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.

Effect of H2O2 concentrations on copper removal using the modified hydrothermal biochar

“…Carboxylic groups were good for Cu (II) binding as they were bidentate ligands including (SCO) 2 Cu 2+ and (SCO) 2 -Cu(OH) À (Corapcioglu and Huang, 1987). Majority of researchers reported the optimum pH for metal sorption by biochars was less than 7.0 (Tan et al, 2015), while the data varied with the different of sorbent species (Meng et al, 2014;Yang and Jiang, 2014;Han et al, 2015). This was in line with the results of sorption behavior of the modified HLG in this study.…”

A novel solid-state fractionation of naphthenic acid fraction components from oil sands process-affected water

“…By contrast AC has reduced surface functionality, as shown by a recent study of these materials (Kwon and Wilson, 2010). The second discriminating feature is the textural properties where AC has a greater BET surface area ($10 3 m 2 /g) compared to the other materials which all are approximately 10 1 m 2 /g (Bismarck et al, 2002;Ayad and Zaghlol, 2012;Sajih et al, 2014;Han et al, 2015). Fig.…”

Removal of Cu(ii) from aqueous solution using Fe3O4–alginate modified biochar microspheres

“…7,8 The magnetic modication can improve the adsorption capacity of the hybrid biochar, 7-10 while some reports have found that the efficiency of adsorption by magnetically modied biochar was correlated to its structure. 11,12 In this regard, the magnetic modication has a negative impact on the adsorption capacity of biochar with poorly developed structure.…”