Batchwise Separation Research Articles

Hollow fiber membranes with Janus surfaces for continuous deemulsification and separation of oil-in-water emulsions

Janus membranes with asymmetric surface wettability are regarded as promising materials for oil/water separation. However, their performances and applications are still limited by diminutive flat structure, dead-end filtration mode, batchwise separation process, low disposal capacity and heavy oil preference. Herein, Janus hollow fiber membranes (JHFMs) are reported to be fabricated by a circulated co-deposition of polydopamine/polyelectrolyte onto lumen surfaces of membranes for addressing these issues. A thin, hydrophilic and charged layer is uniformly and thickness-controllably coated to achieve an asymmetric wettability and a deemulsification function simultaneously. The as-prepared JHFMs feature a high efficiency to separate surfactant stabilized oil-in-water emulsions through successive deemulsification and unidirectional oil delivery. Furthermore, the membrane module assembled by multiple pieces of JHFMs exhibits a large-scale and remarkable ability to separate both heavy and light oils from their oil-in-water emulsions in a cross-flow filtration mode. More importantly, the hollow fiber module shows a record-high recovery ratio toward light oil compared with flat membranes. The purities of filtrates and feeds after the separation totally meet the international purification standards. This work provides an exhilarated opportunity of Janus membranes in the practical application of oily wastewater separation, especially for those surfactant-stabilized oil-in-water emulsions.

Parameters influencing magnetically enhanced centrifugation for protein separation

Magnetically Enhanced Centrifugation is a hybrid method combining the advantages of magnetic separation and centrifugation. Magnetic particles are separated due to magnetic wire forces to a wire matrix within the centrifuge. The deposit slides off the matrix by centrifugation. A pilot machine was set up for batch-wise separation. The discharge takes place by resuspending the particles using the matrix as a stirrer.The influence of the volumetric flow rate, magnetic field strength, and particle concentration is investigated. 200g of magnetic particles are filled in the device. A separation efficiency of more than 99% is possible for the separation of synthetic particles. Concerning discharge, 93% of 200g particles can be recovered in 2 batch volumes of 1.2l of liquid each. In further experiments, a model protein–particle system using hen egg white provides a case study for protein separation by Magnetically Enhanced Centrifugation.

A multicomponent recognition and separation system established via fluorescent, magnetic, dualencoded multifunctional bioprobes

Accurate and rapid recognition and separation of multiple types of biological targets such as molecules, cells, bacteria or viruses from complex sample mixtures is of great importance for a wide range of diagnostic and therapeutic strategies. To achieve this goal, a set of fluorescent, magnetic, dual-encoded multifunctional bioprobes has been constructed by co-embedding different-sized quantum dots and varying amounts of γ-Fe 2O 3 magnetic nanoparticles into swollen poly(styrene/acrylamide) copolymer nanospheres. The dual-encoded bioprobes, which possessed different photoluminescent property and magnetic susceptibility, were proven to be capable of simultaneously recognizing and separating multiple components from a complex sample when three kinds of lectins were used as the targets. The lectins were separated with high efficiency and kept their bioactivity during the process. Compared to the conventional batchwise separation, this method does not require a large number of sequential reaction steps, which is economical of time and can be very reagent-saving. By combining the multiplexing capability of quantum dots with the superparamagnetic properties of iron oxide nanoparticles, this dual-encoded technique is expected to open new opportunities in high-throughput and multiplex bioassays, such as cell sorting, proteomical and genomical applications, drug screening etc.

Selective Separation and Preconcentration of Total Tin Using Quercetin as Chelating Agent

Three methods were developed for rapid and selective extraction of total tin as Sn(IV) using quercetin (H5Q) as chelating agent, prior to its determination by hydride generation atomic absorption spectrometry (HGAAS). H5Q was chemically or physically immobilized onto silica gel or polyurethane foam, respectively, and used for the separation of Sn(IV) by the solid phase extraction (SPE) technique. The SPE methods were compared with flotation technique using the oleic acid as surfactant from H5Q solution in amyl alcohol/kerosene solvent. Elemental analysis, thermogravimetry, spectroscopic measurements (IR, UV/vis and magic angle solid state C13‐NMR) were used to characterize the resulting modified extractors. The experimental conditions for efficient extraction of Sn(IV) such as: pH, time of stirring, interfering ions and eluent concentration, were optimized for the batchwise separation process. The tolerance limits of heavy metal ions in the sorption of Sn(IV) were reported. The methods were applied for the determination of total tin in water samples, zinc shots and canned beans after digestive oxidation. The suggested SPE and flotation techniques were found to be accurate and not subject to random error with especial preference to the SPE technique as it is cheaper and simpler.

