I N D U S T R I ,4L AS D E N G I N E E R I S G C H E M I S T R Y
1402
LITERATURE CITED Bourne, A. O., I n d i a Rubber J., 45, 120 (1913). Bourne, A. O., I n d i a Rubber World, 33, 93 (1905). Kelly, J., IND.EXQ.CHEM.,12, 196,875 (1920). Park, C. R., Ibid., 22, 1004 (1930). Park and Maxwell, Ibid., 24, 148 (1932). Rossem, A. van, Communications Netherlands Gout. Inst. advisino rubber trade and ind., VI,179 (1917).
Vol. 2 5 , s o . 12
(7) Sandstrom, R.V., IND.ENQ.CHEM.,25, 684 (1933). (8) Sheppard, J. R., I n d i a Rubber World, 80,56 (1929). (9) Spence and Young, Z . Chem. I n d . Kolloide, 11, 28 (1912). (10) Trriss and Brazier, J. SOC.Chem. Ind., 39,125T (1920). (11) Vogt (chairman), IND.ENQ.C H m . , 17, 535 (1925). RECEIVEDSeptember 20, 1933. Presented before the Division of Rubber Chemistry a t the 86th Meeting of the American Chemical Society, Chicago, Ill.. September 10 t o 16,1933.
Adsorption of Copper Sulfate by Aluminum Floc C. J. BROCKMAN, University of Georgia, Athens, Ga.
T
HERE is a n enormous quantity of data on the use of
copper sulfate in the control of algae in the raw water supplies of municipalities, and there has been much disagreement as to the quantity which can be safely used without exceeding the tolerance of the human body for copper salts. In order to eliminate a n y differences of opinion on the matter of tolerance, it will be considered that anything over 5 parts per million will be dangerous because this concentration of copper ions imparts t o water a decided flavor. Many references in the literature indicate that very little, if any, of the copper ions get through the filters into the city clear water supply. However, no study has been made of the case in t h e light of modern methods of control in water works, especially control of the p H of raw and filtered water. During the past decade the problem of floc formation in water works has been put on a scientific basis b y the investigations of t h e men connected with the U. S. Public Health Service and others (1, 4, 5 ) who have studied the conditions under which t h e best aluminum flocs are produced and then extended the study to include the floc from ferrous sulfate (copperas). From an examination of these publications on alum and iron flocs, the electrometric titration curves for aluminum sulfate with sodium hydroxide (5) and the similar curve for copper sulfate and sodium hydroxide (S), the writer was led t o believe that at least some of the copper salt would be flocced out in the ordinary alum treatment of raw water and consequently be retained on the filters.
EXPERIMEKTAL PROCEDURE The first series of experiments on this problem was made on t h e raw water supply of Athens, Ga. Jar tests according to the method of the New York State Department of Health were used. Filter alum from the Athens city water works was dissolved in distilled water so that, when 1 cc. of this solution was added to 1 quart of water, the alum concentration was 0.5 grain per gallon-that is, 8.1 grams of alum were dissolved in 1000 cc. of distilled water. The copper sulfate solution was prepared by dissolving 0.3928 gram of CuSOa5H10 in 1000 cc. of distilled water, which made the concentration 0.1 mg. of copper ions per cc. or about 0.1 p. p. m. when 1 cc. was diluted to 1 quart. A quantity of copper sulfate solution and then alum solution were added t o the raw water in quart jars. When the floc had settled, it was filtered through a large funnel. The filtrate was evaporated in a Pyrex vessel to 50 cc., analyzed for copper ions by slightly acidifying with dilute sulfuric acid, then made slightly ammoniacal in order to separate the aluminum hydroxide from the copper ions by filtration. The copper ions in this filtrate were determined after evaporating the excess of ammonia, by the ferrocyanide method according t o Yoe (6). Treatment with ammonia was necessary in order t o remove any residual aluminum salts which were not flocced out. The pH of the filtered water was determined colorimetrically on a 10-cc. sample of the clear filtrate.
Table I indicates that in the ordinary alum treatment of water, up to 1 p. p. m. of copper ions is completely removed in the process of filtration. T h e mechanism by which this removal is accomplished need not concern us at present. It may be either co-precipitation with the alum floc or an adsorption on the alum floc. At a n y rate, there are no copper ions in the clear filtered water. TABLE I. TESTSON ATHESSWATERSUPPLY 7
TEST
PH
1 2 3 4 5 6
7.0 7.0 7.0 7.0 7.0 7.0
.
