Antibiotics have become a hidden pollution problem in modern agriculture. We use them heavily in livestock operations, and much of what animals don’t absorb ends up in the environment. Oxytetracycline is one of the worst offenders—it sticks around in soil and water, messes with microbial ecosystems, and helps antibiotic resistance spread. Scientists have been hunting for practical ways to get rid of it. A research team in China recently published some promising results. They made a composite material from zinc oxide and schwertmannite, an iron mineral, and the combination works better than either ingredient on its own. The clever part is how it handles the contamination: it pulls oxytetracycline out…