Ultrafiltration using graphene oxide surface-embedded polysulfone membranes

Hwang, Taeseon,Oh, Joon-Suk,Yim, Woosoon,Nam, Jae-Do,Bae, Chulsung,Kim, Hyung-ick,Kim, Kwang Jin Elsevier 2016 Separation and purification technology Vol.166 No.-

<P><B>Abstract</B></P> <P>The effect of a hydrophilic layer of graphene oxide on polysulfone membranes was investigated to improve the antifouling properties of the membrane in ultrafiltration. Polysulfone membranes were obtained by the phase inversion method. Polyvinylpyrrolidone was added to generate pores in the membranes, and then a layer of graphene oxide was deposited on the prepared membranes using a vacuum-assisted filtration technique. This study investigated the cross-section/surface morphology, the water-contact angle, and the chemical structure of the prepared polysulfone/graphene oxide membranes. Due to the highly oxygenated structure of the graphene oxide, the surface hydrophilicity of the polysulfone membrane was significantly increased by applying a layer of graphene oxide. Moreover, the antifouling abilities of the membranes were evaluated by comparing the water-flux recovery ratio between the pure water flux before and after ultrafiltration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel Polysulfone/Graphene oxide (PSU/GO) ultrafiltration membranes with enhanced antifouling properties were developed via phase-inversion and a vacuum-assisted filtering method. </LI> <LI> Polysulfone/Graphene oxide membranes were developed for use in ultrafiltration. </LI> </UL> </P>

Ultrafiltration을 이용한 Gouda Cheese의 제조

이용림,김상필,박희경,허태련 한국산업미생물학회 1994 한국미생물·생명공학회지 Vol.22 No.1

본 연구는 일반적인 고다치즈 제조공정과 한외여과막 장치를 이용한 치즈제조와의 차이점을 비교 실험하였다. 한외여과막을 이용하여 2.00 : 1, 2.25 : 1, 2.50 : 1의 농축비로 농축유를 제조한 후 원유와 함께 중온균 스타터에 의한 pH와 적정산도, ˚SH값의 변화, 응유효소에 의한 커드 형성등을 고다치즈 제조과정에서 비교검토하였다. 원유를 농축함에 따라서 완충효과 상승으로 인하여 적정산도와 ˚SH값이 증가하였다. 동량의 중온균 스타터를 접종하여 동일한 시간 배양하였으나 한외여과막으로 농축한 농축유가 원유보다 pH 변화가 적게 일어났다. 한외여과막 농축유는 원유와 동량의 응유효소량을 첨가하였을 때 원유보다 커드형성 시간이 16∼17분 단축되었다. 고다치즈 수율은 12.5∼13.1%로 한외여과 농축유 및 원유 치즈가 거의 비슷한 수준으로 나타났으나 수율효율은 한외여과 농축유 치즈가 약간 높았으나 유청의 주요 구성성분의 함량비율은 농축 정도가 증가할수록 높았다. 치즈 제조중에 배출된 유청의 양은 한외여과 농축과 역관계임이 나타났다. 숙성초기에 유당과 수용성질소 함량은 농축치즈에서 높았다. 원유 치즈의 유당 함량은 3.49%이었고 2.00 : 1, 2.25 : 1과 2.50 : 1의 농축 비율로 된 농축유는 각각 3.77%, 4.89%와 7.03%이었다. 농축 정도가 높은 치즈일수록 많은 양의 유당을 함유하였고 숙성 35일 이내에 모두 분해되었다. 수용성 질소 화합물은 UF 치즈가 1.82∼2.06%로 원유 치즈 1.22%보다 함량이 높았으며 숙성 20일 후 그 양은 급격히 증가하였다. In this study we compared traditional cheesemaking process with the process utilizing ultrafiltration(UF) system. The whole milk retentates were prepared by ultrafiltration to volume concentration ratio(VCR) of 2.00:1, 2.25:1 and 2.50:1. Along with the untreated whole milk, there were studies in terms of the change of pH, titratable acidity and Soxhlet-Henkel(˚SH) value by mesophilic lactic starter and curd formation by rennet during Gouda cheese manufacture. Due to the increase of buffering effect titratable acidity and ˚SH value increased with the higher concentration ratio. When inoculated with the same volume of mesophilic lactic starter, less pH change occurred in UF retentates than in control milk. When added 0.0025% rennet, UF retentates coagulated 16∼17 minutes ealier than the control milk. Gouda cheese yield from raw milk and UF retentates was 12.5∼13.1% equally, but yield efficiency of UF retentate cheese was slightly higher than that of the raw milk cheese. Quantity of whey from retentate cheese was inversely related to VCR. But when from retentate cheese contained higher percentage of major components than that from control milk cheese. In early ripening, the concentrations of lactose and soluble nitrogen compound were higher in retentate cheeses. Lactose content of control milk cheese was 3.49% and that of 2.00:1, 2.25:1, 2.50:1 VCR retentate was 3.77%, 4.89%, 7.03%, respectively. Thus, the more concentrated cheese contained a higher amount of lactose and all the lactose was hydrolyzed during 35-day ripening period. Soluble nitrogen compound of control milk cheese was 1.22% and that of UF cheeses was 1.82∼2.06%. After 20-day ripening, soluble nitrogen compound increased sharply in UF cheese.

