Attachment of a Hydrophobically Modified Biopolymer at the Oil–Water Interface in the Treatment of Oil Spills

Abstract

The stability of crude oil droplets formed by adding chemical dispersants can be considerably enhanced by the use of the biopolymer, hydrophobically modified chitosan. Turbidimetric analyses show that emulsions of crude oil in saline water prepared using a combination of the biopolymer and the well-studied chemical dispersant (Corexit 9500A) remain stable for extended periods in comparison to emulsions stabilized by the dispersant alone. We hypothesize that the hydrophobic residues from the polymer preferentially anchor in the oil droplets, thereby forming a layer of the polymer around the droplets. The enhanced stability of the droplets is due to the polymer layer providing an increase in electrostatic and steric repulsions and thereby a large barrier to droplet coalescence. Our results show that the addition of hydrophobically modified chitosan following the application of chemical dispersant to an oil spill can potentially reduce the use of chemical dispersants. Increasing the molecular weight of the biopolymer changes the rheological properties of the oil-in-water emulsion to that of a weak gel. The ability of the biopolymer to tether the oil droplets in a gel-like matrix has potential applications in the immobilization of surface oil spills for enhanced removal.

Chitosan: Gels and Interfacial Properties

“…Finally, without going into detail, applications of chitosan in industry is by far the most utilized today; including in purification of water and waste water treatment [108,109], treatment of oil spills [110] and treatment of oily waste from the food industry and oil industry [111,112], as well as the potential use in enhanced oil recovery [113].…”

Development of a Coarse-Grained Model of Chitosan for Predicting Solution Behavior

“…The design of self-assembled systems based on chitosan has become an active field of research because chitosan is biocompatible, polycationic, and chemically modifiable as a result of its amine functional group. Chitosan has shown promise for use in applications ranging from wound healing 1-3 and drug delivery [4][5][6][7][8] to water purification [9][10][11] and oil spill remediation 12,13 . Chitosan self-assembly in solution depends strongly on the degree of acetylation (DA) and pH [14][15][16][17][18] .…”

Investigating the role of Pluronic-g-Cationic polyelectrolyte as functional stabilizer for nanocrystals: Impact on Paclitaxel oral bioavailability and tumor growth

“…Our previous studies also helps us to understand that polyelectrolyte's like PSS having both hydrophobic units and hydrophilic units are better stabilizers as compared to conventionally or commonly used non-ionic surfactants as they provide both electrostatic and steric stabilization [22]. On the other hand natural polyelectrolyetes like glycol Chitosan and sodium alginate which are "Generally referred as safe" (GRAS) polyelectrolytes by US-FDA also found unable to stabilize nanocrystals because of their complete hydrophillicilic nature and thus lack of interfacial activity with hydrophobic domains present in drug molecule [23].Since the stabilizing effect largely depends on the affinity of the stabilizer to the surface and the resulting packaging density and thickness of the stabilizer layer [24]. Taking this into consideration, herein we designed hydrophobically modified water soluble Pluronic 127 grafted chitosan (Pl-g-CH) and used it as a functional stabilizer for nanocrystals (NCs) which is anticipated to exhibit several desired properties.…”