Synthesis of hierarchical Ni(OH)2 and NiO nanosheets and their adsorption kinetics and isotherms to Congo red in water
Synthesis of hierarchical Ni(OH)2 and NiO nanosheets and their adsorption kinetics and isotherms to Congo red in water
复制标题
多级Ni(OH)2和NiO纳米片的合成及其对水中刚果红的吸附动力学和等温线
DOI：
10.1016/j.jhazmat.2010.09.104
复制
发表时间：
2011-01-30
影响因子：
13.6
通讯作者：
Yu, Jiaguo
中科院分区：
文献类型：
--
作者：
Cheng, Bei;Le, Yao;Yu, Jiaguo
以氯化镍为前驱体，尿素为沉淀剂，采用简单的化学沉淀法制备了具有多级孔结构的Ni（OH）2和NiO纳米片。采用X射线衍射、扫描电镜和氮气吸附-脱附等手段对样品进行了表征。研究了制备的样品对水溶液中刚果红（CR）的吸附性能。孔结构分析表明，Ni（OH）（2）和NiO纳米片由至少三个层次的多级多孔组织组成：小的介孔（约. 3-5 nm）、大的中孔（约. 10-50 nm）和大孔（100-500 nm）。采用Langmuir和Freundlich模型对CR在所制备样品上的平衡吸附数据进行了分析，结果表明，Langmuir模型能较好地拟合实验数据。采用Langmuir方程确定了Ni（OH）2纳米片、NiO纳米片和NiO纳米颗粒对CR的吸附容量分别为82.9、151.7和39.7 mg/g。吸附数据进行了建模，使用伪一级，伪二级和颗粒内扩散动力学方程。结果表明，准二级动力学方程和颗粒内扩散模型能较好地描述吸附动力学。结果表明，Ni（OH）2和NiO纳米片具有独特的多级孔结构和较高的比表面积，是去除废水中刚果红污染物的有效吸附剂. (C)2010 Elsevier B. V.保留所有权利。
Ni(OH)(2) and NiO nanosheets with hierarchical porous structures were synthesized by a simple chemical precipitation method using nickel chloride as precursors and urea as precipitating agent. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and nitrogen adsorption-desorption isotherms. Adsorption of Congo red (CR) onto the as-prepared samples from aqueous solutions was investigated and discussed. The pore structure analyses indicate that Ni(OH)(2) and NiO nanosheets are composed of at least three levels of hierarchical porous organization: small mesopores (ca. 3-5 nm), large mesopores (ca. 10-50 nm) and macropores (100-500 nm). The equilibrium adsorption data of CR on the as-prepared samples were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of CR was determined using the Langmuir equation and found to be 82.9, 151.7 and 39.7 mg/g for Ni(OH)(2) nanosheets, NiO nanosheets and NiO nanoparticles, respectively. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicate that pseudo-second-order kinetic equation and intra-particle diffusion model can better describe the adsorption kinetics. The as-prepared Ni(OH)(2) and NiO nanosheets are found to be effective adsorbents for the removal of Congo red pollutant from wastewater as a result of their unique hierarchical porous structures and high specific surface areas. (C) 2010 Elsevier B.V. All rights reserved.