Almoisheer Noha, Alseroury F A, Kumar Rajeev, Aslam M, Barakat M A
Department of Physics, Faculty of Science, King Abdulaziz University Kingdom of Saudi Arabia.
Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University Jeddah 21589 Kingdom of Saudi Arabia
RSC Adv. 2019 Jan 2;9(1):560-568. doi: 10.1039/c8ra09562k. eCollection 2018 Dec 19.
Two-dimensional layered materials are gaining much attention in the field of wastewater purification. Herein, we report the synthesis and characterization of an anion selective copper-aluminum-layered double hydroxide/single-walled carbon nanotubes (CuAl-LDH/SWCNTs) composite for the scavenging of organic dye indigo carmine (IC) from aqueous solution. A facile urea hydrolysis method was used for the controlled growth of the metal hydroxides over the SWCNTs. Structural characterization of the prepared materials was investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The obtained results revealed that the CuAl-LDH/SWCNTs composite has a higher potential for the removal of IC in comparison to CuAl-LDH and SWCNTs. The enhanced adsorption capacity of the composite revealed that deposition of CuAl-LDH over SWCNTs increases the active adsorption sites and promotes the interactions between the composite and IC dye anion exchange, electrostatic, π-π, hydrogen bonding Moreover, adsorption kinetics, isotherms, and thermodynamic studies have been also proposed to illustrate the mechanism of the IC adsorption onto the CuAl-LDH/SWCNTs composite. Thermodynamic parameters showed that the adsorption of IC dye onto the CuAl-LDH/SWCNTs composite was exothermic and spontaneous in nature. Intra-particle diffusion was determined to be the rate-limiting step and adsorption of IC followed the Langmuir isotherm model with the maximum monolayer adsorption capacity 294.117 mg g at 20 °C. The results suggest that the CuAl-LDH/SWCNTs composite is a potential material for IC adsorption in aqueous solution.
二维层状材料在废水净化领域正备受关注。在此，我们报道了一种用于从水溶液中清除有机染料靛蓝胭脂红（IC）的阴离子选择性铜铝层状双氢氧化物/单壁碳纳米管（CuAl-LDH/SWCNTs）复合材料的合成与表征。采用简便的尿素水解法在SWCNTs上可控生长金属氢氧化物。使用X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和X射线衍射（XRD）技术对所制备材料进行结构表征。所得结果表明，与CuAl-LDH和SWCNTs相比，CuAl-LDH/SWCNTs复合材料具有更高的去除IC的潜力。复合材料增强的吸附能力表明，CuAl-LDH在SWCNTs上的沉积增加了活性吸附位点，并促进了复合材料与IC染料之间的相互作用（阴离子交换、静电、π-π、氢键）。此外，还开展了吸附动力学、等温线和热力学研究以阐明IC吸附到CuAl-LDH/SWCNTs复合材料上的机理。热力学参数表明，IC染料吸附到CuAl-LDH/SWCNTs复合材料上是放热且自发的过程。颗粒内扩散被确定为限速步骤，IC的吸附遵循朗缪尔等温线模型，在20℃时最大单层吸附容量为294.117 mg/g。结果表明，CuAl-LDH/SWCNTs复合材料是水溶液中IC吸附的潜在材料。
