University of Oulu

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.

Preparation of highly porous nitrogen-doped biochar derived from birch tree wastes with superior dye removal performance

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Author: dos Reis, Glaydson S.1; Bergna, Davide2; Grimm, Alejandro1;
Organizations: 1Department of Forest Biomaterials and Technology, Biomass Technology Centre, Swedish University of Agricultural Sciences, Umeå SE-901 83, Sweden
2Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
3Federal university of Rio Grand do Sul (UFRGS), Porto Alegre, RS, Brazil
4Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh, Saudi Arabia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.9 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-10-30


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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Series: Colloids and surfaces. A, Physicochemical and engineering aspects
ISSN: 0927-7757
ISSN-E: 1873-4359
ISSN-L: 0927-7757
Volume: 669
Article number: 131493
DOI: 10.1016/j.colsurfa.2023.131493
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: Dr. dos Reis thanks Bio4Energy - a Strategic Research Environment appointed by the Swedish government and the Swedish University of Agricultural Sciences, for the funding support. Dr. Alejandro Grimm acknowledges financial support from the Swedish Research Council FORMAS (2021–00877). The authors are grateful to the Researchers Supporting Project number (RSP2023R8), King Saud University, Riyadh, Saudi Arabia, for the financial support.
Dataset Reference: No data was used for the research described in the article.
Copyright information: © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (