A review of biochar-based sorbents for separation of heavy metals from water

Muhammad Bilal Shakoor, Shafaqat Ali, Muhammad Rizwan, Farhat Abbas, Irshad Bibi, Muhammad Riaz, Usman Khalil, Nabeel Khan Niazi, Jörg Rinklebe

Research output: Contribution to journalReview articlepeer-review

118 Citations (Scopus)


Biochar is the low-cost and environmental-friendly material which has shown a great potential for separation of heavy metals from water. The previous studies have established a superior role of biochar over other materials, such as activated carbon and inorganic sorbents (iron based) in efficient removal of toxic heavy metals from aqueous systems. Among the various factors influencing heavy metals sorption ability of biochar, types of feedstock/biomass and pyrolysis temperature play a significant role. The goal of this review is to increase our understanding of heavy metals sorption behavior by biochars–this is important as heavy metals sorption is driven based on biochar type, heavy metals species which involve numerous mechanisms, including the physical binding, complexation, ion exchange, surface precipitation and electrostatic interactions. In addition, this review paper describes various approaches to improve heavy metal sorption capacity of biochars by steam and acids/bases activations and impregnation of biochar-based composites with minerals, organic compounds and carbon-rich materials. The physical/chemical activation of biochars can improve the surface area, thus leading to their improved functionality, while modification/pretreatment methods help in synthesizing composites using biochar as a supporting media to develop new sorbents with efficient surface attributes for heavy metals removal from aqueous solutions.

Original languageEnglish
Pages (from-to)111-126
Number of pages16
JournalInternational Journal of Phytoremediation
Issue number2
Publication statusPublished - 28 Jan 2020
Externally publishedYes


  • Biochar
  • heavy metals
  • sorption


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