• Membrane Journal
• /
• 제8권1호
• /
• pp.42-49
• /
• 1998

Effects of operating time, pH, temperature, concentration and addition of proteolytic enzyme on permeate flux for the ultrafiltration of gelatin and bovine serum albumin(BSA) solutions were studied. The results showed that permeate flux of gelatin solution was maintained almost constant during the operating time, and that of BSA solution was decreased to 66% of the initial value after 40 min operation. The permeate flux of gelatin solution was increased by increasing temperature. The permeate flux of BSA solution was constant in the temperature range of 30~$50{\circ}C$, but increased at $60{\circ}C.$. The permeate fluxes of gelatin and BSA solution showed minimum values near the isoelectric point of pH 5.0. The permeate fluxes of 1%(w/v) and 6% gelatin solution were $43.0l/m^2\cdot hr$ and $13.5l/m^2\cdot hr$, respectively. Those of 1% and 4% BSA solution were $33.0l/m^2\cdot hr$ and $14.0l/m^2\cdot hr$, respectively. The permeate fluxes of gelatin and BSA solutions were decreased to 68.6% and 57.6% of their initial values by increasing their concentration, respectively. The permeate fluxes of gelatin and BSA solutions were enhanced by 30% with the addition of proteolytic enzyme.

• Journal of the Korean Applied Science and Technology
• /
• 제41권1호
• /
• pp.9-18
• /
• 2024

Smilax china is known for its excellent antimicrobial, antioxidant, and anti-inflammatory properties. As a foundational study for applying the functionality of Smilax china extracts to cosmetics, it is necessory to investigate the concentration-dependent skin permation characteristics of the flavonoids in the extract, namely quercetin, catechin, and naringenin. Therefore, it serves as a crucial method for conducting this basic research on the functional aspects fo Smilax china extracts for cosmetic applications. This investigation focused on examining the percutaneous permeability characteristics of flavonoids originating from Smilax china. Applying Marzulli's definition, the Kp value of quercetin was categorized as "fast" at 0.1 mg/mL and "moderate" at 0.2 and 0.4 mg/mL. Notably, the permeation rate exhibited a decline with increasing concentration. For naringenin, Flux values were 0.69, 1.07, and 1.42 ㎍/hr/cm² at concentrations of 0.1, 0.2, and 0.4 mg/mL, respectively, with corresponding Kp values of 6.95, 5.34, and 3.56. Naringenin's Kp value fell into the "moderate" category across all concentrations, and as observed with quercetin, the permeation rate decreased with higher concentrations. Likewise, for catechin, Flux values were 0.75, 1.09, and 1.66 ㎍/hr/cm², and corresponding Kp values were 7.55, 5.46, and 4.16. Catechin's Kp value was consistently classified as "moderate" across all concentrations. The efficacy of quercetin, catechin, and naringenin, active ingredients in high-performance and anti-inflammatory Smilax china extracts, was found to exhibit skin penetration properties above the average. This confirms their suitability as excellent natural materials for use in functional cosmetics, given their outstanding capabilities in preventing acne and reducing inflammation.

• Environmental Engineering Research
• /
• 제19권4호
• /
• pp.339-344
• /
• 2014

Different types of polyethersulfone (PES) support layer for a thin film composite (TFC) membrane were synthesized under various synthesis conditions using the phase inversion method to study the combined effects of substrate, adhesive, and pore former. The permeability, selectivity, pore structure, and morphology of the prepared membranes were analyzed to evaluate the membrane performance. The combined use of substrate, adhesive, and pore former produced a thinner dense top layer, with more straight finger-like pores. The pure water permeation (PWP) of the optimized PES membrane was $27.42L/m^2hr$ (LMH), whereas that of bare PES membrane was 3.24 LMH. Moreover, membrane selectivity, represented as divalent ion ($CaSO_4$) rejection, was not sacrificed under the synthesis conditions, which produced the dramatically enhanced PWP. The high permeability and selectivity of the PES membrane produced under the optimized synthesis conditions suggest that it can be utilized as a potential support layer for TFC membranes.

• Membrane Journal
• /
• 제1권1호
• /
• pp.44-54
• /
• 1991

Sulfonated polystyrene-divinylbenzene(PS-DVB) copolymer membranes were prepared using different diluents (toluene, cyclohexane, cyclohexanol), various diluent ratio and DVB contents. And initial fluxes of organic acids were investigated by varying pH and initial concentration. As a results, water content and ion-exchange capacity decreased with increasing DVB concetration. Among used diluents, cyclohexanol was the most efficient for building up the highest water content and ion-exchange capacity. In the experiment of permeation, carboxylic acid such as formic acid and acetic acid showed higher fluxes when pH was lower than pKa and amino add such as L-alanine showed minimum flux when pH was isoelectric value. The relationaship between initial fluxes and initial concentrations has been expressed by saturation kinetics.

