Valorization of Expired Passion Fruit Shell by Hydrothermal Conversion into Carbon Quantum Dot: Physical and Optical Properties

Expired fruits have always been treated as garbage. In this paper, expired passion fruit shells are processed into carbon quantum dots (CQDs) by hydrothermal synthesis method. Expired passion fruit shells based carbon quantum dots were characterized using TEM-EDS, FTIR, PL, XRD, XPS, Raman spectrum and Uv–vis analysis. The morphology of CQDs shows sphere shape with the size below 5 nm. CQDs exhibit a weak graphite phase structure according to Raman spectrum. The photoluminescence of CQDs shows the obvious excitation-dependent property with the quantum yield of 1.8%. In addition, expired passion fruit pulp was treated using hydrothermal method. The final product was analyzed using TEM and GC–MS. The result shows the high content of furandione in the product, which indicates the potential for further extraction by purification. This paper expands new way for the reuse of expired fruits.