title: Synthesis of carbon-coated, porous and water-dispersive Fe3O4 nanocapsules and their excellent performance for heavy metal removal applications.
abstract: Porous Fe(3)O(4)@C nanocapsules with a diameter of about 120 nm (about 50 nm cavity) were synthesized by combining a sacrificial template method with solvothermal treatment. The N(2) adsorption-desorption isotherms reveals their mesoporous structure and large BET surface area (159.8 m(2) g(-1)). The magnetic investigation indicates their superparamagnetic nature and high saturation magnetization (55.93 emu g(-1)). The nanocapsules also exhibit negative zeta potential (-27.59 mV) and possess carboxyl groups on the outer carbon layer, which keeps them highly dispersive in aqueous solution and provides a chelating function for metal ions. The heavy metals removal test demonstrates the excellent affinity of nanocapsules, the high efficiency for different metals (>90%), 79 mg g(-1) adsorption capacity for Pb(2+) and ultrafast removal process (Pb(2+), 99.57% within 1 minute). Protected by a porous carbon layer, the nanocapsules display excellent acidic resistance and adsorption properties even in an acidic solution (pH = 3). Moreover, the metal ions can be easily adsorbed and desorbed through manipulating the pH value for adsorbent regeneration and heavy metal recycling.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Cheng
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Zhou
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Sun
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Hu
authors.forename: Hao
authors.initials: H
authors.lastname: Zhong
authors.forename: Xiang-Kai
authors.initials: XK
authors.lastname: Kong
authors.forename: Qian-Wang
authors.initials: QW
authors.lastname: Chen