Generating high-value porous materials from fruit and vegetable waste

Abstract

Fruit and vegetable waste is a global concern due to its significant environmental impact, economic loss, and implications for food security. In this study, fruit and vegetable waste was used as whole materials, avoiding extraction, to produce aerogels via supercritical carbon dioxide (SC-CO 2 ) drying for applications of dye removal. Aerogels were produced from banana peel (BPA), broccoli stem (BSA), cabbage leaves (CLA), imperfect carrot (ICA), and orange peel (OPA). The resulting aerogels exhibited low density (<1 g/cm³), high porosity (>93%), and high surface areas (12-172 m²/g), with OPA showing the highest value at 172 m²/g. The CLA samples had the highest pore size (29 nm), contributing to their highest water absorption capacity of 95%.SEM images showed a promising porous structure and highlighted the fibrillar structure in OPA samples. The average methylene blue adsorption capacity was ~84%, except for OPA samples (53%). The methylene blue adsorption was driven by electrostatic interactions, which highly correlated with the pseudo-first order kinetic model (R 2 > 0.98). Overall, this study demonstrates that whole fruit and vegetable waste can be effectively converted into lightweight, highly porous aerogels with potential applications in biomedical and food fields, purification and filtration systems, and other functional materials sectors.