Fruit and Vegetable Peel Characteristics and their Conversion to Biosorbents using Hydrothermal Carbonization and Pyrolysis: A Review

Peels make up a considerable proportion of solid waste generated from fruit and vegetable production and processing. If not properly managed, they could contribute to environmental degradation through the dispersion of nutrient-rich leachate and the release of various greenhouse gases. Alternatively, these peels could be transformed to biosorbents, which could assist in the removal of pollutants of environmental and human health concerns from wastewaters. Using peels as raw material for biosorbent production is an environmentally friendly and cost-effective option for waste disposal. Peels also contain bio-activators, which can be used to activate the biosorbent produced, minimizing the use of synthetic chemicals for biosorbent activation. This review considers the different physicochemical characteristics of vegetable and fruit peels that make them suitable raw materials for biosorbent production. Additionally, their transformation to biosorbents using hydrothermal carbonization and pyrolysis is discussed. The review concludes with a discussion on the efficiency of peel-based biosorbents in the removal of diverse types of pollutants from wastewater.