A host of emerging contaminants, including persistent organic pollutants and pharmaceuticals, pass through current water treatment infrastructure unabated. To date, the broad application of photocatalysis for contaminant degradation in municipal water systems has been limited by cost, catalyst recovery, and potential catalyst leaching into effluent water sources. To overcome these challenges, we synthesized a ZnO-SiO<sub>2</sub>-Ag photocatalytic nanocomposite immobilized in a polydimethylsiloxane (PDMS) polymer foam for chemical-additive-free flow through water treatment. In the presence of UV light, the nanocomposite generates reactive oxygen species (ROSs) for contaminant degradation while the porous PDMS foam scaffold (pore volume ~ 0.65) provides support allowing for continuous water flow while securing the nanocomposite. The heterogeneous foam structure, fabricated via template leaching, was optimized for UV light transmittance and fluid flow by modifying the template grain size and packing density. The ROS generation and lifetimes of the nanocomposite were determined by measuring the chemiluminescence of luminol in the presence of horseradish peroxidase. Nanocomposites synthesized with Ag exhibited a tenfold increase in ROS generation compared to pure ZnO. The optical band gap for direct allowed transitions is 3.2 eV for the synthesized nanocomposites. Spectral absorption above the absorption edge of 380 nm increased 30% with this inclusion of silver. A continuous flow system was designed to determine the degree of contaminant degradation and quantum efficiency. Single contaminant streams (metformin, ciprofloxacin, acetaminophen, caffeine, phenol, herbicides, and dyes), as well as the mixed contaminant systems, were treated to investigate synergistic degradation pathways.

Polymer scaffold for photocatalytic degradation of emerging and persistent contamination in drinking water

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

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