THE E F F E C T OF TEMPERATURE ON RATE OF OSMOSIS
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BY RALPH Ei. TRAXLER
It is a commonly recognized fact that rise in temperature causes a marked increase in the rate of osmosis and dialysis and also increases the osmotic pressure developed by a solution separated from the pure solvent by a semipermeable membrane. A review of the literature covering these subjects shows that relatively little attention has been given to the effect of temperature except in its direct effect on the osmotic pressure of a solution. H. N. Morse and his coworkers' and numerous others have investigated this phase of the subject quite extensively. However, nothing in a quantitative way is recorded concerning the rate of passage of material through a membrane as affected by temperature. G. Flusin has shown by experiments on rubber membranes* and on pig's bladder3that the direction and velocity of transfer of liquids across these membranes depend on the absorption capacity of the membrane for the liquids. Carbon disulphide which is absorbed readily by rubber passes quickly through a rubber membrane into alcohol, whereas chlorobenzene and nitrobenzene which are not readily absorbed pass through very slowly. Water which is taken up in large quantities by hog's bladder passes through rapidly and chloroform which is absorbed much less passes through proportionally slower. He decided that the velocity of osmosis did not depend on the maximum amount of absorption but upon the energy with which the membrane takes up the liquid during the first minute of contact. His experiments were carried out under controlled temperature conditions, but no attempt was made to determine the effect of different temperatures on the velocity. The present paper records the results of experiments made to determine the effects of definite changes of temperature on the rate of establishment of equilibrium in ( I ) a system composed of pure pyridine separated from pure water by a thin rubber membrane and ( 2 ) a system composed of a one-half molar solution of sodium chloride in water separated from pure water by a collodion membrane. Experiments showing the Effect of Temperature Changes on the Passage of Pyridine through a Thin Rubber Membrane into Water. The pyridine was pure and freshly distilled before use. The water was distilled and free from dissolved gases. The rubber used for the membrane was a high grade of dental dam, very uniform in weight and quality. The thickness of the unstretched sheet was 0.3 + .os mm. 'Am.Chem. J.,45,91,237,383,517, (1911). 2Compt. rend., 126, 1497 (1898). Compt. rend., 131, 1308 (1900).
128
RALPH N. TRAXLER
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No originality is claimed for the cell and stirring arrangement, the design of which was derived from the apparatus used by Kahlenberg' in his work on osmosis and dialysis. Fig.1 gives the essential details of the apparatus. The cell was a cylindrical nickel-plated drum, 3 centimeters in diameter and 4.2 centimeters in height. The area of the open end was 7.07 square centimeters. Around the bottom and open end of the drum was a rolled
FIQ.I
flange which made it easy to fasten on the membrane. A bar was fastened across the inside of the cell about 0.5 centimeter from the bottom, the function of which was to prevent the stirrer from dropping down into direct contact with the membrane. The upper and closed end of the cell was fitted with a metallic tube 5 centimeters long and exactly the same diameter as a glass tube which was firmly fastened to it by means of rubber tubing and wire. A hollow cylinder carrying a large number of turns of fine wire formed an electromagnet which operated the stirrer. This electro-magnet was connected to a source of direct current through a rheostat and adjustable make and break contact. The long glass tube extending up from the cell rested against a millimeter scale upon which the rise of the liquid in the cell could be conveniently read. The rubber membrane was tied over the mouth of the cell by means of strong thread, care being taken to obtain a taut surface without J. Phys. Chem., 10, 141 (1906).
EFFECT O F TEMPERATURE OX RATE O F OSMOSIS
129
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stretching the rubber. After the rubber was in place a piece of new, washed muslin, weighing 0.0133 gram per square centimeter was tied over the mouth of the cell. Some such support was obviously necessary to prevent the bulging and stretching of the rubber under the weight of the column of liquid. Xew pieces of rubber and cloth were used for each experiment.
