Synthesis of a 3D hierarchical structure of γ-AlO(OH)/Mg–Al-LDH/C and its performance in organic dyes and antibiotics adsorption
Synthesis of a 3D hierarchical structure of γ-AlO(OH)/Mg–Al-LDH/C and its performance in organic dyes and antibiotics adsorption
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DOI：
10.1039/c5ta04497a
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发表时间：
2015-10
影响因子：
--
通讯作者：
Jia Li;Ning Zhang;D. Ng
中科院分区：
文献类型：
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作者：
Jia Li;Ning Zhang;D. Ng
采用生物模板法合成了一种新型的三维多孔结构，该结构由Mg-Al-层状双氢氧化物纳米片、定向排列的γ-AlO（OH）纳米线和无定形碳组成。其衍生的金属氧化物具有相似的形貌和高孔隙率，也可以通过水热处理，然后煅烧去除碳得到。材料表征证实，所获得的纳米结构具有约2.7 nm的均匀可及中孔、约288 m2 g-1的高表面积和约0.66 cm 3 g-1的大孔体积。Al（OH）3晶种的形成、Mg/Al摩尔比和水热过程中的pH值对这种三维分级多孔结构的形成起了主要作用。合成的样品表现出超快的吸附速率和高的吸附容量，从水溶液中去除阴离子染料和抗生素。Mg-Al-LDH/γ-AlO（OH）/C及其衍生的金属氧化物对米诺环素（MC）和刚果红（CR）的最大吸附容量分别为302和447 mg g−1。吸附过程符合Langmuir等温方程和准二级动力学模型。静电吸附、离子交换和π-π相互作用被认为是主要的吸附机理。
We demonstrated an efficient route to synthesize a novel 3D hierarchically porous superstructure composed of edge-to-face stacks of Mg–Al-layered double hydroxide nanosheets, directionally arranged γ-AlO(OH) nanowires and amorphous carbon by a facile biotemplate method. Its derived metal oxides with similar morphologies and high porosity could also be obtained by carbon removal through hydrothermal treatment followed by calcination. Materials characterization confirmed that the obtained nanostructures had uniform accessible mesopores of ∼2.7 nm, a high surface area of ∼288 m2 g−1, and a large pore volume of ∼0.66 cm3 g−1. The formation of Al(OH)3 seeds, Mg/Al molar ratio and the pH value during the hydrothermal process played major roles in the formation of such 3D hierarchically porous structures. The as-synthesized sample exhibited ultrafast adsorption rates and high adsorption capacities in the removal of anionic dyes and antibiotics from aqueous solution. The maximum adsorption capacities of Mg–Al-LDH/γ-AlO(OH)/C and its derived metal oxides towards minocycline (MC) and Congo Red (CR) were 302 and 447 mg g−1, respectively. The adsorption process was well described by the Langmuir isotherm model and the pseudo second-order kinetic model. Electrostatic adsorption, ion exchange and π–π interactions were considered as the main adsorption mechanisms.