Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions

Damenech Tefera Werku; Getahun Yifru Desta; Tayto Mindahun

doi:doi:10.11648/j.ajcbe.20240901.11

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Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H₃PO₄) for the Removal of Nitrate (NO₃^-) Ions from Aqueous Solutions

Damenech Tefera Werku^*

, Getahun Yifru Desta

, Tayto Mindahun

Published in American Journal of Chemical and Biochemical Engineering (Volume 9, Issue 1)

Received: 22 March 2025 Accepted: 10 April 2025 Published: 29 April 2025

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Abstract

Significant health and environmental hazards are associated with nitrate (NO₃-) contamination in water, which calls for economical and environmentally friendly treatment techniques. This study investigates using phosphoric acid (H₃PO₄) activation to turn flax straw (Linum usitatissimum L.), an underutilized agricultural residue, into activated carbon (FS-AC) for the removal of nitrate from aqueous solutions. The FS-AC was prepared by chemical activation under varying conditions (temperature: 400-600°C, H₃PO₄ concentration: 1-3 M, impregnation ratio: 1:4-1:6) and optimized using response surface methodology (RSM). Characterization via Scanning Electron Microscopy (SEM) revealed a highly porous morphology (surface area: 798.23 m2/g), while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed an amorphous carbon structure with oxygen-rich functional groups and residual crystalline phases. Under optimal conditions (532°C, 1 M H₃PO₄, impregnation ratio 1:5), FS-AC achieved 92.79% nitrate removal at pH 4, 0.25 g/L dose, and 60 min contact time. Adsorption followed the Langmuir isotherm (R2=0.9895), indicating monolayer adsorption, and pseudo-second-order kinetics (R2=0.9408), suggesting chemisorption. Thermodynamic analysis revealed spontaneity (ΔG°: −1.27 to −0.18 kJ/mol) and exothermicity (ΔH°=−14.19 kJ/mol). Generally, the study highlights FS-AC’s competitive performance against biomass-derived carbons, with fixed carbon content up to 34.89%. By converting flax straw waste into an efficient adsorbent, this study addresses dual challenges of agricultural residue management and water pollution, aligning with circular economy principles. Thus, future research should explore scalability, regeneration, and application in real wastewater systems to further validate its industrial viability.

Published in	American Journal of Chemical and Biochemical Engineering (Volume 9, Issue 1)
DOI	10.11648/j.ajcbe.20240901.11
Page(s)	1-17
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Adsorption Isotherms, Flax Straw, Nitrate Removal, Phosphoric Acid Activation

References

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Werku, D. T., Desta, G. Y., Mindahun, T. (2025). Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. American Journal of Chemical and Biochemical Engineering, 9(1), 1-17. https://doi.org/10.11648/j.ajcbe.20240901.11

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Werku, D. T.; Desta, G. Y.; Mindahun, T. Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. Am. J. Chem. Biochem. Eng. 2025, 9(1), 1-17. doi: 10.11648/j.ajcbe.20240901.11

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Werku DT, Desta GY, Mindahun T. Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. Am J Chem Biochem Eng. 2025;9(1):1-17. doi: 10.11648/j.ajcbe.20240901.11

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@article{10.11648/j.ajcbe.20240901.11,
  author = {Damenech Tefera Werku and Getahun Yifru Desta and Tayto Mindahun},
  title = {Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions
},
  journal = {American Journal of Chemical and Biochemical Engineering},
  volume = {9},
  number = {1},
  pages = {1-17},
  doi = {10.11648/j.ajcbe.20240901.11},
  url = {https://doi.org/10.11648/j.ajcbe.20240901.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajcbe.20240901.11},
  abstract = {Significant health and environmental hazards are associated with nitrate (NO3-) contamination in water, which calls for economical and environmentally friendly treatment techniques. This study investigates using phosphoric acid (H3PO4) activation to turn flax straw (Linum usitatissimum L.), an underutilized agricultural residue, into activated carbon (FS-AC) for the removal of nitrate from aqueous solutions. The FS-AC was prepared by chemical activation under varying conditions (temperature: 400-600°C, H3PO4 concentration: 1-3 M, impregnation ratio: 1:4-1:6) and optimized using response surface methodology (RSM). Characterization via Scanning Electron Microscopy (SEM) revealed a highly porous morphology (surface area: 798.23 m2/g), while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed an amorphous carbon structure with oxygen-rich functional groups and residual crystalline phases. Under optimal conditions (532°C, 1 M H3PO4, impregnation ratio 1:5), FS-AC achieved 92.79% nitrate removal at pH 4, 0.25 g/L dose, and 60 min contact time. Adsorption followed the Langmuir isotherm (R2=0.9895), indicating monolayer adsorption, and pseudo-second-order kinetics (R2=0.9408), suggesting chemisorption. Thermodynamic analysis revealed spontaneity (ΔG°: −1.27 to −0.18 kJ/mol) and exothermicity (ΔH°=−14.19 kJ/mol). Generally, the study highlights FS-AC’s competitive performance against biomass-derived carbons, with fixed carbon content up to 34.89%. By converting flax straw waste into an efficient adsorbent, this study addresses dual challenges of agricultural residue management and water pollution, aligning with circular economy principles. Thus, future research should explore scalability, regeneration, and application in real wastewater systems to further validate its industrial viability.
},
 year = {2025}
}

