• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.390-396
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• 2013

Biosurfactants have versatile properties and potential industrial applications. A new producer, B. subtilis TU2, was isolated from the underground oil-extraction wastewater of Shengli Oilfield, China. Preliminary flask culture showed that the titer of biosurfactant obtained from the broth of TU2 was ~1.5 g/l at 48 h (718 mg/l after purification), with a reduced surface tension of 32.5 mN/m. The critical micelle concentration was measured as 50 mg/l and the surface tension maintained stability in solution with 50 g/l NaCl and 16 g/l $CaCl_2$ after 5 days of incubation at $70^{\circ}C$. FT-IR spectra exhibited the structure information of both glycolipid and lipopeptide. MALDI-TOF-MS analyses confirmed that the biosurfactant produced by B. subtilis TU2 was a blend of glycolipid and lipopeptide, including rhamnolipid, surfactin, and fengycin. The blended biosurfactant showed 86% of oil-washing efficiency and fine emulsification activity on crude oil, suggesting its potential application in enhanced oil recovery.

• Membrane and Water Treatment
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• 제13권4호
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Environmental Engineering Research
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• 제24권2호
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• pp.202-210
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• 2019

In order to maximize the utilization of sewage sludge, a waste from wastewater treatment facility, the residual sewage sludge generated after lipid and carbohydrate extraction for biodiesel and bioethanol production was used to produce bio-oil by pyrolysis. Thermogravimetric analysis showed that sludge pyrolysis mainly occurred between 200 and $550^{\circ}C$ (with peaks formed around 337.0 and $379.3^{\circ}C$) with the decomposition of the main components (carbohydrate, lipid, and protein). Bio-oil was produced using a micro-tubing reactor, and its yield (wt%, g-bio-oil/g-residual sewage sludge) increased with an increase in the reaction temperature and time. The maximum bio-oil yield of 33.3% was obtained after pyrolysis at $390^{\circ}C$ for 5 min, where the largest amount of energy was introduced into the reactor to break the bonds of organic compounds in the sludge. The main components of bio-oil were found to be trans-2-pentenoic acid and 2-methyl-2-pentenoic acid with the highest selectivity of 28.4% and 12.3%, respectively. The kinetic rate constants indicated that the predominant reaction pathway was sewage sludge to bio-oil ($0.1054min^{-1}$), and subsequently to gas ($0.0541min^{-1}$), rather than the direct conversion of sewage sludge to gas ($0.0318min^{-1}$).

• 한국응용과학기술학회지
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• 제40권2호
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• pp.332-341
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• 2023

오일샌드 테일링의 방류 예정 소식은 찬반 논쟁을 이끌고 있다. 노천광 채굴연계 비투멘 추출공정은 폐수의 발생이 필연적이며, 테일링 인공호수에 저장된다. 현재, 방치된 테일링 인공호수의 규모는 갈수록 그 양이 커지고 있다. 테일링 처리가 매우 어려운 원인으로, 테일링 내의 MFT(mature fine tailings) 층의 생성과 연관이 깊다. 테일링 처리를 위해서는, MFT내에 분산된 미립자를 효과적으로 응집시켜 고체와 액체를 분리하는 핵심 공정이 필요하다. 본 논문에서는 먼저 채굴연계 비투멘 추출공정을 소개하였고, 이를 통해 테일링의 구성 성분과 MFT 특성에 대해서 정리하였다. 또한, MFT 처리공정에 대해 살펴보았다. 향후, 효과적인 고분자 응집제의 선정과 효율적인 탈수공정의 연계성으로 MFT 처리가 성공적으로 진행되기를 기대한다.

• 한국식품영양과학회지
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• 제21권3호
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• pp.319-326
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• 1992

The Louisiana crawfish industry comprises the largest concentration of crustacean aquaculture in the United States. Processing plants throughout the culture region annually generate as much as 80 million pounds of peeling waste during recovery of the 15% (by weight) edible tail meat. A commercial oil extraction process for recovery of carotenoid astaxanthin from crawfish waste has been developed. Crawfish pigment in its various forms finds applications as a source of red intensifying agents for use in aquaculture and poultry industries. Crawfish shell, separated in the initial pigment extraction step, is an excellent source of chitin. Applicable physicochemical procedures for isolation of chitin from crawfish shell and its conversion to chitosan have been developed. Crawfish chitosan has been demonstrated to be both an effective coagulant and ligand-exchange column material , respectively, for recovery of valuable organic compounds from seafood processing wastewater.