Fruit waste to fuel: A case study on hydrogen generation using pomegranate peels

Abstract

Rapid global population growth has intensified the demand for increased fruit production as well as renewable energy using environmentally sustainable approaches for better life quality. Pomegranate, a widely consumed fruit, generates huge quantities of peel waste that pose significant solid waste management challenges. This study presents a sustainable approach for valorizing pomegranate peels (PP) into efficient biocatalysts for hydrogen generation via alcoholysis of sodium borohydride (NaBH₄). Optimization of calcination temperature and acid mixture ratios yielded high-performing biocatalysts, P3-350 and P4-450, which were further characterized using FTIR, Raman spectroscopy, FESEM, ICP-OES, XPS, XRD, CHNS, Boehm titration and BET surface area analysis (P3-350: 85.22 and P4-450: 38.02 m² g⁻¹). P3-350 achieved hydrogen generation rates (HGR) of 99,000 mL min⁻¹ gcat⁻¹ (5940 L h⁻¹ gcat⁻¹) during methanolysis, while P4-450 depicted HGR of 112,667/137,142.9 mL min⁻¹ gcat⁻¹ (6760/8228.57 L h⁻¹ gcat⁻¹) during methanolysis/ethylene glycolysis of NaBH₄ under optimized reaction conditions. This work highlights the dual benefit of pomegranate peel-derived biocatalysts, by providing an ecofriendly pathway for on-demand hydrogen generation while effectively addressing fruit waste management. The proposed process contributes to sustainable energy production, circular bioeconomy, and resource recovery from agricultural residues, thereby supporting a cleaner and more energy-resilient future.