Electrospinning of Softwood Kraft Lignin With Cellulose Acetate: Dye Adsorption, Carbonization, and Carbon Dioxide Capture.

The development of bio-based materials capable of addressing multiple environmental challenges is critical for advancing sustainable materials design. Herein, we report electrospun nanofibers from unfractionated, chemically unmodified softwood kraft lignin and cellulose acetate, where cellulose acetate acts as a carrier polymer, enabling the formation of uniform precursor fibers with lignin contents of up to 80%. The resulting nanofibers enable sequential dye adsorption from water (methylene blue removal capacity of 19 mg/g) and carbon dioxide (CO2) capture (2.2 mmol/g) after carbonization. When evaluated solely for CO2 capture, the pristine carbonized materials show sorption capacities of 3.1-3.9 mmol/g, which increase as lignin content in the precursor fibers decreases, underscoring the importance of tuning carbon yield and capture performance. The sequential utilization of a single precursor material demonstrates a stepwise transformation that aligns with resource efficiency and sustainable material design. Overall, this study demonstrates a viable route for the direct valorization of industrial lignin into functional materials for both water purification and carbon capture applications.