Paper and Pulp Waste Takes on Role in Carbon Conversion to Make New Products

Researchers at McGill University in Quebec, Canada are using pulp and paper manufacturing waste to facilitate carbon conversion to be able to make green products. Feeding pulp and paper into their process substantially lessens the energy that would otherwise be required, they say.

“This is a new field. We are one of the first groups to combine biomass recycling or utilization with CO₂ capture,” says Roger Lin, one of the researchers doing the work out of McGill, and a graduate student in chemical engineering.

Lin and research partner Amirhossein Farzi, also a McGill graduate student, are applying renewable electricity to convert the captured CO2, leaving behind a zero-carbon footprint. This process using green energy, which is in R&D elsewhere as well, is called electrochemical conversion. It’s one technology in the broader scheme of carbon capture and can produce a spectrum of chemical compounds—methane, carbon monoxide, ethylene and ethanol to name a few.

Farzi explains the paper and pulp application, which is what distinguishes the McGill project from other electrochemical conversion processes.

“In research you need to be profitable to motivate investments in the technology. And the main challenge is the energy costs of electrochemical conversion. Our motivation is to make the process more economically viable by consuming less energy compared to other carbon dioxide conversion methods.”

Using pulp and paper as a reactant is what’s improving the economics and efficiencies. Typically, the process relies on an oxygen reaction. The contamination from pulp and paper requires less energy for conversion compared to dissociating water into oxygen.

Farzi further explains: oxygen is an inherent product that comes out of the electrochemical carbon conversion process. But it serves no purpose, at least not for the McGill team’s process.

“So, we try to substitute oxygen with a more valuable product – waste from the paper and pulp industry that can be converted to make value-added products in a more efficient and economical way. And our process will be more environmentally friendly because we can target two different contaminants: CO2 from the atmosphere and pulp and paper waste,” he says.

Paper and pulp waste is made from hundreds of chemical compounds. The McGill researchers chose just one to use as a reactant for consistency—an aldehyde called HMF.  HMF can be converted to chemicals that can go into various products, including FDCA, which can be used to make biopolymers as a fossil-derived plastics substitute. 

The ultimate plan is to look into what other chemicals from the industry may serve as reactants to produce more green products while helping keep contaminants from paper and pulp making out of waterways and soil.

Outside of McGill, electrochemical technologies are being applied to address issues in other industries such as chemical manufacturing and food production.

At Washington University in St. Louis, electrochemical conversion research is underway to convert CO2 into acetate, which is then transformed into protein through a fermentation process. 

The protein is identical to that produced using traditional fermentation methods and therefore could potentially be used in food manufacturing.

“This new technology can reduce the need for meat and dairy production, which significantly strains our natural resources due to the land required for livestock and the crops needed to feed them,” says Feng Jiao, director of the Center for Carbon Management, Department of Energy, Environmental, and Chemical Engineering, Washington University, who is leading the team.

“Additionally, using acetate derived from CO2 directly in the fermentation process eliminates the need for sugar, a major component in traditional fermentation. This innovation can free up substantial agricultural areas currently devoted to sugar production,” he says.

Jiao’s team is also developing electrochemical technologies to convert CO2 into other high-value chemicals, including ethylene and ethanol. These chemicals serve as feedstock for the production of polymers and various other chemical products. The source of CO2 could be power plants and chemical plants, where CO2 is generated. 

Carbon capture and conversion are gaining investors’, industries’, and regulators’ attention as the need for innovation to address CO2 emissions in the face of climate change becomes clear.

Eyes are especially turning to electrochemical conversion of CO2 in the past 15 years or so, as it’s recognized for its potential to work with a multitude of commodity chemicals and reduce dependence on fossil fuel, while using renewable electricity only as an energy source.

There is still plenty to work out, but there have been advancements in the past few years alone, with improved catalysts, larger-scale reactors, and a better understanding of the CO2 reaction.

These steps forward suggest that commercial applications may not be too far off, especially for chemical manufacturing.

What excites Farzi is that some companies are already at or on the verge of industrial scale-level production. Then there are new ideas just beginning to get off the ground, including more ideas to expand green technologies in partnership with the paper and pulp industry that McGill is looking to. Other researchers are beginning to explore making hydrogen from pulp and paper waste.

“We are trying to stir investments in green research to address climate change. The ultimate goal [with electrochemical conversion] is more energy efficiency; to be able to make more products and use more contaminants from more waste streams.”