Interfacial interactions between Skeletonema costatum extracellular organic matter and metal oxides: Implications for ceramic membrane filtration.
In the current study, the interfacial interactions between the high molecular weight (HMW) compounds of Skeletonema costatum (SKC) extracellular organic matter (EOM) and ZrO2or Al2O3, were investigated by atomic force microscopy (AFM). HMW SKC-EOM was rigorously characterized and described as a hydrophilic organic compound mainly comprised of polysaccharide-like structures. Lipids and proteins were also observed, although in lower abundance. HMW SKC-EOM displayed attractive forces during approaching (i.e., leading to jump-to-contact events) and adhesion forces during retracting regime to both metal oxides at all solution conditions tested, where electrostatics and hydrogen bonding were suggested as dominant interacting mechanisms. However, the magnitude of these forces was significantly higher on ZrO2surfaces, irrespective of cation type (Na+or Ca2+) or concentration. Interestingly, while HMW SKC-EOM interacting forces to Al2O3were practically insensitive to solution chemistry, the interactions between ZrO2and HMW SKC-EOM increased with increasing cation concentration in solution. The structure, and lower charge, hydrophilicity, and density of hydroxyl groups on ZrO2surface would play a key role on favoring zirconia associations with HMW SKC-EOM. The current results contribute to advance our fundamental understanding of Algogenic Organic Matter (AOM) interfacial interactions with metal oxides (i.e., AOM membrane fouling), and would highly assist in the proper selection of membrane material during episodic algal blooms.
Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Saudi Arabia.
Noor
N
Zaouri
Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, Australia; Facultad del Mar y Medio Ambiente, Universidad Del Pacifico, Guayaquil, Ecuador.
Leonardo
L
Gutierrez
Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Saudi Arabia.
Laure
L
Dramas
Escuela Superior Politécnica del Litoral, Facultad de Ingeniería en Ciencias de la Tierra, Ecuador.
Daniel
D
Garces
Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Saudi Arabia; Curtin Water Quality Research Centre, Department of Chemistry, Curtin University, Australia. Electronic address: jean-philippe.croue@curtin.edu.au.
Jean-Philippe
JP
Croue
D002516:Ceramics; D005374:Filtration; D008567:Membranes, Artificial; D008670:Metals; D010087:Oxides
D008567:Membranes, Artificial; D008670:Metals; D010087:Oxides
Atomic force microscopy; Interfacial interactions; Metal oxides; Skeletonema costatum extracellular organic matter