Competitive binding experiments can reduce the false positive results of affinity-based ultrafiltration-HPLC: A case study for identification of potent xanthine oxidase inhibitors from Perilla frutescens extract

Wang, Z.,Kwon, S.H.,Hwang, S.H.,Kang, Y.H.,Lee, J.Y.,Lim, S.S. Elsevier 2017 Journal of chromatography. B, Analytical technolog Vol.1048 No.-

The purpose of this study was to assess the possibility of using competitive binding experiments with ultrafiltration-HPLC analysis to identify potent xanthine oxidase (XO) inhibitors from the Perilla frutescens extract as an attempt to reduce the number of false positive results. To isolate the enzyme-ligand complex from unbound compounds, the P. frutescens extract was either incubated in the absence of XO, in the presence of XO, or with the active site blocked XO before the ultrafiltration was performed. Allopurinaol was used as the XO active site blocker. The unbound compounds were subjected to HPLC analysis. The degree of total binding (TBD) and degree of specific binding (SBD) of each compound were calculated using the peak areas. TBD represents the binding affinities of compounds from the P. frutescens extract for the XO binding site. SBD represents the XO competitive binding between allopurinol and ligands from the extract samples. Two criteria were applied to select putative targets that could help avoid false positives. These include TBD>30% and SBD>10%. Using that approach, kaempferol-3-O-rutinoside, rosmarinic acid, methyl-rosmarinic acid, apigenin, and 4',5,7-trimethoxyflavone were identified, from total 11 compounds, as potent XO inhibitors. Finally, apigenin, 4',5,7-trimethoxyflavone, and luteolin were XO inhibitors verified through an XO inhibition assay and structural simulation of the complex. These results showed that the newly developed strategy has the advantage that the number of targets identified via ultrafiltration-HPLC can be narrowed from many false positives. However, not all false positives can be eliminated with this approach. Some potent inhibitors might also be excluded with the use of this method. The limitations of this method are also discussed herein.

Removal of selected pharmaceuticals in an ultrafiltration-activated biochar hybrid system

Kim, Sewoon,Park, Chang Min,Jang, Am,Jang, Min,Herná,ndez-Maldonado, Arturo J.,Yu, Miao,Heo, Jiyong,Yoon, Yeomin Elsevier 2019 Journal of membrane science Vol.570 No.-

