A new activator developed by Chinese researchers for hydrogen peroxide used to bleach cotton fabrics halves the amount of energy needed for the process. Traditional cotton bleaching techniques used in industry require temperatures in excess of 98°C and high alkalinity to produce the desired whiteness. The process uses large amounts of energy, degrades the cotton fabric so it loses weight and thickness and produces waste water with a high chemical oxygen component.
The team used a spectrophotometer to measure the whiteness index of the cotton treated with its method and found that it was comparable to that of cotton bleached using the traditional method. The cotton loses less weight during the new process, and retains some of its natural waxes, resulting in a softer fabric. The fabric can be dyed to virtually the same color depth as fabric bleached traditionally. The process not only uses less energy, but saves time in water heating, and uses less water, as the traditional process has an extra cooling step.
The only downside of the process is that more hydrogen peroxide is needed than in traditional methods to ensure the same rate of oxidative reactions at the lower temperature. However, this does not significantly affect the strength of the fabric.