Studies on Oxygen Characteristics of YBa_2Cu_3O_(7-x) and Its Applications to Air Separation and Gas Purification

Oxygen diffusion and oxygen selective adsorption properties of rare earths material YBa_2Cu_3O_(7-x) (YBCO) were investigated by thermogravimetric, oxygen static adsorption and selectivity adsorption experiments. The results show that YBCO is a very good deoxidizing material. The oxygen desorption of YBCO begins remarkably at about 400 ℃, mass loss can arrive at 1.2% of its original quantity at 800 ℃. Oxygen can be completely absorbed back into the sample again when temperature descends to 400 ℃. The oxygen adsorption selectivity, reproducibility and oxygen adsorption under very low oxygen partial pressure make the material desirable for air separation and gas purification. High purity nitrogen gas was produced with the YBCO molecular sieves in the air separation and gas purification experiments. 0.017 m^3 of high purity nitrogen (>99.9999%) can be obtained with 1 kg YBCO molecular sieve in one cycle. As a deoxidant, an obvious advantage of YBCO is that no hydrogen is needed in its applications.

Separation and purification of deoxynivalenol(DON) mycotoxin from wheat culture using a simple two-step silica gel column chromatography

Deoxynivalenol（DON） is a type B trichothecenes mycotoxin produced by several Fusarium species, often found in foodstuffs for humans and animals. DON is in great demand for the toxicological researches both in vivo and in vitro. In this work, wheat culture was inoculated with a Fusarium graminearum PH-1 strain for DON production. The solvent system for crude extraction was acetonitrile-water（84：16, v/v）. A simple two-step silica gel column chromatography was employed to separate the DON mycotoxin from wheat culture, combined with preparative high performance liquid chromatography（preparative HPLC） to purify the compound. The solvent system for the second silica gel column chromatography was methylene chloride-methanol（17：1, v/v）, which provided a good elution effect selected on thin layer chromatography（TLC）. The target compound was identified by HPLC, and the chemical structure was confirmed by mass spectrometry（MS） and ~1H and ^（13）C nuclear magnetic resonance（NMR） spectroscopy. A total of 433 mg of purified DON was obtained from 1 kg of wheat culture, with a purity of 99.01%. The study had provided an easy-operating and cost-effective method to isolate an expensive compound in a simple way.

Separation and Purification of Total Phloroglucinols in Dryopteris crassirhizoma with DM-130 Macroporous Adsorption Resin

To improve the purity of the total phloroglucinols from Dryopteris crassirhizoma extracts, the separation and purification conditions of the total phloroglucinols from Dryopteris crassirhizoma were studied with DM-130 macroporous adsorption resin in this study. Adsorption rate, elution rate and purity of the total phloroglucinols were used as indexes to investigate the adsorption and desorption capacity of the total phloroglucinols with DM-130 macroporous adsorption resin. Through the study, the optimum sample concentration of the total phloroglucinols and maximum sample volume were 1.5 mg·mL^-1 and 7 BV （210 mL）, respectively. The optimum desorption conditions were achieved by using 80% ethanol as desorption solvent at elution flow rate of 1.0 mL·min^-1. The result showed DM-130 macroporous adsorption resin performed effective adsorption and desorption. After purification, the purity of the total phloroglucinols increased by 11.5-fold.

Separation and Purification of Monascus Pigments from Red Yeast Rice

It is difficult to extract beneficial components from Monascus pigments due to their complex composition. The low purity of Monascus pigment preparations limits their further application in research and production. Therefore, this study was conducted to optimize the conditions for extraction and isolation of Monascus pigments from red yeast rice, to improve the purity of Monascus pigment preparations. Three fractions were isolated using column chromatography from red yeast rice, they were red, orange and yellow respectively. Then, the three fractions were analyzed for composition and purity using thin layer chromatography and liquid chromatography-mass spectrometry(LC-MS). The chromatograms revealed that the yellow and orange fractions had complex compositions that were difficult to be separated, while the red fraction consisted of fewer components. Finally, a single component was isolated from the red fraction using a thin layer chromatography plate, identified as monascorubramine according to its molecular mass.

Design and optimization of an integrated process for the purification of propylene oxide and the separation of propylene glycol by-product

It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming azeotrope.As for this,a novel PO separation process,in that the deionized water is employed as extractant and 1,2-propylene glycol(MPG)that is formed from the PO hydrolysis reaction is recovered,is presented in this work.The salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol(DPG)are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG column.In addition,the ionic liquid(IL)extractant is screened through the conductorlike screening model for segment activity coefficient(COSMO-SAC)and the comparisons of separation efficiency between the IL and normal octane(nC_(8))extractant for the separation of PO and 2-methylpentane are made.With the non-random two-liquid(NRTL)thermodynamic model,the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio,theoretical stages,feeding stage etc.on separation efficiency are detailedly discussed.The results show that the mass purity and the mass yield of PO can be up to 99.99%and 99.0%,and the condenser duty,reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%,30.21%and 78.86%compared to ones with nC_(8).The total annual cost(TAC)calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC_(8) for the investigated process.The presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.