<P><B>Abstract</B></P> <P>In this study, selected target pharmaceuticals (PhACs) including ibuprofen (IBP), 17 α-ethinyl estradiol (EE2), and carbamazepine (CBM) were removed by an ultrafiltration-activated biochar hybrid system (UF-ABC). Based on characteristic analysis, ABC, a by-product of combustion of waste, is a promising alternative to commercially available powdered activated carbon (PAC) due to its enhanced aromatization and porous properties. Three different systems, including UF only and UF-ABC with/without humic acid (HA) were evaluated. The average retention rate of target PhACs within the UF-ABC system (without HA: 45.2%, and with HA: 34.4%) was much higher than that of the UF only (15.4%), suggesting that hydrophobic adsorption by ABC was the dominant mechanism. In addition, although fouling is expected in UF-ABC due to the presence of ABC, the flux decline of UF-ABC showed similar flux behavior to that of the UF only system. The UF-ABC was compared to UF-PAC with respect to retention rate and permeate flux. The average retention rate for the target PhACs was slightly higher in UF-PAC (46.6%) than in UF-ABC (41.4%) for the target PhACs. However, UF-ABC was considered to be a good alternative system because the normalized flux of UF-ABC (0.85 and 0.77) was superior to UF-PAC (0.76 and 0.70) in the absence/presence of HA, respectively. Consequently, UF-ABC was shown to be a suitable alternative to UF-PAC with respect to both retention and fouling reduction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An ultrafiltration-activated biochar (UF-ABC) hybrid system was employed for pharmaceutical removal. </LI> <LI> UF-ABC showed relatively low flux decline and high pharmaceutical retention trends. </LI> <LI> UF-ABC may serve as a suitable alternative in terms of both retention capacity and fouling reduction. </LI> </UL> </P>

The Effect of Pulsatile Flow on Ultrafiltration In-Vitro Study and Comparison with Roller Pump

Lee K.,Jeong J. H.,Mun C. H.,Lee J. C.,Min B. G. The Korean Society of Medical and Biological Engin 2005 의공학회지 Vol.26 No.5

Blood pulsation has been reported to have an advantageous effect on extracorporeal blood circulation. However, the study of pulsatile blood flow in renal replacement therapy is very limited. The in-vitro experimental results of pulsatile blood flow on ultrafiltration, when compared with the conventional roller pump, are described in this paper. Methods: Blood flow rate (QB) and transmembrane pressure (TMP) were considered as regulating factors that have an influence on ultrafiltration. Experiments were performed under the condition of equal TMP and OB in both pulsatile and roller pump groups, Several kinds of hollow fiber dialyzers were tested using distilled water containing chemicals as a blood substitute. Mean TMP (mTMP) varied from 10 to 90mmHg while the QB was 200ml/min. Results: Ultrafiltration rate (QUF) was found to be linearly proportional to TMP, whereas QB had little influence on QUF. In addition, QUF was higher in the pulsatile group than the roller pump group at the identical TMP. Conclusion: In the controlled test, QUF increased solely as a consequence of blood pulsation, which implies that the pulse frequency represents an additional and important clinical variable during renal replacement therapy.

Membrane Ultrafiltration for Apparent Molecular Weight Distributions of Dissolved Organic Matter

Seo, Jun-Won,Sa, Tongmin,Kim, Jong-Soo 한국응용생명화학회 2000 Journal of Applied Biological Chemistry (J. Appl. Vol.43 No.1

Apparent MWDs of DOM in natural waters and swine wastewaters were determined through membrane ultrafiltration. The nominal MWCOs of ultrafiltration membranes by the manufacturer were confirmed to be similar with those obtained from the ultrafiltration procedures employed in this study using six MW standard compounds. Natural waters showed a wide range of MWOs, but 62.4~87.5% were in the range of MW<10K. High MW fractions were preferentially removed through water treatment processes. Swine wastewater showed two major ranges of MWDs, 49.0% in <1K and 36% in >50k while anaerobically treated swine wastewaters showed 17.5~18.0% in <1K and 53.0~58.8% in <50K. The overall DOM was reduced during anaerobic treatment by 76.8~80.0% as COD; however. the percentage of low MW fractions decreased and that of the high MW fractions increased.

