Abstracts from the science and technology of membrane separation

Desalznatzon, 69 (1988) 183-192 Elsevler Science Publishers B V , Amsterdam

183 -

Prmted

m The Netherlands

Abstracts from the Science and Technology of Membrane Separation (Quarterly Journal m Chmese ) Edited and published by the Edltorlal Department of Membrane Separation Science and Technology, Editor Yuan Al-ping, No. 142 Duan-Jla-tan, Lanzhou, Institute of Membrane Science and Technology, Gansu Provmce, Chma Vol 6, No 4, December 1986

TREATMENT

OF PVA DESIZING

Wang Jmgrong,

Zhang Donghua, Wu Guangxla, Feng Baohe, Guo Xledl, Lm Fuhang and Xu

Shuguang

(Institute

of Environmental

EFFLUENT Chemistry,

BY ULTRAFILTRATION,

Lm Tmghul,

Chmese Academy of Sciences, P 0 Box 934,

Beipng, China )

Sizing agents are used m the textile mdustry to Improve the physlcal properties of warp With the increase m the use of synthetic and cotton-synthetic fabrics, the traditional warp slzmg agents such as starch, etc have been replaced by synthetic matenals hke polyvmyl alcohol (PVA) and sodium carboxymethyl cellulose (CMC) Deslzmg effluent 1s largely composed of slzmg agents, which are non-biodegradable They are major contnbutors to the total ml11 effluent and pose a serious pollution problem In this paper, extensive laboratory and field tests on the treatment of PVA deslzmg solution by ultrafiltration are described Polysulfone hollow fibers of 10 mm diameter were used From laboratory experiments on the treatment of PVA solution, It IS known that the water flux decreases with increasing feed concentration, but the retenkon remams constant, mcreasmg the feed solution velocity can reduce concentration polarlzatlon and enhance the membrane flux, the membrane flux mcreases with mcrease m operating pressure, and feed temperature 1s an important influence on membrane flux On the basis of earlier laboratory expenments, a larger-scale laboratory experiment was carried out, m which deslzed PVA wastewater taken from a printing and dyeing ml11 was treated The deslzmg effluent typlcally contained 1% PVA by weight The hollow fiber module used had a membrane area of 1 1 m2 and was 85 cm long It was found that the pretreatment of the PVA effluent before ultraflltratlon was very important Followmg this experiment, field tests were carried out usmg an ultrafiltration system conslstmg of 5 hollow fiber modules (10 cm diameter, 90 cm long) The membrane area was 28 26 m2 The UF membranes were protected agamst particles by a two-phase prefiltratlon scheme The feed temperature was kept at 70’ C, the operatmg pressure at the mlet was 10 kg/cm’ and at the outlet 0 8 km/cm* At a feed concentration of lo-15 g/l, the ultrafiltratlon permeate concentration was 0 2-O 6 g/l The membrane was cleaned every day with tap water at 80°C for lo-15 mm The polysulfone hollow fiber system proved Itself technologically feasible for the recovery of textile warp size (PVA) The membrane retention of PVA was over 95% When the feed temperature was 70” C and the operating pressure 1 kg/cm*, the membrane flux was 2-4 l/m2 h and the recovery of PVA was over 90% It 1s now necessary to study how the concentrate PVA solution can be reused, how to optimize operating condltlons and how best to clean the membrane

184 EFFECT

OF HEAT-TREATMENT

OF CELLULOSE Kangmm,

ACETATE

AND DRY CONDITIONS

REVERSE

OSMOSIS

Chen Ylmmg and Cal Bangxla

Oceanographic

Admmlstratlon,

ON THE PERFORMANCE

MEMBRANE,

(Second Institute

Lm Yurong, Lang

of Oceanography,

The State

Hang Zhou)

