• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.6
• /
• pp.426-432
• /
• 2001

Perstractive fermentation is a good way to increase the productivity of bioreactors. Us-ing Propionibacteria as the model system, the feasibility of using supported emulsion liquid mem-brane(SELM) fro perstractive fermentation is assessed in this study. Five industrial solvents were considered as the solvent for perparing the SELM. The more polar a solvent, is the higher the par-tition coefficeint However, toxicity of a solvent also increases with its polarity. CO-1055(indus-trial decanol/octanol blend)has the highest partition coefficient toward propionic acid among the solvents that has no molecular toxicity toward Propionibacteria, A preliminary extraction study was conducted using tetradecane as solvent in a hydrophobic hollow fiber contactor. The results confirmed that SELM eliminates the equilibrium limitation of conventional liquid-liquid extrac-tion and allows the use of a non-toxic solvent with low partition coefficient.

• Analytical Science and Technology
• /
• v.24 no.5
• /
• pp.352-359
• /
• 2011

An analytical method for solvent-free determination of benzene, toluene, ethylbenzene, and xylenes (BTEX) in water using repetitive membrane extractions coupled to cryofocusing and GC-MS was derived. BTEX compounds that permeated through a nonporous silicone membrane from the aqueous phase and evaporated into the acceptor phase were purged into a cryofocusing trap ($-100^{\circ}C$) with helium gas. The BTEX compounds, thus enriched in the trap, were thermally desorbed into a capillary column GC and detected using an MS. The flow rate of the donor phase (30 mL water) was set at 10 mL/min, and membrane extractions, accomplished by returning the water drained from the extraction module to the sample container, were repeated three times at $20{\pm}2^{\circ}C$. Although recoveries (%) were variable, from the highest for benzene (approximately 80%) to the lowest for ethylbenzene and xylenes (3.5-10%), the method showed satisfactory precision (RSD 2.2-10%) with good-linearity calibration curves ($r^2$ 0.9976-0.9997 in 1-100 ${\mu}g$/L range) for all of the compounds. The method detection limits (MDLs) ranged from 0.16 to 1.8 ${\mu}g$/L. The results showed the method's advantages such as short analysis time and overall simplicity without solvent compared to the conventional techniques.

• Korean Chemical Engineering Research
• /
• v.47 no.2
• /
• pp.258-261
• /
• 2009

In this work, we the ettect on extraction amounts and general composition content of phytoestrogen genistein and formononetin extracted from Sophoraflavescens Aiton by various ultrasonic waves(35, 72, and 170 KHz) and extraction time(30, and 60 min) were compared using extraction solvent water 100%. The pretreatment step was composed of ultrasonic waves extraction, filtration, concentration, and membrane filtration. The extracted sample was analyzed by reversed-phase high performance liquid chromatography(RP-HPLC). And the mobile phase applied was linearly changed with A/B of 80/20~65/35 vol% for 60 min(A water/acetic acid, 99.9/0.1 vol%, B acetonitrile/acetic acid, 99.9/0.1 vol%). The experimental results, general composition carbohydrate(0.255 to 0.413%) excepts, other ingredients was confirmed almost similarly. Also, The highest yield of extraction amount 3.17g was obtained by ultrasonic waves with a frequency of 170 KHz and an extraction time of 60 min. This work offers would be useful for chemical and biological studies of natural plants and its products.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.12
• /
• pp.1666-1673
• /
• 2011

The presence of sialoglycoproteins (SGPs) in the membranes from goat (Capra aegagrus hircus), buffalo (Bubalus bubalis bubalis) and pig (Sus scrofa domestica) erythrocytes was investigated by partial purification with a chloroform-methanol extraction method followed by Sodium dodecyl sulphate - Polyacrylamide gel electrophoresis in comparison to human (Homo sapiens) erythrocytes. The results show that mammalian erythrocytes possess clear differences in the SGPs numbers and molecular weights although all animals studied in this experiment are from the same class i.e. mammalia. The SGPs number in human, goat, buffalo and pig are four (PAS-1 to PAS-4), ten (PAS-GI to PAS-GX), seven (PAS-BI to PAS-BVII) and four (PAS-PI to PAS-IV) respectively as indicated by staining the polyacrylamide gel with sialoglycoprotein-specific Periodic acid-Schiff's (PAS) stain. The new SGPs could be observed only after the partial purification of membrane fractions named as PAS-HI with molecular weight (Mr) 190 kDa and PAS-HII 150 kDa in human, PAS-BIA in buffalo and PAS-PIA and PAS-PIVA in pig. The gels were also stained with Coomassie brilliant blue (CBB) and Silver stain to check the contamination of other membrane proteins in the purified fractions. The quantitative distribution of SGPs was also determined by densitometry. Present study indicates that there are some basic differences in mammalian erythrocyte membrane SGPs, especially with respect to their number and molecular weights indicating major structural variations.

• Elastomers and Composites
• /
• v.23 no.1
• /
• pp.11-17
• /
• 1988

The transport of chromium(VI) ion from waste water through the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid paraffin oil were analyzed. Extraction experiments were carried out to observe the effect of system variables, such as concentrations of carrier, and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt.% and liquid paraffin oil concentration is 50 vol.%. The theoretical equation on the transport of chromium(VI) ion agreed well with the experimental results.

