Abstract
Fouling behaviors during forward osmosis (FO) and reverse osmosis (RO) are compared. Alginate, humic acid, and bovine serum albumin (BSA) are used as model organic foulants, and two suspensions of silica colloids of different sizes are chosen as model particulate foulants. To allow meaningful comparison of fouling behavior, identical hydrodynamic operating conditions (i.e., initial permeate flux and cross-flow velocity) and feed water chemistries (i.e., pH, ionic strength, and calcium concentration) are employed during FO and RO fouling runs. The observed flux-decline behavior in FO changed dramatically with the type of organic foulant, size of colloidal foulant, and the type of the draw solution employed to generate the osmotic driving force. Based on these experimental data and the systematic comparisons of fouling behaviors of FO and RO, we provide new insights into the mechanisms governing FO fouling. In FO, reverse diffusion of salt from the draw solution to the feed side exacerbates the cake-enhanced osmotic pressure within the fouling layer. The elevated osmotic pressure near the membrane surface on the feed side leads to a substantial drop in the net osmotic driving force and, thus, significant decline of permeate flux. Our results further suggest that the structure (i.e., thickness and compactness) of the fouling layers of FO and RO is quite different. By varying the cross-flow velocity during the organic fouling runs, we were able to examine the fouling reversibility in FO and RO. The permeate flux during organic fouling in FO recovered almost completely with increasing cross-flow velocity, while no noticeable change was observed for the RO system. Our results suggest that organic fouling in FO could be controlled effectively by optimizing the hydrodynamics in the feed stream without employing chemical cleaning.
| Original language | English |
|---|---|
| Pages (from-to) | 34-39 |
| Number of pages | 6 |
| Journal | Journal of Membrane Science |
| Volume | 365 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 2010 Dec 1 |
Fingerprint
Keywords
- Cake-enhanced osmotic pressure (CEOP)
- Forward osmosis
- Fouling reversibility
- Reverse osmosis
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Materials Science(all)
- Biochemistry
- Filtration and Separation
Cite this
Comparison of fouling behavior in forward osmosis (FO) and reverse osmosis (RO). / Lee, Sangyoup; Boo, Chanhee; Elimelech, Menachem; Hong, Seungkwan.
In: Journal of Membrane Science, Vol. 365, No. 1-2, 01.12.2010, p. 34-39.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Comparison of fouling behavior in forward osmosis (FO) and reverse osmosis (RO)
AU - Lee, Sangyoup
AU - Boo, Chanhee
AU - Elimelech, Menachem
AU - Hong, Seungkwan
PY - 2010/12/1
Y1 - 2010/12/1
N2 - Fouling behaviors during forward osmosis (FO) and reverse osmosis (RO) are compared. Alginate, humic acid, and bovine serum albumin (BSA) are used as model organic foulants, and two suspensions of silica colloids of different sizes are chosen as model particulate foulants. To allow meaningful comparison of fouling behavior, identical hydrodynamic operating conditions (i.e., initial permeate flux and cross-flow velocity) and feed water chemistries (i.e., pH, ionic strength, and calcium concentration) are employed during FO and RO fouling runs. The observed flux-decline behavior in FO changed dramatically with the type of organic foulant, size of colloidal foulant, and the type of the draw solution employed to generate the osmotic driving force. Based on these experimental data and the systematic comparisons of fouling behaviors of FO and RO, we provide new insights into the mechanisms governing FO fouling. In FO, reverse diffusion of salt from the draw solution to the feed side exacerbates the cake-enhanced osmotic pressure within the fouling layer. The elevated osmotic pressure near the membrane surface on the feed side leads to a substantial drop in the net osmotic driving force and, thus, significant decline of permeate flux. Our results further suggest that the structure (i.e., thickness and compactness) of the fouling layers of FO and RO is quite different. By varying the cross-flow velocity during the organic fouling runs, we were able to examine the fouling reversibility in FO and RO. The permeate flux during organic fouling in FO recovered almost completely with increasing cross-flow velocity, while no noticeable change was observed for the RO system. Our results suggest that organic fouling in FO could be controlled effectively by optimizing the hydrodynamics in the feed stream without employing chemical cleaning.
AB - Fouling behaviors during forward osmosis (FO) and reverse osmosis (RO) are compared. Alginate, humic acid, and bovine serum albumin (BSA) are used as model organic foulants, and two suspensions of silica colloids of different sizes are chosen as model particulate foulants. To allow meaningful comparison of fouling behavior, identical hydrodynamic operating conditions (i.e., initial permeate flux and cross-flow velocity) and feed water chemistries (i.e., pH, ionic strength, and calcium concentration) are employed during FO and RO fouling runs. The observed flux-decline behavior in FO changed dramatically with the type of organic foulant, size of colloidal foulant, and the type of the draw solution employed to generate the osmotic driving force. Based on these experimental data and the systematic comparisons of fouling behaviors of FO and RO, we provide new insights into the mechanisms governing FO fouling. In FO, reverse diffusion of salt from the draw solution to the feed side exacerbates the cake-enhanced osmotic pressure within the fouling layer. The elevated osmotic pressure near the membrane surface on the feed side leads to a substantial drop in the net osmotic driving force and, thus, significant decline of permeate flux. Our results further suggest that the structure (i.e., thickness and compactness) of the fouling layers of FO and RO is quite different. By varying the cross-flow velocity during the organic fouling runs, we were able to examine the fouling reversibility in FO and RO. The permeate flux during organic fouling in FO recovered almost completely with increasing cross-flow velocity, while no noticeable change was observed for the RO system. Our results suggest that organic fouling in FO could be controlled effectively by optimizing the hydrodynamics in the feed stream without employing chemical cleaning.
KW - Cake-enhanced osmotic pressure (CEOP)
KW - Forward osmosis
KW - Fouling reversibility
KW - Reverse osmosis
UR - http://www.scopus.com/inward/record.url?scp=78049293209&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=78049293209&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2010.08.036
DO - 10.1016/j.memsci.2010.08.036
M3 - Article
AN - SCOPUS:78049293209
VL - 365
SP - 34
EP - 39
JO - Jornal of Membrane Science
JF - Jornal of Membrane Science
SN - 0376-7388
IS - 1-2
ER -