Mass transfer analysis of ultrafiltration using spacers based on triply periodic minimal surfaces: Effects of spacer design, directionality and voidage

Sreedhar, Nurshaun,Thomas, Navya,Al-Ketan, Oraib,Rowshan, Reza,Hernandez, Hector H.,Abu Al-Rub, Rashid K.,Arafat, Hassan A. Elsevier 2018 Journal of membrane science Vol.561 No.-

<P><B>Abstract</B></P> <P>An ideal feed spacer balances high flux and low pressure drop while minimizing fouling. In this work, several feed spacer with complex triply periodic minimal surface (TPMS) geometries were designed and fabricated using additive manufacturing (AM) processing. AM technology was employed to vary the voidage and directionality of the spacers. The fabricated spacers were tested to determine their impact on mass transfer, pressure drop and critical flux in a flat-sheet ultrafiltration (UF) setup for protein separation in aqueous medium. Dimensionless numbers analysis was conducted with dextran filtration, while critical flux was determined via the flux-stepping method by filtration of bovine serum albumin (BSA). All the tested TPMS spacers displayed an increase in mass transfer compared to a commercial spacer design, with the Gyroid spacer (84% voidage) exhibiting a 67% increase in Sherwood number. The Gyroid design also showed an 8% improvement in critical flux. Modification of the spacer voidage and direction also showed significant influence on performance. By increasing the voidage of the Gyroid spacer from 84% to 90%, we observe a 97% increase in Sherwood Number and an 18% decrease in Power number, compared to commercial spacer. The findings of this study show the advantages of TPMS architectures as candidates for spacer design in UF.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spacers based on triply periodic minimal surfaces (TPMS) were made. </LI> <LI> Mass transfer study of TPMS spacers in ultrafiltration. </LI> <LI> Modification of directionality and porosity of TPMS spacers evaluated. </LI> <LI> Spacer with gradually changing porosity fabricated and tested. </LI> <LI> Superior critical flux using some TPMS architectures compared to commercial design. </LI> </UL> </P>

오계란 단백질 가수 분해물 제조 및 한외여과 분획물의 in vitro 항산화 활성 특성

하유진(Yoo Jin Ha),김슬기(Seul Ki Kim),유선균(Sun Kyun Yoo) 한국유화학회 2017 한국응용과학기술학회지 Vol.34 No.3

식물 및 동물성 단백질 유래 펩타이드 형태의 단백질 가수 분해물들은 항산화, 고혈압 완화, 면역조절, 진통완화 및 항균작용 등 생리활성이 있는 것으로 알려져 왔다. 본 연구는 연산오계란 단백질 가수 분해물을 Ultrafiltration를 이용하여 HDS(분획되지 않은 가수 분해물), 1 kDa, 5 kDa, 10 kDa, 50 kDa로 분획된 기능성 펩타이드의 DPPH radical scavenging activity, superoxide anion radical scavenging activity, hydroxyl radical scavenging activity 및 Fe²⁺ chelation ability을 평가하였다. 그 결과 DPPH radical scavenging activity 최대값은 1 kDa(70.83 %), hydroxyl radical scavenging activity 최대값은 5 kDa (47.01 %), superoxide anion radical scavenging activity 최대값은 5 kDa(40.57 %), Fe²⁺ chelation ability 최대값은 5 kDa(29.87 %)로 나타났다. Ultrafiltration를 이용하여 fractionation된 단백질 가수 분해물의 항산화 저해 능력 IC₅₀ 평가하였다. 그 결과 HDS의 최대값은 superoxide anion radical scavenging activity(IC₅₀, 5.42 mg/ml)이고, 1 kDa의 최대값은 Fe²⁺ chelation ability(IC₅₀, 1.67mg/ml)이고, 5 kDa의 최대값은 Fe²⁺ chelation ability(IC₅₀, 2.09 mg/ml)이고, 10 kDa의 최대값은 Fe²⁺ chelation ability(IC₅₀, 2.61 mg/ml)이고, 50 kDa의 최대값은 Fe²⁺ chelation ability(IC₅₀, 4.53 mg/ml)이다. 그러므로 본 연구 결과를 바탕으로 5 kDa를 이용하여 오계란 단백질에서 분획한 펩타이드는 항산화 기능성 식품소재로서 활용할 가치가 높을 것으로 기대한다. Protein hydrolysates derived from plants and animals having antioxidant, suppression of hypertension, immunodulatory, alleviation of pain, and antimicrobial activity has been known as playing important role like hormone. This study was fractioned to hydrolysis of Ogae egg white protein using the ultrafiltration. The antioxidant activity of the produced peptides was analyzed. As a result, the maximum value of DPPH radical scavenging was 1 kDa(70.83 %), hydroxy radical scavenging was 5 kDa(47.01 %), superoxide anion radical scavenging was 5 kDa(40.57 %), and Fe²⁺ chelation ability was 5 kDa(29.87 %). Furthermore, the antioxidant Inhibition concentration (IC₅₀) of peptides was evaluated for each fraction. As a result, the maximum value of HDS was superoxide anion radical scavenging(IC₅₀, 5.42 mg/ml). 1 kDa was Fe²⁺ chelation ability(IC₅₀, 1.67 mg/ml), 5 kDa was Fe²⁺cheating ability(IC₅₀, 2.09 mg/ml), 10 kDa was Fe²⁺ ability(IC₅₀, 2.61 mg/ml), papain was Fe²⁺ cheating ability(IC₅₀, 4.53 mg/ml). Therefore, we expect that peptides produced from Ogae egg white protein using 5 kDa fraction are useful as an antioxidant functional food ingredients.