25
50
75
100
M/NC/T€.S
1P5
150
FIG.2
The cell, filled with water and free from air bubbles and with the meniscus on the scale, was placed in a glass cup or beaker containing the pyridine. The beaker was covered by a slit cover fitting around the cell, and then placed in a thermostat capable of regulation to less than 0.j°C. The cell was always immersed to the same depth in the pyridine. The water in the cell and the pyridine in the beaker were brought to the temperature of the thermostat before lowering the cell into position. The rise of the liquid in the glass tube was observed and recorded in centimeters. By careful calibration it was found that the tube, which was excep-
RALPH N. TRAXLER
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130
tionally uniform in bore, contained 5 2 cubic millimeters for every centimeter of its length. From this the scale readings were converted into volumes passing through the membrane. Dividing this value by the area of the membrane gave the volume passing through one square centimeter. These are the values used in plotting the results. Stirring of the inner liquid took place every 18 or 2 0 seconds. Kahlenberg' has shown that stirring is absolutely necessary in quantitative measurements of osmosis and osmotic pressure. His contentions in regard to this point of t,echnique were again shown to be correct in the experiments herein recorded. More or less rapid and uniform stirring was necessary in order to obtain uniform and concordant results in the experiments recorded below. It is only reasonable to assume that, without stirring, the pyridine passing through the rubber would form a very concentrated solution of pyridine in water which would remain in close proximity to the membrane. The pyridine would only diffuseslowlyintothe water intheupper part of the cell. Thislayer of concentrated solution would retard the flow of pyridine through themembrane. A false equilibrium would thus be set up between this layer and the pure pyridine emerging from the membrane. The purpose of the experiments is to measure the rate of attainment of equilibrium between the uniform contents of the cell and pure pyridine. Stirring the contents of the cell causes the concentration to be maintained nearly uniform throughout. Experiments were conducted at ten degree intervals from 5'C. to 85°C. The results are given in Tables I to IX and are plotted in Fig. 2. Checking experiments were made a t each temperature. To conserve space the averages are given in the tables, except at 35%. where two runs are given to indicate the small differences usually occurring. At 65", 75' and 85'C. the amount of error increases slightly due probably to thc greater difficulties of manipulation at the higher temperatures. Toward the end of the experiments at these higher temperatures the rate of passage increased somewhat. This is shown
. TABLE I Pyridine and Water at 5°C. Time in minutes 0
Time in minutes
5.00
3.00 2.25
50 5s 60 70 80
5.25
1.87
90
IO
3.90 4.30
I5
4.70
20
25
30
5.45
I . 50
IO0
35
5.65 6.00 6. IO
I . 50
IIO
50
120
'75
130
5
40 45 I
Total cms. Vol. in cu. mm. rise in tube passing through I cm.*membrane 3.20 5.25
3.00
I.
J. Phys. Chem., 10,141 (19061.
Total ems. 1'01. in cu. mm rise in tube passing through I em.* membrane
6.35 6,50 6.85 7.10 7.35 7.60 7.85 8.IO 8.35 8.60
,94 94 94 '94 94 .94 ' 94 ' 94 ' 94 94 ' '
'
'
EFFECT O F TEMPERATURE O N RATE O F OSMOSIS
131
by the upward trend of the curves a t 6 5 O , 75" and 8s'. This result is undoubtedly due to the solvent action of the hot pyridine on the rubber, causing the membrane t o be thinner et the end of the experiment than it was at the beginning. The membranes in contact with pyridine at a temperature of 85°C. were YO far disintegrated at the end of 70 to 80 minutes that they would no longer sustain the column of liquid.
