ADVANCED MEMBRANE TECHNOLOGY

Ｏｃｔｏｂｅｒ 1 4— 1 9,2 0 0 1　Ｂａｒｇａ (Ｔｕｓｃａｎｙ) ,ＩｔａｌｙＡｂｏｕｔｔｈｉｓｃｏｎｆｅｒｅｎｃｅＴｈｉｓｉｓａｎｅｗｃｏｎｆｅｒｅｎｃｅｏｆｆｅｒｅｄｂｙｔｈｅＵｎｉｔｅｄＥｎｇｉｎｅｅｒｉｎｇＦｏｕｎｄａｔｉｏｎ .Ｍｅｍｂｒａｎｅｔｅｃｈｎｏｌｏｇｙｉｓａｎｉｍｐｏｒｔａｎｔｐａｒｔｏｆｔｈｅｓｅｐａｒａｔｉｏｎｔｅｃｈｎｏｌｏｇｙ .Ｉｔｓｕｓａｇｅｉｎｔｈｅｉｎｄｕｓｔｒｙｉｓｇｒｏｗｉｎｇｄｕｅｔｏｉｔｓｖｅｒｓａｔｉｌｉｔｙａｎｄｌｏｗ -ｅｎｅｒｇｙｃｏｎｓｕｍｐｔｉｏｎ…     

ELECTROSTATIC PSEUDO LIQUID MEMBRANE SEPARATION TECHNOLOGY

Electrostatic pseudo liquid membrane(ESPLIM)separation process,developed recently in this laboratory,is a novel chemical separation technology.ESPLIM is an interdisciplinary technology evolved from thecombination of solvent extraction,liquid membrane and electrostatic techniques.It can be used to separate,purify and concentrate specific solutes from aqueous solutions.Therefore,it is suitable for the recovery ofvaluable metals from aqueous solutions in the field of hydrometallurgy(including nuclear fuel cycles)and forthe processes of waste water treatment.This paper discusses the basic principles of this new technology.Taking the extraction of Co~(2+)by D2EHPA as an example,effects on metal extraction of electrical fieldstrength,extractant concentration and the flow ratio of feed to stripping solution have been studied.Exper-iments show that the once through extraction efficiency of Co~(2+)can reach 99% while Co~(2+)can be concen-trated up to 40—50g/L in the stripping solution.     

CHARACTERIZATION OF MEMBRANE FOULING PROCESS BY ζ-POTENTIAL

<正>对于膜污染机理及其解决方法的研究是膜分离技术研究领域中的一个重点问题.已有的研究主要从膜的材料特性、待分离体系的物化特性及操作方式与条件等3个方面来考察膜污     

MASS TRANSFER IN MEMBRANE ABSORPTIONDESORPTION OF AMMONIA FROM AMMONIA WATER

Hydrophobic membrane can provide fast mass transfer for absorption-desorption of gasesform liquid to absorbent.The removal of ammonia from ammonia water and absorption with dilutesulphuric acid was studied in a pilot plant with polypropylene hollow fiber column,The removalrate and influences of operation temperature,flow rate and concentration on mass transferperformances were discussed mathematically.Experimental results and computer calculation show thatthe ammonia removal rate is not affected by the feed concentration for a given system.Both partialand overall mass transfer coefficients vary along the axis of the fiber,and the mass transfer for themembrane process is controlled by membrane resistance.     

RECOVERY OF PHENOL WITH CYANEX® 923 IN MEMBRANE EXTRACTION-STRIPPING SYSTEMS

The recovery of phenol from aqueous solutions with CYANEX® 923 was studied. Classical dispersive extraction and three membrane extraction-stripping systems (bulk liquid membranes, three-phase hollow fiber contactor and two hollow fiber modules set-up) were used. It was found that CYANEX® 923 was a convenient carrier for recovery of phenol from aqueous streams in extraction-stripping membrane processes. The problem of emulsion formation, so important in dispersive extraction, was avoided. Both mass transfer experiments in different membrane systems and measurement of the dynamic interfacial tension demonstrated importance of the interfacial phenomena occurring in the stripping stage. A blocking of this interface was observed that resulted in a decrease of phenol mass transfer.     