SEPARATION OF MERCURY (II), LEAD (II), AND SILVER (I) FROM AQUEOUS SOLUTION USING AN AMINOPOLYCARBOXYLATE SILICA

A quartz crystal microbalance modified by the attachment of silica particles derivatized with the aminopolycarboxylate ligand N-[(3-trimethoxysilyl)propyl]ethylenediamine-N,N′,N′-triacetic acid has been employed to assess conditions under which mercury (II), lead (II), and silver (I) nitrates may be separated in aqueous solution. The separation protocol, which involved removal of Hg(II), as [HgI4]2−, and Pb(II) with H+ was successfully applied to a batch-wise separation of the 3 metal ions.

Batchwise separation of gallium by an anion exchange resin loaded with a sulphonated azo dye

Gallium(III) is sorbed by a strong base anion exchange resin loaded with a sulphonated azo-dye, T-azo-R [1-(tetrazolylazo)-2-hydroxynaphthalene-3,6-disulphonic acid], which is able to complex it in aqueous solution. As sorption takes place at acidities at which the hydrolysis of gallium is not negligible, it must be considered as conconmitant equilibrium. The distribution equilibria depend on the amount of ligand sorbed, and on the volume, acidity and ionic composition of the aqueous solution, according to the Gibbs-Donnan model. The thermodynamic complexation constant in the resin phase can be calculated from the experimental distribution coefficients; the value of log K = −1.24(0.20) is in acceptable agreement with that in aqueous solution [log K = −0.75(0.33)] which was also determined in the present investigation. Two equations deriving from the Gibbs-Donnan model are used for predicting the conditions for sorption and elution of gallium by a batch procedure, and for separating it from aluminium.

Controlling factors of batchwise separation of hydrocarbons by liquid membranes.

Controlling factors of batchwise separation of hydrocarbons by liquid membranes were derived from the model proposed previously, which predicts hydrocarbon permeation through liquid emulsion membranes. The range of values for the factors were determined from reported experimental data. The present paper further describes effets of factors and initial operating parameters on the relationship between yield and selectivity in hydrocarbon separation.

Cytoplasmic Factor Required for Entry of Malaria Parasites Into RBCs

Resealed ghosts of human RBCs, containing diluted cytosol, are susceptible to invasion by Plasmodium falciparum. If ATP is present, a dilution of up to about 30-fold, corresponding to an intracellular hemoglobin concentration of approximately 10 mg/mL, can be tolerated without total loss of susceptibility to invasion. Up to a dilution of about one-half this, the parasites also develop normally. When the cytosol is diluted by more than the critical amount, invasion of the resulting resealed ghosts falls off abruptly. If the diluent buffer is replaced by extraneous concentrated hemolysate, an indefinite dilution is possible without loss of invasion. There is thus an intracellular constituent, which must be present at a concentration above some critical level if the parasite is to enter the cell. The factor in question is not dialyzable. It is largely inactivated when the hemolysate is kept for approximately 1 day in the cold or for approximately 20 minutes at 45 degrees C. The inability of a heat-treated hemolysate to support invasion is not due to the generation of inhibitory products, because such a solution can be used as a diluent of a fresh hemolysate without inhibition of invasion. When the inactivated hemolysate is present as a major component, however, the parasites fail to develop to the trophozoite stage. The invasion-linked factor remains in the strongly adsorbed nonheme fraction when a batchwise separation from hemoglobin on an anion exchanger is made and is thus probably acidic in character; the adsorbed fraction, recovered from the ion-exchanger, substantially restores capacity for invasion when sealed into ghosts. Its activity is destroyed by treatment with trypsin. The adsorbed fraction contains many proteins. When fractionated on a gel filtration column by fast liquid chromatography, active material eluted at a volume corresponding to a mol wt for a globular protein in the region of 10,000. A component of apparent subunit mol wt of 13,000 was observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of this eluate fraction.