• Membrane and Water Treatment
• /
• v.8 no.5
• /
• pp.483-498
• /
• 2017

Novel mixed matrix membranes of Sodium Alginate (NaAlg) were developed by the incorporation ofunmodified, modified Phosphomolybdic acid (PMA) then cross-linked with glutaraldehyde externally. These membranes were prepared by the solution casting technique. Pervaporation (PV) experiments have been performed with pure NaAlg, unmodified NaAlg-PMA5, NaAlg-PMA10, modified NaAlg-mPMA5, and NaAlg-mPMA10 (wt. % of PMA 5 and 10) at 30, 40 and $50^{\circ}C$, to separate water-isopropanol feed mixtures containing 10-30 wt. % of water. Pervaporation results of NaAlg-mPMA10 produced a highest separation factor of 9028 with a flux of $0.269kg/m^2.h$ for 10 wt. % of water containing feed mixture. Both separation factor and flux for water increased significantly with increasing content of mPMA into NaAlg; a significant improvement in PV performance was observed for NaAlg-mPMA5 and NaAlg-mPMA10 membranes when compared to pure NaAlg& PMA-5, PMA-10 membrane.

• Membrane Journal
• /
• v.5 no.1
• /
• pp.44-57
• /
• 1995

A mathematical model was proposed to describe the behavior of the liquid emulsion membrane(LEM) conraining sodium carbonate as internal stripping reagent. Experimental results of the batch extraction of lactic acid were compared with computed results by using the model. it was found that the model computations could predict fairly well the effects of parameter variations such as the carrier concentration, the stripping reagent concentration, the stirrer speed and the treatment ratio. An attempt has been made to reduce emulsion swelling which is one of the main problem of LEM. As the additives for swelling control, liquid paraffin, n-decanol, cyclohexanone and Span 85 were used. All the additives that were investigated tend to reduce the quantity of swelling to some extent. Cyclohexanone was found not only to reduce the swelling but also to increase largely the acid transport rate.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.3 no.1
• /
• pp.24-31
• /
• 1998

The separation and concentration of L-phenylalanine (L-Phe) using a supported liquid membrane (SLM) is investigated. A cation complex agent, di-2-ethylhexyl phosphoric acid (D2EHPA), is used as a carrier in the SLM with n-Heptane as a solvent. The reaction order and equilibrium constant in the formation reaction of L-phe-carrier complex are obtained from the extraction experiment. A mathematical model for a carrier mediated counter transport process is proposed to estimate the diffusion coefficient of L-phe-carrier complexly in the liquid membrant. Permeation experiments of L-phe using a SLM are performed under various operating conditions and optimum conditions for the transport of L-phe are obtained. Concentration of L-phe in the strip phase against its concentration is observed. Transport rate of glucose through liquid membrane is less than that of L-phe in the competitive transport of L-phe and glucose. And the existence of glucose reduced the transport rate of L-phe. The performance of separation with continuous strip phase is increased due to the dilution effect in the strip phase.

• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.4
• /
• pp.441-447
• /
• 2016

Development of shale gas has drawn increasing attention since it is one of promising alternative energy resources. However, contamination of groundwater and surface water during the extraction of shale gas is becoming a serious environmental issues, which brings the needs to treat wastewater generated from hydraulic fracking. In this study, the feasibility of membrane distillation (MD) for the treatment of shale gas wastewater was investigated using a laboratory scale experimental setup. Flat-sheet MD membranes were used to treat produced water from a shale gas well in the United States. Different configurations such as direct contact MD (DCMD) and air gap MD (AGMD) were compared in terms of flux and fouling propensity. The foulants on the surface of the membranes were examined. The results suggest that MD can treat the shale gas produced water containing more than 200,000 mg/L of total dissolved solids, which is impossible by other technologies such as reverse osmosis (RO) and forward osmosis (FO). In this study, we investigated the possibility of processing and characterization of shale gas produce wastewater using membrane distillation. Laboratory scale membrane distillation experimental device was developed. It was compared the flat-sheet direct contact membrane distillation and flat-sheet air gap membrane distillation. AGMD flux in lower than the flux of DCMD, it was expected that the contamination caused by organic matters.

• Membrane Journal
• /
• v.5 no.4
• /
• pp.129-136
• /
• 1995

This study is concerned with the treatment of dye wastewater by carrier meditated emulsion liquid membrane. Optimum conditions for the removal of anionic dye and cationic dye by the emulsion liquid membrane(ELM) containing Aliquat 336 or D2EHPA were obtained in the batch operation, an actual dye wastewater was tested under these conditions. Dye reagents used were Sirius Red(Direct dye), Reactofix Supra Blue(Reactive dye), and Apollo Blue(Basic dye). The experimental variables were surfactant(Span 80) and carrier(Aliquat 336 or D2EHPA) concentration in the membrane phase, the counter ion($Na_2SO_4$) concentration in the internal phase and the amount of emulsion. Extraction equilibrium arrived within 5 minutes after starting reaction and more than 95% of dye ion could be removed. The carrier concentration in the membrane phase was the most crucial for the removal efficiency, but other variables effected to the reaction time more than the removal efficiency. The dye wastewater was treated under the optimum conditions in two steps. The absorbance at 550nm of wastewater was decreased 0.53 to below 0.03 after 10 minutes treatment.