Microfiltration (0·1 μm) of milk: effect of protein size
 and charge

Microfiltration (MF) of milk with a ceramic membrane (0·1 μm mean pore diam.) for the separation of casein micelles from soluble proteins was studied. Experiments were performed at constant flux density (J=65 or 75 l h−1 m−2) and wall shear stress (τw=100 or 110 Pa) with milks containing particles and solutes with different sizes and charges, produced by physicochemical change (heat and mechanical treatment, pH, ionic strength, addition of ions). Membrane separation performance was limited by the build up of a cake with characteristics that depended on the size of particles and soluble proteins. Best performance (higher permeability and whey protein transmission) was obtained with milk containing fat on the one hand and calcium phosphate on the other. An optimal value of the particle size was found, close to 0·5–3·0 μm; above this separation performance decreased. In addition, the present study confirmed that the transfer of charged solutes is the consequence of both size and ionic exclusion. Better performance was achieved with higher ionic strength (1 M).

Download Full-text

The Optimization of RHS-polysulfone Membrane towards Operating Condition for Humic Acid Removal

Emerging Advances in Integrated Technology ◽

10.30880/emait.2021.02.01.002 ◽

2021 ◽

Vol 02 (01) ◽

Author(s):

Mohd Riduan Jamalludin ◽

◽

Siti Khadijah Hubadillah ◽

Zawati Harun ◽

Muhamad Zaini Yunos ◽

...

Keyword(s):

Response Surface Methodology ◽

Ionic Strength ◽

Membrane Separation ◽

Pure Water ◽

Water Flux ◽

Separation Process ◽

Transmembrane Pressure ◽

Polysulfone Membrane ◽

Optimal Value ◽

Pure Water Flux

This study investigates the effects of rice husk silica (RHS) as additive in the polysulfone membrane to enhance antifouling properties in membrane separation process. The performance (of what?) was evaluated in term of pure water flux (PWF), rejection and antifouling properties. The optimized of normalized flux (Jf /Jo) at different parameter in filtration (pH, ionic strength and tranmembrane-pressure) was carried out by using the response surface methodology (RSM). The results showed that the addition of 4 wt. % RHS give the highest flux at 300.50 L/m².hour (LMH). The highest rejection was found at 3 wt. % of RHS membrane with value 98% for UV254 and 96% for TOC. The optimal value of Jf/Jo was found at 0.62 with the condition of pH: 6.10, ionic strength: 0.05 mol/L and transmembrane-pressure: 2.67 bars. Optimize of RSM analysis from ANOVA also proved that the error of model is less than 0.05% which indicates that the model is significant.

Download Full-text

Application of the ceramic membrane with hydrophobic skin layer to separation of activated sludge

Water Science & Technology ◽

10.2166/wst.1997.0306 ◽

1997 ◽

Vol 35 (8) ◽

pp. 137-144 ◽

Cited By ~ 1

Author(s):

Tsuyoshi Nomura ◽

Takao Fujii ◽

Motoyuki Suzuki

Keyword(s):

Activated Sludge ◽

Pore Size ◽

Ceramic Membrane ◽

Membrane Separation ◽

Porous Ceramic ◽

Porous Membrane ◽

Skin Layer ◽

Gas Permeation ◽

Wide Range ◽

Cake Layer

Porous membrane of poly(tetrafluoroethylene) (PTFE) was formed on the surface of porous ceramic tubes by means of heat treatment of the PTFE particles deposit layer prepared by filtering PTFE microparticles emulsified in aqueous phase. By means of inert gas permeation, pore size was determined and compared with scanning electron micrograph observation. Also rejection measurement of aqueous dextran solutions of wide range of molecular weights showed consistent results regarding the pore size. Since the membrane prepared by this method is stable and has unique features derived from PTFE, it is expected that the membrane has interesting applications in the field of water treatment. Membrane separation of activated sludge by this composite membrane and original ceramics membrane showed that the PTFE membrane gives better detachability of the cake layer formed on the membrane. This might be due to the hydrophobic nature of the PTFE skin layer.

Download Full-text

Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽

10.3390/membranes11050369 ◽

2021 ◽

Vol 11 (5) ◽

pp. 369

Author(s):

Shengji Xia ◽

Xinran Zhang ◽

Yuanchen Zhao ◽

Fibor J. Tan ◽

Pan Li ◽

...

