Waste milk could be used to reduce power plant CO2 emissions, Clarkson finds

POTSDAM — Clarkson University research — which shows how surplus milk may be used to capture carbon dioxide (CO2) from fossil-fuel based power-plant emissions — is featured on the front cover of the November issue of Advanced Sustainable Systems.

The cover features a North Country landmark, the surge tank of a Raquette River hydroelectric plant in nearby Hannawa Falls, where two of the paper’s authors reside, per a Clarkson University news release.

Advanced Sustainable Systems is an international, peer-reviewed, interdisciplinary journal publishing research results on the development and implementation of systems, solutions, technologies, and applications that share the focus on the advancement of sustainable living, Clarkson said.

The article, titled “CO2 Capture: Dry and Wet CO2 Capture from Milk-Derived Microporous Carbons with Tuned Hydrophobicity,” explains that it is possible to greatly reduce power plant CO2 emissions by using surplus or waste milk from cows to create “activated carbons, which will adsorb or scrub the CO2 from the output.”

“Our challenge was to create an inexpensive ‘green’ activated carbon,” Mario Wriedt, paper co-author, associate professor of chemistry & biomolecular science, said. “Powdered milk can be converted into advanced activated carbons with the right porosity and surface chemistry to adsorb the CO2, allowing much better control than with the current materials used for this process, like coconut shells or coal.”

This is the first report of “state-of-the-art” performance for an activated carbon derived from a natural compound. The process for making the sorbents is similar to what is done to roast coffee, but with a secondary agent that etches nanoscale holes onto the material.

“Think of extremely dark roast holey coffee beans,” David Mitlin, paper co-author, a former Clarkson professor, and current instructor at the University of Texas at Austin, said. “The nanoscale holes, because of their strict sizes and surface chemistry, are very effective in trapping CO2 while keeping out water vapor. The CO2 is trapped reversibly in the carbon sorbent’s micropores, which can be reused once the CO2 is released from its pores.”

Wriedt notes that the dairy product used in the process would not be taken from the food supply.

He says that although milk consumption has declined more than 30 percent since 1980, annual milk production per dairy cow has increased 13 percent, creating an oversupply in which farmers now dispose of more than 50 million gallons of milk annually. 

“This use of waste milk could actually be a boost for the dairy industry,” according to Wriedt.

The researchers also say that these milk-derived carbon sorbents could also be used in other applications as well, like indoor air purification or water treatment, and that commercialization of the process “may be in the future.”

The paper’s other co-authors are former Clarkson graduate students Jesse Pokrzywinski, Darpandeep Aulakh, and Hubert Bilan, Clarkson chemical engineering undergraduate student Sam Marble, and Mitlin’s postdoctoral researcher Viet Hung Pham.

A Clarkson University Craig-Ignite Research Fellowship enabled the research, the school said.