Hydrothermal conversion of biomass for co-production of carbon quantum dots and biofuels

Agro-processing industries generate a substantial quantity of biomass wastes. Conversion of these wastes into valuable material could be profitable considering both environmental and economic aspects. Among various biomass conversion methods, hydrothermal conversion can be used for co-production of biofuel and other valuable materials like carbon quantum dots (CQDs) and activated carbons. This study investigates the applicability of hydrothermal conversion in simultaneous production of biofuel and carbon quantum dots from biowastes obtained from flour mill. Water soluble CQDs of average size ranging between 4.67 and 4.88 nm were produced from various biowastes generated during wheat processing. Hydrochars obtained during the conversion exhibited calorific values between 12.95 and 25.94 MJ/kg. The influence of the composition of feedstock on hydrochar properties was also investigated. This study revealed that hydrothermal conversion technique could lead to the production of high-value materials along with the proper management of agro-industrial wastes, paving the way for a circular economy and bioeconomy. This would also help to mitigate environmental problems caused by open dumping and burning of the biowastes.