Artificial Trees Can Absorb Carbon Dioxide?

Artificial Trees Can Absorb Carbon Dioxide?

Artificial Trees Bring New Surprises: Absorbing Carbon Dioxide

Researchers have been searching for ways to eliminate greenhouse gases in the air and lower global temperatures. The ability of plants to absorb carbon dioxide is undeniable, but the efficiency is not high. Colombian scientists have designed an artificial tree that can passively inhale carbon dioxide through its leaves. The efficiency of inhaling carbon dioxide is 1,000 times that of natural leaves that use photosynthesis. Let's get to know this surprising artificial tree together.

Researchers have been searching for ways to eliminate greenhouse gases in the air and lower global temperatures. Will this artificial plant with super adsorption become the key to solving the problem?
Although carbon dioxide is colorless, odorless, and pure natural gas, it has brought us a lot of trouble. Although it accounts for only 0.04% or 395 parts per million of all gases by volume in the air, it has a huge impact on the Earth's atmosphere. Although carbon dioxide molecules can allow light to pass through, they absorb the heat rays of the sun, forming a greenhouse effect.

Scientists are searching for ways to eliminate some greenhouse gases and regulate global temperatures. If this method is feasible, it will not only lower atmospheric temperature but also bring other benefits.

Like the metabolism of all other living organisms, we emit carbon dioxide every time we breathe. Meanwhile, photosynthetic organisms such as plants and algae inhale carbon dioxide and expel oxygen. This balance keeps the Earth's temperature at a pleasant temperature of 14 ℃. If there is no carbon dioxide in the atmosphere, the temperature will drop to -18 ℃.

Since the emergence of humans, we have emitted a large amount of carbon dioxide, exceeding the amount that plants can absorb, thus disrupting this balance. Since the Industrial Revolution, the consumption of fossil fuels by humans has gradually increased, releasing carbon stored millions of years ago. In the end, due to the increase in carbon dioxide content and temperature, the atmosphere reached a new equilibrium and it was difficult to return to the previous level.

The carbon dioxide we release changes the climate, wind, and rainfall patterns, causing ocean acidification, warming the habitats of plants and animals, frequent forest fires, melting ice sheets and glaciers, and raising sea levels. The rate at which we emit carbon dioxide is increasing so rapidly that animals and plants cannot adapt to the new environment through evolution.

Human beings do not necessarily need to rely on evolution, but we need to spend billions of dollars to rebuild cities and other infrastructure and find ways to grow crops in new environments.

Because carbon dioxide is a persistent gas, even if we no longer use fossil fuels today, the current amount of carbon dioxide in the atmosphere is enough to keep temperatures rising for hundreds of years. Of course, we will not immediately abandon the use of fossil fuels. In the next 100 years, we will at least reduce the global average temperature. We will also raise the global average temperature to at least 3 ℃ higher than before the Industrial Revolution.

Carbon dioxide collection

Therefore, people have come up with many ways to remove carbon dioxide, one of which is to plant plants, absorb a large amount of carbon dioxide, and then store it. Although we can plant trees and forests, we still need land to grow food for the growing global population, and the amount of trees and forests we can plant is limited.

In recent years, some people have come up with the idea of removing carbon dioxide by controlling emission sources in power plants. In pilot projects around the world, workers have installed cleaning equipment in the chimneys of power plants, so that when fossil fuels are burned, the greenhouse gases emitted from the exhaust gas will be removed. The removed carbon dioxide will be cooled and pumped into a stone chamber built deep underground, instead of being discharged into a saline-alkali aquifer in liquid form.

Another storage method is to use the collected gas to replace crude oil reserves and help drilling companies extract crude oil from areas with dangerous terrain. This method is called the "advanced oil recovery method".

The method of removing carbon dioxide from power plants is also known as the "carbon capture and storage method". This method is very effective in preventing more carbon dioxide from entering the atmosphere. However, how should we deal with the carbon dioxide that already exists in the atmosphere?

