PDF Publication Title:
Text from PDF Page: 138
dryness, strong heatmg reoxIdIzes the chromnim Add 0 5 m1 concentrated HN03 and agam evaporate to dryness to destroy any excess sulfite Take up m im i concentrated HN03 wIth warmIng and dIlute to 200 0 m1 wIth demmeralIzed water 55 Trivalent chromIUm workIng solutIOn, 10 m1 = 0 005 ~g Cr~3 ImmedIately before use, dIlute 250 m1 of tnvalent chromIUm stock solutIOn (54) to 1000 m1 wIth demmeralIzed water 56 PotassIUm permanganate, 0 1 N DIssolve 0 3 2 g potassIUm permanganate m 100 m1 demIneralIzed water 57 SodIUm aZIde, 0 1 % DIssolve 100 mg sodIum aZIde m demineralIzed water and dIlute to 100m1 58 Methyl Isobutyl ketone (MIBK) 59 SodIUm hydroxIde SolutIon, 1 M DIssolve 40 g NaOH m demmeralIzed water and dIlute to 1lIter 5.10 Sulfunc aCId, 0 12 M Slowly add 65 m1 concentrated H2S04 (sp gr 1 84) to demIneralIzed water and dIlute to 1 lIter 6. Procedure PIpet a volume ofsample contaImg less than 2 5 ug chromIUm (100 m1 maxImum) mto a 200 m1 volumetnc flask, and adjust the volume to approxImately 100 m1 The pH must be 2 0 or less Add concentrated HN03 Ifnecessary ACIdIfy a lIter of demmeralIzed water wIth 1 5 m1 concentrated HN03 Prepare a blank and suffiCIent standards usmg tnvalent chromIUm and adjust volumes to approxImately 100 m1 wIth the aCIdIfied demmeralIzed water Add 0 1 N KMn04 dropwise to both standards and samples untIl a famt pInk color persIsts Heat on a steam bath for 20 mmutes If the color dIsappears, add addItIOnal KMn04 solutIon dropwise to maIntam a slIght excess WhIlestIllonthesteambath,addsodIUmaZIdesolutIOndropwiseuntIltheKMn04color Justdisappears Heatforabout2mmbetweeneachadditIonandaVOidaddmganyexcess Contmue heatmg for 5 mm after addIng the last drop ofsodIUm aZIde solutIOn Transfer the flasks to a water bath and cool to room temperature Remove from the water bath and filter (through Whatman No 40 filter paper or eqUIvalent) any sample WhICh has a browmsh preCIpItate or coloratIon whIch may mterfere wIth the pH adjustment Add 2 0 ml of I 1\1 NaOH and 2 drops bromophenol blue IndICator solutIon ContInue the addltlOn of I M NaOH dropwIse to all samples and standards In whIch the IndIcator change from yellow to blue has not occurred Add 0 12 M H2S04dropWIse untIl the blue colorJust disappears, then add 2 0 m1 m excess The pH at tills pomt Will be 24 The pH adjustment to 2 4 may also be made wIth a pH meter mstead of USIng an mdIcator Add 50 m1 APDC SolutIon and mIX The pH should then be approxImately 2 8 Add 10 0 m1 MIBK and shake vIgorously for 3 mmutes 61 62 63 64 65 6 6 67 68 6 9 completely m the neck of the flask 6.10 6 11 6 12 Allow the layers to separate and add demIneralIzed water untIl the ketone layer IS 2183-2PDF Image | Methods for Chemical Analysis of Water and Wastes
PDF Search Title:
Methods for Chemical Analysis of Water and WastesOriginal File Name Searched:
epa600_4_79_020.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)