Publications Repository - Gdańsk University of Technology

Waste biomass, a renewable energy source, is inexpensive material that has great potential in sorp-tion and electrochemical application. The selected waste materials (corncobs, coconut shells, wal-nuts, and pistachio husks) allow to close the production cycle and enable material recycling, which are important aspects in the hierarchy of waste management. The proposed methodology for pro-duction and activation of biochars can be used industrially due to highly porous structure, devel-oped surface area and sorption ability of the obtained activated carbons (AC). A significant increase (from 4 up to more than 10 times) in specific surface area (SSA) is observed for all samples after the CO2 activation process (0.5 h at 800°C) up to 725 m2⸱g-1 for corncobs, 534.9 m2⸱g-1 for pistachio husks, 523 m2⸱g-1 for coconut shells, and 393 m2⸱g-1 for walnut husks. The highest value of SSA is achieved for the AC derived from corncobs. This material is evaluated for use as an adsorbent, re-vealing 99% removal of Rhodamine B (dye/AC ratio of 0.0017) and 69% removal of chromium (dye/AC ratio of 0.0028). Based on the adsorption kinetics analysis, it is demonstrated that the Cr (VI) undergoes physical adsorption, while RhB - chemisorption. In addition, corncob-derived AC exhibits superior electrochemical performance in 6 M KOH compared to the non-activated biochar. A specific capacitance of 70 F⸱g-1 at 5 A⸱g-1 is achieved, along with outstanding rate capability (45 F⸱g-1 at 50 A⸱g-1) and cycling stability (94% at 10 A⸱g-1 after 10 000 cycles). In contrast, the non-activated sample shows only 34 F⸱g-1 at 5 A⸱g-1 and 13 F⸱g-1 at 50 A⸱g-1, with a stability of 91.4%.

Authors

• dr hab. inż. Katarzyna Januszewicz link open in new tab ,
• Paweł Kazimierski,
• Anita Cymann-Sachajdak link open in new tab ,
• Paulina Hercel,
• Beata Barczak link open in new tab ,
• dr hab. inż. Monika Wilamowska-Zawłocka link open in new tab ,
• Dariusz Kardas,
• dr hab. inż. Justyna Łuczak link open in new tab