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.
Dalton Trans. 2012 May 21;41(19):5854-61. doi: 10.1039/c2dt12312f. Epub 2012 Mar 28.
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.
多孔 Fe(3)O(4)@C 纳米胶囊的直径约为 120nm（约 50nm 的空腔），通过牺牲模板法与溶剂热法相结合合成。N(2)吸附-解吸等温线表明其具有介孔结构和大的 BET 比表面积（159.8m(2)g(-1)）。磁性研究表明其具有超顺磁性和高饱和磁化强度（55.93emu g(-1)）。纳米胶囊还具有负的 zeta 电位（-27.59mV），并且在外壳的碳层上具有羧基，这使其在水溶液中具有高度分散性，并提供了金属离子的螯合功能。重金属去除测试表明了纳米胶囊的优异亲和力，对不同金属的高效去除率（>90%），对 Pb(2+)的吸附容量为 79mg g(-1)，去除过程超快（Pb(2+)，1 分钟内达到 99.57%）。由于受到多孔碳层的保护，纳米胶囊即使在酸性溶液（pH=3）中也表现出优异的耐酸性和吸附性能。此外，通过调节 pH 值，可实现金属离子的吸附和解吸，从而实现吸附剂的再生和重金属的回收。
