5 research outputs found
DEVELOPING MULTIFUNCTIONAL FORWARD OSMOSIS (FO) DRAW SOLUTES FOR SEAWATER DESALINATION
Ph.DDOCTOR OF PHILOSOPH
Thermoresponsive Magnetic Nanoparticles for Seawater Desalination
Thermoresponsive
magnetic nanoparticles (MNPs) as a class of smart materials that respond
to a change in temperature may by used as a draw solute to extract
water from brackish or seawater by forward osmosis (FO). A distinct
advantage is the efficient regeneration of the draw solute and the
recovery of water via heat-facilitated magnetic separation. However,
the osmotic pressure attained by this type of draw solution is too
low to counteract that of seawater. In this work, we have designed
a FO draw solution based on multifunctional Fe<sub>3</sub>O<sub>4</sub> nanoparticles grafted with copolymer poly(sodium styrene-4-sulfonate)-<i>co</i>-poly(<i>N</i>-isopropylacrylamide) (PSSS-PNIPAM).
The resulting regenerable draw solution shows high osmotic pressure
for seawater desalination. This is enabled by three essential functional
components integrated within the nanostructure: (i) a Fe<sub>3</sub>O<sub>4</sub> core that allows magnetic separation of the nanoparticles
from the solvent, (ii) a thermoresponsive polymer, PNIPAM, that enables
reversible clustering of the particles for further improved magnetic
capturing at a temperature above its low critical solution temperature
(LCST), and (iii) a polyelectrolyte, PSSS, that provides an osmotic
pressure that is well above that of seawater
A Dendrimer-Based Forward Osmosis Draw Solute for Seawater Desalination
A dendrimer-based
forward osmosis (FO) draw solute, poly(amidoamine)
terminated with sodium carboxylate groups (PAMAM-COONa), was investigated
for seawater desalination. Compared with existing FO draw solutes,
PAMAM-COONa offers unique advantages: (1) Its aqueous solution can
generate high osmotic pressure because of the large number of −COONa
groups. (2) The low viscosity of PAMAM-COONa solution can reduce internal
concentration polarization (ICP), which adversely affects FO water
flux. (3) PAMAM-COONa has a relatively large molecular size, favoring
reduced reverse solute flux. In our FO tests using 2.5-generation
(2.5G) PAMAM-COONa draw solution (33.3 wt %) and seawater (Singapore
coast) feed solution, a relatively high water flux of 9 L m<sup>–2</sup> h<sup>–1</sup> was achieved with commercial
HTI FO membrane. In addition, a considerably reduced reverse solute
flux of PAMAM-COONa compared to that of NaCl was attained. After FO
testing, the diluted PAMAM-COONa solution was reconcentrated to its
original osmotic pressure with membrane distillation to produce desalinated
water and to regenerate the draw solution. In addition to seawater
desalination, the dendrimer-based FO draw solute may find applications
in wastewater treatment and protein enrichment
Zwitterions coated hollow fiber membranes with enhanced antifouling properties for osmotic power generation from municipal wastewater
Thermoresponsive magnetic nanoparticles for seawater desalination
10.1021/am403719sACS Applied Materials and Interfaces52111453-1146