• Membrane Journal
• /
• 제13권4호
• /
• pp.229-238
• /
• 2003

Pervaporation is mainly used to separate liquid mixtures because it exhibits a high selectivity compared with traditional distillation processes and it is known to be an energy saying separation process. Zeolite membranes show better thermal. mechanical, chemical stability than polymer membranes and especially silicalite-1 membrane can effectively separate organic compounds from water because of its high hydrophobicity. In this study, volatile organic compounds of ketone are separated by pervaporation using silicalite-1 membrane. As a feed concentration of acetone and MEK increases, a permeation flux of acetone and MEK increases while a selectivity decreases.

• Computers and Concrete
• /
• 제7권5호
• /
• pp.469-482
• /
• 2010

This paper investigates the concrete permeability through a numerical and statistical approach. Concrete is considered as a random heterogeneous composite of three phases: aggregates, interfacial transition zones (ITZ) and matrix. The paper begins with some classical bound and estimate theories applied to concrete permeability and the influence of ITZ on these bound and estimate values is discussed. Numerical samples for permeability analysis are established through random aggregate structure (RAS) scheme, each numerical sample containing randomly distributed aggregates coated with ITZ and dispersed in a homogeneous matrix. The volumetric fraction of aggregates is fixed and the size distribution of aggregates observes Fuller's curve. Then finite element method is used to solve the steady permeation problem on 2D numerical samples and the overall permeability is deduced from flux-pressure relation. The impact of ITZ on overall permeability is analyzed in terms of ITZ width and contrast ratio between ITZ and matrix permeabilities. Hereafter, 3680 samples are generated for 23 sample sizes and 4 contrast ratios, and statistical analysis is performed on the permeability dispersion in terms of sample size and ITZ characteristics. By sample theory, the size of representative volume element (RVE) for permeability is then quantified considering sample realization number and expected error. Concluding remarks are provided for the impact of ITZ on concrete permeability and its statistical characteristics.

• Journal of Korean Society of Water and Wastewater
• /
• 제30권3호
• /
• pp.321-325
• /
• 2016

The Pressure Retarded Osmosis (PRO) is the next generation desalination technique and is considered as a eco-friendly energy. This was conducted to evaluate the effect of the temperature and pressure on the PRO performance. The flux of the permeation was measured under different operating conditions and estimated the power density. An improvement of PRO performance is depend on increasing solution temperature and optimum pressure. The effect of increasing feed solution temperature has stronger impact on the PRO performance comparing to the draw solution temperature. The reason of the results was due to the change of osmotic power, viscosity, water permeability and structure parameter(s).

• Membrane Journal
• /
• 제26권2호
• /
• pp.87-96
• /
• 2016

Ceramic materials have attracted increasing attention in the last 10 years because of their high thermal stability and high permeation property compared with polymeric nanofiber membranes. Recently, novel nanofiber ceramic membranes with high porosity and flux have been fabricated from metal oxide nanofibers. To improve the performance of ceramic membranes and reduce their costs, a new ceramic membrane with a selective separation layer made of nanofibers was fabricated by electrospinning process and modification process for filtration system. This review summarizes the research trends for the development of ceramic nanofiber membrane over the past few years.

• Membrane Journal
• /
• 제5권2호
• /
• pp.81-88
• /
• 1995

Separation performance was measured for the disc plate and frame type reverse osmosis module using NaCl and sucrose solutions. An analysis of membrane performance was done following the equations proposed by Kimura-Sourirajan[8]. The membrane permeability was $2.17 \times 10^{-6}$(gmol/$cm^2$-sec-bar) and independent of operating pressure. The effect of concentration polarization for sucrose solution was higher than that of NaCl. Permeation flux for sucrose solution above 40 bar was decreased as operating pressure was increased. Solute rejection for NaCl solution was decreased, but that of sucrose was increased as operating pressure was increased.

• Membrane Journal
• /
• 제21권1호
• /
• pp.13-21
• /
• 2011

This study investigated the fouling behavior of $Al_2O_3$ colloids on polyethylene microfiltration membrane. To examine the effect of operation variation on fouling, operating pressure was increased from 0.49 to 1.96 bar along with time elapses and then was reduced to 0.49 bar reversely. A hysteresis behavior was observed in the membrane permeate flux over pressure, revealing different fluxes at the same pressure according to the pressure control type, increasing and decreasing. Permeate resistance and its rate of increase was higher in the decreasing pressure cycle than in the increasing pressure cycle. At the initial period of filtration, fouling mechanism for the both cycles was governed by the cake filtration. The degree of fouling was higher in the decreasing pressure cycle compared with in the increasing pressure cycle.