• Membrane and Water Treatment
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• 제12권1호
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• pp.1-9
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• 2021

This study optimized the chemical cleaning process of discarded RO membranes for reuse in less demanding separation processes. The effect of physicochemical parameters, including the temperature, cleaning time, pH of the cleaning solution, and addition of additives, on the cleaning process was investigated. The membrane performance was evaluated by testing the flux recovery rate and salt rejection before and after the cleaning process. High temperatures (45-50 ℃) resulted in a better flux recovery rate of 71% with more than 80% salt rejection. Equal time for acid and base cleaning 3-3 h presented a 72.43% flux recovery rate with salt rejection above 85%. During acid and base cleaning, the best results were achieved at pH values of 3.0 and 12.0, respectively. Moreover, 0.05% concentration of ethylenediaminetetraacetic acid presented 72.3% flux recovery, while 69.2% flux was achieved using sodium dodecyl sulfate with a concentration of 0.5%; both showed >80% salt rejection, indicating no damage to the active layer of the membrane. Conversely, 0.5% concentration of sodium percarbonate showed 83.1% flux recovery and 0.005% concentration of sodium hypochlorite presented 85.2% flux recovery, while a high concentration of these chemicals resulted in oxidation of the membrane that caused a reduction in salt rejection.

• Fisheries and Aquatic Sciences
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• 제24권12호
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• pp.394-399
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• 2021

Song-Gang^® bio-stone (SGS) is a microporous crystalline hydrated aluminosilicate which has found various applications because of their very unique physiochemical characteristics such as ion exchange and absorptive-desorptive properties. Significant progress has been made in recent years on applications of these inorganic adsorbents in different industries including agriculture, aquaculture, water and wastewater treatment. This review article intends to summarize the published reports on the applications of SGS in aquaculture industry. SGS application as a feed additive to enhance fish growth and promote their health and nutritional parameters is the most important discussed areas. According to the technical data that are discussed in this review, SGS should be considered as a material with tremendous potential for application in the aquaculture industry. Considerable amounts of research works are under way to explore other opportunities for application of SGS to benefit aquaculture industry.

• 한국축산식품학회지
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• 제34권5호
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• pp.591-596
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• 2014

This study evaluated the effect of sodium diacetate and sodium lactate solutions for reducing the cell count of Pseudomonas spp. in frankfurters and hams. A mixture of Pseudomonas aeruginosa (NCCP10338, NCCP10250, and NCCP11229), and Pseudomonas fluorescens (KACC10323 and KACC10326) was inoculated on cooked frankfurters and ham. The inoculated samples were immersed into control (sterile distilled water), sodium diacetate (5 and 10%), sodium lactate (5 and 10%), 5% sodium diacetate + 5% sodium lactate, and 10% sodium diacetate + 10% sodium lactate for 0-10 min. Inoculated frankfurters and ham were also immersed into acidified (pH 3.0) solutions such as acidified sodium diacetate (5 and 10%), and acidified sodium lactate (5 and 10%) in addition to control (acidified distilled water) for 0-10 min. Total aerobic plate counts for Pseudomonas spp. were enumerated on Cetrimide agar. Significant reductions (ca. 2 Log CFU/g) in Pseudomonas spp. cells on frankfurters and ham were observed only for a combination treatment of 10% sodium lactate + 10% sodium diacetate. When the solutions were acidified to pH 3.0, the total reductions of Pseudomonas spp. were 1.5-4.0 Log CFU/g. The order of reduction amounts of Pseudomonas spp. cell counts was 10% sodium lactate > 5% sodium lactate ${\geq}$ 10% sodium diacetate > 5% sodium diacetate > control for frankfurters, and 10% sodium lactate > 5% sodium lactate > 10% sodium diacetate > 5% sodium diacetate > control for ham. The results suggest that using acidified food additive antimicrobials, as dipping solutions, should be useful in reducing Pseudomonas spp. on frankfurters and ham.

• 터널과지하공간
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• 제19권6호
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• pp.534-544
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• 2009

지표 하부 공동의 붕괴는 인간 활동의 대상인 도로 및 건물의 안정성에 영향을 미치는 지반침하를 야기할수 있다. 그러므로 이러한 지반침하를 사전에 예방하기 위해서는 지하공동 충전에 의한 지반보강공법의 적용이 필요하다. 본 연구에서는 장기적으로 친환경적인 칼슘알루미네이트 광물을 지반침하보강공법에 적용하고자 급결 충전물질 및 충전시스템, 급경사 광산채굴적 충전 손실 개선에 관한 현장적용성 연구를 수행하였다. 본 연구에서 개발된 급결 경화 충전물질은 급결 성능재료와 보조 재료로 구성된다. 개발된 재료는 급결 성능 및 수중 불분리 특성을 가지고 있어 수중공동에서 재료의 손실을 최소화하면서 효과적으로 지하댐을 형성하였다. Hg, Cd, As, $Cr^{6+}$, Pb와 같은 중금속 용출시험결과, 환경적으로도 적합한 물질로 분석되었다.

