Surface functional groups of carbon-based adsorbents and their roles in the removal of heavy metals from aqueous solutions: A critical review

Xiaodong Yang, Yongshan Wan, Yulin Zheng, Feng He, Zebin Yu, Jun Huang, Hailong Wang, Yong Sik Ok, Yinshan Jiang, Bin Gao

Research output: Contribution to journalReview articlepeer-review

829 Citations (Scopus)


Carbon-based adsorbents such as graphene and its derivatives, carbon nanotubes, activated carbon, and biochar are often used to remove heavy metals from aqueous solutions. One of the important aspects of effective carbon adsorbents for heavy metals is their tunable surface functional groups. To promote the applications of functionalized carbon adsorbents in heavy metal removal, a systematic documentation of their syntheses and interactions with metals in aqueous solution is crucial. This work provides a comprehensive review of recent research on various carbon adsorbents in terms of their surface functional groups and the associated removal behaviors and performances to heavy metals in aqueous solutions. The governing removal mechanisms of carbon adsorbents to aqueous heavy metals are first outlined with a special focus on the roles of surface functional groups. It then summarizes and categorizes various synthesis methods that are commonly used to introduce heteroatoms, primarily oxygen, nitrogen, and sulfur, onto carbon surfaces for enhanced surface functionalities and sorptive properties to heavy metals in aqueous solutions. After that, the effects of various functional groups on adsorption behaviors of heavy metals onto the functionalized carbon adsorbents are elucidated. A perspective of future work on functional carbon adsorbents for heavy metal removal as well as other potential applications is also presented at the end.

Original languageEnglish
Pages (from-to)608-621
Number of pages14
JournalChemical Engineering Journal
Publication statusPublished - 2019 Jun 15

Bibliographical note

Publisher Copyright:
© 2019 Elsevier B.V.


  • Adsorption mechanism
  • Biochar
  • Carbon nanomaterials
  • Carbonaceous adsorbents
  • Heavy metal contamination
  • Surface functionalization

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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