The carbon cycle is nature’s way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again. Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms.

The unreacted hydrogen and nitrogen gases are recycled by being fed back through pipes to pass through the hot iron catalyst beds again. The reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. The mixture is cooled and compressed, causing the ammonia gas to condense into a liquid.

Recycling carbon dioxide is a great deal more involved than setting out separate bins for glass, aluminum, and paper. But science has long known that it’s possible to recombine carbon from CO2 with hydrogen from water to make hydrocarbons—in other words, to make familiar fuels such as gasoline.

Recycling helps reduce greenhouse gas emissions by reducing energy consumption. Using recycled materials to make new products reduces the need for virgin materials. This avoids greenhouse gas emissions that would result from extracting or mining virgin materials.

Why is recycling carbon important? Recall that carbon is the cornerstone of organic compounds, the compounds necessary for life. Carbon must be recycled from other living organisms, from carbon in the atmosphere, and from carbon in other parts of the biosphere.

Carbon moves from plants to animals. Through food chains, the carbon that is in plants moves to the animals that eat them. Animals that eat other animals get the carbon from their food too. Animals and plants need to get rid of carbon dioxide gas through a process called respiration.

The recycle gas scheme is used in the HDS process to minimize physical losses of expensive hydrogen. HDS reactions require a high hydrogen partial pressure in the gas phase to maintain high desulfurization reaction rates and to suppress carbon laydown (catalyst deactivation).

The acidic carbon dioxide is attracted to an alkaline liquid within the towers that is then taken into the factory where acid and base are separated. The carbon-dioxide containing liquid is frozen and then reheated into a slurry that is combined with hydrogen to make liquid fuels like gasoline and jet fuel.

Other forms of carbon dioxide in the atmosphere are already being recycled everyday, via the carbon cycle. Plants, trees and humans are all, quite literally, inhaling oxygen, and exhaling co2. That co2 is turned around and put back into plants and absorbed into the earth—a complete recycling system.

Scientists at Berkeley demonstrated in a recent paper that some of these copper sites are specifically shaped to convert carbon dioxide into ethanol, ethylene, and propanol efficiently when submerged in water. This discovery presents a potential way to recycle harmful greenhouse gases into useful carbon-based fuel.

Project Drawdown estimates that recycling between 2020 and 2050 will reduce emissions by 5.5-6.02 gigatons of carbon dioxide (equivalent to taking over 1 billion cars off the streets for one year).