Direct conversion of lignin-rich black liquor to activated carbon for supercapacitor electrodes

The escalating industrialization trend underscores the imperative for sustainable waste management practices. The present investigation explores a sustainable methodology for managing the waste generated from the kraft process by directly converting it into activated carbon (BLAC) through a cost-effective hydrothermal-assisted activation method. The research involved a comparative analysis of BLAC with acid -washed black liquor ligninderived activated carbon (ABLAC) and commercial lignin -derived activated carbon (SALAC). The analysis revealed that BLAC possesses a well -developed micro and mesoporous structure, yielding a significantly higher surface area of 2277.2 m 2 /g as compared to ABLAC (1260 m 2 /g) and SALAC (1558.4 m 2 /g). The presence of inherent alkali in the black liquor is the main factor influencing the surface area of the BLAC. Furthermore, it demonstrated impressive electrochemical performance, showing a specific capacitance value of 871.4 F/g at 1 A/ g current density, positioning it as a formidable electrode material for supercapacitor applications. The proposed direct conversion strategy will eliminate the need for high -temperature pre-carbonization and additional lignin extraction, reducing chemical usage and presenting a greener approach.