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Magnetite Impregnation Effects on the Sorbent Properties of Activated Carbons and Biochars

Lookup NU author(s): Dr Zhantao Han, Badruddeen Sani, Dr Wojciech MrozikORCiD, Professor David WernerORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


This paper discusses the sorbent properties of magnetic activated carbons and biochars produced by wet impregnation with iron oxides. The sorbents had magnetic susceptibilities consistent with theoretical predictions for carbon-magnetite composites. The high BET surface areas of the activated carbons were preserved in the synthesis, and enhanced for one low surface area biochar by dissolving carbonates. Magnetization decreased the point of zero charge. Organic compound sorption correlated strongly with BET surface areas for the pristine and magnetized materials, while metal cation sorption did not show such a correlation. Strong sorption of the hydrophobic organic contaminant phenanthrene to the activated carbon or biochar surfaces was maintained following magnetite impregnation, while phenol sorption was diminished, probably due to enhanced carbon oxidation. Copper, zinc and lead sorption to the activated carbons and biochars was unchanged or slightly enhanced by the magnetization, and iron oxides also contributed to the composite metal sorption capacity. While a magnetic biochar with 219 ± 3.7 m2/g surface area nearly reached the very strong organic pollutant binding capacity of the two magnetic activated carbons, a magnetic biochar with 68 ± 2.8 m2/g surface area was the best metal sorbent. Magnetic biochars thus hold promise as more sustainable alternatives to coal-derived magnetic activated carbons.

Publication metadata

Author(s): Han Z, Sani B, Mrozik W, Obst M, Beckingham B, Karapanagioti HK, Werner D

Publication type: Article

Publication status: Published

Journal: Water Research

Year: 2015

Volume: 70

Issue: 1

Pages: 394-403

Print publication date: 01/03/2015

Online publication date: 17/12/2014

Acceptance date: 09/12/2014

Date deposited: 18/09/2015

ISSN (print): 0043-1354

ISSN (electronic): 1879-2448

Publisher: IWA Publishing


DOI: 10.1016/j.watres.2014.12.016


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