Rice-husk biochar filter captures industrial dyes and stays reusable five times

Researchers converted discarded rice husks into a sponge-like filter that captures industrial synthetic dyes and can be reused at least five times without loss of effectiveness, Florida International University reported via phys.org. Rice is the world's most-eaten food, and its outer husk yields some 300 billion pounds of waste per year. An international team including FIU chemistry researcher Islam Ibrahim Hussein published findings in Sustainable Chemistry and Pharmacy. In first-round tests, the material captured brilliant green and malachite green dyes. The process heats husks in a low-oxygen environment to make biochar, then combines it with magnesium and aluminum into a composite designed to trap pollutants more effectively. The paper notes the textile industry alone accounts for roughly 17% to 20% of industrial water pollution. Hussein said more work is needed before larger-scale use, including tests on additional dyes, heavy metals, and real-world water samples. The study is DOI: 10.1016/j.scp.2026.102474.