Advances in Researches of Extraction, Separation, and Purification Technologies for Total Saponins of Panax notoginseng

Total saponins of Panax notoginseng have the functions of promoting blood circulation and removing phlegm, thus they have high medicinal value. There are many different extraction methods in the extraction and separation of total saponins of P. notoginseng . The extraction methods of total saponins of P. notoginseng are mainly divided into traditional extraction methods, modern extraction methods and compound extraction methods.

Separation and purification of proteinases from Gastric Mucosa of Northern Sheatfish,Silurus soldatovi

The separation and purification method for pepsin of Northern Sheatfish (Silurus soldatovi) was established by using the combination technology of salting-out,gel chromatography and gel electrophoresis,and the enzymic properties were also analyzed.The experimental results indicated that 28% and 56% (NH4)2SO4 saturation could separate the activated protease from the pepsin extract of gastric mucosa of Sheatfish (Silurus soldatovi) ;compared with the homogenate extraction,the pepsin specific activity of purified extraction by Sephadex G-75 gel chromatography system increased 598 fold,was 5 times higher than that of activated liquid,and the total production rate was 10.1%.The purified pepsin liquor at the conditions of pH3.3 0.01 M alanine-formic acid buffering solution,60 cm chromatography column,and the flowing rate of 0.8 ML/min was analyzed by SDS-PAGE,which indicated that there were two bands and the molecular weight was 34.0 kDa and 40.4 kDa,respectively.There were two peaks in the enzyme activity determination of the separated collecting liquor in gel chromatography,and the SDS-PAGE showed the concentrations of the two proteins was different,which indicated that it existed at least two pepsins in the gastric mucosa of Sheatfish (Silurus soldatovi).

Separation and Purification of GST-glycerol-3-phosphate Dehydrogenase

In order to investigate the expression of glycerol-3 -phosphate dehydrogenase by GCY1 gene in recombinant Saccharomyces cerevisiae, induction culture of the S. cerevisiaestrain was performed with SD-URA 2% galactose, 3 × YP ＋ 6% glucose, SC-URA 2% galactose, and SC-URA 2% galactose ＋ 5% NaCI glyeerol-3-phosphate dehydregenase, the cultured S. cerevisiaewas comminuted followed by full-automatic high-speed purification, and SDS-PAGE gel electrophoresis was performed for molecular weight of the GST fusion protein. The results showed that after shaking culture of the S. cerevisiae containing GCY1 at 25 ℃, the OD values of its 3 × YP ＋ 6% glucose culture and SC-URA 2% galaetose ＋ 5% NaC1 culture were 8.75 and 7.35, respectively. It was shown by purification with a Profinia low-pressure liquid chromatograph that only the S. cerevisiae cultured in SC-URA 2% galactose ＋ 5% NaC1 medium expressed glycerel-3-phosphate de- hydrogenase, the molecular weight of which was detected as 65 ku by SDS-PAGE gel electrophoresis.

Separation and Purification of Dodecanedioic Acid from Its Homologous Compounds by Falling Film Crystallization

Separation and purification of dodecanedioic acid (DDDA) from its homologous compounds were studied experimentally by falling film crystallization (FFC). The influences of various operation parameters, including crystallizing time, flow rate of melt and temperature of glycerine bath, on purity of DDDA and crystallizing rate were investigated. Over 99% (by mole) DDDA was obtained for a feed composition of 96% (by mole). The main factors affecting the separation efficiency are flow rate of melt and temperature of glycerine bath. The crystallizing layer of DDDA was further purified by sweating and blasting. A set of optimized operation data are provided for better understanding the mechanism of heat and mass transfer in FFC, and for further industrial application of DDDA purification process.

High-performance SSZ-13 membranes prepared using ball-milled nanosized seeds for carbon dioxide and nitrogen separations from methane

SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis.Separation performances of SSZ-13 membranes in CO2/CH4 and N2/CH4 mixtures were enhanced after synthesis modification.Single-gas permeances of CO2,N2 and CH4 and ideal selectivities were recorded through SSZ-13 membranes.The effects of temperature,pressure,feed flow rate and humidity on separation performance of the membranes were discussed.Three membranes prepared after synthesis modifications had an average CO2 permeance of 1.16×10-6 mol·(m2·s·Pa)-1(equal to 3554 GPU)with an average CO2/CH4 selectivity of 213 in a 50 vol%/50 vol%CO2/CH4 mixture.It suggests that membrane synthesis has a good reproducible.The membrane also displayed a N2 permeance of 1.07×10-7 mol·(m2·s·Pa)-1(equal to 320 GPU)with a N2/CH4 selectivity of 13 for a 50 vol%/50 vol%N2/CH4 mixture.SSZ-13 membrane displayed stable and good separation performance in the wet CO2/CH4 mixture for a long test period over 100 h at 348 K.The current SSZ-13 membranes show great potentials for the simultaneous removals of CO2 and N2 in natural gas purification as a facile process suitable for industrial application.

