Our overarching aim is to determine the environmental fate and impacts of emerging, organic materials and contaminants. We focus on: wildfire-derived pyrogenic organic matter; conventional/biodegradable plastics; and natural material-based plastic alternatives.

A central theme of our research is photochemistry. We use cutting-edge laser spectroscopy and aquatic photochemistry principles to understand the fundamental transformation mechanisms, transformation products formed, and reactive intermediates generated from organic materials during sunlight exposure. Our unique expertise is singlet oxygen and its direct measurement through its near-IR phosphorescence emission.

Publications Scholar

Pyrogenic dissolved organic matter photochemistry

We are exploring the fundamental photochemistry of pyrogenic dissolved organic matter to understand the impacts of wildfires on surface waters. Our main focus is measuring the singlet oxygen quantum yields from pyrogenic dissolved organic matter using novel singlet oxygen phosphorescence techniques. This technique allows us to probe the reactivity of triplet excited state pyrogenic dissolved organic matter, a reactive intermediate that is challenging to measure. We are also interested in wavelength dependent photolysis processes.

Plastic phototransformation in agricultural and aquatic systems

We address critical knowledge gaps on the environmental fate and impacts of plastic and its photodegradation products formed during sunlight weathering. Our major focus is biodegradable plastics and other emerging natural material-based plastic alternatives. By studying these materials, we aim to advance their safe, sustainable use towards designing a future without pollution or waste. We are developing tools to monitor plastic degradation products in agricultural soils, evaluating the aquatic toxicity of the photoproducts from natural material-based plastic alternatives, and exploring new sustainable plastic additives.

Facilities

Our lab is housed in the Utah Water Research Lab, where we work in the shared use Environmental Quality Laboratory, which supports extensive analytical instrumentation.

A central instrument in our lab is our laser system, an Edinburgh LP980 that is powered by a tunable Opotek Radiant laser. This system allows us to follow the kinetics of photochemical processes at the nanosecond scale. We have the ability to measure transient absorption kinetics and time-resolved singlet oxygen phosphorescence. The Opotek Radiant laser is tunable, allowing us to set the excitation wavelength anywhere from 210-2500 nm to investigate wavelength dependent photochemical processes.

We also have various UV light sources to study steady-state photochemical processes.