• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.392-393
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• 2018

• 한국산학기술학회논문지
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• 제14권11호
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• pp.6015-6022
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• 2013

자동차용 고광택 크롬 도금 박리액에는 질산과 유가금속인 구리가 다량 함유되어 있는 것으로 알려져 있다. 질산($HNO_3$) 및 유가금속은 고가이며 유독하므로, 경제 및 환경을 고려하여 반드시 회수하여 재활용하여야 한다. 본 연구에서는 도금박리액으로부터 질산과 구리는 용매 추출법을 이용하여 후 분리하였다. 수상에 존재하는 질산의 농도는 0.01 ~ 1N NaOH를 이용하여 적정하여 분석하고, 금속의 농도는 ICP-MS 및 ICP-AES 등을 이용하여 분석하였다. 도금 박리액을 분석한 결과, 구리 이온은 76,850 mg/L이 함유되어 있음을 알 수 있었다. 용액 내 질산의 양을 NaOH 용액을 이용하여 적정법으로 측정하였을 때 대략 1.02 M 임을 알 수 있었다. 50% Tributylphosphate (TBP)를 이용하여 3단 추출한 유기층의 용액을 증류수를 이용하여 각각 3회의 역추출을 하였을 때, 원액으로부터 48.1%의 질산을 회수할 수 있음을 알 수 있었으며, 순도는 99.9% 이상이었다. 질산 회수 후, 용액 내에 남은 구리는 PC 88A, D2EPHA, LIX 84 및 ISE 106을 이용하여 용매추출 하였으며, 각 용매의 추출률을 비교하였을 때, ISE 106의 경우, 1단 추출 후 30% 황산으로 역세척 하였을 경우, 92%의 구리를 회수할 수 있었다. 추출된 구리는 $N_2H_4$를 이용하여 환원시켰고, 다양한 조건 하에서 구리 분말을 제조하였다.

• Journal of Microbiology and Biotechnology
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• 제28권3호
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• pp.401-408
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• 2018

The waste seaweed from Gwangalli beach, Busan, Korea was utilized as biomass for ethanol production. Sagassum fulvellum (brown seaweed, Mojaban in Korean name) comprised 72% of the biomass. The optimal hyper thermal acid hydrolysis conditions were obtained as 8% slurry contents, 138 mM sulfuric acid, and $160^{\circ}C$ of treatment temperature for 10 min with a low content of inhibitory compounds. To obtain more monosaccharides, enzymatic saccharification was carried out with Viscozyme L for 48 h. After pretreatment, 34 g/l of monosaccharides were obtained. Pichia stipitis and Pichia angophorae were selected as optimal co-fermentation yeasts to convert all of the monosaccharides in the hydrolysate to ethanol. Co-fermentation was carried out with various inoculum ratios of P. stipitis and P. angophorae. The maximum ethanol concentration of 16.0 g/l was produced using P. stipitis and P. angophorae in a 3:1 inoculum ratio, with an ethanol yield of 0.47 in 72 h. Ethanol fermentation using yeast co-culture may offer an efficient disposal method for waste seaweed while enhancing the utilization of monosaccharides and production of ethanol.

• 한국재료학회지
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• 제27권12호
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• pp.672-678
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• 2017

In the production of zirconium cladding tube, a pickling acid solution is used to remove surface contaminants, which generates tons of pickling acid waste. The waste pickling solution is a valuable resource of Hf-free Zr. Many studies have investigated separating the Hf-free Zr source from the waste pickling acid. The results showed that $Ba_2ZrF_8$ precipitates prepared from the waste pickling acid were useful as an electrolyte for the electrorefining of Zr in molten salt. In the present work, electrorefining was performed in a $Ba_2ZrF_8-LiF$ binary electrolyte to recover Zr from a Hf-free CuZr ingot anode prepared by electroreduction. Before electrorefining, two pretreatments are performed. First, electrolyte melting was carried out to determine the eutectic temperature, and second, the electrolyte was treated to eliminate impurities, mainly hydride. After electrorefining, the cathode deposits were analyzed by $O_2$ gas analyzer and SEM-EDX to explore the possibility of recovering nuclear-grade Zr metal. Moreover, the anode was analyzed by SEM-EDX to determine the Zr dissolution depth.

• 한국균학회지
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• 제20권1호
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• pp.77-82
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• 1992

자실체 생장을 위한 액체 정치 배양에서 탄소원, 질소원, pH의 효과를 검출한 결과 dextrin, aspartic acid, pH 4.0에서 각각 가장높은 건물중을 보였으며, 0.8% triacylglycerol 첨가시 자실체 생장이 촉진되었다. 고체배지 사용시 포플라, 백양나무, 참나무 톱밥 그리고 coffee waste 중 coffee waste에서 가장높은 자실체 건물중을 얻었으며 0.1% tannic acid의 첨가시 자실체 및 균사체 생장에 좋은 결과를 얻었다.

