Organic water pollutants such as petroleum are difficult to treat using traditional methods like filtration. Photocatalysts have been proposed to facilitate the breakdown of these pollutants into less harmful forms and have already been shown to be effective in this regard. However, when photocatalysts are added to polluted water, they form a suspension which can be difficult to remove. One possible solution to this issue is the use of buoyant, porous, polymer substrates to prevent the formation of a suspension. Our group tested the ability of polydimethylsiloxane (PDMS) beads to meet these substrate criteria using titanium(IV) oxide, zinc oxide, and tungsten(VI) oxide as photocatalysts. The beads were created with the photocatalysts incorporated into their structure using dispersion polymerization to maximize their surface-area-to-volume (SAV) ratios. Their structure and SAV ratios were observed using scanning electron microscopy, and Brunauer-Emmet-Teller isotherms. Energy dispersive X-ray spectroscopy, X-ray diffraction, and Raman spectroscopy were used to determine that the photocatalysts had been incorporated successfully and that the photocatalyst structure remained unchanged. UV/Vis spectroscopy was then used to measure the rate at which the photocatalytic PDMS beads degraded methylene blue, a sample pollutant. It was found that the rate was within an order of magnitude of the rate measured using a photocatalyst suspension. Current work is focused on transitioning from PDMS to polystyrene in order to reduce production costs.

Porous polydimethylsiloxane beads as a substrate to assist in the breakdown of organic water pollutants using photocatalysts

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.