This paper descmbes the effect on membrane performance of some factors of the post-treatment, such as the temperature and duration of thermal treatment, the concentration of plastlclzer or surfactant and the nature of the drymg atmosphere For a gwen composltlon of the casting solution, the final pore structure and reverse osmosis performance of the membrane can be Improved by changmg the temperatures of heat-treatment and drymg The effects of the above two temperature changes can be simulated by using a smaller amount of plastlclzer or surfactant and varying atmosphenc condltlons during post-treatment, without actually changmg the two temperatures It was found that the temperature of the heattreatment could be lowered by 5-18°C and the duration of the post-treatment could also be shortened, wlthout affecting membrane performance When the membrane cast by machme m the selected condltlons was fitted mto a splralwound element to treat 300-500 ppm tap water, the reJectIon exceeded 90% The membrane IS effective for concentrating some dilute solutions of medicine and food The apphcatlon of surfactant not only saves power, but also creates the conditions for contmuously producing dry reverse osmosis membrane DEVELOPMENT SULFONE

OF A LOW-PRESSURE

MODULE

HOLLOW FIBER COMPOSITE

OF ORGANOSILICON-POLY-

MEMBRANE

FOR OXYGEN ENRICHMENT,

Yang Qlhan, Cal Xuegong, Yu Jmgh, Dong Lquan, Bal Yl, Wu Guohang, Wang Wenzhen, Jmgul and Chen Jlang (Gansu Institute

of Membrane

SI

Science and Technology)

A hollow fiber module of organoslhcon-polysulfone composite membrane for obtammg oxygenenriched air was developed The module can produce oxygen-enriched air containing 25-28% O2 from an with a single pass The product rate 1s 2 5 l/m’*h at an operatmg pressure of 0 l-l 3 kg/ cm* THE PREPARATION

OF ULTRATHIN

A BLEND OF METHYL

SILICONE

OXYGEN-ENRICHMENT

RUBBER

MEMBRANES

WITH

AND POLY (4-METHYLPENTENE-l),

Zhang Keda, Lu Nanan and Xu Jlpmg (Changchun

Institute

of Apphed Chemistry,

Academia

Simca) Ultrathin oxygen-ennchment membranes were prepared by solution casting method on a porous PP support (Durard 2400) with methyl slhcone rubber (MSR) , poly (4-methylpentene-l ) (TPX) , and a mixture of the two The oxygen-enrichment performance of the composite membranes was then compared The results for a blend of MSR and TPX were better than those for MSR or TPX alone or a comblnation of them The best result, Jo2 = l-l 8 X 10e4, (YO,/Nz= 2 0, was obtamed at an MSR TPX ratio of 1 3 1 0 THE OXYGEN AND NITROGEN MEMBRANES

PERMEABILITIES

OF VARIOUS THICKNESSES,

and Chen Guanwen

(Institute

The oxygen and mtrogen

of Chemistry,

permeablhtles

OF POLY-4-METHYLPENTENE-1

Zhang Shlmm, Sun Qlushl, Hou Xlaohual

Academia Smlca, Belling)

of homogeneous

packed planar membranes

of poly-l-

185 methylpentene-1 (PMP) were studled at different temperatures and for dfierent thicknesses ( 17, l&45,60 and 84 p) by means of a low-pressure vacuum method It was found that at any gwen temperature the PO* and PNP values of membranes thinner than 20 jnn were higher than those of membranes thicker than 45 pm, but the (Y0,/N, values were low, above 45 pm, the PO*, PNP and (YOz/Nz values tended to be about the same

ANTITHROMBOGENIC GRAFTING

DIALYSIS

MEMBRANES

OF /9-HYDROXYETHYL

FILM, Fang Yue-e and Shl Tmnyl (Department and Technology

I STUDY OF RADIATION

METHACRYLATE

ONTO POLYETHYLENE

of Applied Chemistry,

Urnverslty

of Science

of China, Hefel, Anhul, China)

We have prepared polyethylene dialysis membranes by Irradiating the polymer with 6oCo y-rays m the presence of B-hydroxyethyl methacrylate m the grafting solution The influence of different doses on the degree of grafting and water uptake ( % ) was observed The morphology and structure of the grafted membrane were observed by SEM and IR, respectively The grafted membrane was then tested m dialysis expenmenta The dmlysls results indicate that the permeation coefficient of urea through 30% graft membrane 1s about 24 times higher than that of ungrafted polyethylene membrane

STEPWISE ASSISTED

REGRESSION DESIGN,

METHOD

IN MEMBRANE

PREPARATION

- COMPUTER-

Guo Yunlau, Hn JiaJun and Bal Yufeng (Beipng Polytechnic

Umverslty,

East Suburb, Beijing, China)

