다. 또한 McCabe-Thiele 그림으로부터 질산성분을 추출과 탈거에 필요한 이론적인 단수를 분석하였다. 실험 결과 TBP가 Alamine336에 비하여 질산의 회수에는 유리하였으며 TBP는 유기상의 60∼70%가 적합하였으며 폐액상의 질산농도가 0.1N 이상인 경우에는 각 금속성분들이 추출되지 않았으며 60%TBP를 사용하여 O/A비가 3인 경우 5단으로 95%이상의 질산이 추출되었다. 한편, 질산이 추출된 유기상으로부터 탈거 실험의 경우 초기농도가 80 g/l일 때 증류수에 의해 O/A비가 2에서 4단으로 98%이상의 탈거율을 나타내었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.140-143
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• 2001

A study has been made on the recovery of nitric acid and valuable metals such as Cu, Sn, Pb from the spent nitric etching solutions. The nitric acid was extracted effectively by TBP but the heavy metals such as Fe, Cu, Sn, Pb were not extracted by TBP from the spent nitric etching solutions. From the experimental results, 95% of nitric acid in spent etching solution was extracted at O:A ratio of 3:1 with five stage by 60% TBP and 98% of nitric acid was stripped from the loaded organic phase at O:A ratio of 1:1 with four stages by distilled water. After extracting nitric acid, Cu was recovered as a metal by electrowinning effectively and Sn was successfully removed by precipitation method by adjusting the pH of raffinate solution. Finally, Pb was recovered by cementation with iron scrap at $65^{\circ}C$. Parameters controlling the cementation process, such as temperature, pH and the effect of the additives were investigated.

• 한국가금학회지
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• 제34권2호
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• pp.99-104
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• 2007

본 연구는 식용유 정제 폐백토(spent bleaching clay)를 육계 사료 원료로 가치를 평가하기 위해서 실시하였다. 식용유 정제 폐백토(spent bleaching clay)는 대두유의 정제 과정에서 생산되어지며, 생 식용유 정제 폐백토(spent bleaching clay)속에는 조지방(26.0%)과 조회분(68.3%)은 풍부하나, 수분(5.2%)과 조단백질(0.5%)의 함량은 낮게 평가되었다. 식용유 정제 폐백토(spent bleaching clay)와 대두유의 산가는 각각 9.72 및 0.001로 유의한 차이가 인정되었다(P<0.05). 뿐만아니라 식용유 정제 폐백토(spent bleaching clay)의 과산화물가는 대두유보다 유의하게 높아서(P<0.05) 식용유 정제 폐백토(spent bleaching clay)의 빠른 산패 가능성을 시사한 결과이다. 그러나 식용유 정제 폐백토(spent bleaching clay)의 산패는 인공적인 방법으로 막을 수 있을 것이다. 한편 식용유 정제 폐백토(spent bleaching clay)의 육계 사육에서의 $2.0{\sim}4.0%$의 첨가는 사료 섭취량, 증체량 및 사료 효율을 개선시켰다. 결론적으로 육계 사료에 $2.0{\sim}4.0%$의 식용유 정제 폐백토(spent bleaching clay)의 이용이 가능할 것으로 사료된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.478-481
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• 2001

The spent petrochemical catalyst used in the manufacturing process of terephthalic-acid contains valuable metals such as cobalt and manganese. To recover these metals, sulfuric acid leaching was performed with hydrogen peroxide as a reducing agent. Low extractions of Mn, Co and Fe were obtained by sulfuric acid leaching without reducing agent. With adding hydrogen peroxide as a reducing agent, the high extraction of these metals could be obtained. Different from general leaching experiment, the extraction rates of metal components were decreased with increasing reaction temperature in this case. Under the optimum condition, the extraction rates of Mn, Co and Fe were 93.0%, 87.0% and 100% respectively.