MIT chemical engineers rise to the challenge of carbon removal


First developed at MIT, Verdox-enabled technology allows a stream of air or flue gas (blue) containing carbon dioxide (red) to enter the system from the left. As it passes between the thin battery electrode plates, the carbon dioxide attaches to the charged plates as the cleaned airflow passes through and exits to the right. Credit: Image courtesy of Hatton Lab

Verdox, founded by MIT chemical engineers and winner of an XPRIZE Carbon Removal milestone award, strives to make a difference on climate change.

By most benchmarks, MIT chemical engineering spinoff Verdox had a bumper year. Launched in 2019, the carbon capture and removal startup announced $80 million in funding in February from a group of investors including Bill Gates’ Breakthrough Energy Ventures. Then, in April — after being recognized by Bloomberg New Energy Funding as one of the top energy pioneers of the year – the company and its partner Carbfix won a $1 million XPRIZE Carbon Removal award. It was the first round of the Musk Foundation’s four-year, $100 million competition, which is the largest prize offered in history.

“While our core technology has been validated by the significant improvement in performance metrics, this external recognition further confirms our vision,” says Sahag Voskian SM ’15, PhD ’19, Co-Founder and Chief Technology Officer at Verdox . “It shows that the path we have chosen is the right one.”

In recent years, the search for practical carbon capture technologies has intensified, as scientific models show with increasing certainty that any hope of preventing catastrophic climate change means limiting CO2 concentrations below 450 parts per million by 2100. Because alternative energy will only get humanity so far, vast removal of CO2 will be an essential tool in the race to remove the gas from the atmosphere.

Voskian began developing the company’s cost-effective and scalable technology for carbon capture in the lab of T. Alan Hatton, Ralph Landau Professor of Chemical Engineering at MIT. “It’s exciting to see ideas move from the lab to potential commercial production,” says Hatton, the company’s co-founder and science advisor. He says Verdox quickly overcame the initial technical issues faced by many start-up companies. “This recognition adds credibility to what we do and really validates our approach.

Verdox Carbon Capture

Gas enters each cell from one side and is routed through the electrodes that make up the cell, where carbon dioxide is absorbed. The remaining gas simply passes through the chimney and comes out the other side. Once the cell is saturated with CO2the incoming gas is stopped and the pure CO2 comes out of the stack on the other side. The installation of chimneys in parallel with alternating cycles allows a continuous flow of incoming mixed gas and outgoing pure CO2. Credit: Image courtesy of Verdox

Technology that Voskian describes as “sleek and efficient” is at the heart of this approach. A lot of energy is required for most approaches to extract carbon from an exhaust stream or from the air itself. However, Voskian and Hatton proposed a design whose electrochemistry makes carbon capture appear almost effortless. Their invention is a kind of battery: conductive electrodes coated with a compound called polyanthraquinone, which has a natural chemical attraction for carbon dioxide under certain conditions, and no affinity for CO2 when these conditions are relaxed. When activated by a low-level electric current, the battery charges, reacting to the passage of CO molecules2 and draw them on its surface. Once the battery is saturated, the CO2 can be released as a stream of pure gas with voltage reversal.

“We have shown that our technology works in a wide range of CO2 concentrations, from the 20% or more found in cement and steel industry exhaust streams, to the very diffuse 0.04% in the air itself,” says Hatton. Current science of climate change indicates that removal of CO2 directly from the air “is an important part of the whole mitigation strategy,” he adds.

“It was an academic breakthrough,” says Brian Baynes PhD ’04, CEO and co-founder of Verdox. Baynes, a chemical engineering alumnus and former associate of Hatton, has numerous startups to his name and a history as a venture capitalist and mentor for young entrepreneurs. When he first encountered Hatton and Voskian’s research in 2018, he was “impressed that their technology showed it could reduce energy consumption for certain types of carbon capture by 70% compared to to other technologies,” he says. “I was encouraged and impressed by this low-energy footprint, and recommended them to start a business.”

Co-founders of Verdox

Left to right: Verdox co-founders Sahag Voskian, Brian Baynes and T. Alan Hatton. Credit: Brian Baynes

Because neither Hatton nor Voskian had ever marketed a product before, they asked Baynes to help them get started. “I normally decline these requests because the costs are usually higher than the upside,” Baynes says. “But this innovation had the potential to make progress on climate change, and I saw it as a rare opportunity.”

The Verdox crew is well aware of the difficult challenges ahead. “The scale of the problem is huge,” Voskian says. “Our technology must be able to capture mega and gigatonnes of CO2 air and emission sources. Indeed, to limit the rise in global temperature to less than 2 degrees Celsiusthe Intergovernmental Panel on Climate Change (IPCC) estimates that the world needs to eliminate 10 gigatonnes of CO2 per year by 2050.

As Baynes puts it, Verdox must become “a company that operates in a techno-economic sense”, to grow successfully and at a pace that could meet the global climate challenge. This means, for example, ensuring that its carbon capture system offers clear and competitive cost advantages when deployed. That’s not a problem, Voskian says: “Our technology, because it uses electric power, can be easily integrated into the grid, working with solar and wind power on a plug-and-play basis. ” The Verdox team is confident that its carbon footprint will surpass that of its competitors by orders of magnitude.

The company continues to overcome a series of technical hurdles as it scales: enabling the carbon capture battery to operate hundreds of thousands of cycles before its performance declines and improving the chemistry of polyanthraquinone so that the device is even more selective for CO2.

After reaching critical milestones, Verdox is now working with its first announced commercial customer: Norwegian aluminum company Hydro. They are trying to remove the CO2 exhaust from their foundries as they transition to carbon-free production.

Verdox also develops systems capable of efficiently extracting CO2 out of the ambient air. “We’re designing units that would look like rows and rows of big fans blowing air into boxes that hold our batteries,” he says. Such methods could be particularly beneficial in areas with above-average CO2 emission concentrations, such as aerodromes.

All that captured carbon has to go somewhere. With partner XPRIZE Carbfix, Verdox will have a final resting place for CO2 that cannot be immediately reused for industrial applications such as new fuels or building materials. Their solution is a proven decade-old method for mineralizing captured CO2 and deposit it in deep underground caverns.

Together with its customers and partners, the team seems well positioned for the next round of the XPRIZE carbon elimination competition. This milestone will award up to $50 million to the group that best demonstrates a working solution at scale of at least 1,000 tonnes disposed per year, and can present a viable plan for scale-up to gigatons of disposal per year.

Can Verdox significantly reduce the planet’s rising CO2 charge? Voskian is sure of it. “Getting on with our current momentum and seeing the world embrace carbon capture, this is the right way to go,” he said. “Together with our partners, deploying manufacturing facilities globally, we will solve the problem in our lifetime.”


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