Cytoplasmic factor required for entry of malaria parasites into RBCs

Resealed ghosts of human RBCs, containing diluted cytosol, are susceptible to invasion by Plasmodium falciparum. If ATP is present, a dilution of up to about 30-fold, corresponding to an intracellular hemoglobin concentration of approximately 10 mg/mL, can be tolerated without total loss of susceptibility to invasion. Up to a dilution of about one-half this, the parasites also develop normally. When the cytosol is diluted by more than the critical amount, invasion of the resulting resealed ghosts falls off abruptly. If the diluent buffer is replaced by extraneous concentrated hemolysate, an indefinite dilution is possible without loss of invasion. There is thus an intracellular constituent, which must be present at a concentration above some critical level if the parasite is to enter the cell. The factor in question is not dialyzable. It is largely inactivated when the hemolysate is kept for approximately 1 day in the cold or for approximately 20 minutes at 45 degrees C. The inability of a heat- treated hemolysate to support invasion is not due to the generation of inhibitory products, because such a solution can be used as a diluent of a fresh hemolysate without inhibition of invasion. When the inactivated hemolysate is present as a major component, however, the parasites fail to develop to the trophozoite stage. The invasion-linked factor remains in the strongly adsorbed nonheme fraction when a batchwise separation from hemoglobin on an anion exchanger is made and is thus probably acidic in character; the adsorbed fraction, recovered from the ion-exchanger, substantially restores capacity for invasion when sealed into ghosts. Its activity is destroyed by treatment with trypsin. The adsorbed fraction contains many proteins. When fractionated on a gel filtration column by fast liquid chromatography, active material eluted at a volume corresponding to a mol wt for a globular protein in the region of 10,000. A component of apparent subunit mol wt of 13,000 was observed in sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) of this eluate fraction.

Partial Purification and Characterization of a Polysaccharide Depolymerase Associated with Phage-Infected Erwinia amylovora

Erwinia amylovora infected with bacteriophage ERA103 produced an enzyme which degraded the extracellular polysaccharide of noninfected cells. The depolymerase enzyme was purified 15-fold by a procedure which included ammonium sulfate precipitation, ultracentrifugation, CM-Sephadex batchwise separation, Sephadex G-50 column chromatography, and Sephacryl S-200 column chromatography. The enzyme had a molecular weight of approximately 21,000 and a pH optimum of 6.0. Activity was enhanced by supplements of 2-mercaptoethanol or dithiothreitol.

Purification and characterization of rhodanese from Acinetobacter calcoaceticus.

Rhodanese (thiosulfate : cyanide sulfur transferase, EC 2,8,1,1) was found to be contitutively present as an intracellular enzyme in Acinetobacter calcoaceticus. The soluble enzyme was purified 40.9-fold by a procedure which included ultracentrifugation, ethanol precipitation, CM-Sephadex batchwise separation, QAE-50 ion exchange chromatography, and socrose density gradient ultracentrifugation. The enxyme had a molecular weight of approximately 35000 with a pH optimum of 8-8.5. Activity was substantially enhanced by supplements of 2-mercaptoethanol and to a lesser extent by cysteine-HCl or reduced gluthatione. No degradation of the enzyme into smaller subunits was observed when treated with 2-mercaptoethanol.

Application of affinity chromatography to the purification of collagenase for the isolation of insoluble elastin

Clostridium histolyticum collagenase (clostridiopeptidase A, EC 3.4.4.19) was purified by batchwise separation with DEAE-cellulose followed by affinity chromatography on a column of alkali-treated elastin. The N-terminal amino acid profile of elastin isolated from bovine ligamentum nuchae using this enzyme preparation was compared with that of a duplicate sample purified with a mixture of collagenase I and II (Yoshida, E. and Noda, H. (1965) Biochim. Biophys. Acta 105, 562–574). An approx. three-fold decrease in the molar concentration of N-terminal residues and a considerable reduction in their number was obtained by using the former enzyme preparation.

Chromatography on cellulose phosphate of polysaccharide hydrolases from fungi

1. 1. A method is described for the gradient elution of enzymes from a column of cellulose phosphate. By starting with 0.05 M each of citric acid, acetic acid, and sodium chloride in a constant volume mixing chamber, and 0.05 N NaOH in the reservoir, a pH gradient is produced. When this buffered solution passes through the column of cellulose phosphate, the pH of the effluent rises in a nearly linear manner from pH 2.2 to 7, whereupon the pH rises precipitously. 2. 2. With this system of separation, the chromatographic behavior at room temperature is described of three polygalacturonases (one exo and two endo), two xylanases (exo and endo), two cellulases, an arabanase, a galactanase, a proteinase, and what appear to be three amylases and three enzymes hydrolyzing galactomannan. The enzymes were derived from a commercial “Pectinase” from Rhizopus tritici. Continuous recording of the ultraviolet absorption is also shown. 3. 3. A batchwise separation of the crude R. tritici enzymes on a preparative column of cellulose phosphate is described and the resulting four fractions analyzed by the above procedure. A purification of endopolygalacturonase activity of 93-fold on a nitrogen basis and 1000-fold on a solids basis was achieved in this preparative separation.

Steady-state distribution. New instrument for continued batchwise separation by extraction

Steady-state distribution. New instrument for continued batchwise separation by extraction