Within the framework of computer-assisted design (CAD), a more effective stepwlse regression method IS discussed m this paper and we look at its apphcatlon m the membrane preparation process The FORTRAN program used to sift through the mam factors affecting membrane properties 1s also ducussed, after which we show how a membrane system such as polysulfone can be computerized Two cases are presented m which we investigated whether or not the Mutual Action of every element can be neglected Finally, we establish two regression equations for each case The results show that Mutual Action cannot be omitted The conclusions of this paper agree with S SourlraJan’s findings

EXTRACTION

OF ZINC IN AN OLDSHUE-RUDSTON

SURFACTANT

MEMBRANES,

(Institute

COLUMN BY LIQUID

Wang Shlzhu, Ma Nlancl, Jlang Changym and Yu Jlanhan

of Nuclear Energy Technology,

Qmghua Umverslty)

The results of extracting zmc by hquld surfactant membranes from synthetic solutions and mdustrlal wastewater are presented The results of contmuous extraction show that the zmc concentration m feed solution can be reduced from 200 ppm to less than 5 ppm and the zmc concentration m the internal phase IS more than 20 g/l Content of hydrocarbon m the raffinate IS less than 7 5 ppm, which m less than the discharge standard Electrostatic coalescence 1s an effective method for breaking the emulsion The 011phase can be reused for preparmg emulsion Laboratory-scale expenments demonstrated that the use of liquid surfactant membranes 1s an efficient new technique for recovenng zmc from dilute mdustnal wastewater

186 THE PREPARATION MEMBRANE, Synthetic

AND PROPERTIES

OF HOMOGENEOUS

Sa Ymgfu, Xu Guoqm and Hau Shuhong

CATION-EXCHANGE

(The Shanghai

Research Institute

of

Resin)

Homogeneous cation-exchange membrane prepared from copolymer of styrene, dlvmylbenzene and other compounds, with glass fibre cloth as reinforcer, was used to produce base membrane by the coatmg method It was treated with sulfomc acid to make it a catlon-exchange membrane, and reinforced with glass fibre cloth to improve its dimensional stablhty, make it less brittle and mcrease its burst strength, ao that it would be suitable for mdustruil use The charactenstlcs of the homogeneous cation-exchange membranes were as follows capacity 1 8 mequlv/g dry resin, electrical resistance ~6 cm 2, burst strength 36 kg/cm’, transference number > 0 91, and thickness > 0 4 mm This membrane has several marked advantages better electrochemical properties and burst strength, a simple production process and lower cost The mam characterlstlcs of homogeneous catlon-exchange membrane are slmllar to those of membranes already on the Japanese market, such as selemlon CMV (Asakl Glass Co ), Aclplex KlOl (Asahl Chemical Industry Co ) or Neosepta CH-45T (Tokyyama Soda Co ) It 1s especially clear from the results of the experiments with a three-compartment electrodlalyzer that all homogeneous cation-exchange membranes have high current densities and good desahnatmg propertles All the membranes studied have a similar pore size dlstrlbutlon, apparent from SEM observation of the microstructure of the membrane surface and cross-sectlon The membrane composltlon was also mvestlgated by looking at the functional sulfomc group dlstrlbutlon m infrared spectra

Vol 7, No. 1, March 1987

THE PERMEABILITY MEMBRANE Umverslty,

OF LIQUID CRYSTAL

(EBBA)/POLYMER

FOR 02, Qlao LlJun and Wang Llangyu (Department

(PVC) COMPOSITE of Chemistry,

Qmghua

Belling)

The addition of an amount of hquld crystallme material to a polymer solution can greatly improve the permeability of polymer membrane for gases The study of the permeation of 0, through PVC/ EBBA composite membrane shows that when It 1s above the phase-transltlon temperature TKN of EBBA, the composite membrane acts as a hquld crystal membrane, the change m the permeation mechamsm and the Improvement m membrane permeablhty both depend upon the vlscoslty, expanslblhty and polanzablhty of the liquid crystal The function of the hquld crystal 1s the formation of liquid crystal domains m the composite membrane

THE MORPHOLOGY

OF POLY (4-METHYL-l-PENTENE)

Chengfen, Fu Changlun and Chen Guanwen

(Institute

MEMBRANES,

of Chemistry,

Long

Academia China, Beijing)

