Researcher develops new ways to convert CO2, glycerol into valuable chemicals

Yanet Rodriguez Herrero, left, developed two innovative methods to convert CO2 and glycerol into value-added materials during her doctoral research under supervisor Aman Ullah. (Photo: University of Alberta)

A University of Alberta researcher has developed novel ways to convert carbon dioxide, a harmful greenhouse gas, and glycerol, a leftover of biodiesel production, into value-added materials with wide-ranging uses including liquid-hydrogen storage.

The pair of procedures, which will be tested on a larger scale for industry-level viability, represents an important step forward in sustainability, said Yanet Rodriguez Herrero, who conducted the work to earn a Ph.D. in bioresource technology and food engineering from the faculty of agricultural, life and environmental sciences at the University of Alberta.

“We’ve broken a barrier in terms of improving difficult conversion processes and making them more efficient,” Herrero said.

Though CO2 is a major contributor to climate change, it also has potential to be converted into methanol, a highly valuable chemical that can be used in several industrial applications including automotive, electronic, clothing, adhesives, paints and coatings, packaging, solvents, pharmaceuticals and agricultural chemicals.

Methanol also holds promise as a method of transporting and storing hydrogen in liquid form.

But one of the major barriers to successfully converting CO2 into methanol is the water formed as a byproduct during the hydrogenation process, which deactivates a catalyst needed for the transformation.

Using nanotechnology, Herrero successfully developed a process in the lab to prepare a stable catalyst that has the ability to repel water so it works well at low pressure and temperature, making the conversion less energy-intensive and more economically efficient.

Once the process can be successfully scaled up for use by industry, it could mean direct utilization of large amounts of CO2 that has been captured and stored, along with its potential for liquid-hydrogen storage, said Aman Ullah, a professor who supervised Herrero’s work.

“The conversion of CO2 into various value-added products would be a more logical idea to reduce emissions, with huge benefits for the chemical industry,” Ullah said.

The new process also opens the door for improving other catalytic chemical-conversion processes that are deactivated by water, such as ammonia synthesis, Herrero noted.

“It is difficult to find catalytic supports that are thermally stable and water repellent,” she said. “In achieving that, our process could be very useful to manufacturing other products such as ammonia and catalytic converters.”

A patent application is underway for the new process.

Similarly, glycerol—a thick, colorless and odorless liquid—holds potential to be used in the food, pharmaceutical and cosmetics industries, but not in its crude form.

Glycerol is the main byproduct left behind from manufacturing biodiesel and compounds called oleochemicals derived from vegetable and animal oil and fat. But it is expensive to purify, making it costly for large-scale industrial use.

To help overcome that challenge, Herrero developed a patented process to convert the crude glycerol into monomers.

The chemicals are important in creating polymers—synthetic substances with a wide range of uses, such as making biopolymers for the consolidation of fluid fine tailings (FFT).

Slow consolidation of FFT has been identified as the major challenge for the oilsands industry toward sustainable reclamation.

The biopolymers created through Herrero’s process proved more effective in consolidating tailings and improving water recovery compared to PAM, a polymer currently being tested by the resource industry, the research showed.

The conversion process can also help the biodiesel industry address an emerging question of how to make use of more glycerol as production ramps up, Ullah noted.

“The industry is facing the dilemma on the one hand of how to meet a growing demand for biofuels, while also managing excessive crude glycerol so it doesn’t pose a threat to the environment,” Ullah said.

During the course of their research, Herrero and Ullah also investigated sustainability as an additional aspect of the conversion process.

By comparing the use of a microwave-heating process with conventional-heating sources such as hotplates, they showed that using microwave technology was more than 16 times less energy-intensive than conventional-heating sources.

The process is currently being used by an Edmonton-based biorefining company to produce chemicals more efficiently using lipids and waste glycerol.

Collectively, all of the research results show promising benefits to the energy, hydrogen, biofuel, food and chemical industries, Ullah said.

“By potentially offering sustainable alternatives for creating value-added products, our processes provide a win-win situation economically and environmentally,” Ullah added.

The research was funded by the Natural Sciences and Engineering Research Council of Canada and Alberta Innovates, and in-kind support from SBI BioEnergy Inc.