TABLE I1 Downloaded by RYERSON UNIV on September 12, 2015 | http://pubs.acs.org Publication Date: January 1, 1927 | doi: 10.1021/j150283a010
Pyridine and Water at I 5°C. Time in minutes
Total crns. Vol. in cu. mm. rise in tube passing through I cm.2 membrane
0
5.2
5
6.6
IO
IS 20 25
30 3s 40 4s 50 55 60
Time in minutes
IO.SO
7.4 7.9 8.3 8.7 9.0 9.3 9.6 9.9 10.3
6.00 3.75 3.00 3 .oo
10.6
2.25
10.9
2.25
65
11.2
2.25
70
11.5
2.25
75
11.8
2.25
80
12.1
2.25
85 90
12.4
2.25
12.7 13.3 13.9 14.I 14.5
2.25
2.25
15.0
2.40
2.25
IO0 I IO
2.25
I20
2.25
'25 130
2.25
2.25
Total cms. Vol. in cu. mm. rise in tube passing through I cm.* membrane
2.25
2.25 2.25
TABLE I11 Pyridine and Water at 25°C Time in minutes 0
5 IO 15
20 25
30 35
Total crns. Vol. in cu. mm. rise in tube passing through I cm.*membrane
2.6 6.8 8.5
9.15 9.75 10.30 10.90 11.40
Time in minutes
16.25
85
16.75
90 95 IO0
17.35 17.85 18.35
105
18.85
I IO
'9.35 19.85 20.35 20.85 2 1 .35 21.85 22.35
4.00 4.00 4.00 4.00 4.00 4.00
22.85
4.00 4.00
115 I20
12.00
55 60 65 70
13.60
125 130 '35
14.IO
140
14.75 15.25
I45 150
7s
15.75
1 3 . IO
Vol. in cu. mm. passing through
I cm.2 membrane
80
40 4s 50
12.60
Total cms. rise in tube
23.35
4.00 4.00 4.00 4.00 4.00 4.00
4.00
RALPH N. TRAXLER TABLE ITr (a) Pyridine and Water at 3 5OC
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Time in minutes
Total cms. 1'01. in cu. mm. rise in tube passing through I membrane
0
2.0
5
7 . 2
IO
8.4 9.3
-
Time in minutes
Total crns. rise in tube
1'01. in cu. mm. passing through I cm.2 membrane
39.00 9.00
85 90 95
2 0 .I
6.00
21.7
6.00 6.00 6.75
22.7
15 20
6,7j 6.00
IO0 10;
22.7
IO. I
25
10.9
6.00
IIO
24.2
6.00
11.7
6.00 6.75
11.5
25.0
6.00
I20
25.8
4.75
23
'
4
6.00
30 35 40 45
13.4 14.2
6.00
125
26.7
6.00
6.00
27.5
6.00
50
15.0
6.00
130 I35
28.3
6.00
55 65
15.9
6.75 6.75
140 I45
29.0
5.35 6.00
70
17.6 18.4 19.3
6.00
150
6.00
15;
29.8 30.6 31,4
Time in minutes
Total cms. rise in tube
I10
24.3
'15
2 5 .I
Vol. in cu. mm. passing through I cm.2 membrane 6.00 6.00
I20
25.9 26.7
75 80
12.6
16.8
6.00 6.00
6.75
TABLE IT- (b) Pyridine and Water a t 35OC Ti,me in minutes
Total crns. Vol. in cu. mm. rise in tube passing through I om.* membrane
0
2.0
__
5 20
7.3 8.3 9.2
39.80 7,jo 6.75
25
IO 0
6.00
30 35
10.9 11.8
40
12.7
6.75 6.75 6.75 6.00 6.75 6.00 6.00 6.00 6.7j 6.00
15
45
I3 5
50
14.4
55 60 65
I j . 2
70
17.7
75 80
18.5 '9.3
85 90 95
20.2
103
roj
16.0 16.8
.o 21.9 22,7 23 5 21
125
130 '35
27.5
6.75 6.00
185 190 I95
6.75
2 00
28.3 29. I 30.9 31.7 32.5 33.3 34.1 34,9 35.7 36.5 37.3 38. I 38.9 39.;
205
40.5
6.00
6.00 6,oo
140 I45 150
155 I 60
16j IjO
Ii5 I 80
6.00
6.00
6.00 6.00 6.00 6.00 6.00 6.00
6.00 6.00 6,00 6,00
6.00 6.00 6.00 6.00 6.00 6.00
EFFECT O F TEMPERATURE O X RATE OF OSMOSIS
I33
TABLE T.' Pyridine and Water at 4 5 T Time in minutes 0
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5
Total crns. Vol. in cu. mm. rise in tube passing through I cm.? membrane 1.5
-
Time in minutes
Total cms. rise in tube I
Vol. in cu. mm. passing through cm.2 membrane 9.00
43.00
80 85
26.0 27.2
IO. 50
90
28.4
9,00
9.00
IO
7.3 8.7
'5
10.0
9.75
95
29.5
8.25
20
11.3 12.6
9.75 9.75
IO0
9.00 9.00
30 35
14.0
IO. 50
IIO
30.7 31.9 33.0
15.2
9.00
115
34.2
40
16.5
I20
45 50
17.7 18.9
9.75 9.00
125
35.3 36.4
55
20.0
9.00 8.25
130 I35
37,4 38.4
60
21.2
65
22.4
9.00 9.00
140 I45
39.5 40,6
io
23.6 24.8
9.00 9.00
150
41,7
25
75
105
8.25 9.00 8.25 8.25 9.00 8.25 8.25
7.50 7.50
TABLE VI Pyridine and Water at jg°C Time in minutes
Total cms. Vol. in cu. mm. rise in tube pasaing through I cm.2 membrane
0
0 . j0
5
8.50
IO 15
10.45 12.30
20
14.15
25
45
15.95 '7.75 19.55 21.30 23.00
50
55
Time in minutes
__
7s
59.50 14.70
80
'3.85 13.85
85 90 .