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TY  - JOUR
T1  - Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions

AU  - Damenech Tefera Werku
AU  - Getahun Yifru Desta
AU  - Tayto Mindahun
Y1  - 2025/04/29
PY  - 2025
N1  - https://doi.org/10.11648/j.ajcbe.20240901.11
DO  - 10.11648/j.ajcbe.20240901.11
T2  - American Journal of Chemical and Biochemical Engineering
JF  - American Journal of Chemical and Biochemical Engineering
JO  - American Journal of Chemical and Biochemical Engineering
SP  - 1
EP  - 17
PB  - Science Publishing Group
SN  - 2639-9989
UR  - https://doi.org/10.11648/j.ajcbe.20240901.11
AB  - Significant health and environmental hazards are associated with nitrate (NO3-) contamination in water, which calls for economical and environmentally friendly treatment techniques. This study investigates using phosphoric acid (H3PO4) activation to turn flax straw (Linum usitatissimum L.), an underutilized agricultural residue, into activated carbon (FS-AC) for the removal of nitrate from aqueous solutions. The FS-AC was prepared by chemical activation under varying conditions (temperature: 400-600°C, H3PO4 concentration: 1-3 M, impregnation ratio: 1:4-1:6) and optimized using response surface methodology (RSM). Characterization via Scanning Electron Microscopy (SEM) revealed a highly porous morphology (surface area: 798.23 m2/g), while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed an amorphous carbon structure with oxygen-rich functional groups and residual crystalline phases. Under optimal conditions (532°C, 1 M H3PO4, impregnation ratio 1:5), FS-AC achieved 92.79% nitrate removal at pH 4, 0.25 g/L dose, and 60 min contact time. Adsorption followed the Langmuir isotherm (R2=0.9895), indicating monolayer adsorption, and pseudo-second-order kinetics (R2=0.9408), suggesting chemisorption. Thermodynamic analysis revealed spontaneity (ΔG°: −1.27 to −0.18 kJ/mol) and exothermicity (ΔH°=−14.19 kJ/mol). Generally, the study highlights FS-AC’s competitive performance against biomass-derived carbons, with fixed carbon content up to 34.89%. By converting flax straw waste into an efficient adsorbent, this study addresses dual challenges of agricultural residue management and water pollution, aligning with circular economy principles. Thus, future research should explore scalability, regeneration, and application in real wastewater systems to further validate its industrial viability.

VL  - 9
IS  - 1
ER  -

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Damenech Tefera Werku

Department of Chemical Engineering, Debre Berhan University, Debre Berhan, Ethiopia

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http://orcid.org/0009-0007-9243-7742
Getahun Yifru Desta

Department of Chemical Engineering, Debre Berhan University, Debre Berhan, Ethiopia

Contact Email

http://orcid.org/0009-0003-8245-4187
Tayto Mindahun

Department of Chemical Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia

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http://orcid.org/0000-0001-8775-8006

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Werku, D. T., Desta, G. Y., Mindahun, T. (2025). Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. American Journal of Chemical and Biochemical Engineering, 9(1), 1-17. https://doi.org/10.11648/j.ajcbe.20240901.11

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ACS Style

Werku, D. T.; Desta, G. Y.; Mindahun, T. Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. Am. J. Chem. Biochem. Eng. 2025, 9(1), 1-17. doi: 10.11648/j.ajcbe.20240901.11

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AMA Style

Werku DT, Desta GY, Mindahun T. Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions. Am J Chem Biochem Eng. 2025;9(1):1-17. doi: 10.11648/j.ajcbe.20240901.11

