Removal of aqueous Cr(VI) by a magnetic biochar derived from Melia azedarach wood
2018; Elsevier BV; Volume: 256; Linguagem: Inglês
10.1016/j.biortech.2018.01.145
ISSN1873-2976
AutoresXin Zhang, Lei Lv, Yingzhi Qin, Min Xu, Xianbin Jia, Zhihua Chen,
Tópico(s)Nanomaterials for catalytic reactions
ResumoMagnetic biochar (MMABC) prepared from Melia azedarach wood was used for aqueous Cr(VI) removal. MMABC was a mesoporous material with SBET 5.219 m2/g and superparamagnetic magnetization 17.3 emu/g contributed by the contained Fe3O4. The MMABC showed higher removal efficiency (99.8%) than biochar under conditions of dosage 5 g/L, pH = 3.0, and Cr(VI) concentration 10 mg/L. The saturation magnetization (16.1emg/g) of MMABC still remained after adsorption. According to FTIR and Raman results, the benzene-ring adjacent carbonyl did not showed obvious positive effects on Cr(VI) removal. A potential mechanism and corresponding apparent kinetic model indicated the Cr(VI) removal process by MMABC followed adsorption-reduction-adsorption steps. Cr(VI) was firstly adsorbed on surface and subsequently reduced to Cr(III), which was further adsorbed on MMABC surface. Langmuir isotherm (with maximal adsorption capacity of 25.27 mg/g) and pseudo second-order kinetic model were suitable for adsorption step.
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