The morpholomcal structure of poly(4-methyl-pentene-1) membranes prepared by different methods was observed by TEM and SEM It 1s shown that spheruhtes and mlcrocrystals are produced m the membrane by castmg and spreading on the surface of water, respectively On the other hand, a global, network structure IS found m membranes prepared by plasma polymerlzatlon of 4-methyl-pentene-1 monomer on porous polypropylene film and tracing paper substrate

187 THE EFFECT

OF MEMBRANE-FORMING

GAS-SEPARATION

MEMBRANE,

Guodong (Institute

CONDITIONS

Zhao Xlaoguang,

of Applied Chemistry,

ON THE MORPHOLOGY

OF

Yu JleJuen, Zhuo EnJe, LIU LI and Zhen

Chang Chun)

Using transmlsslon electron microscopy (TEM) we studied the morphology of ultra-thin membrane made of poly(4-ethyl-pentene) and its modified polymer (formed on the surface of the water) with a view to determining the relationship between the composltlon and temperature of the membrane-forming medium and the structure and thickness of the membrane We determined the optimum condltlons for forming the membrane and produced a smooth, pore-free membrane with a thickness of about 570-480 A THE APPLICATION PERMEABILITY

OF A COMPUTER

OF MEMBRANES

Huang Liming, Chen Shanmel, Lanzhou Institute

TO THE MEASUREMENT

OF THE GAS

USING THE VACUUM-PRESSURE

Hua Man and LI Xmmel

(Department

of Chemical Physics, Chinese Academy of Sciences),

Zhaorul (Computer

Department,

Lanzhou Institute

METHOD,

of Synthetic

Membrane,

Zhang Xlxlan and Lm

of Chemical Physics, Chmese Academy of

Sciences) To reduce error m the measurement of the gas permeability of membranes using the vacuumpressure method, a system controlled by microcomputer was developed The mlcrocomputer, which includes an lsolatmg clrcult and an A/D converter, performs data collectmg and processing Durmg the expenments, the computer collected samples for every time umt, selected channels and converted the measurmg range automatically A smooth permeability curve 1s obtained after fittmg the curve by the least squares method As a result, the coefficients P, D and S can be more accurately and reliably calculated TESTING STABILITY Technology,

A POLYIMIDE IN ORGANIC

ULTRAFILTRATION SOLVENTS,

MEMBRANE

FOR CHEMICAL

Dong Bo (The Research Office of Water Treatment

Lanzhou Railway Institute)

In this paper, a method for preparing poly(methylene-4,4’-dlphenylene pyromelhtlmlde) ultrafiltration membrane 1s introduced Thirty kinds of orgamc solvents were chosen according to the difference m their solublhty parameter (6)) to test the chemical stablhty of the membrane The membrane was left m these solvents for about 200 h, and was found to possess excellent chemical stablhty, and to be suitable for use m the separation of vanous organic solutions CHARACTERISTICS

AND APPLICATIONS

OF NUCLEOPORE

Changlm, L1 Changlm, L1 Changxl and Jla Chengzhang

(Southwest

MEMBRANE, Institute

Xlang

of Nuclear

Physics and Chemistry) The properties of nucleopore track-etch membrane made of polycarbonate and polyester are bnefly described m this article When compared with tradltlonal membranes, the new membrane exhibits better propertles, mcludmg sharply defined pore size and shape, a very smooth surface, high flow rates, supenor mechanical strength while remaining soft and flexible, excellent physical and chemical stablhty, etc Also, the membrane 1s highly compatible blologlcally, contammg as It does low contents of trace elements, and undergomg no mass migration For these reasons It IS becommg widely used m various fields

