title: Cr(VI) reduction and immobilization by novel carbonaceous modified magnetic Fe3O4/halloysite nanohybrid.
abstract: In this work, a novel "Dumbbell-like" magnetic Fe3O4/Halloysite nanohybrid (Fe3O4/HNTs@C) with oxygen-containing organic group grafting on the surface of natural halloysite nanotubes (HNTs) and homogeneous Fe3O4 nanospheres selectively aggregating at the tips of modified halloysite nanotubes was successfully synthesized. XRD, TEM, IR spectroscopy, XPS and VSM were used to characterize this newly halloysite nanohybrid and its formation mechanism was discussed. Cr(VI) ions adsorption experiments showed that the Fe3O4/halloysite nanohybrid exhibited higher adsorption ability with a maximum adsorption capacity of 132 mg/L at 303K, which is about 100 times higher than that of unmodified halloysite nanotubes. More importantly, with the reduction of Fe3O4 and electron-donor effect of oxygen-containing organic groups, Cr(VI) ions were easily reduced into low toxicity Cr(III) and then adsorbed onto the surface of halloysite nanohybrid. In addition, appreciable magnetization was observed due to the aggregation of magnetite nanoparticles, which make adsorbent facility separated from aqueous solutions after Cr pollution adsorption.
authors.affiliation: Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, PR China. Electronic address: xktian@cug.edu.cn.
authors.forename: Xike
authors.initials: X
authors.lastname: Tian
authors.affiliation: Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, PR China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, PR China.
authors.forename: Na
authors.initials: N
authors.lastname: Tian
authors.affiliation: Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, PR China.
authors.forename: Chaoxin
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yang
authors.affiliation: Materials Research Laboratory, Materials Research Institute and Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Sridhar
authors.initials: S
authors.lastname: Komarneni
keywords: Cr(VI) immobilization; Cr(VI) reduction; Fe(3)O(4)/halloysite nanohybrid; Magnetic separation