Green synthesis of biocompatible rice straw-derived carbon dots for ferric ion detection and antioxidant applications

The high-value utilization of rice straw can not only unlock its potential economic and environmental benefits but also reduce greenhouse gas emissions, significantly enhancing resource efficiency and promoting sustainable agricultural development. In this study, rice straw was used as a biomass-derived carbon source to synthesize biocompatible rice straw-derived carbon dots (H 2 O-CDs) via a green hydrothermal method. The fluorescent sensor constructed based on H 2 O-CDs offered the advantages of wide range (8–100 μM), high sensitivity (2.27 μM), and wide pH stability (2.0–8.0), making it suitable for detecting ferric ions within cells. Additionally, H 2 O-CDs were innovatively studied the antioxidant properties and had been proven excellent antioxidant enhancement potential by 2 times, suggesting their future practical application as a cigarette filter additive for the efficient removal over 40 % of harmful oxidizing free radicals in cigarette smoke. With their low cost and outstanding biocompatibility, H 2 O-CDs not only enable the high-value utilization of rice straw but also provide new insights and technical support for sustainable agricultural development.