ASTM_E_1343_-_90_2001.pdf

Designation:E 1343 90(Reapproved 2001)Standard Test Method forMolecular Weight Cutoff Evaluation of Flat SheetUltrafiltration Membranes1This standard is issued under the fixed designation E 1343;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the evaluation of the molecularweight cutoff of flat sheet ultrafiltration membranes withcutoffs between 4500 and 1 000 000 daltons.The nonadsorbingcharacteristics of the test penetrant utilized by this test methodpermit the test to be performed on a wide variety of membranesubstrates,excluding those which strongly adsorb dextran,from highly hydrophilic to highly hydrophobic.This testmethod is not applicable for microfiltration membranes withpore sizes of 0.01 m or larger,nor for reverse osmosis ordialysis membranes with less than 4500 molecular weightcutoff.(It is possible that this test method could be modified toexpand the range from 100 to 2 000 000 daltons.)This testmethod is not applicable to membrane materials that stronglyadsorb dextrans since these materials will potentially changethe value of the measured molecular weight cutoff and hencewill invalidate the test results.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Summary of Test Method2.1 The membrane is rinsed with purified water and in-stalled in the test cell.The precalibrated dextran T-fraction feedis pumped through the cell and the flux through the membraneis set at the value of 0.0001 cm/s and an ultrafiltrate sampletaken and compared to a sample of the feed for molecularweight distribution.Gel permeation chromatography is used tocompare the feed to the permeate and the rejection at each 3-sdata slice is calculated.The resulting rejection is then plotted asa function of the molecular mass average of the sample for thedata slice.3.Significance and Use3.1 This test method provides a convenient,rapid,reproduc-ible method of comparing the intrinsic properties of ultrafil-tration membranes.The use of nonfouling dextrans allows adirect comparison of membranes without interference frommaterials that may foul one membrane and not affect another.The degree of correlation between this test and actual perfor-mance on a commercial feed stream has not been completelyestablished;however,a membrane can be exposed to thefouling solution in question and then the effect of that foulantdetermined by then running the test and comparing to theresults on an appropriate unfouled membrane.It should bemade clear that this test method does not substitute for theactual testing of a commercial or experimental membrane on afeed stream of interest.The low transmembrane pressures,lackof adsorption of the test permeants onto the membrane,andlow recovery/pass are intended to eliminate interferences suchas polarization and fouling that mask the properties of themembrane.It is likely that any system operated in a commer-cial fashion will experience fouling,adsorption,and polariza-tion to some degree as well as a“compaction”phenomenonover the first several h of operation.4.Apparatus4.1 The basic membrane test system consists of the follow-ing:4.1.1 Standard Flat Membrane,Stirred Ultrafiltration TestCell,for 62-mm membrane disc,modified as shown in Fig.1,24.1.2 Diaphragm Pump,approximately 0 to 200 mL/minvariable pumping range,30 psig pressure capability at 100mL/min,all wetted parts of 316 stainless steel and polyfluo-rocarbon construction,34.1.3 Back Pressure Regulator and Pressure Gage,0 to 30psig,316 stainless steel,4.1.4 Electronic Digital Flowmeter,with direct readout ofvolumetric flow in the approximate range 0.06 to 5 mL/min,4.1.5 Magnetic Stirplate with Tachometer,44.1.6 Magnetic Stir Plate,Stirbar,and Container,(1000cm3Erlenmeyer)for test solution,4.1.7 Pulse Dampener,500-Ml,316 stainless steel,1This test method is under the jurisdiction of ASTM Committee E48 onBiotechnology and is the direct responsibility of Subcommittee E48.03 on UnitProcesses and Their Control.Current edition approved March 30,1990.Published May 1990.2Membrane equipment,model 8200 or equal,available from Amicon Divisionof W.R.Grace,1114-T Avenue of the Americas,New York,NY 10036,has beenfound suitable for this purpose.3Diaphram pump,model EP-C40 or equal,available from CHEM/TECHInternational Industries,1655-T Des Peres P.O.Box 31000,St.Louis,MO 63131,has been found suitable for this purpose.4Stirplate,model 4650-54,or its equivalent,available from Cole ParmerSpincadet,7427-T N.Oak ParkAve.,Chicago,IL60648,has been found suitable forthis purpose.1Co