Abstract
In this study, we systematically investigated the propensity and reversibility of combined organic-colloidal fouling in forward osmosis (FO) under various solution chemistries (pH and calcium ion concentrations) and applied hydraulic pressure on the feed side. Alginate, silica colloids, and their mixture (i.e., combined organic-colloidal) were used as model foulants. Our findings demonstrate that combined organic-colloidal foulants caused more rapid flux decline than the individual foulants due to the synergistic effect of alginate and silica colloids. As a result, much lower flux recovery was achieved by physical cleaning induced by increasing the cross-flow rate, in contrast to single foulants of which the fouling layer was easily removed under all solution conditions. Interestingly, less flux decline was observed at neutral pH for combined fouling, while acidic conditions were favorable for alginate fouling and basic solutions caused more silica fouling, thereby providing clear evidence for the combined fouling effect. It was also found that calcium ions enhanced water flux decline and induced the formation of less reversible combined organic-colloidal fouling layers. Lastly, the role of applied hydraulic pressure on the feed side in FO was examined to elucidate the mechanism of fouling layer formation, fouling reversibility, and water flux recovery. Higher fouling propensity and lower fouling reversibility of combined organic-colloidal fouling were observed in the presence of applied hydraulic pressure on the feed side. This observation suggests that the lower fouling propensity and greater fouling reversibility in FO compared to reverse osmosis (RO), are attributable to unpressurized operating conditions in FO.
| Original language | English |
|---|---|
| Pages (from-to) | 206-212 |
| Number of pages | 7 |
| Journal | Journal of Membrane Science |
| Volume | 460 |
| DOIs | |
| Publication status | Published - 2014 Jun 15 |
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Keywords
- Alginate fouling
- Combined organic and colloidal fouling
- Forward osmosis
- Fouling reversibility
- Silica fouling
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Materials Science(all)
- Biochemistry
- Filtration and Separation
Cite this
Combined organic and colloidal fouling in forward osmosis : Fouling reversibility and the role of applied pressure. / Kim, Yeowon; Elimelech, Menachem; Shon, Ho Kyong; Hong, Seungkwan.
In: Journal of Membrane Science, Vol. 460, 15.06.2014, p. 206-212.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Combined organic and colloidal fouling in forward osmosis
T2 - Fouling reversibility and the role of applied pressure
AU - Kim, Yeowon
AU - Elimelech, Menachem
AU - Shon, Ho Kyong
AU - Hong, Seungkwan
PY - 2014/6/15
Y1 - 2014/6/15
N2 - In this study, we systematically investigated the propensity and reversibility of combined organic-colloidal fouling in forward osmosis (FO) under various solution chemistries (pH and calcium ion concentrations) and applied hydraulic pressure on the feed side. Alginate, silica colloids, and their mixture (i.e., combined organic-colloidal) were used as model foulants. Our findings demonstrate that combined organic-colloidal foulants caused more rapid flux decline than the individual foulants due to the synergistic effect of alginate and silica colloids. As a result, much lower flux recovery was achieved by physical cleaning induced by increasing the cross-flow rate, in contrast to single foulants of which the fouling layer was easily removed under all solution conditions. Interestingly, less flux decline was observed at neutral pH for combined fouling, while acidic conditions were favorable for alginate fouling and basic solutions caused more silica fouling, thereby providing clear evidence for the combined fouling effect. It was also found that calcium ions enhanced water flux decline and induced the formation of less reversible combined organic-colloidal fouling layers. Lastly, the role of applied hydraulic pressure on the feed side in FO was examined to elucidate the mechanism of fouling layer formation, fouling reversibility, and water flux recovery. Higher fouling propensity and lower fouling reversibility of combined organic-colloidal fouling were observed in the presence of applied hydraulic pressure on the feed side. This observation suggests that the lower fouling propensity and greater fouling reversibility in FO compared to reverse osmosis (RO), are attributable to unpressurized operating conditions in FO.
AB - In this study, we systematically investigated the propensity and reversibility of combined organic-colloidal fouling in forward osmosis (FO) under various solution chemistries (pH and calcium ion concentrations) and applied hydraulic pressure on the feed side. Alginate, silica colloids, and their mixture (i.e., combined organic-colloidal) were used as model foulants. Our findings demonstrate that combined organic-colloidal foulants caused more rapid flux decline than the individual foulants due to the synergistic effect of alginate and silica colloids. As a result, much lower flux recovery was achieved by physical cleaning induced by increasing the cross-flow rate, in contrast to single foulants of which the fouling layer was easily removed under all solution conditions. Interestingly, less flux decline was observed at neutral pH for combined fouling, while acidic conditions were favorable for alginate fouling and basic solutions caused more silica fouling, thereby providing clear evidence for the combined fouling effect. It was also found that calcium ions enhanced water flux decline and induced the formation of less reversible combined organic-colloidal fouling layers. Lastly, the role of applied hydraulic pressure on the feed side in FO was examined to elucidate the mechanism of fouling layer formation, fouling reversibility, and water flux recovery. Higher fouling propensity and lower fouling reversibility of combined organic-colloidal fouling were observed in the presence of applied hydraulic pressure on the feed side. This observation suggests that the lower fouling propensity and greater fouling reversibility in FO compared to reverse osmosis (RO), are attributable to unpressurized operating conditions in FO.
KW - Alginate fouling
KW - Combined organic and colloidal fouling
KW - Forward osmosis
KW - Fouling reversibility
KW - Silica fouling
UR - http://www.scopus.com/inward/record.url?scp=84896461179&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84896461179&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2014.02.038
DO - 10.1016/j.memsci.2014.02.038
M3 - Article
AN - SCOPUS:84896461179
VL - 460
SP - 206
EP - 212
JO - Jornal of Membrane Science
JF - Jornal of Membrane Science
SN - 0376-7388
ER -