Separation and Purification of Tobacco Peroxidase I from Nicotiana Tobaccum

A new isoenzyme of tobacco peroxidase(TOP) I was purified from tobacco (K326) by using acetone powder, ammonium sulfate precipitation and column chromatography on DEAF-52 cellulose, Sephadex G-75 and DEAE-Sephadex A-50. It is an iron-protein containing haemachrome, whose molecular weight is 21888.5 and the isoelectric point is 3.5. The optimum pH value and temperature of this enzyme is 6.0 and 45℃ respectively. The enzyme is stable in the pH range from 3.0 to 10.0 and has a favorable thermostability.

Applications of metal–organic frameworks for green energy and environment: New advances in adsorptive gas separation, storage and removal

The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.

Review of Alloy Membranes/Films for Hydrogen Separation or Purification

Hydrogen separation and purification are two important chemical processes in the extensive application of hydrogen energy. Membrane technology has opened up a potential solution to the problems of separation and purification in an energy effective way. Membranes of adequate hydrogen permeability, good thermal and mechanical stability are the key to successful application of membrane technology in hydrogen separation and purification. In this paper, the relative parameters concerning hydrogen permeability, the development of different types of membranes namely: palladium composite membranes; V-based alloy membranes, specific functionality embraced alloy membranes, metal hydride (MH) thin films and fabrications, were reviewed and discussed. Pd-free membranes are found to be the ideal alternatives. Suitable MH thin films with mono- or multi-layer microstructures produced by novel fabrication techniques, is likely to be the promising candidates due to possessing properties distinct from those of bulk materials in membrane form.

Study on Preparation and Separation of SIC Whiskerand Particle from Rice Hulls

The growth mechanism of paramorphic SiC whisker (SiCw) and SiC particle (SiCp) produced from rice bulls under the catalytic actions is studied. The results indicate that the growtb mechanism of the SiCw is vapour-liquid-solid (VLS) , while the crystalline structure of the SiCw is β-SiC. Some SiCp will be formed during the production of the SiCw. Under the pilot-plant condition, the grade of SiCw is over 20%, and SiCp is over 50%. The micron-grade of SiCw and SiCp are separated successfully by flotation and other traditional mineral separation and purification technology. So the grade of the high purity SiCw is over 95 %.

KAOLIN CLAY PURIFICATION BY DRY HIGH GRADIENT MAGNETIC SEPARATION

A new method-dry High Gradient Magnetic Separation （HGMS）-to remove iron from ultrafine kaolin powder is described. A new kind of disperser, which breaks down the particle clusters in the powder by high speed gas flow from an air compressor, is used to completely disperse the powders. The dispersed particles are passed through vibrating HGMS by a vacuum pump to remove the iron. The magnetic and nonmagnetic fractions are separately collected by cloth collectors. Dry HGMS laboratory experiments are carried out. A product containing 0.90％ Fe2O3 was obtained, and the recovery was 70％.

One-step ethylene separation from ternary C_(2) hydrocarbon mixture with a robust zirconium metal-organic framework

One-step separation of high-purity ethylene(C_(2)H_(4))from C_(2) hydrocarbon mixture is critical but challenging because of the very similar molecular sizes and physical properties of C_(2)H_(4),ethane(C_(2)H_(6)),and acetylene(C_(2)H_(2)).Herein,we report a robust zirconium metal-organic framework(MOF)Zr-TCA(H3TCA=4,4',4"-tricarboxytriphenylamine)with suitable pore size(0.6 nm×0.7 nm)and pore environment for direct C_(2)H_(4) purification from C_(2)H_(4)/C_(2)H_(2)/C_(2)H_(6) gas-mixture.Computational studies indicate that the abundant oxygen atoms and non-polar phenyl rings created favorable pore environments for the preferential binding of C_(2)H_(2) and C_(2)H_(6) over C_(2)H_(4).As a result,Zr-TCA exhibits not only high C_(2)H_(6)(2.28 mmol·g^(-1))and C_(2)H_(2)(2.78 mmol·g^(-1))adsorption capacity but also excellent C_(2)H_(6)/C_(2)H_(4)(2.72)and C_(2)H_(2)/C_(2)H_(4)(5.64)selectivity,surpassing most of one-step C_(2)H_(4) purification MOF materials.Dynamic breakthrough experiments confirm that Zr-TCA can produce high-purity C_(2)H_(4)(>99.9%)from a ternary gas mixture(1/9/90 C_(2)H_(2)/C_(2)H_(6)/C_(2)H_(4))in a single step with a high C_(2)H_(4) productivity of 5.61 L·kg^(-1).