A MATHEMATICAL MODEL FOR OXYGEN TRANSFER IN FLAT PLATE MEMBRANE OXYGENATOR

Mass transfer in a flat plate membrane oxygenator was studied and a convective mass transfer modelfor instantaeous reversible oxygenation of Cassonian fluid was presented. Numerical solution of the model canbe obtained with finite difference method. When a     

ESTERIFICATION COUPLED PERVAPORATION MEMBRANE PROCESS MODELING (Ⅰ) INFLUENCE OF CATALYST SYSTEM

1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｆｏｒｍｅｒｒｅｐｏｒｔ,ｔｈｅｋｉｎｅｔｉｃｍｏｄｅｌｆｏｒａｎｅｓｔｅｒｉｆｉｃａｔｉｏｎ ｐｒｏｃｅｓｓｃｏｕｐｌｅｄｂｙ ｐｅｒｖａｐｏｒａｔｉｏｎｗａｓｅｓｔａｂｌｉｓｈｅｄａｎｄｔｈｅｍｏｄｅｌｉｎｇｒｅｓｕｌｔａｇｒｅｅｄｗｅｌｌｗｉｔｈｔｈｅｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔ[1] .Ｓｔｕｄｙｉｎｇｗｉｔｈｔｈｅｍｏｄｅｌｉｎｇｗｏｒｋｉｓｈｅｌｐｆｕｌｆｏｒｔｈｅｅｃｏｎｏｍｉｃｅｖａｌｕａｔｉｏｎｏｆａｐｒｏｃｅｓｓ ,ｔｈｅｏｐｔｉｍｉｚａｔｉｏｎ…     

STUDY ON THE ELECTROCHEMICAL BEHAVIOR OF ION EXCHANGE MEMBRANE IN PREPARING POTASSIUM CARBONATE

This investigation describes the one step preparation of potassium carbonate by electrolysis of potas-sium chloride solution in electrolyzers with various Nation membranes.Potassium bicarbonate solution wasfed to the cathode compartment,where it was converted into carbonate by reaction with the hydroxideformed at cathode.Because of the low OH~- concentration in the cathode compartment,the back migrationof OH~- through the membrane was almost negligible,resulting in a higher current efficiency,say 90% or more.In this study,electroconductivity,mass transfer,current efficiency and cell voltage were measured.Thefeasibility of the process was discussed and the optimal conditions examined.     

PREPARATION OF FLAT SHEET MICROPOROUS MEMBRANES FROM IPP VIA TIPS FOR MEMBRANE DISTILLATION

Membrane distillation (MD) isenergy saving alternative toa low cost,conventional separation processes such as distillation and reverse osmisis (RO). MD is widely used in the field of desalination, concentration of aqueous solutions,food industry and so on.     

A PRELIMINARY STUDY ON LIQUID MEMBRANE SEPARATION IN ROTATING DISK CONTACTORS WITH PERFORATED DISKS

A rotating disk contactor (RDC) with perforated disks was employed for liquid membrane separation. Hydrodynamic characteristics and rate of mass transfer in the contactor were studied. Experimental results indicated that the rotating perforated disks contributed tremendously to liquid-liquid dispersion as well as to the rate of mass transfer. It is claimed, therefore, that contactors equiped with perforated disks is well adaptable to the continuous processing of liquid membrane separations     

CALCULATION METHOD FOR EVALUATING THE SEPARATION PERFORMANCES OF HOLLOWFIBER MEMBRANE N_2-H_2 SEPARATORS

A mathematical model for evaluating the separation performances of hollow-fiber membrane N_2—H_2 separators has been established. The influences of operating parameters and membrane characteristics on the hydrogen concentration of the permeated gas and the percentage recovery of hydrogen have been studied with the help of a digital computer using this model. The correctness of the model is proved by comparing the calculation results with the data obtained from the field test of three φ100×3000mm industrial scale separators.     

DETERMINATION OF MASS TRANSFER COEFFICIENTS AND THEIR BEHAVIOR IN PERMEABLE MEMBRANE PROCESSES BY LIMITING DIFFUSION CURRENT METHOD

The mass transfer coefficient k is an important parameter for predicting the concentration polar-ization of reverse osmosis and other membrane separation processes.In order to determine the k valueprecisely,a limiting diffusion current method with specially designed porous electrode has been devel-oped.This method can be used to determine the k values for both one dimensional and two dimensionalflow.It seems that the actual situation of membrane process is closely approached,so the dimensionlessempirical equations obtained have a practical significance.The equations of present work have been compared with the data of previous authors,and manyresults seem to be in good agreements.Therefore this paper offers useful reference for the investiga-tion and design of diversified membrane separation systems in future.     