Copy | Download

@article{10.11648/j.ajcbe.20240901.11,
  author = {Damenech Tefera Werku and Getahun Yifru Desta and Tayto Mindahun},
  title = {Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions
},
  journal = {American Journal of Chemical and Biochemical Engineering},
  volume = {9},
  number = {1},
  pages = {1-17},
  doi = {10.11648/j.ajcbe.20240901.11},
  url = {https://doi.org/10.11648/j.ajcbe.20240901.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajcbe.20240901.11},
  abstract = {Significant health and environmental hazards are associated with nitrate (NO3-) contamination in water, which calls for economical and environmentally friendly treatment techniques. This study investigates using phosphoric acid (H3PO4) activation to turn flax straw (Linum usitatissimum L.), an underutilized agricultural residue, into activated carbon (FS-AC) for the removal of nitrate from aqueous solutions. The FS-AC was prepared by chemical activation under varying conditions (temperature: 400-600°C, H3PO4 concentration: 1-3 M, impregnation ratio: 1:4-1:6) and optimized using response surface methodology (RSM). Characterization via Scanning Electron Microscopy (SEM) revealed a highly porous morphology (surface area: 798.23 m2/g), while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed an amorphous carbon structure with oxygen-rich functional groups and residual crystalline phases. Under optimal conditions (532°C, 1 M H3PO4, impregnation ratio 1:5), FS-AC achieved 92.79% nitrate removal at pH 4, 0.25 g/L dose, and 60 min contact time. Adsorption followed the Langmuir isotherm (R2=0.9895), indicating monolayer adsorption, and pseudo-second-order kinetics (R2=0.9408), suggesting chemisorption. Thermodynamic analysis revealed spontaneity (ΔG°: −1.27 to −0.18 kJ/mol) and exothermicity (ΔH°=−14.19 kJ/mol). Generally, the study highlights FS-AC’s competitive performance against biomass-derived carbons, with fixed carbon content up to 34.89%. By converting flax straw waste into an efficient adsorbent, this study addresses dual challenges of agricultural residue management and water pollution, aligning with circular economy principles. Thus, future research should explore scalability, regeneration, and application in real wastewater systems to further validate its industrial viability.
},
 year = {2025}
}

Copy | Download

TY  - JOUR
T1  - Application of Flax (Linum Usitatissimum L.) Straw Derived Activated Carbon Using Phosphoric Acid (H3PO4) for the Removal of Nitrate (NO3-) Ions from Aqueous Solutions

AU  - Damenech Tefera Werku
AU  - Getahun Yifru Desta
AU  - Tayto Mindahun
Y1  - 2025/04/29
PY  - 2025
N1  - https://doi.org/10.11648/j.ajcbe.20240901.11
DO  - 10.11648/j.ajcbe.20240901.11
T2  - American Journal of Chemical and Biochemical Engineering
JF  - American Journal of Chemical and Biochemical Engineering
JO  - American Journal of Chemical and Biochemical Engineering
SP  - 1
EP  - 17
PB  - Science Publishing Group
SN  - 2639-9989
UR  - https://doi.org/10.11648/j.ajcbe.20240901.11
AB  - Significant health and environmental hazards are associated with nitrate (NO3-) contamination in water, which calls for economical and environmentally friendly treatment techniques. This study investigates using phosphoric acid (H3PO4) activation to turn flax straw (Linum usitatissimum L.), an underutilized agricultural residue, into activated carbon (FS-AC) for the removal of nitrate from aqueous solutions. The FS-AC was prepared by chemical activation under varying conditions (temperature: 400-600°C, H3PO4 concentration: 1-3 M, impregnation ratio: 1:4-1:6) and optimized using response surface methodology (RSM). Characterization via Scanning Electron Microscopy (SEM) revealed a highly porous morphology (surface area: 798.23 m2/g), while X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed an amorphous carbon structure with oxygen-rich functional groups and residual crystalline phases. Under optimal conditions (532°C, 1 M H3PO4, impregnation ratio 1:5), FS-AC achieved 92.79% nitrate removal at pH 4, 0.25 g/L dose, and 60 min contact time. Adsorption followed the Langmuir isotherm (R2=0.9895), indicating monolayer adsorption, and pseudo-second-order kinetics (R2=0.9408), suggesting chemisorption. Thermodynamic analysis revealed spontaneity (ΔG°: −1.27 to −0.18 kJ/mol) and exothermicity (ΔH°=−14.19 kJ/mol). Generally, the study highlights FS-AC’s competitive performance against biomass-derived carbons, with fixed carbon content up to 34.89%. By converting flax straw waste into an efficient adsorbent, this study addresses dual challenges of agricultural residue management and water pollution, aligning with circular economy principles. Thus, future research should explore scalability, regeneration, and application in real wastewater systems to further validate its industrial viability.

VL  - 9
IS  - 1
ER  -

Copy | Download