Molten Salt Carbonization and Activation of Biomass to Functional Biocarbon

Abstract

Figure 1. Biomass examples for biocarbon production.

Research advancement in molten salt-mediated thermochemical upcycling of biomass waste

“…In addition to value-added chemicals and biofuels, much interest has been attracted in the production of porous carbon materials for emerging electrochemical applications ( e.g. , supercapacitor), 112–114 and environmental remediation ( e.g. , adsorption and catalytic conversion).…”

“…117 The molten salt-mediated carbonization and activation method has a high potential to simplify the process into a single thermal step coupled with in situ activation of biochar at lower temperatures (500–800 °C). 112 Acting as both catalyst and template, molten salts efficiently optimize the activation and regulate the pore structure of biochar. Concentrated solar heating stored in molten salts can be employed for the carbonization process (Fig.…”

“…For the immersion approach, the salt is firstly melted, followed by immersion of the biomass in molten salt under a suitable condition. 112 The mixing approaches including dry mixing ( e.g. , grinding) and wet mixing ( e.g.…”

“…Interactions will occur between the salt and biomass in the solid-state before proceeding into a liquid phase at elevated temperatures as the carbonization process proceeds. 112 For example, glucose was used as a carbon precursor for the synthesis of porous carbon using a molten salt (a mixture of LiCl and KCl containing different dissolved oxysalts). The biomass and salts mixed by ball milling were pyrolyzed at 900 °C for 5 h. These oxysalts dissolved in molten LiCl–KCl can greatly influence pore formation.…”

“…In addition to value-added chemicals and biofuels, much interest has been attracted in the production of porous carbon materials for emerging electrochemical applications (e.g., supercapacitor), [112][113][114] and environmental remediation (e.g., adsorption and catalytic conversion). 115,116 Large scale production of these functional carbon materials is still expensive as the existing routes often involve multi-steps.…”