REMOVAL OF HARDNESS AND DEIONIZATION OF WATER BY THE ION EXCHANGE METHOD
1tj8&Id i
Submitted by: A. W. Sangster, University College of the West Indies, Jamaica Checked by: Marcus Kraus and James Ramer, Tenth Chemistry Institute, Montana State College Materials: Cation Exch. Resin, Amhertite IR-120 (Col. A); Anion Exch, Resin, Amberlite IRA-400 (Col. B); hard water, 1 liter of 2% CaCl, d n ; 500 ml of 10% NaCI soln; 250 ml of 1 M HCI; 250 ml of 1 M NaOH; 0.5 M (NH4)sC30isoln for C a + + test; 0.25 M AgNOi s o h for Cl- teat.
PART I-Removal
I COLUMN A OR
a
of Hardness (Ca++)
Preparation of column A: Pass through 250 ml NaCI soln slowly until effluent positive for Na+ with Nichrome wire. Wash column thoroughly with 500 ml distilled water. Test: Add 4 drops methyl orange to 250 ml hard water. Pass through column. Test pink effluent for absence of Ca++. Demonstrate removal of Ca++ from column A by passing through 200 ml NaC1 mln. Test for CSL++.
PART 11-Deionization
(Ca++ and Cl-)
Preparation Column B Pass through NaOH soln until positive for alkali (litmus). Wash with 500 ml distilled water. Test: Add 5 drops methyl orange to 300 rnl CaCL soh. Pass through column A. Then pass pink effluent through column B. Test for absence of Ca++and Cl". Note: Respective column muat be thoroughly washed with HC1 and NaOH before test.
Preparation Column A Pass through HC1 soln until negative for Na+. Test with Nichrome wire. Waah until effluent negative for Cl-.
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G L ~ WOOL S
PART Ill Removal of Ca++: (cation exchange)
+ 2Na+ + Ca++ + 2C1- e [(RSOl-b Ca^] + 2H+ + 201-
2[RS08-Na+l
Dewn~zntwm: (cation exchange): 2[RSOa-H+]
+ Ca4+
;=Â [(RSO,-)sCa++]
VAPOR SHADOWGRAPHS
Submitted b y L. Carroll King and A D. Templer, Noithwestern University, Evanston, Illinom
Checked b y
John Shotwell, Detroit Public Schools, Michigan
DEMONSTRATION
The fluorescent screen is placed in the ultraviolet light beam and the beaker of test liquid is placed near the screen. With the long glass tube blow across the liquid surface. The shadow of the vapor may be observed on the fluorescent screen. REMARKS
Pyridine, benzene, and mercury absorb strongly in
shorter wavelengths and should be equipped with a filter to remove as much of the visible light as possible.
Note on Fluorescent Screens
A laundered white shirt makes a fine fluorescent screen. White paper used for letterheads is usually satisfactory. Crystalline anthracene or uranyl acetate spread evenly over a cardboard which is covered with a thin layer of glue will work very well. Volume 40, Number 12, December 1963
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A987
