Influence of solution pH, ionic strength, and humic acid on cadmium adsorption onto activated biochar: Experiment and modeling

Chang Min Park, Jonghun Han, Kyoung Hoon Chu, Yasir A.J. Al-Hamadani, Namguk Her, Jiyong Heo, Yeomin Yoon

Research output: Contribution to journalArticlepeer-review

152 Scopus citations

Abstract

Biochar was prepared by pyrolysis of torrefied loblolly pine and used as a sorbent for the removal of Cd(II) ions from aqueous solutions. The effects of pH, ionic strength, and humic acid (HA) on Cd(II) adsorption on biochar were investigated in comparison with other sorbents, commercially available powdered activated carbon (PAC) and multi-walled carbon nanotubes (MWNT). The order of overall adsorption for Cd(II) was biochar > PAC > MWNT for the adsorbents. In addition, the results indicated that the sorption behaviors of Cd(II) were strongly dependent on pH and ionic strength. The maximum adsorption capacity of Cd(II) on biochar at pH 7.5 ± 0.1 and T = 25 °C was calculated to be 167.3 mg/g, much higher than other reports. The presence of HA modifies the surface properties of biochar and enhances complexation of Cd(II) with adsorbed HA. Surface complexation modeling gave an excellent fit with the predominant mononuclear monodentate >SOCd2+ in the absence of HA and the ternary surface >SOL1Cd species in the presence of HA as well as binuclear bidentate >(SO)2Cd species at higher pH. The results of this study highlight that biochar is a suitable material for the removal of environmental cadmium pollution.

Original languageEnglish
Pages (from-to)186-193
Number of pages8
JournalJournal of Industrial and Engineering Chemistry
Volume48
DOIs
StatePublished - 2017

Bibliographical note

Publisher Copyright:
© 2017 The Korean Society of Industrial and Engineering Chemistry

Keywords

  • Adsorption
  • Biochar
  • Cadmium
  • Humic acid
  • Surface complexation modeling

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