Sustainable Synthesis of ZnO Nanoparticles From Melon (Cucumis melo L.) By-Products: RSM Optimization, Structural Characterization, Antioxidant Activity, and Photocatalytic Performance


Bozkurt R. N., KABA İ., Kahraman Y. S., Altınkeser T.

Chemistry and Biodiversity, vol.23, no.4, 2026 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 4
  • Publication Date: 2026
  • Doi Number: 10.1002/cbdv.71224
  • Journal Name: Chemistry and Biodiversity
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, EMBASE, MEDLINE
  • Keywords: antioxidant activity, Box–Behnken design, Cucumis melo L., green synthesis, methyl orange, methylene blue, waste valorization, ZnO nanoparticles
  • Istanbul University-Cerrahpasa Affiliated: No

Abstract

This study explores the eco-friendly synthesis of zinc oxide nanoparticles (ZnO-NPs) using polyphenol-rich extracts from melon (Cucumis melo L.) peel and seeds as natural reducing and stabilizing agents. Optimization via response surface methodology (RSM) determined the ideal synthesis conditions at a 0.078 mol/L metal concentration, 14.73 mL extract, and pH 10.77. Characterization through XRD confirmed a hexagonal wurtzite crystal structure with an average size of 21.7 nm, while SEM and TEM imaging revealed predominantly spherical morphologies. UV–visible DRS analysis showed a 368 nm absorption edge with a calculated band gap of 3.21 eV. DLS measurements indicated a hydrodynamic diameter of 135.6 nm with a PDI of 0.206 and a zeta potential of −20.5 mV, confirming good colloidal stability. The resulting NPs exhibited strong antioxidant activity (IC50 = 40.7 µg/mL) and acted as effective heterogeneous photocatalysts for the degradation of organic dyes. Specifically, ZnO-NPs enabled the photodegradation of methyl orange (MO) and methylene blue (MB), achieving 63.56% degradation for 5 mg L−1 MO. These findings demonstrate that melon-waste-derived ZnO-NPs are sustainable and promising candidates for wastewater treatment and environmental remediation.