95
Total crns. rise in tube
Vol. in cu. mm. pafising through I cm.2 membrane
33.00 34.65 36.25
12.00
12.75
12.20
37.90
12.20 12.20
12.70 11.90
I3 ' 50
IO0
39.50 41. I O
13.j o
'05
42.90
I3 ' 5 0 13.IO
I10
44.40
"5 I20
46.40 47.90
12.70
12.70
2 4 . 70
13. IO
130
jl.50
I2
12.00
140
55.10
13.40
I2.3j
150
12.40
io
31.35
12.40
160 170
58.50 63.80 65.50
12.70
65
26.3j 28.00 29,80
30
35 40
60
12.50
12.70
12.
io
io
12.70
RALPH N. TRAXLER
I34
TABLEVI1 Pyridine and Water a t 65°C Time in minutes
0.40
__
Time in minutes
Totalcms. rise in tube I
Vol. in cu. mm. passing through cm.2 membrane
5
11.00
79.50
IO0
IO
13.80
21.00
IO j
16.40 18.70 21 .oo
19.jo
I10
59.00
16.j o 16.50 16.jo 16.j o
17.20
115
61.30
17.20
17.20
I20
30 35
23.30
17.20
130
16.50 16.90
25.50
16.5 0
140
63 ' 5 0 69.00 72.60
40 45
27.80
Ij.20
150
77.30
17.60
3 0 . IO
17.20 17.20
17.20
Ij.20
170
17.20
I75 180
79.60 81.90 84.20 86.50 88.80
85
32.40 34.70 37.00 39.30 41 ' 50 43.7 0 45.90 48.IO
I55 160 16j
90
50.20
0
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Total cms. Vol. in cu. mm. rise in tube passing through I cm.l membrane
15
20 25
50 55
60 65 70 75 80
16.50 16.j o 16.50 16.50 15.60
52.40 j4,60 56.80
95
17.20
17.20
17.20 17.20 17.20
17.20
90.30
17.20
I90
95.80 98.20
20.60 18.00
I95
r o o , 30
200
1 0 2 . IO
'85
18.70 18.70
TABLE VI11 Pyridine and Water at 75°C Time in minutes
Total cms. Vol. in cu. mm. rise in tube passing through I cm.2 membrane
0
2.1
5
13.I
__
25
25.j
82.5 28.3 24.6 23.4 22.6
30
28.2
23.0
35
31.0
40
33,8
45
,3 6.6
24.0 24.0 22.6
10
16.7
I5
20.0
20
22.9
Time in minutes
Total cms. Vol. in rise in tube passing through I cm.2membrane
50
39,s
22.0
55 60
42 5 45.6
22.7
70
51.8
22.
75 80 85
55.0
23.4 22.6 23.4 23.4
90 95
'
58. I
61.3 64.5 67.8
23.6 j
24.0
EFFECT O F TEMPERATURE ON RATE OF OSMOSIS
I35
TABLE IX Pyridine and Water a t 85°C Time in minutes
25
3.0 19.0 24.7 29.3 33.3 37.2
30 35
41 . o 45.1
0
5 IO
'5 Downloaded by RYERSON UNIV on September 12, 2015 | http://pubs.acs.org Publication Date: January 1, 1927 | doi: 10.1021/j150283a010
Total crns. Vol. in cu. mm. rise in tube passing through I cm.2 membrane
20
120.0
43.6 34.2 30.8 28.5 28.5 30.8
Time in minutes
Total crns. rise in tube
Vol. in cu. mm. passing through I cm.* membrane 28.5
40 45
48.9 52.5
27.0
50
56.3 60.0 63.8 67.8
28.5 27.8 28.5 30.0 31.4
55 60 65 io
72.0
Experiments showing the Effect of Temperature Changes on the Passage of Sodium Chloride from a One-half Molar Solution through a Collodion Membrane into Water. The sodium chloride was purified by precipitation with hydrogen chloride. The water was distilled and had been boiled to free it from dissolved gases. The collodion sack was prepared by pouring an alcohol-ether solution of nitrocellulose into a large test tube, rotating the tube and draining out the excess solution. After a short time had elapsed the membrane was removed from the tube and washed thoroughly in distilled water. The membrane was perfectly transparent. X large cork stopper which had a large hole cut in the center and which had been thoroughly covered on its entire surface with collodion was fitted into the mouth of the sack. The sack itself was 13 centimeters long and 4 centimeters in diameter. When IOOCC. of solution were placed in the sack 85 square centimeters of surface were presented for dialysis. The bag was suspended in a one and one-half liter beaker by means of a wire clamp attached to the cork and fitted over the side of the beaker. The beaker was immersed in the same thermostat used in the esperiments with rubber membranes. A glass stirrer passed through the hole in the cork stopper and effectively agitated the contents of the sack. Another stirrer circulated rhe contents of the beaker. IOOCC. of the salt solution were placed in the bag and IPOOCC. of distilled water in the beaker. The solution and the water in the beaker were both brought to the temperature of the thermostat before lowering the sack into the water IOCC. samples were drawn every 5 minutes from the beaker. The contents of the beaker were agitated with a current of air just before drawing each sample. This was done to make certain that there was not a layer of concentrated solution a t the bottom of the beaker which had not been completely eliminated by the action of the mechanical stirrer. IOCC. of pure water at the temperature of the experiment were added for every IOCC.of solution withdrawn. Corrections were made for this continual dilution.