R A WWATER FILTERED WATER Alum solution Copper solution pH Copper Cc. Grains/gal. Cc. P.p . m. P. p . m. 1.0 8.55 1.0 0.1 6.4 0 . 0 0 1.0 8.55 2.0 0.2 6.4 0 . 0 0 1.0 8.55 3.0 0.3 6.4 0.00 4.0 0.4 1.0 8.55 6.4 0.00 6.4 0 . 0 0 1.0 8.65 5.0 0.5 6.4 0 . 0 0 1.0 8.65 10.0 1.0
TABLE 11. TESTSWITH BUFFERSOLUTIONS TEST
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 31 33
34 35 36 37 38 39 40 41 42 43 44 45 46
-BUFFERED WATER-pH Alum solution Copper solution cc. P . p . m. Cc. P. p . m.,, 10 1160 10 14.3 7.4 10 16.7 0 0 7.4 10 1160 10 14.3 7.2 10 1000 20 25.0 7.2 10 1160 10 14.3 7.0 1 150 3 5.5 7.0 10 16.7 0 0 7.0 15 20.0 10 1080 7.0 20 25.0 10 1000 7.0 2 1 153 3.8 7.0 10 14.3 10 1160 6.8 10 1160 10 14.3 6.6 3 5.5 1 150 6.6 10 1000 20 25.0 6.6 7.3 4 1 148 6.6 3.8 2 1 153 6.6 10 1160 10 14.3 6.4 5.5 1 150 3 6.4 5 550 20 26.7 6.4 20 25.0 10 1000 6.4 10 16.7 0 0 6.4 1 1.9 1 156 6.4 2 3.8 1 153 6.4 5 8.8 2 285 6.4 5 9.0 1 144 6.4 10 14.3 10 1160 6.0 3 5.5 1 150 6.0 20 26.7 5 550 6.0 25.0 20 1 0 1000 6.0 15 20.0 10 1080 6.0 25 29.4 10 950 6.0 30 33.3 100 900 0 6.0 10 16.7 6.0 10 1160 10 14.3 6.0 5.5 3 1 150 5.6 10 16.2 2 130 5.6 20 28.6 0 0 5.6 10 14.3 10 1160 5.6 20 25.0 10 1000 5.6 10 16.: 0 0 5.6 10 1 6 . f 0 0 5.2 10 1160 10 14.3 5.2 20 25.0 10 1000 5.0 10 16.7 0 0 5.0 10 1160 10 14.3 5.0 20 25.0 10 1000 5.0
FILTERED WATER Copper p H Copper removed 7.2 7.3 7.0 6.9 6.8 7.0 6.9 6.7 6.7 7.0 6.6 6.4 6.5 6.4 6.5 6.6 6.0 6.3
...
6.0 6.2 6.4 6.3 6.2 6.2 5.2 6.0
... ...
...
... ... ,..
Mg.
%
0.00 0.00 0.00 0.00 0.00 0.00
100.0 100.0
0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.10 0.00
0.10 0.00
0.00
0.05 0.10 0.05
0.05 0.20
0.10 0.05 0.20 0.10 0.10
, . .
0.00
5.5
0.05 0.30 0.20 0.50
... ,..
...
... ...
.. .. .. ...
... ...
...
1.00
0.10 0.50 0.50 1.00 0.70 0.50 1.00
100.0 100.0 100.0
100.0 95.0. 100.0 100.0 100.0 100.0 100.0 100.0
100.0 100,0
100,0
100.0 100.0 95.0 100.0 90.0 100.0 100.0 90.0 80.0
95.0 84.0 90.0 95.0 97.0 92.0 90.0 90.0 100.0 85.0
70.0 90.0 50.0 50.0 90.0 50.0 50.0 50.0 30.0 50.0 50.0
These preliminary experiments on raw water indicated that the problem should be further studied, This was done.
December, 1933
INDUSTRIAL AND ENG INEERING CHEMISTRY
by using solutions in which the p H could be controlled over a considerable range of p H values. It was found that t'he phosphate buffers described by Clark ( 2 ) were the most logical to use. The buffer solutions were prepared in 50-cc. volumes at a definite pH, to which were added in order the copper sulfate solution with stirring, and then the alum solution rrith stirring. The copper sulfate and alum solutions are described above. These solutions were allowed to stand until the floc had settled. This required from 4 to 15 hours. Then the supernatant liquid was filtered by decantation so that only about 35 cc. ran through, and very little of the floc came on to the filter paper. Of these 35 cc., 25 cc. were used for the determination of the copper by the ferrocyanide method, and 10 cc. were used for the colorimetric determination of the pH. The results of these experiments are given in Table 11. The composition of the floc was not determined in any case. In tests 2 , 7, 21, 33, 37, 40, 41, and 44 no alum solution was added after the copper solution. These tests show that the copper is flocced out more at' the higher p H values than at the lower, and that even a t a p H of 5.0 half the copper ions are removed in the floc. This is in accord with the potentiometric titration curve for copper sulfate with sodium hydroxide (S), which is similar to t h a t for aluminum sulfate with sodium hydroxide ( 5 ) . However, the copper curve is displaced upwards in p H with respect t o the aluminum curve. The copper curve bends a t about pH 5.0 and the aluminum
1403
curve a t about pH 4.2; therefore it is to be expected that a buffer solution with a p H around 5.0 would not cause a complete flocculation of the copper salt. Table I1 indicates that when the residual p H of the buffer solution is 6.3 or above, there is a complet'e removal of the copper ions by the aluminum floc. It also indicates that a t a residual p H of about 6.0 to 6.4 there is an average of almost 90 per cent removal, and that from a p H of 5 to 6 there is better than 50 per cent removal of the copper ions. The conclusions which must be drawn from these data are that, so long as the p H of filtered water remains above 6.3, a very heavy dose of copper sulfate may be used without any danger of the copper salt getting through the filters in a water filtration plant which is using the alum treat'ment method. (1) Buswell, A.