• 대한화학회지
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• 제56권6호
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• pp.725-730
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• 2012

본 연구는 ethyl 및 propyl gallate를 첨가제로 사용하여 대표적인 친수성 렌즈 재료로 사용되는 HEMA (2-hydroxyethyl methacrylate)와 교차결합제인 EGDMA (ethylene glycol dimethacrylate), MMA (methyl methacrylate), AA (acrylic acid) 그리고 개시제인 AIBN (azobisisobutyronitrile)과 함께 공중합 하였다. 생성된 고분자의 물리적 특성을 측정한 결과, 굴절률 1.433-1.435, 함수율 38.71-38.99%, 가시광선 투과율 85.4-88.8%, 인장강도 0.2468-0.2740 kgf 그리고 접촉각의 경우 $49.77^{\circ}$에서 $36.29^{\circ}$ 범위의 분포를 나타내었다. Ethyl 및 propyl gallate를 0.1-1.0% 첨가한 친수성 콘택트렌즈의 경우, UV-B 영역에서 49.0-7.4%, UV-A 영역에서 71.0-43.4%의 투과율을 나타내어 자외선 차단 효과가 있는 것으로 나타났다. 본 실험 결과 중합된 ethyl gallate와 propyl gallate를 첨가한 친수성 안의료용 콘택트렌즈 재료의 경우, 기본적인 의료용 렌즈의 물성을 만족하였으며 함수율의 큰 변화를 나타내지 않으면서도 우수한 습윤성과 자외선 차단효과를 증가시키는 결과를 보였다.

• 멤브레인
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• 제24권2호
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• pp.167-175
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• 2014

수증기 투과성과 DMMP 방호성능을 가지는 cellulose acetate butyrate (CAB)/polyethyleneimine (PEI) 기반의 선택투과막에 대해 여러가지 첨가제를 적용하여 CEES에 대한 방호성능 개선을 시도하였다. 시험결과, CAB/PEI 기반의 선택투과막은 수증기 투과성은 그대로 유지하면서(${\geq}1,800g/m^2/day$), CEES에 대한 방호성능의 개선을 보여주었다($7.1{\sim}11.5{\mu}g/cm^2{\cdot}24hr$). 이 중, $Ag^+$ 이온과 이온교환수지 혼합물을 포함한 CAB/PEI 선택투과막에서 가장 우수한 방호성능을 확보하였다. 그리고 시험한 모든 선택투과막은 생물학작용제를 모사할 수 있는 다양한 크기의 에어로졸 입자($0.005{\sim}3{\mu}m$)에 대해서도 방호성능을 가짐을 확인하였다.

• Membrane and Water Treatment
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• 제9권1호
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• pp.43-51
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• 2018

Hollow fiber (HF) membranes are gaining wide interest over flat membranes due to their compaction and high area to surface volume ratio. This work addresses the fabrication of HF from polysulfone (PS) and polyethersulfone (PES) using N-methylpyrrolidone (NMP) as solvent in addition to other additives to achieve desired characteristics. The semi-pilot spinning system includes jacketed vessel, four spinneret block, coagulation and washing baths in addition to dryer and winder. Different parameters affecting dry-wet spinning phase inversion process were investigated. Dope compositions of PES, NMP and polyvinyl pyrrolidone (PVP) of varying molecular weights as additive were addressed. Some critical parameters of importance were also investigated. Those include dope flow rate, air gap, coagulation & washing baths and drying temperatures. The measured dope viscosity was in the range from 1.7 to 36.5 Pa.s. Air gap distance was adjusted from 20 to 45 cm and coagulation bath temperature from 20 to $46^{\circ}C$. The HF membranes were characterized by scanning electron microscope (SEM), atomic force microscope (AFM) and mechanical properties. Results indicated prevalence of finger like structure and average surface roughness from about 29 to 78.3 nm. Profile of stress strain characteristics revealed suitability of the fibers for downstream interventions for fabrication of thin film composite membrane. Different empirical correlations were formulated which enable deeper understanding of the interaction of the above mentioned variables. Data of pure water permeability (PWP) confirmed that the fabricated samples fall within the microfiltration (MF)-ultrafiltration (UF) range of membrane separation.

