Efficient removal of crystal violet using Fe3O4-coated biochar: the role of the Fe3O4 nanoparticles and modeling study their adsorption behavior

• Published in: Scientific reports 2015-07, Vol.5 (1), p.12638-12638, Article 12638
• Main Authors: Sun, Pengfei, Hui, Cai, Azim Khan, Rashid, Du, Jingting, Zhang, Qichun, Zhao, Yu-Hua
• Format: Article
• Language: English
• Subjects: 639/301/357/997; 639/925/357/354; 704/172/169/896; Adsorption; Charcoal; Gentian violet; Humanities and Social Sciences; Iron oxides; multidisciplinary; Nanoparticles; pH effects; Pollutants; Science; Temperature effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep12638

Biochar shows great promise for use in adsorbing pollutants. However, a process for enhancing its adsorption capacity and re-collection efficiency is yet to be further developed. Hence, in this study, we developed a type of biochar coated with magnetic Fe 3 O 4 nanoparticles (i.e., magnetic biochar (MBC)) and assessed its use for crystal violet (CV) adsorption as well as its recycling potential. The coating of Fe 3 O 4 nanoparticles, which was not only on the surface, but also in the interior of biochar, performed two functions. Firstly, it produced a saturation magnetization of 61.48 emu/g, which enabled the biochar being efficiently re-collected using a magnet. Secondly, it significantly enhanced the adsorption capacity of the biochar (from 80.36 to 99.19 mg/g). The adsorption capacity of the MBC was determined to be the largest by so far (349.40 mg/g) for an initial CV concentration of 400 mg/L, pH of 6.0 and temperature of 40 °C and the adsorption capacity of re-collected MBC was 73.31 mg/g. The adsorption of CV by the MBC was found to be a spontaneous and endothermic physical process in which the intraparticle diffusion was the limiting step. These findings inspire us to use other similar materials to tackle the menace of pollutions.