Keyword(s):

Water Treatment ◽

Membrane Fouling ◽

Membrane Filtration ◽

Ceramic Membrane ◽

Membrane Separation ◽

Membrane System ◽

Coagulation System ◽

Fouling Control ◽

Filtration System ◽

Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

Download Full-text

Effect of Small, Acid-Soluble Proteins on Spore Resistance and Germination under a Combination of Pressure and Heat Treatment

Journal of Food Protection ◽

10.4315/0362-028x-70.9.2168 ◽

2007 ◽

Vol 70 (9) ◽

pp. 2168-2171

Author(s):

JONG-KYUNG LEE ◽

SARA MOVAHEDI ◽

STEPHEN E. HARDING ◽

BERNARD M. MACKEY ◽

WILLIAM M. WAITES

Keyword(s):

Heat Treatment ◽

High Pressure ◽

High Temperature ◽

Spore Germination ◽

Soluble Proteins ◽

Wild Type ◽

Spore Resistance ◽

Pressure Resistance ◽

The One

To find the range of pressure required for effective high-pressure inactivation of bacterial spores and to investigate the role of α/β-type small, acid-soluble proteins (SASP) in spores under pressure treatment, mild heat was combined with pressure (room temperature to 65°C and 100 to 500 MPa) and applied to wild-type and SASP-α−/β− Bacillus subtilis spores. On the one hand, more than 4 log units of wild-type spores were reduced after pressurization at 100 to 500 MPa and 65°C. On the other hand, the number of surviving mutant spores decreased by 2 log units at 100 MPa and by more than 5 log units at 500 MPa. At 500 MPa and 65°C, both wild-type and mutant spore survivor counts were reduced by 5 log units. Interestingly, pressures of 100, 200, and 300 MPa at 65°C inactivated wild-type SASP-α+/β+ spores more than mutant SASP-α−/β− spores, and this was attributed to less pressure-induced germination in SASP-α−/β− spores than in wild-type SASP-α+/β+ spores. However, there was no difference in the pressure resistance between SASP-α+/β+ and SASP-α−/β− spores at 100 MPa and ambient temperature (approximately 22°C) for 30 min. A combination of high pressure and high temperature is very effective for inducing spore germination, and then inactivation of the germinated spore occurs because of the heat treatment. This study showed that α/β-type SASP play a role in spore inactivation by increasing spore germination under 100 to 300 MPa at high temperature.

Download Full-text

Anomalous Salt Dependence Reveals an Interplay of Attractive and Repulsive Electrostatic Interactions in α-synuclein Fibril Formation

QRB Discovery ◽

10.1017/qrd.2020.7 ◽

2020 ◽

Vol 1 ◽

Cited By ~ 1

Author(s):

Ricardo Gaspar ◽

Mikael Lund ◽

Emma Sparr ◽

Sara Linse

Keyword(s):

Ionic Strength ◽

Electrostatic Interactions ◽

Intrinsically Disordered Protein ◽

Lipid Vesicles ◽

Intrinsically Disordered ◽

Catalytic Surfaces ◽

Disordered Protein ◽

Salt Dependence ◽

Fluorescence Measurements ◽

The One

Abstractα-Synuclein (α-syn) is an intrinsically disordered protein with a highly asymmetric charge distribution, whose aggregation is linked to Parkinson’s disease. The effect of ionic strength was investigated at mildly acidic pH (5.5) in the presence of catalytic surfaces in the form of α-syn seeds or anionic lipid vesicles using thioflavin T fluorescence measurements. Similar trends were observed with both surfaces: increasing ionic strength reduced the rate of α-syn aggregation although the surfaces as well as α-syn have a net negative charge at pH 5.5. This anomalous salt dependence implies that short-range attractive electrostatic interactions are critical for secondary nucleation as well as heterogeneous primary nucleation. Such interactions were confirmed in Monte Carlo simulations of α-syn monomers interacting with surface-grafted C-terminal tails, and found to be weakened in the presence of salt. Thus, nucleation of α-syn aggregation depends critically on an attractive electrostatic component that is screened by salt to the extent that it outweighs the screening of the long-range repulsion between negatively charged monomers and negative surfaces. Interactions between the positively charged N-termini of α-syn monomers on the one hand, and the negatively C-termini of α-syn on fibrils or vesicles surfaces on the other hand, are thus critical for nucleation.