188 A GRAFT-MODIFIED EFFECT

HOLLOW

OF STYRENE

AND MEMBRANE Hulxm (Institute

FIBER MEMBRANE

CONTENT

PERFORMANCE, of Membrane

OF CELLULOSE

AND ACID MEDIUM

ACETATE

ON GRAFTING

-

QUANTITIES

Yan Wener, Yang Puchen, Zhang XmJmg and Zhang

Separation

Engmeermg,

TlanJmg College of Textile

Technology) The effect of acid medium on graft-modified hollow fiber membrane of cellulose acetate was studled In acid medium, a grafting degree of 18 3% can be reached with styrene, and the rejection can be up to 92 4% (for tap water at a pressure of 10 kg/cm’ ) , which IS much higher than the mltlal reJection (80 8% ) and IS also higher than the reJectlon of heat-shrunken membrane (90 2% ) The flux (0 0418 X 10-3/cm2*s) 1s higher than that of heat-shrunken cellulose membrane (0 0346 X 10e3 cm3.s), but 1s lower than the mltlal flux (0 1750x 10e3 cm3/cm2.s) This 1s mainly the result of the “solvent effect”, and to a lesser extent the “grafting effect” Acid 1s favorable for mduced shortgraftmg and lmprovmg RO desaltmg of graft membrane Meanwhile, m the same kmd of medium, membrane reJectIon increased with grafting degree increase, but the water flux decreased slightly The experimental results on the effect of pressure on membrane performance show that the RO performance of the membrane IS Improved by grafting

DEVELOPMENT

OF SILVER - SILVER CHLORIDE

CONCENTRATION Institute

POLARIZATION

of Light Industry)

IN REVERSE

ELECTRODES OSMOSIS,

and Chen Yeqm (Begmg Polytechnic

FOR MEASURING

Wang Lml (Belling Umverslty)

This paper starts with the first and second laws of thermodynamics and uses the chemical potential concepts to derive the theoretical relatlonshlp between concentration and electromotive force This relation 1s the theoretical basis for Ag-AgCl electrodes measunng electromotive force m salt solutions of different concentrations The procedure and the techniques used m the development of Ag-AgCl electrodes are described The experimental results are m good agreement with the theoretical values

COMPUTER

SIMULATION

Chao Xmmmg

OF PERVAPORATION

and Zhu Changlue

(Department

IN CAPILLARY

of Chemical Engmeermg,

PERMEATORS, ZheJlang Unmerslty)

In this paper a mathematical model 1s developed for pervaporatlon m capdlary permeators, and the model, expressed m terms of a set of algebraic and ordmary dlfferentlal equations, 1s subjected to various kmds of numerical methods Some suitable methods and algonthms were finally developed and employed m numerical slmulatlon The results of the numerical slmulatlon reveal some useful charactenstlcs of pervaporatlon m capdlary permeators

SEPARATION BY MEMBRANE Wen Jlanbo

AND CONCENTRATION DISTILLATION,

(Gansu Institute

OF NaCl and Na2S0, FROM NATURAL

Wang Ymg, Wang Jmxl, Xu Xuezhen,

of Membrane

BRINE

Zhang Yahul and

Science and Technology)

Natural brme contams a great deal of NaCl and Na2S04 which can be crystahzatlon from the solution usmg a membrane dlstllatlon process m this paper, usmg natural brme as feedwater, were carned out at Province Salt rejection was 95 1% for NaCl and 98 8% for Na2S0,

separated by concentratlonThe expenments described the Chemical Plant, Hubel when usmg capillary mem-

189 brane of polyvmyhdene fluonde The productlvlty of the module was 125-140 l/d-m2 The membrane showed good chemical stablhty and anti-fouhng qualities after 500 h of operation

Vol. 7, No. 3, September 1987 BASIC ASPECTS

AND APPLICATIONS

Xu Yongfu (Department

OF PERVAPORATION,

of Chemical Engmeermg,

I BASIC RESEARCH,

Qmghua Unmerslty,

BelJmg)

Pervaporatlon 1s a membrane separation technology developed recently which gwes a high sepaThe separation mechanism, the mathematical model and the ration factor and 1s easy to operate most important factors affecting separation are fully discussed THE DESIGN URANIUM

AND OPERATION

REMOVAL

OF A WATERSUPPLY

STATION

USING RO FOR

IN AKSAI COUNTY, Cal Tamyu, Ma Douhng, Kang Zhongru, Gao

Hm, Chang Llh, Lu Ylpmg and Wang Ymg (Institute

of Membrane

Science and Technology,

Gansu Province) The membrane equipment and pretreatment system which has been used to produce 60 m3 of water per day for more than a year was examined The system IS set up m Aksal County (Western Gansu Province ) and uses RO for uramum removal and the desahnatlon of bltt.em/bracklsh water contammg uramum The results show that the RO equipment 1s producing drmkmg water which satisfies the quality requirements of the local people COMPARATIVE

