Polymer beads in washing machine lead to 70% reduction in water usage

09-Jan-14

The Xeros washing machine from a company based in Rotherham, UK, is looking to revolutionize domestic and industrial laundry alike with “bead cleaning.” The technology is claimed to be superior to traditional soap and water as well as environment friendly. Xeros is a six-year-old spinoff from the University of Leeds, where textile chemist Stephen Burkinshaw had the original inspiration to reverse the dyeing process. Instead of adding pigment to textiles, the team experimented with removing pigment—stains. Nylon readily takes up dye, and forming the polymer into round beads yielded the most effective stain extractor. The beads' surface area, weight, and chemistry have since been engineered with regard to four independent factors—temperature, chemistry, time, and mechanics—that affect the washing process. The proprietary Xeros washer looks like a standard front-loading machine. About 50 kilograms of beads, held in a wet sump below the machine, are pulsed in with water through the top of the drum. The beads fall out of the drum and then recirculate. The process to laundry is like taking a shower that also aids in water savingsl. Xeros claims a 70% reduction in water usage compared with standard washing. The bead cleaning works in cold water (20 °C), hence heating is not required, which cuts energy use in half by Xeros’s estimate. The one and a half million or so beads used per load constitute the fundamental ingredient in the cleaning cocktail. Xeros now has two main bead compositions—polyester (specifically, polyethylene terephthalate) and nylon (nylon 6,6). The mechanical action of the beads passing over clothing removes soil, and the weight of the beads reduces creasing by pinning the fabric down. But it is the beads' polymeric structure that attracts and traps dirt. Thanks to the presence of polar groups, the beads adsorb solubilizable stains. Because the beads are particularly good at clinging to dirt and grease, they might require a periodic wash themselves—perhaps once a month when used in lightly soiled washes. The beads are reusable and have been tested to last through 500 washes.