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Sustainable removal of Cd(II) and Cr(VI) from aqueous solution via agro-waste derived biochar
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  • Published: 19 February 2026

Sustainable removal of Cd(II) and Cr(VI) from aqueous solution via agro-waste derived biochar

  • Salah Ud Din1,
  • Khairia Mohammed Al-Ahmary2,
  • Saedah R. Al-Mhyawi2,
  • Hamad AlMohamadi3,
  • Nuha Y. Elamin4,
  • Ibtehaj F. Alshdoukhi5,
  • Favour Abumere Imohiosen6,
  • Edwin A. Ofudje6 &
  • …
  • Jamelah S. Al-Otaibi7 

Scientific Reports , Article number:  (2026) Cite this article

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We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Subjects

  • Chemistry
  • Environmental sciences

Abstract

This work explores agro-waste biochar derived from corn cob as a low-cost and sustainable adsorbent for the uptake of Cd(II) and Cr(VI) from aqueous solutions. The novelty of this study lies in the combined use of acid-washed corn cob precursors, inclusive structure–property–performance analysis, and evaluation under environmentally relevant concentration ranges, signifying that corncob biochar can achieve considerable adsorption performance without chemical activation. The biochar was produced via pyrolysis and characterized with Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analysis. Batch adsorption experiments were carried out to assess the effects of pH, temperature, contact time, and adsorbent dosage on the metal ions sorption. FT-IR assessment confirmed the participation of –OH, C = O, and C–O functional groups in metal binding, while SEM images indicated a porous surface that became agglomerated after adsorption. Optimal removal efficiencies were achieved at pH 4.5 for Cd(II) and pH 5.0 for Cr(VI), with lower biochar dosages (0.35 g for Cd(II) and 0.3 g for Cr(VI)) enhancing adsorption due to increased availability of active sites. Adsorption kinetics followed a pseudo-second-order model, with maximum capacities of 70.2 mg/g for Cd(II) and 55.4 mg/g for Cr(VI). Thermodynamic analyses indicated that adsorption was spontaneous and endothermic. The adsorption mechanism is assigned to hydrogen bonding, electrostatic attraction, and ion-exchange interactions between metal ions and biochar functional groups. These findings demonstrate that corn cob biochar is an efficient and eco-friendly adsorbent for heavy metal remediation from wastewater.

Data availability

The datasets used and/or analyzed in this study are available from the corresponding author upon reasonable request.

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Acknowledgements

The authors wish to acknowledge the research support from Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2026R13), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Funding

This work was supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2026R13), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Author information

Authors and Affiliations

  1. Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan

    Salah Ud Din

  2. Department of Chemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia

    Khairia Mohammed Al-Ahmary & Saedah R. Al-Mhyawi

  3. Department of Chemical Engineering, Faculty of Engineering, Islamic University of Madinah, Madinah, Saudi Arabia

    Hamad AlMohamadi

  4. Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box 5701, Riyadh, 11623, Saudi Arabia

    Nuha Y. Elamin

  5. Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Science, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia

    Ibtehaj F. Alshdoukhi

  6. Department of Chemical Sciences, Mountain Top University, Ibafo, Ogun State, Nigeria

    Favour Abumere Imohiosen & Edwin A. Ofudje

  7. Department of Chemistry, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia

    Jamelah S. Al-Otaibi

Authors
  1. Salah Ud Din
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  2. Khairia Mohammed Al-Ahmary
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Contributions

Salah Ud Din: Contributed resources, software, Performed the experiments; Khairia Mohammed Al-Ahmary and Saedah R. Al-Mhyawi: Performed the data analysis, contributed software and vetted the first draft, Hamad AlMohamadi : Contributed software and performed characterization, ‏ Nuha Y. Elamin and Ibtehaj F. Alshdoukhi : Contributed reagents; Performed data analysis and vetted the second draft, Favour Abumere Imohiosen and Edwin A. Ofudje : Conceived the experiments; performed the experiments; and wrote the first draft paper;, and Jamelah S. Al-Otaibi Contributed finance, Carried out editting, and Performed data analysis.

Corresponding author

Correspondence to Favour Abumere Imohiosen.

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Din, S.U., Al-Ahmary, K.M., Al-Mhyawi, S.R. et al. Sustainable removal of Cd(II) and Cr(VI) from aqueous solution via agro-waste derived biochar. Sci Rep (2026). https://doi.org/10.1038/s41598-026-40608-1

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  • Received: 25 November 2025

  • Accepted: 13 February 2026

  • Published: 19 February 2026

  • DOI: https://doi.org/10.1038/s41598-026-40608-1

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Keywords

  • Adsorption
  • Biochar
  • Corn cob
  • Heavy metal
  • Wastewater
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