By Marcius Extavour
Surely you've heard of carbon dioxide (CO2), a greenhouse gas and major contributor to climate change. It's a clear, colorless, odor-less gas, and we produce a ton of it. Over 35 billion tons per year, actually. To put number that in perspective, that's more than all of the concrete, steel produced on earth every year!
What does it mean to actually make a material out of carbon dioxide (CO2)? Unless you are a professional chemist, chemical engineer, or materials synthesis expert, the concept probably sounds like science fiction. Possibly even magical and unfathomable. After all, how can a colorless, odorless gas be transformed into, say, shoes, bricks, or green fuels, as some are proposing? A lot of people are starting to ask how CO2 recycling really works or if it could become a full-fledged industry. CO2 conversion is real, and may be poised more than ever before to make a transformational leap forward.
As an introduction, here are six tangible (and delicious) things that can be made from CO2, a gas.
When you think about baking soda (and if you're reading this, you probably are) cupcakes and cookies probably come to mind much more than industrial gases. Yet baking soda (calcium bicarbonate) is a great example of a cheap, useful and economic product that can be manufactured from CO2. Aside from the baking and food sector, baking soda has a number of uses in industrial processes, including water treatment, steelmaking and metallurgy, concrete, and others.
Lego figures are a favorite example of durable plastics, but they are only one example of a range of polymers that can be produced from CO2. Ethylene and styrene, for instance, crucial materials used to manufacture many of the products that we use and take for granted every day, such as carpets, furniture, and packaging. All can be made using CO2. The concept of recycling greenhouse gas emissions into plastics and other polymers is truly amazing. It's also a growing focus of the green chemistry movement, and receiving significant uptake and investment from traditional and new companies in the materials synthesis space.
One of the most mentally jarring concepts in CO2 conversion is the idea that a gas can be transformed into a durable, solid building material. CO2 emissions are associated with almost every aspect of conventional cement and concrete manufacturing. That's why there is growing interest and technology development focused on using those emissions in the fabrication of those same materials. The first step is trapping CO2 in a mineralized form. From there, the solid mineralized form of carbon (often a carbonate) can be incorporated into cements, concretes, bricks, and other building materials.
Alternatives to traditional gasoline and diesel are not new, and have been fighting for market share for decades. Ethanol, methane ("natural gas"), butanol, and bio-gas and bio-diesel can all be made using CO2 as an input. There are many research teams and companies working on this around the world using a variety of approaches, including electrochemistry, artificial photosynthesis, algae, and others. Using CO2 as an ingredient in the production of fuels opens the pathway toward liquid fuels that are truly carbon neutral, or even carbon-negative.
Yes, carbon dioxide can be used to improve crop yields. This isn't so strange if you remember that while we animals inhale oxygen and exhale CO2, plants, on the other hand, thrive on CO2 and produce oxygen as a waste product. The link between CO2 and farming is fertilizer. Most nitrogen fertilizers use the chemical "urea". These are not specialty fertilizers or chemicals; they are actually the used regularly in farms around the world. Urea can and has been produced from CO2 for decades, and may be on the of the most important CO2-derived products globally in decades to come.
Some of the most advanced carbon-based materials are graphene, carbon nanotubes, and carbon fiber. Graphene may be the most hyped material of the early 21st century, while carbon nanotubes and carbon fiber have already found their way into lab-scale, high-tech, and consumer goods markets. As their names suggest, these materials are heavily carbon-based, and extremely tantalizing candidates for CO2 conversion. The prospect of "supermaterials" like graphene and carbon fiber being produced from a waste product is great marketing, but also great engineering. Research on new materials tends to focus on possible applications, but also techniques to fabricate and manufacture products using the material. Since methods for manufacturing these advanced materials are still rapidly evolving, new approaches like CO2 conversion can have an important influence on the industry.
The diversity of products we can make from CO2 is truly astounding. Imagine a world where one of our greatest liabilities (CO2) becomes an asset. CO2 has the potential to be harnessed as valuable input to our materials industries in a way that reduces the carbon intensity of our energy sector and other heavy industries.
Dr. Marcius Extavour is the Director of Technical Operations of the $20 Million NRG COSIA Carbon XPRIZE, a competition designed to showcase new ways to transform carbon dioxide into materials we can use, instead of allowing it to escape into the atmosphere. Registration deadline is July 15th, 2016. Form or join a team today!