MECHANICAL

CONFIGURATIONS CONVERTER,

EFFICIENCY

S Loeb (Negev Department

Israel), T Honda (Energy Conversion Japan)

OF SEVERAL

USING A PRESSURE-RETARDED

of Chemical Engmeermg,

Section, Electrotechmcal

and M Real1 (ENEL-DSR-CRIS,

PLANT

OSMOSIS

ENERGY Ben Gunon Umverslty,

Laboratory,

Via Omato, 90/14,20162

l-l-4 Umezono,

Mllano, Italy)

The mechamcal efficlencles of several plant conflguratlons utlhzmg a pressure-retarded osmosis (PRO ) energy converter are compared on the basis of data obtamed by Honda for a reasonably sized PRO module with hollow fibers suitable for PRO use These data were obtamed with a 3 5% NaCl solution, 1 e one fairly close to water The comparison suggests that the aboveground contmuous flow PRO plant will be too mefficlent to be of any use, while the much more efficient underground contmuous flow PRO plant would require that most of the equipment be located m an underground cavern at about 90 m below sea level The aboveground altematmg flow PRO plant 1s extremely efficient but requires the use of two pressure vessels m addltlon to the usual PRO eqmpment PREPARATION FOR TREATING

OF A HAND-OPERATED BITTERN/BRACKISH

Zhou Zhengguo (Gansu Institute

DB-I TYPE SPIRAL-WOUND

RO DESALTER

WATER, Jm Taogen, Yang Q&an, Wang Ymg and

of Membrane

Science and Technology)

The hand-operated DB-I spiral-wound RO desalter for treatmg blttern/bracklsh water was developed m 1984 This piece of eqmpment was a breakthrough m our country, bemg small m volume, hght m weight, simple m structure, and easy to operate Laboratory and field tests carried

190 out during contmuous operation for 300 h showed that It meets the required performance standards Under an operatmg pressure of 20 kg/cm’, it gwes a rejection of 80% and can treat 5-6 l/h of bittern/brackish water with a salt content of 3-5 g/l A STUDY OF THE ION-EXCHANGE ETHANOL-WATER of Industrial

MIXTURES,

Chemistry,

MEMBRANES Qlan Jmtang

USED FOR THE SEPARATION

and Wang Honghang

OF

(Chen Guang Institute

Chen Du)

In this paper, the performance of three Ion-exchange membranes based on polyethylene film for the separation of ethanol-water mixture by pervaporatlon 1s presented and evaluated The separation factor and permeablhty were determined for each membrane and the results show that the quaternary ammonmm ion-exchange membrane of ahphatlc compound gave the best performance, when the feed concentration of ethanol was 80%, the permeation flux was 700 g/m’*h and the separation factor was 20 for the D-type membrane Methods for calculatmg the membrane area needed for contmuous pervaporatlon separation and the subsequent recovery rates on the basis of these results are also described THIN-FILM ENERGY

HIGH MOLECULAR

INTO MECHANICAL

Petrochemical

Technology,

POLYMERS ENERGY,

FOR THE CONVERSION

Zhou Zhongqmg

(Shanghai

OF CHEMICAL

College of

Shanghai)

In this paper, the use of thin-film high molecular polymers as deformable function-material or deformable memory-material m converting chemical energy mto mechanical energy IS discussed, the basic prmclples, clasaflcatlon, apphcatlons and prospects for development are presented

Vol 7, No 4, December BASIC ASPECTS MEMBRANE University,

1987

AND APPLICATIONS

MATERIALS,

OF PERVAPORATION

Xu Yongfu (Department

II SELECTION

of Chemical Engmeenng,

OF

Qmghua

Beijing)

This paper, the second part of a comprehensive review of pervaporatlon, focuses on the selection of the membrane material The mass transfer separation mechamsm of pervaporatlon requires that membranes are dense The effects of prlorlty sorption and selective permeation on pervaporatlon, and the couphng effect are discussed The slgmflcance of the solublhty parameter m the choice of membrane matenal IS also considered Finally, the balance theory on the hydrophlhc/ hydrophobic nature of selected membrane materials 1s introduced, and the four ways of measuring pervaporatlon characterlstlcs are pointed out A STUDY OF CHITOSAN Textile Technology,

