Thermochemical upcycling of food waste into engineered biochar for energy and environmental applications: A critical review

Environmental issues caused by food waste are important concerns for human well-being and ecosystem health. Valorization of food waste into energy and carbon materials has been extensively investigated. Here, we reviewed the most recent advancements in the thermochemical conversion of food waste into engineered biochar. Synthesis routes and practical applications of the food waste-derived biochar was succinctly reviewed. Engineered biochar is a promising alternative for mitigating environmental pollution and alleviating energy crisis. The underlying relationships between engineered biochar properties and specific applications are still unclear, therefore, machine learning-aided engineered biochar design and process optimization was proposed. Moreover, before any industrial scale implementation, detailed assessments of the environmental benefits and economic feasibility must be conducted. In the context of carbon neutrality, thermochemical upcycling of food waste into engineered biochar for energy and environmental applications can significantly contribute to attaining sustainable food waste management, mitigating environmental pollution, and addressing the energy shortage crisis, and thus will eventually facilitate the fulfillment of United Nations Sustainable Development Goals (SDGs). Furthermore, the existing challenges in the practical valorization of food waste into engineered biochar are comprehensively discussed, and outlooks are proposed.