LITERATURE CITED M.,et al., IllinoisState Water Survey, Bull. 22 (1926).
(2) Clark, W. M., "Determination of Hydrogen Ions," 2nd ed., p. 114, Williams & Wilkins, 1927. (3) Hopkins, 4.J.,and Beebe, R. A, J. Phys. Chem., 34, 570 (1930). (4) Miller, L. B., Public Health R e p l s . , 38, 1995 (1923); 40, 351 (1925); 40, 1413 (1925). (5) Theriault, E. J.,and Clark, W. M., Ibid., 38, 181 (1923). (6) Yoe, "Photometric Chemical Analysis," Vol. I, p. 182 (1928). RECEIVED September 19, 1933. Presented before the Division of Water. Sewage, and Sanitation Chemistry a t the 86th Meeting of t h e .-lmerican Chemical Society, Chicago, Ill., September 10 t o 15, 1933.
Effect of Previous Starching upon Ease of Washing Cotton Fabrics LAWRENCE E. STOUT AND KR'APELF. SCHIERMEIER, Washington University, St. Louis, Mo. Starching prerious to soiling aids in the redressing formulas will be used. HE value of s t a r c h as of the dirt f r o m material by washing. ? v I o r e o v e r , any factor which an aid in the removal tends t o facilitate the washing of dirt from fabrics has Boiled wheat and rice starch is superior to a n y of operation w i t h o u t decreasing b e e n recognized qualitatively for a long t i m e . H o w e v e r , the other grades sfudied. Soluble ulheatand rice the life of the fabrics treated is few if any quantitative studies starch ranks second, and the boiled corn starch of major chemical engineering have been c a r r i e d out on the third. Quantitative data give definite compariimportance t o the industry. subject. Guernsey ( l )states sons of the values of the different types and quantithat the addition Of EXPERIMENTAL PROCEDURE ties of starch as a washing aid f o r the removal of such as starch to an a l k a l i n e .. . solution lessens the destructive dzrt* Test s t r i p s of c l o t h w e r e action of the a l k a l i p r e s e n t washed free from all starch or and increases the cleansing power of the detergent. Harvey dressing materials, dried, and ironed. These test pieces ( 2 ) also points out t h a t the removal of old starch or previous were then starched in a definite manner, dried, ironed, and starch effectively removes much of the mechanically held soiled in a standard soiling solution. The dry soiled samples dirt and makes subsequent washing processes easier. These were washed repeatedly, and the cleansing effected b y each men have recognized some effects of prestarching in washing washing was measured quantitatively, operations, but no quantitative data have been published. CHEMICALS AND MATERIALS USED. Tests were made upon The modern power laundry is interested in ease of washing two grades of white cotton sheeting. The first weighed 2.2 and uniformity of the washed articles. Moreover, it is con- grams per sq. cm., had twenty threads per cm., and in this fronted with the problem of washing heavily dressed fabrics report is designated as the coarse grade. The second weighed and returning them t o the owner with their original appear- 1.6 grams per sq. cm., had 26 threads per crn., and is desigance. Heavily starched materials contain from 4 t o 5 per nated as the fine grade. Three commercial grades of starch cent, white shirts and collars about 9 per cent starch. Imita- were used: (1) a soluble starch consisting of about 80 per tion linens are heavily dressed, and starch is a n essential cent rice and 20 per cent wheat, ( 2 ) a boiled starch of approxiconstituent in the dressing used. Therefore, i t was felt t h a t mately 50 per cent rice and 50 per cent wheat, and (3) a these quantitative data on the effect of previous starchings boiled corn starch. The soiling solution consisted of a upon the ease of washing of cotton fabrics might justify suspension of lampblack in water as described b y Vail ( 3 ) . heavy starching. The higher starch concentrations studied PREPARATION OF SOILEDSAMPLE.T h e starch solutions can serve as a basis for the interpretation of furthm work on used were made up to various concentrations. Test strips t h e washing of dressed fabrics in which t h e more complicated were saturated n-ith the starch solution in question and then
T
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