title: Stabilization of nanoscale zero-valent iron (nZVI) with modified biochar for Cr(VI) removal from aqueous solution.
abstract: Three types of modified biochar (BC) were produced respectively with acid (HCl) treatment (HCl-BC), base (KOH) treatment (KOH-BC) and oxidation (H2O2) treatment (H2O2-BC) of raw biochar. Both the raw biochar and modified biochars supported zero valent iron nanopartilces (nZVI) (i.e. nZVI@BC, nZVI@HCl-BC, nZVI@KOH-BC and nZVI@H2O2-BC) were synthesized and their capacities for Cr(VI) removal were compared. The results showed that the nZVI@HCl-BC exhibited the best performance and the underlying mechanisms were discussed. The surface elemental distribution maps of the nZVI@HCl-BC after reaction with Cr(VI) showed that Fe, Cr and O elements were deposited on the surface of HCl-BC evenly, indicating that the formed Cr(III)/Fe(III) could settle on the surface of HCl-BC uniformly rather than coated only on the nZVI surface. This reveals that the supporter HCl-BC could also play a role in alleviating the passivation of nZVI. Besides, the effects of mass ratio (nZVI/HCl-BC), pH, and initial Cr(VI) concentration on Cr(VI) removal were examined. At lower mass of HCl-BC, nZVI aggregation cannot be fully inhibited on the surface of HCl-BC, whereas excessive biochar can block the active sites of nZVI. Additionally, it was found that Cr(VI) removal by nZVI@HCl-BC was dependent on both pH and initial Cr(VI) concentration.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China. Electronic address: dongh@hnu.edu.cn.
authors.forename: Haoran
authors.initials: H
authors.lastname: Dong
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Junmin
authors.initials: J
authors.lastname: Deng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Yankai
authors.initials: Y
authors.lastname: Xie
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Kunjie
authors.initials: K
authors.lastname: Hou
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D002857:Chromium / Q000302:isolation & purification*; D007501:Iron / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: C540010:biochar; D002857:Chromium; D002606:Charcoal; C074702:chromium hexavalent ion; D007501:Iron
keywords: Biochar; Chromium removal; Modification; Nanoscale zero-valent iron; Reduction