Capsules of the Poly(α-olefin) PAO₄₃₂ for Removal of BTEX Contaminants from Water

Abstract

Poly­(α-olefins) (PAOs) are nonvolatile and nontoxic liquid hydrocarbon oligomeric solvents with solubility properties similar to heptane. PAOs can be used in traditional liquid–liquid extractions, but handling difficulties arise due to the formation of emulsions. In this study, PAO432, a low viscosity PAO with a molar mass of 432 g/mol, is encapsulated in a polymer-based shell using a Pickering emulsion stabilized by graphene oxide nanosheets and interfacial polymerization. The capsules are spherical with a diameter of approximately 50 μm and are 70 wt % PAO432. We demonstrate that these capsules can remove different low molecular weight organic contaminants from water, specifically benzene, toluene, ethylbenzene, and p-xylene (BTEX). In suspension, capsules of PAO432 were able to remove 97% of benzene from a saturated water solution, and >93% removal was observed for all BTEX components. We also showed that passing a contaminated aqueous solution through a column packed with the capsules resulted in removal of the contaminant and collection of water as the eluent. Encapsulation of PAO thus removes the need for emulsification as with traditional liquid–liquid extractions, allows for a lower PAO432:water ratio to be used, and gives the opportunity to develop a continuous extraction system. The favorable properties also indicate that PAO432 capsules might be suitable for other applications, including removal of BTEX gases from air.

Additive manufacturing: modular platform for 3D printing fluid-containing monoliths

“…GO was selected because of previous work demonstrating its effectiveness for stabilizing oil-in-water emulsions. [20][21][22][23][24] Optical microscopy images of the emulsion before polymerization are provided in Fig. S1 † and demonstrate that the interface between the dispersed and continuous phases was successfully stabilized by GO.…”

Sequestration of Phenols from Water into Poly(α-olefins) Facilitated by Hydrogen Bonding Polyisobutylene Additives

“…Our previous work showed that PAO itself worked well to sequester nonpolar contaminants by liquid−liquid extraction. 37,38 That work also showed that a functionalized PIBbound additive (PIB 450 -catechol) facilitated the sequestration of hydrogen bond-accepting contaminants. We hypothesized that PIB oligomers functionalized with hydrogen bondaccepting groups such as amines could similarly be useful for the targeted removal of hydrogen bond-donating water contaminants such as phenols.…”

“…Our recent work showed that poly­(α-olefin)­s (PAOs) could serve as recyclable extraction solvents for removal of trace amounts of nonpolar organic compounds from water in liquid/liquid extractions and in biphasic extractions using PAOs that were encapsulated within a polyurea shell. − In these applications, PAOs do not contaminate the aqueous phase during mixing of the PAO and aqueous phases. In these systems, the PAO phases quantitatively separate from the cleaned aqueous phase by gravity separation.…”

Temperature-Dependent Capsule Shell Bonding and Destruction Based on Hindered Poly(urea-urethane) Chemistry

“…Furthermore, Landfester and colleagues prepared glycerol-encapsulated nanocapsules through interfacial polyaddition of glycerol and toluene diisocyanate using an oil-in-water emulsion stabilized by polyglycerol polyricinoleate, where the capsules can be used for improving the lubricant performance in metal–metal contact cases . Additionally, the Pentzer group constructed capsules from Pickering emulsions stabilized by 2D particles using interfacial polymerization between diisocyanate and diamine in oil/water, oil/oil, IL/water, and IL/oil systems, with the identity of the two phases dependent on the nanosheet functionalization. Using these systems, Luo et al and Edgehouse et al produced capsules with composite shells of polyurea and nanosheets and cores of IL or polyalpholefin for use in CO 2 uptake , and benzene removal from water, respectively.…”

“…Additionally, the Pentzer group constructed capsules from Pickering emulsions stabilized by 2D particles using interfacial polymerization between diisocyanate and diamine in oil/water, oil/oil, IL/water, and IL/oil systems, with the identity of the two phases dependent on the nanosheet functionalization. Using these systems, Luo et al and Edgehouse et al produced capsules with composite shells of polyurea and nanosheets and cores of IL or polyalpholefin for use in CO 2 uptake , and benzene removal from water, respectively. The ability to tailor not only the composition of the shell and core of the capsules but also their responsiveness to external stimuli will have broad impact across many fields.…”