Fruit waste-derived aerogels for the removal of dyes, heavy metals and oils in water: a review

Most fruit peels after harvest crops are intentionally discarded into landfills, resulting in the waste of carbon resources and environmental pollution. Since fruit waste is rich in cellulose, hemicellulose, and pectin, transforming fruit waste into ultralight and ultraporous aerogels can contribute to environmental mitigation. Here we review aerogel production from fruit waste with emphasis on fruit waste occurrence and composition, synthesis of aerogels, properties of aerogels, applications to water treatment, and economical aspects. Pretreatment, cross-linking, the drying process, and post-treatment modification are major steps that influence the porosity, hydrophobicity, surface area, and morphology of fruit waste-derived aerogels. Fruit waste-derived aerogels are recyclable, up to 15 times in the cases of dye and oil treatments.