Skip to main content
Log in

Removal of hexavalent chromium upon interaction with biochar under acidic conditions: mechanistic insights and application

  • Research Article
  • Published:
Environmental Science and Pollution Research Aims and scope Submit manuscript

Abstract

Chromium pollution of soil and water is a serious environmental concern due to potential carcinogenicity of hexavalent chromium [Cr(VI)] when ingested. Eucalyptus bark biochar (EBB), a carbonaceous black porous material obtained by pyrolysis of biomass at 500 °C under oxygen-free atmosphere, was used to investigate the removal of aqueous Cr(VI) upon interaction with the EBB, the dominant Cr(VI) removal mechanism(s), and the applicability to treat Cr(VI)-contaminated wastewater. Batch experiments showed complete removal of aqueous Cr(VI) at pH 1–2; sorption was negligible at pH 1, but ~55% of total Cr was sorbed onto the EBB surface at pH 2. Detailed investigations on unreacted and reacted EBB through Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry (XPS) indicate that the carboxylic groups in biochar played a dominant role in Cr(VI) sorption, whereas the phenolic groups were responsible for Cr(VI) reduction. The predominance of sorption–reduction mechanism was confirmed by XPS studies that indicated ~82% as Cr(III) and ~18% as Cr(VI) sorbed on the EBB surface. Significantly, Cr(VI) reduction was also facilitated by dissolved organic matter (DOM) extracted from biochar. This reduction was enhanced by the presence of biochar. Overall, the removal of Cr(VI) in the presence of biochar was affected by sorption due to electrostatic attraction, sorption–reduction mediated by surface organic complexes, and aqueous reduction by DOM. Relative dominance of the aqueous reduction mechanism depended on a critical biochar dosage for a given electrolyte pH and initial Cr(VI) concentration. The low-cost EBB developed here successfully removed all Cr(VI) in chrome tanning acidic wastewater and Cr(VI)-contaminated groundwater after pH adjustment, highlighting its potential applicability in effective Cr(VI) remediation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

Reference

Download references

Acknowledgements

This work was supported by Ministry of Environment and Forest, India (Grant#19/45-2010-RE) awarded to DP and TG to carry out this research. AS acknowledges support by the Indian Institute of Technology Kanpur Faculty Initiation Grant (INI-IITK-CE-20130151). We sincerely thank the two anonymous reviewers and Guilherme L. Dotto (Editor) for the thoughtful and thorough reviews, which have significantly improved the clarity of the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Debajyoti Paul.

Additional information

Responsible editor: Guilherme L. Dotto

Electronic supplementary material

ESM 1

(DOCX 1608 kb).

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Choudhary, B., Paul, D., Singh, A. et al. Removal of hexavalent chromium upon interaction with biochar under acidic conditions: mechanistic insights and application. Environ Sci Pollut Res 24, 16786–16797 (2017). https://doi.org/10.1007/s11356-017-9322-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11356-017-9322-9

Keywords

Navigation