• 한국균학회지
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• 제24권3호통권78호
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• pp.176-179
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• 1996

느타리버섯의 볏짚 배지 대용으로 산업폐기물인 폐면포(메리야스 조각)를 이용하여 배지의 가능성이 인정된 그 결과는 다음과 같다. 균사 생장 및 수량성은 볏짚 배지에 비하여 폐면포에 미강 20%를 첨가한 배지에서 균사활착이 양호하였고 수량도 $47.5\;kg/3.3\;m^2$으로 11%가 증수되었다. 느타리버섯의 영양성분은 볏짚 배지보다 폐면포 배지에서 생성된 자실체가 조단백질이 많았고 조회분은 적었으나 조지방과 조섬유는 같은 함량이었다. 느타리버섯의 아미노산 함량은 Glutamic acid가 많았고, Cystine이 가장 적었으며 볏짚 배지보다 폐면포 배지에서 생성된 자실체가 총 아미노산과 필수아미노산 함량이 많았다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• 한국균학회지
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• 제22권4호
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• pp.338-342
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• 1994

배지 재료를 달리한 느타리 버섯의 갓 크기와 자루속의 아미노산을 분석해 본 결과는 다음과 같다. 1. 배지 재료별 느타리 버섯의 아미노산 함량은 톱밥배지와 폐솜배지에 비해 볏짚배지에서 적었으며 아미노산 17종이 확인 정량되었다. 2. 느타리버섯의 아미노산은 Glutamic acid 함량이 가장 많았으며, Cystine 함량이 가장 적었다. 3. 느타리 버섯의 갓 크기별 아미노산 함량은 볏짚재배는 $3{\sim}7\;cm$, 톱밥재배는 3cm 이하, 폐솜재배는 7cm 이상에서 많았으며 버섯의 부위별은 자루보다 갓에서 많았다.

• 농업과학연구
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• 제43권5호
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• pp.734-741
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• 2016

Lily (Lilium davidii) is a high-yielding flowering plant. Besides roses and chrysanthemums, lily bulbs have long been used as food and in oriental medicine. However, the usage and value of cut lily bulbs has not been recognized. A bulb whose yield has been decreased is called a waste bulb, and a large amount of such bulbs is discarded every year. In this study, the functionality of waste bulbs from cut lilies was investigated to explore their potential use as a value-added product. We divided lily bulbs into two groups, one group with six varieties of new bulbs (Medusa, Siberia, Woori Tower, Yelloween, Le Reve, and Morning Star) used for cultivation and the other group with six varieties of waste bulbs (Medusa, Siberia, Woori Tower, Yelloween, Sorbonne, and Sheila). Physiological activities (${\alpha},{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl: DPPH) and 3-ethlbenzthiazolne-6-sulfonic acid (ABTS) radical scavenging capability and tyrosinase inhibiting activity), the amount of total as well as eight individual phenolic compounds (chlorogenic acid, epicatechin, rutin hydrate, p-coumaric acid, kaempferol 3-O-${\beta}$-rutinoside, phloridzin dihydrate, myricetin, and quercetin), and total flavonoid content were measured in the bulbs by high performance liquid chromatography. We detected high amounts of total phenol and total flavonoid as well as high DPPH and ABTS radical scavenging ability. More tyrosinase inhibiting activity was detected in the new bulbs than in the waste bulbs. However, both the new and waste bulbs showed a higher inhibitory activity than the standard (100 ppm ascorbic acid). Although the content of phenolic compounds differed among varieties, under the conditions of the experiment, the most abundant phenolics were epicatechins, followed by chlorogenic acid, and rutins. Overall, the waste bulbs had a higher content of these compounds than the new bulbs. Based on these results, we concluded that bulbs from cut lilies could be used as functional foods in the future and farmers could expect economic gain from the hitherto neglected waste bulbs.

• 환경위생공학
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• 제15권2호
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• pp.34-40
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• 2000

In the tungsten industry, molybdenum wire which used as the center supporter for coil shape tungsten wire was removed. Nitric acid dissolution method which used prevalently up to the present, takes nitric acid as major component and use noxious material such as sulfuric acid and hydrochloric acid remove molybdenum wire which used as center supporter by dissolve selectively within the range of no damage on tungsten wire. Mixed acid waste water occurred to the process were difficult to be decomposed by the conventional methords. This mixed acid waste water was treated by ozone, and It was obtained using possible by-product through the treatment waste water. For the three reactors with the same volume ; Blank reactor, Disturbance plate reactor, Packed-bed reactor ; the results were as follows : For the blank reactor COD removal efficiency in the pH = 4 (HRT : 6hr) was 28.5%, COD removal efficiency in the pH = 7 (HRT : 6hr) was 28.6%, and COD removal efficiency in the pH = 10 (HRT : 6hr) was 27.8%. For the disturbance plate reactor COD removal efficiency in the pH = 4 (HRT : 6Min.) was 86.5%, COD removal efficiency in the pH =7 (HRT : 6Min.) was 84.4%, and COD removal efficiency in the pH = 10 (HRT : 60Min.) was 86.8%. For the packed-bed reactor COD removal efficiency in the pH = 4 (HRT : 40Min.) was 76.0%, COD removal efficiency in the pH = 7 (HRT : 40Min.) was 81.3%, and COD removal efficiency in the pH = 10 (HRT : 40Min.) was 84.6%. After O3 treatment using possible by-product(Na2SO4) was 150g/ℓ.