The main problem we face when removing carbon dioxide from the atmosphere is that the amount of carbon dioxide in the atmosphere is not currently concentrated. For example, in the chimney of a power plant, the proportion of carbon dioxide in the exhaust gas only accounts for 4% to 12%. Clearing these gases requires a lot of energy. It is expensive, and not practical. To extract 0.04% of carbon dioxide from the atmosphere, it is necessary to deal with extremely large volumes of air. Therefore, most scientists are not optimistic about this method.

Artificial plastic trees

Klaus Leckner, director of Columbia University's Lanfiste Center for Sustainable Energy, proposed another solution. He designed an artificial tree that can passively inhale carbon dioxide through its leaves, and the efficiency of inhaling carbon dioxide is 1,000 times that of natural leaves that use photosynthesis.

Lekner explained, "We don't need to place these leaves under sunlight like real trees, so our leaves can be arranged more tightly, and even designed in a honeycomb arrangement to make them more effective."

These artificial leaves look like thin plastic sheets, wrapped in resin-like substances containing sodium carbonate, which can absorb carbon dioxide from the air and form bicarbonate (baking soda) stored in the leaves. Leaves washed by water vapor will remove carbon dioxide and naturally air dry, absorbing more carbon dioxide.

According to Lekner's calculation, his artificial tree can remove one ton of carbon dioxide per day. Ten million such trees can remove 3.6 billion tons of carbon dioxide annually, equivalent to about 10% of global carbon dioxide emissions each year. Lekner said, "100 million trees can eliminate all carbon dioxide emissions, and if the same effect is achieved with real trees, the number would increase by 1,000 times."

He said that if this type of tree enters mass production, the initial cost of each tree is about $20,000, which is lower than the average price per car in the United States, and the annual production of cars in the United States is 70 million. As production returns to normal, the price of artificial trees will gradually decrease. After the artificial tree is completed, it will be loaded onto trucks and transported to various parts of the world. He said, "The most important thing is that the atmosphere is a hodgepodge, so the carbon dioxide produced by a city in the United States can be cleared in Oman."
Social cost 

Although this method can cool and store carbon dioxide, many scientists are concerned that even if we can completely remove carbon dioxide from the atmosphere, there may not be enough underground saltwater layers or oil wells to store it. However, geologists offer some options, such as peridotite. This olive-colored rock with a winding surface can absorb a large amount of carbon dioxide and convert it into a stable magnesium carbonate mineral. There is a mountain peak in Oman that contains 30,000 cubic kilometers of peridotite.

Another method is basalt. Millions of years ago, a volcanic eruption formed bubbles in the lava that solidified, causing many small pores to form on the basalt. Injecting carbon dioxide into these small pores will produce stable limestone calcium carbonate.

These carbon dioxide absorption methods are all naturally generated but require a certain amount of geological time to complete. To accelerate the reaction time, scientists are attempting to dissolve carbon dioxide in water first and then inject it into these rocks under high pressure.

However, Lekner believes that carbon dioxide has a high utilization value and should not be petrified of anything. His idea is to turn carbon dioxide into liquid fuel for use in transportation. Carbon dioxide can react with water to produce carbon monoxide and hydrogen. As a mixture of the two gases is easily made into hydrocarbon fuels such as methanol or diesel, their mixture is also known as a "mixture gas". Lekner also stated that this chemical reaction process also requires energy, but renewable energy sources. For example, wind energy can be used.

We have a way to absorb carbon dioxide and a way to preserve it. The only problem we need to solve now is whether this method is economically feasible. Lekner said that the cost of removing one ton of carbon dioxide from his artificial tree is around $200, and once the project scale increases, the cost will drop to $30 per ton. Due to the American Physical Society's most optimistic cost estimate of $600 per ton of carbon dioxide collection and removal, this price has been deemed overly optimistic. However, it still holds great economic significance for some oil companies as they use carbon dioxide for advanced oil recovery for $100 per ton.

Ultimately, we must determine whether the social value of this technology is worth this price, and as the costs caused by climate change itself gradually increase, its social value may decrease. From an economic perspective, the same applies. If the price of carbon rises, it also brings two impacts. Gas collection may be seen as an investment opportunity similar to reducing gas emissions, making it profitable.