With a growing number of consumers demanding more earth-friendly practices from the fashion world, scientists are developing new ways to produce textiles that could help meet rising expectations. They report in the ACS journal Industrial & Engineering Chemistry Research one such method that can dramatically reduce the amount of energy it takes to bleach cotton while improving the quality of the popular material.
Quan Zu and colleagues point out that the cotton industry’s current whitening techniques require bleaching the natural fiber at very high temperatures with hydrogen peroxide. Although this method results in the bright white material consumers have grown so fond of, it also lowers the quality of the material and takes a lot of energy to carry out. Multiply that by the 7.3 billion pounds of cotton produced in the U.S. alone, and the energy needs soar. To cut down on the energy the textile industry uses to make cotton, Zu’s team targeted its efforts toward lowering the bleaching technique’s high temperatures.
They developed a novel compound that, when used with hydrogen peroxide, drops the bleaching temperature down to 140 degrees Fahrenheit from 200 degrees. The authors estimated that 60 degree difference would result in a process requiring less than half the energy as the commercial technique. It also produced less wastewater, improved the weight of the material and performed its original function — whitening the cotton. Since many materials destined to become clothing eventually take on various hues, the scientists also tested dyes and found the cotton bleached at the lower temperature could be made just as vibrant as its high-heat counterpart. They successfully showed the treatment’s effectiveness on knitted cotton fabric in commercial scale trials.