Performance of titanium salts compared to conventional FeCl 3 for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristics

Handle URI:
http://hdl.handle.net/10754/625627
Title:
Performance of titanium salts compared to conventional FeCl 3 for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristics
Authors:
Chekli, L.; Corjon, E.; Tabatabai, S. Assiyeh Alizadeh ( 0000-0002-4997-3861 ) ; Naidu, G.; Tamburic, B.; Park, S.H.; Shon, H.K. ( 0000-0002-3777-7169 )
Abstract:
During algal bloom periods, operation of seawater reverse osmosis (SWRO) pretreatment processes (e.g. ultrafiltration (UF)) has been hindered due to the high concentration of algal cells and algal organic matter (AOM). The present study evaluated for the first time the performance of titanium salts (i.e. titanium tetrachloride (TiCl4) and polytitanium tetrachloride (PTC)) for the removal of AOM in seawater and results were compared with the conventional FeCl3 coagulant. Previous studies already demonstrated that titanium salts not only provide a cost-effective alternative to conventional coagulants by producing a valuable by-product but also minimise the environmental impact of sludge production. Results from this study showed that both TiCl4 and PTC achieved better performance than FeCl3 in terms of turbidity, UV254 and dissolved organic carbon (DOC) removal at similar coagulant dose. Liquid chromatography – organic carbon detection (LC-OCD) was used to determine the removal of AOM compounds based on their molecular weight (MW). This investigation revealed that both humic substances and low MW organics were preferentially removed (i.e. up to 93% removal) while all three coagulants showed poorer performance for the removal of high MW biopolymers (i.e. less than 50% removal). The detailed characterization of flocs indicated that both titanium coagulants can grow faster, reach larger size and present a more compact structure, which is highly advantageous for the design of smaller and more compact mixing and sedimentation tanks. Both titanium coagulants also presented a higher ability to withstand shear force, which was related to the higher amount of DOC adsorbed with the aggregated flocs. Finally, TiCl4 had a better recovery after breakage suggesting that charge neutralization may be the dominant mechanism for this coagulant, while the lower recovery of both PTC and FeCl3 indicated that sweep flocculation is also a contributing mechanism for the coagulation of AOM.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC)
Citation:
Chekli L, Corjon E, Tabatabai SAA, Naidu G, Tamburic B, et al. (2017) Performance of titanium salts compared to conventional FeCl 3 for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristics. Journal of Environmental Management 201: 28–36. Available: http://dx.doi.org/10.1016/j.jenvman.2017.06.025.
Publisher:
Elsevier BV
Journal:
Journal of Environmental Management
Issue Date:
20-Jun-2017
DOI:
10.1016/j.jenvman.2017.06.025
Type:
Article
ISSN:
0301-4797
Sponsors:
This work was supported by the SMEs Partnership Project for strengthening tech-competitiveness funded by Korea Small and Medium Business Administration in 2016 (Grant n° S2317919). Support was also provided to LC by the University of Technology Sydney (UTS) through an Early Career Research (ECR) Grant.
Additional Links:
http://www.sciencedirect.com/science/article/pii/S0301479717306060
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorChekli, L.en
dc.contributor.authorCorjon, E.en
dc.contributor.authorTabatabai, S. Assiyeh Alizadehen
dc.contributor.authorNaidu, G.en
dc.contributor.authorTamburic, B.en
dc.contributor.authorPark, S.H.en
dc.contributor.authorShon, H.K.en
dc.date.accessioned2017-10-03T12:49:30Z-
dc.date.available2017-10-03T12:49:30Z-
dc.date.issued2017-06-20en
dc.identifier.citationChekli L, Corjon E, Tabatabai SAA, Naidu G, Tamburic B, et al. (2017) Performance of titanium salts compared to conventional FeCl 3 for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristics. Journal of Environmental Management 201: 28–36. Available: http://dx.doi.org/10.1016/j.jenvman.2017.06.025.en
dc.identifier.issn0301-4797en
dc.identifier.doi10.1016/j.jenvman.2017.06.025en
dc.identifier.urihttp://hdl.handle.net/10754/625627-
dc.description.abstractDuring algal bloom periods, operation of seawater reverse osmosis (SWRO) pretreatment processes (e.g. ultrafiltration (UF)) has been hindered due to the high concentration of algal cells and algal organic matter (AOM). The present study evaluated for the first time the performance of titanium salts (i.e. titanium tetrachloride (TiCl4) and polytitanium tetrachloride (PTC)) for the removal of AOM in seawater and results were compared with the conventional FeCl3 coagulant. Previous studies already demonstrated that titanium salts not only provide a cost-effective alternative to conventional coagulants by producing a valuable by-product but also minimise the environmental impact of sludge production. Results from this study showed that both TiCl4 and PTC achieved better performance than FeCl3 in terms of turbidity, UV254 and dissolved organic carbon (DOC) removal at similar coagulant dose. Liquid chromatography – organic carbon detection (LC-OCD) was used to determine the removal of AOM compounds based on their molecular weight (MW). This investigation revealed that both humic substances and low MW organics were preferentially removed (i.e. up to 93% removal) while all three coagulants showed poorer performance for the removal of high MW biopolymers (i.e. less than 50% removal). The detailed characterization of flocs indicated that both titanium coagulants can grow faster, reach larger size and present a more compact structure, which is highly advantageous for the design of smaller and more compact mixing and sedimentation tanks. Both titanium coagulants also presented a higher ability to withstand shear force, which was related to the higher amount of DOC adsorbed with the aggregated flocs. Finally, TiCl4 had a better recovery after breakage suggesting that charge neutralization may be the dominant mechanism for this coagulant, while the lower recovery of both PTC and FeCl3 indicated that sweep flocculation is also a contributing mechanism for the coagulation of AOM.en
dc.description.sponsorshipThis work was supported by the SMEs Partnership Project for strengthening tech-competitiveness funded by Korea Small and Medium Business Administration in 2016 (Grant n° S2317919). Support was also provided to LC by the University of Technology Sydney (UTS) through an Early Career Research (ECR) Grant.en
dc.publisherElsevier BVen
dc.relation.urlhttp://www.sciencedirect.com/science/article/pii/S0301479717306060en
dc.subjectCoagulationen
dc.subjectAlgal organic matter (AOM)en
dc.subjectPolytitanium tetrachlorideen
dc.subjectTitanium tetrachlorideen
dc.subjectFloc characteristicsen
dc.titlePerformance of titanium salts compared to conventional FeCl 3 for the removal of algal organic matter (AOM) in synthetic seawater: Coagulation performance, organic fraction removal and floc characteristicsen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalJournal of Environmental Managementen
dc.contributor.institutionSchool of Civil and Environmental Engineering, University of Technology, Sydney, Post Box 129, Broadway, NSW, 2007, Australiaen
dc.contributor.institutionPlant Functional Biology and Climate Change Cluster (C3), Faculty of Science, University of Technology Sydney (UTS), Sydney, NSW, 2007, Australiaen
dc.contributor.institutionDepartment of Civil Engineering, Dong-A University, 37 Nakdong-Daero 550beon-gil, Saha-gu, Busan, 604-714, South Koreaen
kaust.authorTabatabai, S. Assiyeh Alizadehen
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