• Asian-Australasian Journal of Animal Sciences
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• 제28권9호
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• pp.1281-1287
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• 2015

This study was performed to determine the effect of field pea silages which were the organic acid (OA) alternative of oregano and cinnamon essential oils on fermentation quality and aerobic stability. Whole crop pea was harvested at full pod stage and wilted in the laboratory at the 48 h. The chopped pea was mixed and divided into equal portions allocated to five groups: CON (non-treated), distilled water, denoted as control group; OA group, a mixture of 60% formic acid, 20% sodium formate and 20% water applied at a rate of 5 g/kg fresh forage (Silofarm Liquid, Farmavet); origanum (ORE) group, Origanum onites essential oil at 400 mg/kg fresh forage; cinnamon (CIN) group, cinnamon essential oil at 400 mg/kg fresh forage; origanum+cinnamon (ORECIN) group, a mixture of ORE and CIN applied at an equal rate of 400 mg/kg fresh forage. Cinnamon decreased acetic acid (AA), ammonia nitrogen ($NH_3-N$) and weight loss (WL) at the end of 60 days silage. Crude protein (CP) and dry matter (DM) increased by cinnamon essential oil. Yeasts were not detected in any treatments, including the control, after 7 days of air exposure. The $CO_2$ amount decreased and the formation mold was inhibited in the aerobic period by the addition of cinnamon oil. Oregano did not show a similar effect, but when it was used with cinnamon, it showed synergic effect on AA and during aerobic period, it showed antagonistic effect on mold formation and DM losses. It was found in this study that cinnamon can be an alternative to organic acids.

• 대한화학회지
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• 제19권4호
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• pp.258-268
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• 1975

유기폐물을 다량으로 배출하는 산업중에서 대표적인 제지·펄프공업, 식품공업을 선택하여 고형유기폐물과 폐수처리오니의 합리적인 자원화 방법으로서 이들물질의 비료적 가치 및 humus원으로서의 개발가치를 중심으로 이들 물질의 물리적 및 화학적 특성을 조사한 결과이다. 제지${\cdot}$펄프공업 유기고형폐물은 비료성분이 적고 lignin 함량이 높아 비료로서 보다는 humus화하여 토양개량제로서 개발하는 것이 합리적이다. 제혁공업 폐수처리오니는 비료로서 효과도 기대되어 산성토양 개량효과도 기대되나 다량으로 함유한 Cr 으로 인해 오염효과가 문제가 된다. 식품공업의 고형 유기폐물 또는 폐수처리오니는 비료로서 또는 미량요소 공급원으로서 가치가 인정되며 수용성 당류의 량이 높거나 C/N율이 20이하로 낮은 물질은 속성 humus화를 위한 첨가 재료로서의 가치도 인정된다.

• 한국식품조리과학회지
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• 제15권3호
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• pp.224-230
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• 1999

The purpose of this study was to find out the optimal mixing ratio of green tea powder, sugar, and water for the preparation of Seolgiddeok through Response Surface Methodology based on the color, sensory, and texture test. The oganoleptic and textural properties of Seolgiddeok prepared with various concentrations of green tea powder (0% (control group), 0.5% (GT-0.5 group), 1% (GT-1.0 group), 1.5% (GT-1.5 group), 2% (GT-2.0 group)), and their quality changes during storage were also investigated. The optimal mixing ratio of green tea powder, sugar, and water for preparing the best quality Seolgiddeok was 1.0%, 12%, and 22%, respectively. The proximate composition of green tea powder was 21.70% of crude protein, 8.49% of crude lipid, 2.95% of reducing sugar, and 6.40% of ash. The contents of crude lipid, reducing sugar, and catechins in Seolgiddeok added with a green tea powder were increased with increasing the content of green tea powder. The hardness and gumminess of GT-1.0 group were the lowest among four groups, whereas GT-1.0 and GT-2.0 groups had the lowest cohesiveness. While the control group was the lowest in adhesiveness, the springness was not significantly different among all groups. GT-0.5 and GT-1.5 groups were the highest in sweet taste and colorfulness, respectively. However, GT-1.0 group had the best overall quality. Total microbial numbers, the acidity and pH in Seolgiddeok during storage were decreased with increasing green tea powder content, and especially those of GT-1.0 and GT-1.5 groups were relatively the lower than others. The “L” value (lightness) of the control group (no additives) was the highest among five groups, and the value was decreased with storage period, and especially GT-0.5 groups had the lowest brightness. The“a”value (reddness) of the control group was the highest, followed by GT-0.5, GT-1.0, GT-1.5, and GT- 2.0 group in order. The“b”value (yellowness) was increased with the increase of green tea powder content. Above results indicated that GT-1.0 group showed the best quality of Seolgiddeok through organoleptic and rheology tests.