How CO₂ Could Become a Useful Raw Material
The use of fossil fuels is the main cause of climate change since their burning releases carbon dioxide (CO₂), the most important greenhouse gas. It may be necessary to extract massive amounts of CO₂ from the atmosphere to combat climate change. Fortunately, we won’t have to store the gas, because it could be put to better use in the future.
One of the great climate sins is the release of CO₂ in the atmosphere. CO₂ isn’t the only greenhouse gas nor the most effective — for example, methane is many times worse — but the massive release of CO₂ from burning fossil fuels is the primary source of global warming.
Radical reduction of CO₂ emissions is the best and simplest way to combat global warming, but with a growing global middle class and the associated growing energy consumption, not a lot suggests that it will happen in the necessary degree. Hence, more and more speak of the necessity of extracting CO2₂ from the atmosphere as an important measure for avoiding extreme climate change. A problem with this is that it is expensive to extract CO2 from the atmosphere and store it underground, and the energy costs are so great that the net reward is modest. Other methods could prove not just cheaper, but even capable of transforming the CO₂ into useful materials.
The simplest solution is to plant more trees which absorb CO₂ and transform it into wood. There is a lot of variation in how much different tree species grow in a year and hence, how much CO2 they absorb; for instance, a Douglas fir absorbs around 16 tons a year, where an oak tree absorbs 8 tons. If the trees are used for firewood or left to rot where they fall, the benefit is short term, but wood is an excellent material for making both furniture and buildings, e.g. as an alternative to concrete which has a high climate footprint. Danish researchers have calculated that if woodland areas in Denmark are increased from 14 percent to 25 percent, it will reduce carbon emissions per Dane by 2 tons a year — corresponding to a 30 percent reduction.
Another option is to turn Another option is to turn CO₂ into fuel. For instance, scientists from Rice University in Houston, Texas have succeeded in binding CO2 to hydrogen by using a catalyst, producing formic acid, which is an efficient liquid fuel with almost 1,000 times the energy density of gaseous hydrogen. The formic acid can be used in fuel cells where the acid reacts with oxygen and creates electricity, water, and CO₂. The process produces electricity corresponding to 42 percent of the energy that was used to create the formic acid, and there is considerable energy loss in the process, but it can be useful for storing excess energy from variable sources such as solar and wind power while also creating a compact fuel for e.g. cars into fuel. For instance, scientists from Rice University in Houston, Texas have succeeded in binding CO2 to hydrogen by using a catalyst, producing formic acid, which is an efficient liquid fuel with almost 1,000 times the energy density of gaseous hydrogen. The formic acid can be used in fuel cells where the acid reacts with oxygen and creates electricity, water, and CO₂. The process produces electricity corresponding to 42 percent of the energy that was used to create the formic acid, and there is considerable energy loss in the process, but it can be useful for storing excess energy from variable sources such as solar and wind power while also creating a compact fuel for e.g. cars.
In Australia, researchers have found an effective way to extract pure carbon from CO₂ using nanoparticles of the element cerium dissolved in the metal gallium, which is liquid at 30° C. The process requires neither high pressure nor high temperature. The produced carbon is pure enough to be used in supercapacitors for electric cars or for making the miracle material graphene, which among other things potentially can be used to make superconductors. Whether the market for such materials is large enough to make a real difference in the climate account is another question.
Scientists from the University of Toronto have found a way to turn CO₂ into plastic. Offhand, this doesn’t sound particularly ecofriendly, but plastic is normally made from oil and other fossil fuels, so if it could instead be made from Scientists from the University of Toronto have found a way to turn CO₂into plastic. Offhand, this doesn’t sound particularly ecofriendly, but plastic is normally made from oil and other fossil fuels, so if it could instead be made from CO₂, you don’t just remove CO₂ from the atmosphere, but also reduce the use of fossil fuels. The scientists use copper as a catalyst to combine CO₂ with hydrogen to ethylene, a precursor to the widely used plastic polyethylene, so the method has a lot of potential.
The big problem with these methods is that they require extracting CO₂ from the atmosphere before it can be turned into useful products. A team of researchers from Kyoto University may have a solution for that: They have produced a so-called porous coordination polymer (PCP) from zinc ions, which is ten times as effective in extracting CO₂ from the atmosphere than earlier known PCPs. The energy use for this process is supposedly very small, though the research article in Nature doesn’t specify exactly how low. The collected CO₂ can be used to make organic polymers, which in turn can be used to make polyurethane, a plastic often used in textiles and packaging — and the PCP can be reused to collect more CO₂.
