Table 2. Comparison of the Osmotic Pressures of Draw Agents from the Literature.
| draw agent | concentration | osmotic pressure | ref. |
|---|---|---|---|
| P4444 DMBSa | 70 wt % | 25 barb | (11) |
| P4444 TFAc | 70 wt % | 38 barb | (11) |
| polyethylene glycold | 40 wt % | 50 bare | (46) |
| PAGBf | 40 wt % | 20 bare | (46) |
| ethylene oxide-propylene oxide copolymerg | 70 wt % | 96 bare | (47) |
| PAANah | 0.12 g/mL | 8.1 bari | (48) |
| PSSS-PNIPAMj | 33.3 wt % | 28.6 bark | (49) |
| trimethylaminel | 1.0 M | 48.8 barl | (50) |
| l-PDMAAm | 50 wt % | >170 barm | This work |
a
P4444 = tetrabutylphosphonium, DMBS = 2,4-dimethylbenzene sulfonate.
b
Measured by vapor pressure osmometer.
c
TFA = trifluoroacetate.
d
Mw = 4000 g/mol.
e
Measured by water activity method. The water activity aw of the DS solutions at 25 ± 1 °C was measured using a water activity meter.
f
PAGB = poly (propylene glycol-ran-ethylene glycol) monobutyl ether, Mw = 4000 g/mol.
g
Ethylene oxide-propylene oxide copolymer, Mw = 2000 g/mol.
h
PAA Na= poly(acrylic acid) sodium salts, Mw = 1800 g/mol.
i
The osmolality of draw solutions was converted to osmotic pressure using a model 3250 osmometer.
j
PSSS-PNIPAM = poly(sodium styrene-4-sulfonate-co-n-isopropylacrylamide), 15 wt % SSS.
k
Measured by direct membrane osmometer.
l
Measured by a stream analyzer, under CO2.
m
Under CO2.