The facile method developed for preparing polyvinylidene fluoride plasma separation membrane via macromolecular interaction

The design of membrane pore is critical for membrane preparation. Polyvinylidene fluoride(PVDF) membrane exhibits outstanding properties in the water-treatment field. However, it is a huge challenge to prepare PVDF macro-pore plasma separation membrane by non-solvent induced phase separation(NIPS). Herein, a facile strategy is proposed to prepare PVDF macro-pore plasma separation membrane via macromolecular interaction. ATR-FTIR and ^(1)H NMR showed that the intermolecular interaction existed between polyethylene oxide(PEO) and polyvinylpyrrolidone(PVP). It could significantly affect the PVDF macro-pore membrane structure. The maximum pore of the PVDF membrane could be effectively adjusted from small-pore/medium-pore to macro-pore by changing the molecular weight of PEO. The PVDF macro-pore membrane was obtained successfully when PEO-200 k existed with PVP. It exhibited higher plasma separation properties than the currently used plasma separation membrane.Moreover, it had excellent hemocompatibility due to the similar plasma effect, hemolysis, prothrombin time, blood effect and complement C_(3a) effect with the current utilized plasma separation membrane,implying its great potential application. The proposed facile strategy in this work provides a new method to prepare PVDF macro-pore plasma separation membrane by NIPS.

Study on Optimizing High-Gradient Magnetic Separation—Part 1: Improvement of Magnetic Particle Retention Based on CFD Simulations

The introduction of functionalized magnetizable particles for the purification of enzymes or for the multi-use of pre-immobilized biocatalysts offers a great potential for time and cost savings in biotechnological process design. The selective separation of the magnetizable particles is performed for example by a high-gradient magnetic separator. In this study FEM and CFD simulations of the magnetic field and the fluid flow field within a filter chamber of a magnetic separator were carried out, to find an optimal separator design. The motion of virtual magnetizable particles was calculated with a one-way coupled Lagrangian approach in order to test many geometric and parametric variations in reduced time. It was found that a flow homogenisator smoothed the fluid flow, so that the linear velocity became nearly equal over the cross section in the direction of flow. Furthermore the retention of magnetizable particles increases with a high total edge length within the filter matrix.

Experiments and model development of p-nitrochlorobenzene and naphthalene purification in a continuous tower melting crystallizer

With the increasing demand for high-purity products,the industrial application of melt crystallization technology has been highly concerned.In this study,the purification process of nitrochlorobenzene binary eutectic system(NBES)and naphthalene–benzothiophene solid solution system(NBSSS)in tower melting crystallizer is analyzed,and a mathematical model of crystallization process is established.The key parameters in terms of feed concentration,crystal bed height,reflux ratio and stirring speed effi-ciency on purification effects were discussed by the established model.The results show that the concentration of p-nitrochlorobenzene was purified from 90.85%to 99.99%,when the crystal bed height is 600 mm,the reflux ratio is 2.5,and the stirring speed is 12 rmin^(-1).The naphthalene concentration is purified from 95.89%to 99.99%,when the crystal bed height is 400 mm,the reflux ratio is 1.43,and the stirring speed is 16 rmin^(-1).The quality of the model is evaluated by the ARD(average relative deviation).The minimum ARD values of the NBES and NBSSS are 2.39%and 5.22%,respectively,indicating the model satisfactorily explains the purification process.

Bioinspired and biomimetic membranes for water purification and chemical separation: A review

Bioinspired and biomimetic membranes that contain biological transport channels or attain their structural designs from biological systems have been through a remarkable development over the last two decades.They take advantage of the exceptional transport properties of those channels,thus possess both high permeability and selectivity,and have emerged as a promising solution to existing membranes.Since the discovery of biological water channel proteins aquaporins(AQPs),extensive efforts have been made to utilize them to make separation membranes–AQP-based membranes,which have been commercialized.The exploration of AQPs’unique structures and transport properties has resulted in the evolution of biomimetic separation materials from protein-based to artificial channelbased membranes.However,large-scale,defect-free biomimetic membranes are not available yet.This paper reviews the state-of-the-art biomimetic membranes and summarizes the latest research progress,platform,and methodology.Then it critically discusses the potential routes of this emerging area toward scalable applications.We conclude that an appropriate combination of bioinspired concepts and molecular engineering with mature polymer industry may lead to scalable polymeric membranes with intrinsic selective channels,which will gain the merit of both desired selectivity and scalability.