Enhanced removal of ionic dyes by hierarchical organic three-dimensional layered double hydroxide prepared via soft-template synthesis with mechanism study
Enhanced removal of ionic dyes by hierarchical organic three-dimensional layered double hydroxide prepared via soft-template synthesis with mechanism study
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软模板合成多级有机三维层状双氢氧化物增强离子染料去除效果及机理研究
DOI：
10.1016/j.cej.2018.10.179
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发表时间：
2019
影响因子：
15.1
通讯作者：
Frost Ray L.
中科院分区：
文献类型：
--
作者：
Zhang Ping;Ouyang Sida;Li Peng;Huang Yun;Frost Ray L.
本文首次报道了以十二烷基硫酸钠（SDS）为软模板剂，采用一步水热法成功合成的多级有机三维MgAl-LDH对阳离子染料（罗丹明B，RhB）和阴离子染料（甲基橙子，MO）的有效去除。对RhB和MO的去除机理进行了深入的研究，确定其去除机理分别为表面吸附和阴离子交换。此外，还考察了投加量、接触时间、染料初始浓度和温度等反应参数对染料去除率的影响。MO的最大吸附量（377.89 mg·g-1）远高于RhB（48.29 mg·g-1）和其他吸附剂。在低浓度下，RhB和MO的吸附主要为多层吸附，而在高浓度（>200 mg·L-1）下，MO的吸附主要为单层吸附。热力学计算表明，吸附RhB和MO的过程均为自发吸热过程。本研究通过对3D-LDHs的表面改性，探索了O3 D-LDHs作为有机污染物吸附剂在环境修复中的应用前景。
In this work, we report, for the first time, that cationic (Rhodamine B, RhB) and anionic dyes (Methyl orange, MO) were removed efficiently by hierarchical organic three-dimensional MgAl-LDH, which was successfully synthesized via a one-step hydrothermal strategy using sodium dodecyl sulfate (SDS) as a soft template agent. The removal mechanisms of RhB and MO were extensively investigated and determined to be surface adsorption and anion exchange, respectively. In addition, the influence of reaction parameters affecting dyes removal including dosage, contact time, initial dye concentrations and temperature were investigated. The maximum adsorption capacity of MO (377.89 mg·g−1) was far beyond that of RhB (48.29 mg·g−1) as well as other adsorbents. Multilayer adsorption occurred in RhB or MO at a low concentration, while monolayer adsorption was the dominant process in MO at high concentration (>200 mg·L−1). The thermodynamic calculations demonstrated that the adsorption process for both RhB and MO was spontaneous and endothermic. This work significantly broadens the application prospects of 3D-LDHs by modifying their surface properties and exploring O3D-LDHs as excellent adsorbents for organic pollutants in environmental remediation.