BULETIN TEKSTIL.COM/Jakarta – The issue of increasing the concentration of CO2 gas, as one of the industrial emission products, has become a global problem.
Based on the results of observations of CO2 measurements in the atmosphere from the National Oceanic Atmospheric Administration (NOAA) in the United States in 2020, it was found that CO2 gas levels in the atmosphere had increased by more than 50% from pre-industrial levels at atmospheric levels of 421 parts per million (ppm).
CO2 pollution is produced by burning fossil fuels for transportation and power generation, cement manufacturing processes, and other human activities. Carbon dioxide along with other greenhouse gases traps heat radiating from the surface of the planet Earth.
This gas, if it doesn’t escape into space, causes the atmosphere to continue to heat up. This impacts a range of weather conditions, including extreme heat, droughts, wildfires, higher rainfall, floods and tropical storms.
Naturally, trees and plants have a role in absorbing CO2 levels in the atmosphere, but the limited green open land and forestry have become a fact that is currently being faced.
This can be used as a reminder that we need to take urgent and serious steps regarding this matter, including possible innovative solutions to this problem.
Conventional Carbon Capture Technology
Currently, researchers are developing several types of innovative carbon capture technologies which are expected to be a solution to the CO2 pollution problem faced by the world.
One example of a solution that has been found at this time is the method of carbon capture by electrochemical processes.
However, this method still requires high electricity costs and must be removed in the CO2 gas reduction process in electrochemical cells.
This shows that we still need to develop innovative technologies in terms of capturing CO2 pollution to be more comprehensive in terms of cost and effectiveness.
Illustration of conventional carbon capture method by electrochemical process using electrical energy
Functional Textiles for Carbon Capture
Functional textile materials that can absorb CO2 from the air are one of the latest innovative breakthroughs from NCSU researchers today. North Caroline State University (NCSU) in the United States has published the results of its research in the journal ACS Sustainable Chemical Engineering a few months ago.
In order for the textile material to have functional properties, then an active ingredient called carbonic anhydrase is inserted, so that the fabric can absorb CO2 gas from the air or gas in the environment.
This project was successfully funded by the U.S. Department of Energy, with the collaboration of Dr. Min Zhang (National Renewable Energy Laboratory) and Dr. Jesse Thompson (University of Kentucky’s Center for Applied Energy Research), and sponsored by the company Novozymes as the producer of the carbonic anhydrase enzyme.
A functional textile material that can absorb CO2 from the air, developed by a research team from NCSU
The functional textile material is made with a substrate in the form of cotton cloth on which carbonic anhydrase enzyme is attached to the surface.
Carbonic anhydrase is an enzyme found in all tissues of mammals, plants, algae, and bacteria. Carbonic anhydrase helps in the conversion of CO2 and water into bicarbonate (HCO3-) and protons (H+) (and vice versa).
This process is essential for life and central to respiration, digestion, and regulation of cellular pH levels.
In this case water is needed in the process of converting carbon dioxide gas, so cotton cloth was chosen as the main substrate because it has hygroscopic properties and can easily absorb water.
This provides an advantage because the area that can be wetted by water is increasing. The fabric and gas contact area can also make the conversion wider.
Conversion of carbon dioxide gas and water into bicarbonate with the help of the enzyme carbonic anhydrase
To make the functional fabric, enzymes are attached to a two-ply piece of cotton cloth by ‘dipping’ the cloth in a solution containing chitosan. Chitosan acts like the glue that attaches carbonic anhydrase to cotton fabrics. The material binds to enzymes, which then stick to the surface of the fabric.
A series of experiments were carried out by the researchers to see how efficiently the cloth could separate carbon dioxide from a mixture of carbon dioxide and nitrogen.
This research was conducted to determine the ability of textile materials to selectively absorb carbon dioxide from a mixture of gases in the atmosphere.
In this experiment, the cloth was rolled into a spiral and put into a test tube chimney. Then the researchers put carbon dioxide and nitrogen gas into the chimney of the tube containing the cloth.
Researchers then sprayed dew simultaneously into the tube. When CO2 gas reacts with water and enzymes in the flue tube, the CO2 turns into bicarbonate and drips into the filter.
The process produces a bicarbonate solution that can be used for more useful purposes.
The advantages demonstrated through this system are that the fabric can capture CO2 from the environment, can operate passively without requiring electricity in the chemical process, and produce a by-product in the form of a bicarbonate solution that can be used for more useful purposes.
When the researchers pushed a mixture of CO2 and N2 gases through the chimney containing the cloth at a rate of 4 liters per minute (lpm), they found that the cloth could absorb as much as 52.3 percent of the carbon dioxide it passed.
Researchers also claim that the absorption process with this method as much as two passages can absorb and 81.7 percent of the carbon dioxide that is passed. This shows a fairly positive potential for the usefulness of the materials proposed by the researchers.
The researcher also revealed that the application of technology in vehicle gas exhaust still needs to be studied further.
This is related to the environmental temperature in the vehicle exhaust system which tends to be hot which can reduce the stability of the carbonic anhydrase enzyme performance to absorb CO2 from exhaust gases.
Carbon Looper (CO2 Catching Cloth)
Carbon Looper is a brand of carbon-capturing cotton fabric products in collaboration with the H&M Foundation and HKRITA (Hong Kong Research Institute of Textiles and Apparel).
These functional fabrics can be produced by treating cotton fabrics with a solution containing amines and making the fabric surface able to capture carbon dioxide from the surrounding air.
Carbon dioxide can then be released from the fabric by heating to 30-40°C, in a greenhouse for example, where CO2 is taken up by plants during photosynthesis, so that the carbon dioxide is looped back into the natural carbon cycle.
In other words, the captured carbon is not converted into other products, but is still released under certain conditions. Back when the cloth is warmed to 40oC.
The amount of CO2 absorbed by standard-sized clothing per day is roughly the equivalent of 1/3 of the amount absorbed by trees (assuming trees absorb 15 – 60 grams of CO2 per day).
Carbon Looper product in the form of a cooking apron used in a restaurant in Stockholm
The current stage of the research involves hands-on testing in collaboration with Fotoska Stockholm, where restaurant staff will wear Carbon Loopers in the form of an apron. The restaurant’s hydroponic garden in the basement can serve as a CO2 release facility.
So when the apron is finished (which has absorbed CO2 during employee use), the apron can be stored in a warm room in the hydroponic garden so that CO2 gas can be released from clothing, then further absorbed by plants.
Illustration of carbon dioxide release from carbon looper cloth when heated, then carbon dioxide is reabsorbed by plants.
Until this article was written, researchers are still looking for possible carbon capture technology methods that can be applied as a solution to the global problem of increasing CO2 gas pollution.
(Red B-Teks/Andrian Wijayono)
Magister Rekayasa Tekstil dan Apparel, Politeknik STTT Bandung