Download Full-text

A Comprehensive Membrane Process for Preparing Lithium Carbonate from High Mg/Li Brine

Membranes ◽

10.3390/membranes10120371 ◽

2020 ◽

Vol 10 (12) ◽

pp. 371

Author(s):

Wenhua Xu ◽

Dongfu Liu ◽

Lihua He ◽

Zhongwei Zhao

Keyword(s):

Reverse Osmosis ◽

Membrane Separation ◽

Lithium Carbonate ◽

High Mass ◽

Separation Performance ◽

Mass Ratio ◽

Total Recovery ◽

Industrial Grade ◽

Electrochemical Intercalation ◽

New Perspective

The preparation of Li2CO3 from brine with a high mass ratio of Mg/Li is a worldwide technology problem. Membrane separation is considered as a green and efficient method. In this paper, a comprehensive Li2CO3 preparation process, which involves electrochemical intercalation-deintercalation, nanofiltration, reverse osmosis, evaporation, and precipitation, was constructed. Concretely, the electrochemical intercalation-deintercalation method shows excellent separation performance of lithium and magnesium, and the mass ratio of Mg/Li decreased from the initial 58.5 in the brine to 0.93 in the obtained lithium-containing anolyte. Subsequently, the purification and concentration are performed based on nanofiltration and reverse osmosis technologies, which remove mass magnesium and enrich lithium, respectively. After further evaporation and purification, industrial-grade Li2CO3 can be prepared directly. The direct recovery of lithium from the high Mg/Li brine to the production of Li2CO3 can reach 68.7%, considering that most of the solutions are cycled in the system, the total recovery of lithium will be greater than 85%. In general, this new integrated lithium extraction system provides a new perspective for preparing lithium carbonate from high Mg/Li brine.

Download Full-text

Influence of solvent exchange time on mixed matrix membrane separation performance for CO2/N2 and a kinetic sorption study

Journal of Membrane Science ◽

10.1016/j.memsci.2014.11.008 ◽

2015 ◽

Vol 476 ◽

pp. 590-601 ◽

Cited By ~ 16

Author(s):

Z.A. Jawad ◽

A.L. Ahmad ◽

S.C. Low ◽

T.L. Chew ◽

S.H.S. Zein

Keyword(s):

Membrane Separation ◽

Mixed Matrix Membrane ◽

Separation Performance ◽

Solvent Exchange ◽

Mixed Matrix ◽

Exchange Time ◽

Kinetic Sorption ◽

Sorption Study ◽

Influence Of Solvent

Download Full-text

Effects of Ionic Liquid Blending in Polymeric Membrane: Physical Properties and Performance Evaluation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.625.680 ◽

2014 ◽

Vol 625 ◽

pp. 680-684 ◽

Cited By ~ 2

Author(s):

Dzeti Farhah Mohshim ◽

Hilmi Mukhtar ◽

Zakaria Man

Keyword(s):

Ionic Liquid ◽

Ionic Liquids ◽

Membrane Separation ◽

Initial Study ◽

Polymeric Membranes ◽

Polymeric Membrane ◽

Separation Performance ◽

Operating Pressure ◽

Membrane Gas Separation ◽

Pes Membrane

— Polymeric membranes have been extensively used in membrane gas separation process. Nowadays, peoples are modifying the membrane by many ways like coating with ionic liquids to further enhance the membrane separation performance. In this project, ionic liquid modified polymeric membranes (ILMPM) have been successfully developed by blending the ionic liquids with the polymer via solvent evaporation method. The ionic liquid used was 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, ([emim][Tf2N]) and for comparison purpose, the compositions were varied at 10 and 20 wt/wt%. In general, the blending of [emim][Tf2N] and PES has produced dense membrane with miscible mixture without any phase separation. It was observed that, the CO2permeance of ILMPM has been improved about 271% as compared to the pure PES membrane. However, the CO2permeance decreased with increasing operating pressure, yet the ILMPM CO2permeance still higher than CO2permeance of pure PES membrane. In addition, the CO2/CH4separation performance has greatly increased about 162% as the IL composition is increased. This initial study has proven that IL helps to enhance of CO2permeation and improve selectivity.

Download Full-text