Institute

RO MEMBRANE, of Membrane

Ll Xm and Yang Puchen

Separation

(Tlan Jm College of

Engmeermg)

Chltosan RO membrane was fabricated by spreading solutions of chltosan m acetlc acid on a polysulphone porous membrane In Its alkali resistance and pressure realstance the CS membrane IS supenor to the CA membrane By solution of 2,4-dnsocyanotoluene crosshnked membrane m n-hexane, its durablhty and acid resistance can be Improved

191 THE PREPARATION COUPLING

OF IMMOBILIZED

ON CHLOROMETHYLATED

Guo Zhenyou

(Institute

of Membrane

GLUCOAMYLASE

BY AMINATING-

POLYSULPHONE

Separation

Engmeermg,

MEMBRANE, Tlanpn

Institute

Du Qlyun and of Textile

Science and Technology) This paper describes a method for preparmg lmmoblhzed glucoamylase by ammatmg-couphng on CPS The effect of certain factors on the ammatmg and the couphng were mvestlgated, these include the membrane material charactenstlcs, the capacity of the ammatmg agent, ammatmg temperature, ammatmg time, pH of the crude glucoamylase solution, coupling temperature, coupling time and enzyme solution concentration The results indicate that the ammatmg and coupling reaction IS very straightforward The relative actlvlty of the lmmoblhzed enzyme 1s 2 x lo4 U/m2 This activity did not change when the enzyme was stored m a buffer of cltnc acid at pH 4 5 for 14 days at 5°C In the case of contmuous saccharlficatlon of 30% hquefled starch at pH 4 5 at 55”C, the enzyme half-life IS 24 days

THE PREPARATION METHOD, Technology,

OF LIPOSOME

Tu Pmguan,

USING THE REVERSE

Ma Hong and Zhen Changxle

Qmhua Unmeraty,

(Department

PHASE EVAPORATION of Biology Science and

Beijing)

This paper describes m detail the experimental condltlons for the preparation of hposome using the reverse phase evaporation method Usmg natural phosphohplds as basic material, expenments and measurements were carried out to determine the mfluence of various elements and the conditions most suitable for hposome encapsulating The method presented 1s easy to use and extremely efficient As well as encapsulatmg various drugs, hposome can encapsulate RNA and other genetic mater& and IS of slgmficant value for practical apphcatlons

DYNAMIC

FILTRATION

NUCLEOPORE Engmeermg

AND CLASSIFICATION

MEMBRANE,

Department,

OF BENTONITE

WITH

Zhao Zong Al, Xlang A1 Ymg and Jm Ding-wu (Chemical

Tianpn Umverslty )

Sodium bentomte 1s of great practical value m metallurgy, castmg and drllhng Raw bentomte can be broken mto a very fine powder with particles smaller than 2 5 pm If the finer part (for example, particle diameter less than 1 or 2 pm) of the powder IS separated further, many kinds of hlghquahty grade chemical matenals can be obtained To classify such a fme powder, a screen-like precision filter medium 1s needed, nucleopore membrane IS Just such a medium Its mlcropore structure means that it acts as a high-selectlvlty filter of great accuracy The tests were carned out m a rotary filter-press, which permitted the classlflcatlon to be carried out at a high filtermg rate A nucleopore membrane with 5 pm diameter pores was used to separate the fmer particles from the suspension of the bentomte powder, where the average partlcle diameter was 2 1 pm The content of finer particles (particle diameter less than 12 p) mcreased from 27 6% m the feed to 72 7% m the discharge, evmg a classlficatlon efficiency of 62% for fine particles Our expenmental results show that IS possible to class@ bentomte with a nucleopore membrane, and that the operation can be carried out at a high filtering rate and still have a high classlficatlon efficiency

192 RECENT DEVELOPMENTS

IN LIQUID MEMBRANE TECHNOLOGY, Shao Gang

(Central Research Institute of Bmldmg and Construction, Mmlstry of Metallurgy) In this paper, the separation mechamsm of Impregnated liquid membrane and recent developments and apphcatlons of emulsified and impregnated liquid membrane are discussed The apphcations of gas separation and other apphcatlons of impregnated hquld membrane are summarized