TY - JOUR
T1 - Osmotic equilibrium in the forward osmosis process
T2 - Modelling, experiments and implications for process performance
AU - Phuntsho, Sherub
AU - Hong, Seungkwan
AU - Elimelech, Menachem
AU - Shon, Ho Kyong
N1 - Funding Information:
This study was supported by the National Centre of Excellence in Desalination Australia (NCEDA) , which is funded by the Australian Government through the Water for the Future initiative . This study was also partly supported by the World Class University Program funded by the Ministry of Education, Science and Technology through the National Research Foundation of Korea ( R33-10046 ).
PY - 2014/3/1
Y1 - 2014/3/1
N2 - Forward osmosis (FO) has gained significant research interest due to the wide range of potential applications in desalination and wastewater reuse. However, the FO process being concentration (osmosis) driven has its own intrinsic limitations. Net transfer of water across the membrane occurs until the point of osmotic equilibrium between the draw solution (DS) and the feed solution (FS). Without external intervention, it is impossible to dilute the DS beyond the point of osmotic equilibrium. In this study, the concept of osmotic equilibrium in the FO process is introduced by simulating conditions in a plate-and-frame FO membrane module using established mass transport models. The simulations evaluated the influence of various operating parameters on process performance, assessed in terms of water flux, feed recovery rate and the final concentration of the diluted DS. The counter-current crossflow mode of operation has been observed to be advantageous because it can achieve higher module average water flux, higher feed water recovery rates and higher DS final dilution. Based on the osmotic equilibrium concept and mass balance analysis, a modified equation for the water extraction capacity of a draw solute has been proposed. This study underscores the need for process optimisation for large-scale FO operations.
AB - Forward osmosis (FO) has gained significant research interest due to the wide range of potential applications in desalination and wastewater reuse. However, the FO process being concentration (osmosis) driven has its own intrinsic limitations. Net transfer of water across the membrane occurs until the point of osmotic equilibrium between the draw solution (DS) and the feed solution (FS). Without external intervention, it is impossible to dilute the DS beyond the point of osmotic equilibrium. In this study, the concept of osmotic equilibrium in the FO process is introduced by simulating conditions in a plate-and-frame FO membrane module using established mass transport models. The simulations evaluated the influence of various operating parameters on process performance, assessed in terms of water flux, feed recovery rate and the final concentration of the diluted DS. The counter-current crossflow mode of operation has been observed to be advantageous because it can achieve higher module average water flux, higher feed water recovery rates and higher DS final dilution. Based on the osmotic equilibrium concept and mass balance analysis, a modified equation for the water extraction capacity of a draw solute has been proposed. This study underscores the need for process optimisation for large-scale FO operations.
KW - Crossflow direction
KW - Desalination
KW - Forward osmosis
KW - Modelling
KW - Osmotic equilibrium
UR - http://www.scopus.com/inward/record.url?scp=84888799086&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2013.11.009
DO - 10.1016/j.memsci.2013.11.009
M3 - Article
AN - SCOPUS:84888799086
SN - 0376-7388
VL - 453
SP - 240
EP - 252
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -