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.

Highly efficient removal of Cr(VI) from wastewater via adsorption with novel magnetic Fe3O4@C@MgAl-layered double-hydroxide

“…To improve the dispersion stability 27 of the nano-size iron oxides in suspension medium, surface 28 functions of magnetic iron oxide coated with polymers or inorganic 29 compounds has won increasing attention [8][9][10][11][12][13][14][15][16][17]. Deposition of 30 mesoporous carbon layers on magnetic nanoparticles is considered 31 as an effective way to inhibit the aggregation of magnetic 32 nanoparticles [18][19][20]. It has been also reported in our previous 33 publications that mesoporous carbon layer homogenously coated 34 on the surface of Fe 3 O 4 could effectively inhibit the aggregation of 35 Fe 3 O 4 nanoparticles [21].…”

Selective removal of transition metal ions from aqueous solution by metal–organic frameworks

“…However, according to the Le Châtelier's principle, the lower solution pH can restrain the above response and the adsorption of Cu 2+ . 49 MOF-2COOH + Cu 2+ = MOF-2(COO)Cu + 2H + (4) 240 In aqueous medium, there are several kinds of other metal ions, such as Zn 2+ , Mg 2+ , Ca 2+ . Bearing these in mind, we further investigated the influence of the interfering ions in this study.…”

Applications of hollow nanomaterials in environmental remediation and monitoring: A review

“…Cheng et al [25] synthesized hollow Fe 3 O 4 -C nanomaterials that showed high Pb(II) adsorption capacity. Moreover, the hollow Fe 3 O 4 -C nanomaterials could be regenerated easily through magnetic separation at low pH.…”