136
RALPH N. TRAXLER
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The chloride was determined in each sample drawn by means of a N, I O O solution of silver nitrate, using potassium chromate as indicator. Experiments were performed at ten-degree intervals from z ; O C to 6 j"C. Two or more experiments were conducted at each temperature and it was found possible to check within small margins between two runs at the same temperature. The quantity of salt in the system a t the end of a run as calculated from the analytical results checked the amount in the original IOOCC.
FIQ.3
of one-half molar solution within o . I j 5 to o.zoc/;. When the transfer of sodium chloride became almost zero the contents of the sack in each experiment measured approximately I IOCC. indicating a flow of water through the collodion membrane toward the salt solution. The same membrane was used for the first seven runs. This membrane was accidentally broken and a new one had to be prepared. To determine whether results from two different membranes were comparable, some of the determinations made with the first membrane were repeated with the new one. These determinations checked almost as closely as those made with the same membrane. It is thus possible to prepare two collodion membranes from the
EFFECT OF TEMPERATURE O S RATE OF OSMOSIS
I37
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same material and following the same procedure which will show the same rate of permeability to a soluble salt such as sodium chloride. It should be noted at this point that the membranes were soaked thoroughly in distilled water between experiments.
FIQ.4
The amount of sodium chloride in milligrams passing through one square centimeter of the collodion membrane in five minutes was calculated from the analytical data. These are the values given in column three of Tables X to XIV and used in plotting against time in Figs. 3 and 4.
138
RALPH N. TRAXLER
TABLE X KaC1 through Collodion at
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Time in cc. I/IOO N Mgs. S a C l passminutes &?io8required ing through I for NaCl enterc n 2 ?f membrane in 5 min. ing 10c.c. in five minutes
25OC
Time in cc. I / I O O S Mgs. TaCl minutes AgXOa required passing for S a C l enter- through ing 10c.c. in five I cm*. of minutes membrane in j mtn.
5
4.90
4.20
50
1.10
IO
4.25
55
I
15
3.50
3.66 3.02
20
2.90
2.47
25
2.20
30 35
2.00
40
1.60 1.35
1.86 1 ' 73 1.39 1.29
45
I.20
I .O$
,oo
.95 .86 .61 .61
60 65 70
.70
.j0
.44
-1+3
.60 .60 .4j
.5 1
80
85 90
.io
.40
'51 .39 .35
TABLE XI XaC1 through Collodion at 3 j°C Time in C.C. I / I O O S hlgs. KaC1 ass minutes AgKOsrequired ing througg I for NaC1 entering em.* of mem10c.c. in five brane in 5 min. minutes
5
5 ' 40
IO
4.85
15
4. IO 3.10 2.65
20
25
30 35 40 45
2.10
50 55 60 65
3 65 4 18
3 65 2 67 2 28 I 83
1.80 1.60
I 1
37
1.20
1
03
Time in C.C. I/IOOS Wgs. S a C l minutes A g S 0 3 required passing for S a C l enter- through ing 10c.c. in five I em.* ot minutes membrane
io
75 80 85
j2
TABLEXI1 KaC1 through Collodion at j.
