USC’s efforts to become more sustainable have reached into nearly every corner of the University Park and Health Science campuses — including the chemistry labs.
At the USC Dornsife College of Letters, Arts and Sciences, chemistry professors Jessica Parr and Travis Williams have recently implemented techniques to make their respective research labs greener, advancing both the university’s priorities and the best practices of their discipline.
In 1998, the American Chemical Society developed 12 principles of green chemistry, which include measures such as designing safer chemicals, energy efficiency and pollution prevention.
The chemistry world has also emphasized the proper disposal of wastes, Parr said. At USC, this includes practices as simple as properly labeling waste for USC Environmental Health and Safety to ensure proper disposal.
“I think that the community at large sees this as our responsibility to figure out how to fix and how to turn things around and show that, as a whole, we are interested in the environment,” Parr said.
For example, Parr’s freshman labs have nearly eliminated the use of mercury in experiments, including the replacement of old mercury thermometers. Likewise, during experiments that produce water or salt that can be poured down the drain, students are instructed to use a waste container for the product.
“If we introduce students to these practices early, as they go on to other laboratory experiences, they hopefully will retain with them some of these ideas and sustainable processes,” she said.
Replacing equipment for greater energy efficiency
Efforts such as switching from Bunsen burners or any other open flame to electric hot plates have become common in chemistry in the last 50 years, as the field has tried to move away from using fossil fuels, primarily for safety. The next challenge is how labs can reduce the use of energy in general, Williams said. Hot plates might not make the list of largest energy consumers in a lab, but X-ray machines are definite contenders.
When it comes to sustainability, generating X-rays for things like diffraction and tomography is a tremendously energy-intensive activity. And when machines consume so much energy, coolers must run to prevent them from overheating, consuming even more energy.
That’s why Williams’ lab brought in a new machine — with help from the Anton Burg Foundation and the National Science Foundation — for the chemistry department’s X-ray lab that has reduced energy usage significantly.
“We upgraded to a new microfocus diffractometer, which is not only a much better scientific instrument, but it uses a fraction of the electricity,” Williams said. “Then we put some blinds on the windows to keep the solar heat out, and now we’ve nearly halved the amount of electricity we use.”
The method is known as X-ray crystallography, which is used to obtain a three-dimensional molecular structure from a crystal. Through this technology, the locations of atoms in any crystal can be precisely mapped by looking at the diffraction pattern of the crystal from an X-ray beam.
Chemistry’s core lab features three X-ray machines of different sizes. The largest machine, which Williams referred to as a “beast,” was replaced in November with a newer model that consumes a fraction of the energy. The old machine used a maximum of around 16 kilowatts (kW) of power to run, compared to the new machine which only uses a maximum of around 7 kW. If the new machine runs continuously for an hour, that’s a maximum of 7 kilowatt-hours (kWh), though Williams usually measures a usage around 5 or 6 kWh.
In terms of heat generated, the old machine produced around 24,000 British thermal units (Btus) per hour; the new machine only produces 8,500 Btus per hour. To put that into perspective, an air conditioning unit needed to cool 24,000 Btus is the same unit needed to cool a four-bedroom apartment.
“This isn’t like a stir plate where you’re saving a couple of amps,” Williams said. “We could retire two air conditioners because of how much less electricity we used and heat we generate.”
Green chemistry, sustainability and the road ahead
Earlier this year, around 3 p.m. on a sunny Sunday in May, California ran on 100% renewable energy for the first time. Though it was relatively brief, Williams said that moment was remarkable to see, and a step in the right direction.
“That we kissed the intersection of exporting green electricity from California makes me re-think my research directions toward our new life in a post-scarcity electricity market,” Williams said. “Should we be desalinating? How do we manufacture? How do we fuel planes, trains and automobiles in this new world?”
Parr knows there’s no end-all technology that’s going to solve the major problems we face, but she said it’s the small changes from people in all fields that will make the biggest impact.
“Similar to climate change, I’m not sure we have that silver bullet just yet,” she said. “But I think everybody can always do a little bit better than what they’re doing now.”