Preparation of highly porous nitrogen-doped biochar derived from birch tree wastes with superior dye removal performance
dos Reis, Glaydson S.; Bergna, Davide; Grimm, Alejandro; Lima, Eder C.; Hu, Tao; Naushad, Mu.; Lassi, Ulla (2023-04-20)
dos Reis, G. S., Bergna, D., Grimm, A., Lima, E. C., Hu, T., Naushad, Mu., & Lassi, U. (2023). Preparation of highly porous nitrogen-doped biochar derived from birch tree wastes with superior dye removal performance. In Colloids and Surfaces A: Physicochemical and Engineering Aspects (Vol. 669, p. 131493). Elsevier BV. https://doi.org/10.1016/j.colsurfa.2023.131493.
© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
https://urn.fi/URN:NBN:fi-fe20231030141901
Tiivistelmä
Abstract
Heteroatom doping is a highly effective strategy that can be used to modify carbonaceous adsorbents to improve their chemical reactivity and increase their adsorptive properties. Herein, a simple method is reported for the preparation of nitrogen-doped biochar using a natural and abundant biowaste from birch trees and melamine as a nitrogen dopant for the adsorption of Acid red 18 (AR-18) dye from water. The doped biochars were also characterized for their performance during the treatment of synthetic effluents. The physicochemical characterization results showed that the N-doping process provoked remarkable chances on the biochar morphology, pore structure, and surface functionalities. N-doped biochar showed abundant nitrogen functional groups with 5.4 % of N in its structure while non-doped carbon showed traces with 0.47 %. Moreover, the specific surface area of doped biochar was dominated by mesopores (86.4 %) while non-doped was dominated by micropores (67.8 %). Raman analysis showed that the incorporation of N created more defects in the biochar structure. The adsorption experiments showed that the N-doping boosted the biochar adsorptive performance. The maximum adsorption capacity of the doped biochar was 545.2 mgg−1, while the non-doped exhibited 444.5 mgg−1, i.e., an increase of 22.6 %. The kinetic and equilibrium studies showed that Avrami fractional order and Liu models were the most suitable for describing the experimental AR-18 dye adsorption data. The equilibrium parameters were found to obey a nonlinear relationship with the temperature. Since the biochars are highly porous, pore filling was the main adsorption mechanism, however; AR-18 dye removal suggests that interactions such as electrostatic, hydrogen bonds, Lewis acid-base, and π-π between the adsorbent and the dye are involved. The thermodynamic studies showed that the removal of the AR-18 dye from the solution is dependent on temperature, exothermic, and spontaneous. The N-doped biochar showed excellent removal performances of contaminants from synthetic effluents confirming their high efficiency for color removal. This research shows that N-doping is an efficient strategy to design effective, low-cost, and sustainable adsorbents to remediate dye contamination in wastewater.
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