POLY(ETHERSULFONE)/N,O-CARBOXYMETHYL AMPHOTERIC CHITOSAN COMPOSITE MF MEMBRANE: PREPARATION AND ITS CHARGED CHARACTERISTICS

1　ＩＮＴＲＯＤＵＣＴＩＯＮＣｈａｒｇｅｄｍｅｍｂｒａｎｅｓｈａｖｅｂｅｅｎａｔｔｒａｃｔｅｄｍｏｒｅａｔｔｅｎｔｉｏｎｉｎｍｅｍｂｒａｎｅｐｒｏｃｅｓｓｅｓ.Ｆｉｒｓｔｌｙ ,ｔｈｅｙｈａｖｅｓｔｒｏｎｇａｎｔｉ -ｆｏｕｌｉｎｇｐｏｔｅｎｔｉａｌｄｕｅｔｏｔｈｅｉｒｃｈａｒｇｅｄｇｒｏｕｐｓ .Ｓｅｃｏｎｄｌｙ ,ｔｈｅｙｃａｎｂｅｕｓｅｄａｓｉｏｎ -ｅｘｃｈａｎｇｅｍｅｍｂｒａｎｅｓｆｏｒｐｒｏｔｅｉｎｓｅｐａｒａｔｉｏｎｓ.Ｃｈｉｔｏｓａｎｉｓｔｈｅｓｅｃｏｎｄａｂｕｎｄａｎｔｂｉｏｐｏｌｙｍｅｒ…     

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE(Ⅰ)MODELING OF THE PERMEATION-SWELLING PROCESS

Water transfer through the organic phase of kerosene containing surfactant Span 80,L113B and certain carrier wasstudied theoretically and experimentally in(W/O)/W liquid surfactant membranes.The process of swelling owing to os-motic pressure can be pictured as solubilization of water in membrane phase caused by surfactant and certain carriers andthen diffusion of it through the membrane between the two aqueous phases due to the gradient of chemical potential.Amathematical model for estimating the permeation-swelling rate has been developed.This mathematical model does notcontain any adjustable parameters and the predicted values agree well with the experimental data of Fujinawa et al.,Xinsheng Ma and Yajun Shi and the authors.Using an apparatus developed for measuring the solubility of water in membrane phase,data for solubilization ofwater in oil caused by some surfactants and carrier were measured.     

PREPARATION AND SEPARATING PROPERTIES OF MoS_2/γ-Al_2O_3 CERAMIC COMPOSITE MEMBRANE FOR H_2S-H_2 MIXTURE

MoS2/γ－Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and viscosity are 97% and 1.2 × 10-3 Pa. s, respectively, can be formed through adjusting the ratio of the peptizing agent H+ to Al3+ to 0.3. The aluminum hydrate gel at 110℃ is amorphous in structure and is heat-treated in air at 800℃ to form γ－Al2O3. The precursor derived from the mixture solution of ammonium molybdate, thioacetamide and a reducing agent, can be transformed into crystal MoS2 under reducing condition at 800℃. MoS2/γ－Al2O3 composite membrane is an organic whole and bps no gradation from MoS2 layer to γ－Al2O3 Iayer. The separation factor a H2/H2S through the MoS2/γ－Al2O3 composite membrane increase with rising temperature and a H2/H2S at 600℃ is 4.45 higher than the theoretical separation factor produced by the ideal Knudsen diffusion.     

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE (Ⅰ) ADSORPTION OF SURFACTANT AT THE INTERFACE AND THE SWELLING CAUSED BY EMULSIFICATION

The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C_2,can be estimated by Eq.(7)—(9).The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the“Emulsification”swelling rate,F_(se),has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.(26)gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.     

STUDIES ON “THE THREE CRITICALS AND THE TWO OPTIMUMS”IN MEMBRANE GAS SEPARATION PROCESSES ( I ) “THE THREE CRITICALS”AND THEIR RELATIONSHIPS

提出了“三临二优”（系指临界操作压力比R~-、临界选择系数α~-、临界进料浓度x_f~-和最优操作压力比R~+、最优选择系数α~+）新概念,通过计算、分析和优化等手段,在x_f≥0.40、R≤100、a≤100范围内获得如下通用回归公式R~-=2+B/（α~-+A）,式中A、B仅与临界进料浓度x_f~-有关,并对他们分别进行了回归。此外,还在R≤1000、a≤1000范围内给出了x_f~-=0.95和0.50时的回归公式。     

STUDY ON THE DIFFUSION OF Cu~(2 )-H~ COUPLE IN A CATION EXCHANGE MEMBRANE——A RAPID METHOD TO DETERMINE SELF-DIFFUSION COEFFICIENTS OF COUNTER-IONS WITH UNEQUAL VALENCE

1 INTRODUCTIONKnowledge of the basic transport phenomena of ions in an ion exchange membrane isimportant for the application of such a membrane.Various studies on the developmentof mathematical models for predicting and correlating membrane transport rate havebeen published in recent years.More exact estimation of the diffusion coefficientshas been the subject of chief concern in many of these papers.For a bi-ionic systemwith the same valence,Sato et al.gave a method for estimating diffusion coefficients in