MICROWAVE-ASSISTED GREEN SYNTHESIS OF CARBON DOTS DERIVED FROM MELON PEEL WASTE AS AN ECO-FRIENDLY FLUORESCENT SENSOR FOR Fe³⁺ CONTAMINATION

Rahmat Firman Septiyanto (Physics Education Department, Faculty of Teacher Training and Education, Universitas Sultan Ageng Tirtayasa)
Azfa Restu Putra (Physics Education Department, Faculty of Teacher Training and Education, Universitas Sultan Ageng Tirtayasa)
Yudi Guntara (Physics Education Department, Faculty of Teacher Training and Education, Universitas Sultan Ageng Tirtayasa)

Indonesian Physical Review
Vol. 9 No. 3 (2026)

This research successfully demonstrates the valorization of melon peel waste into fluorescent carbon dots (CDs) using a straightforward microwave-assisted synthesis method. The synthesized CDs were comprehensively characterized, revealing optimal optical properties for sensing applications. Ultraviolet-visible spectroscopy revealed characteristic absorption peaks at 260 nm and 305 nm, corresponding to the carbon core and surface functional groups, respectively. Furthermore, photoluminescence spectroscopy under 245 nm excitation showed a strong blue emission peak at 453 nm. The practical utility of these nanoparticles was confirmed through their application as a fluorescent sensor for Fe³⁺ ions. The interaction resulted in significant fluorescence quenching and a distinct blue shift of the emission peak to 448 nm, indicating high sensitivity and a strong quenching response, leading to a ~67% decrease in emission intensity. These findings confirm that melon peel-derived CDs are a promising, eco-friendly material for developing effective probes for detecting heavy metals in environmental monitoring.