The textile industry uses copious amounts of water to dye fabrics — by some estimates, 25 liters of water just to dye a T-shirt. Not only that, but many textile factories are located in Eastern Asia, where chemical-laden water is sometimes dumped directly into local rivers.
A technology recently showcased by Sustainia has the ability to substitute carbon dioxide for the water. Applied Separations developed a technique that uses supercritical CO2 to take up the dye. Supercritical fluids are highly compressed gases that exhibit properties of both gases and liquids and can simultaneously move through solids and dissolve materials.
Supercritical carbon dying allows color pigment to penetrate fabrics easily without the use of harmful chemicals, salts or water. The method cuts dyeing time in half, and fabric emerges already dried. This means energy and costs could theoretically be reduced by 50 percent. The process also removes CO2, a greenhouse gas, from the air.
Hefty start-up costs deter many East Asian factories from adopting supercritical dying systems. Nonetheless, supercritical carbon technology has the potential to revolutionize the textile industry, and a small number of plants are taking hold across East Asia and the United States.