title: Magnetite impregnation effects on the sorbent properties of activated carbons and biochars.
abstract: 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 m(2)/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 m(2)/g surface area was the best metal sorbent. Magnetic biochars thus hold promise as more sustainable alternatives to coal-derived magnetic activated carbons.
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, England, United Kingdom; Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China; Hebei Key Laboratory of Groundwater Remediation, Shijiazhuang 050061, China.
authors.forename: Zhantao
authors.initials: Z
authors.lastname: Han
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, England, United Kingdom.
authors.forename: Badruddeen
authors.initials: B
authors.lastname: Sani
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, England, United Kingdom; Department of Inorganic Chemistry, Medical University of Gdańsk, 80-210 Gdańsk, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Mrozik
authors.affiliation: Department of Geosciences, Center for Applied Geoscience, University of Tübingen, 72074 Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Obst
authors.affiliation: Department of Geosciences, Center for Applied Geoscience, University of Tübingen, 72074 Tübingen, Germany; Department of Geology and Environmental Geosciences, College of Charleston, Charleston, SC 29401, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Beckingham
authors.affiliation: Department of Chemistry, University of Patras, 26504 Patras, Greece.
authors.forename: Hrissi K
authors.initials: HK
authors.lastname: Karapanagioti
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, England, United Kingdom. Electronic address: david.werner@ncl.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Werner
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal; D052203:Ferrosoferric Oxide
keywords: Activated carbon; Biochar; Magnetic sorbents; Soil and sediment remediation; Wastewater treatment