Advanced Water Treatment by Tubular Alumina Ceramic Ultrafiltration: Effect of Periodic Water-back-flushing Period

Park, Jin-Yong,Lee, Song-Hui The Membrane Society of Korea 2009 Korean Membrane Journal Vol.11 No.1

The periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in tubular ceramic ultrafiltration (UF) system for Gongji stream water treatment in Chuncheon city. The filtration time (FT), which was the water-back-flushing period, 2 min with periodic 15 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume ($V_T$) of 6.35 L. Consequently FT 2 min at back-flushing time (BT) 15 sec could be the optimal condition in advanced UF water treatment of Gongji stream. Then the average rejection rates of pollutants by our tubular ceramic UF system were 99.4% for Turbidity, 31.8% for $COD_{Mn}$, 22.6% for $NH_3$-N and 65.9% for T-P.

한외여과를 통한 난백 중 라이소자임의 분리정제

구자경,손동호,전회진,이윤희,조남준,장동일 한국막학회 2005 멤브레인 Vol.15 No.2

한외여과를 통하여 난백으로부터 라이소자임을 분리, 정제하는 연구를 수행하였다. 교반식 한외여과장치에 분획 분자량(MWCO)이 각각 10 kDa, 30 kDa 및 100 kDa의 셀룰로즈 재질 분리막을 사용하여 알부민과 라이소자임의 투과실험 데이터를 수집하였다. 단백질 용액은 20 mM, pH 6, 7, 8의 인산염 완충용액에 난단백 함량을 1%,;2%,;3% 및 10% 첨가하여 제조하였으며, 막간압력차(TMP)는 0.5~3 bar의 구간에서 실험을 하였다. 분리막의 분획분자량이 증가하면서 투과유속은 증가하였으며, 분리막에서의 막간압력차가 증가하면서 그리고 공급원액의 난백농도가 감소하면서 투과유속은 증가하였다. 또한, 분리막의 분획분자량이 감소하면서 알부민의 라이소자임에 대한 선택도는 증가하였으며, 모든 분리막에서 pH 와 공급원액의 난백농도 그리고 막간압력차가 증가하면서 라이소자임의 알부민에 대한 선택도는 증가하였다. Separation and purification of lysozyme from chicken egg white was studied using ultrafiltration. We have obtained experimental data through the cellulose membranes with the molecular weight cut off (MWCO) of 10 kDa, 30 kDa and 100 kDa in a stirred ultrafiltration device. Certain amounts of egg white were dissolved into 20 mM phosphate buffers of pH 6, 7 and 8 to make protein solutions of 1%,;2%,;3%;and;10% concentration. Permeation flux increased with increasing MWCO of the membrane. Permeation flux increased with increasing transmembrane pressure (TMP) and decreasing the protein concentration. As the MWCO of membrane decreased, the selectivity increased. The selectivity increased with increasing TMP and protein concentration of the solution.