Valorization of Jew’s Ear Mushroom Spent Substrate into High-Value Carbon Materials and Effect of Pyrolysis Temperature

Spent mushroom substrate (SMS), a prevalent agricultural waste, poses environmental challenges if left unmanaged. Converting SMS into carbon materials offers a sustainable pathway to produce eco-friendly, value-added materials. In this work, carbon-based materials were prepared from Jew’s Ear mushroom SMS via facile pyrolysis, which converts biomass into stable carbon for sustainability. The raw material SMS was analyzed to determine its basic structure and composition using TGA and proximate analysis for fixed carbon, volatile matter, and ash content. SMS samples were pyrolyzed at temperatures ranging from 400 to 800°C. The resulting carbon-based material was then examined using several techniques, including proximate and ultimate analysis, XRD, Raman spectroscopy, FTIR, FE-SEM, TEM, and EDS. After pyrolysis at 800°C, the carbon-based product contained >80% carbon (dry ash-free basis). The study investigates the effects of pyrolysis temperature on phase formation and the HHV of SMS-derived materials. Higher pyrolysis temperatures increase the carbon content and reduce the HHV of pyrolyzed materials by promoting the formation of more inorganic compounds. This confirms that lime and salts used during mushroom cultivation can be retained in SMS, thereby affecting pyrolysis and the resulting products. BET surface characterization of the product confirmed its mesoporous nature, indicating suitability for adsorption. Sustainably managing SMS involves using carbon-based products during the nursery phase of tissue-cultured cassava seedling cultivation, which have demonstrated the ability to achieve 100% survival and to promote plant growth alongside other planting materials.