WET WORK:The guts of the prickly pear have an agent that works as a natural dispersant, much like dishwashing detergent.
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GOOD SCIENCE
SOMETIMES AN ANCESTOR’S primitive trick can solve a complex problem. University of South Florida researcher Norma Alcantar’s grandmother used cactus to remove sediment from river water when growing up in rural Mexico. Now a team of chemical engineers led by Alcantar is testing this tactic on cleansing everything from oily seawater to water for farmed fish. Typically, when you want to purify water you need a dispersant, a chemical mixture that can break down unwanted substances so they can be washed away. Alcantar’s team has found that sugars within mucilage—the gooey part of the cactus responsible for keeping it hydrated—are just as good as chemical dispersant and more environmentally friendly.