From trash to tech: Plastic bags now help monitor drinking water safety

Researchers in Indonesia, led by Dr. Indriana Kartini from Universitas Gadjah Mada, have developed an innovative method to upcycle discarded polyethylene plastic bags into carbon quantum dots (CQDs)—tiny, glowing nanomaterials capable of detecting toxic metals in drinking water. This breakthrough addresses two major global challenges simultaneously: plastic pollution and water safety. Unlike traditional recycling, their process uses modified pyrolysis and hydrothermal treatment with a small amount of hydrogen peroxide to convert plastic waste into CQDs within 10 hours. These CQDs exhibit strong fluorescence, stability under various conditions, and a high sensitivity for detecting iron ions (Fe³⁺) in water, with a detection limit as low as 9.50 micromoles and excellent measurement accuracy (R² = 0.9983). The plastic-derived CQDs’ ability to selectively bind iron ions makes them promising, affordable, and portable sensors for monitoring water quality, especially in areas lacking advanced laboratory facilities. This innovation exemplifies a circular