摘要:随着人类社会的发展和工业化进程的加快,水污染越来越突出,受到人们的广泛关注。在水介质中常见的污染物包括染料、有机物、重金属、农药和药品等。近几十年来,染料广泛应用于纺织、皮革、印染、化妆品等行业。由于其毒性高、难降解、容易抑制水生植物光合作用等原因,给人类的健康和生态系统带来了严重的威胁。为了人类社会和生态环境的可持续发展,必须开发一种行之有效的技术来解决废水处理中的染料问题。现如今,染料废水处理技术主要有生物法、物理法、化学法以及一些组合工艺等。随着染料废水的成分越来越复杂,排放的标准越来越高,处理难度也就越来越大。吸附法由于具有处理效率高,廉价和易于操作等优点被认为是优选的方法之一。因此,发展高效,环保的吸附剂材料去除水中染料污染物是一项非常有意义的工作。本文研究了分等级多孔金属氧化物复合材料的制备及其对水中有机染料的吸附性能。主要工作内容及研究结论如下: (1)通过简单的水热法制备了Ni2+/Fe3+摩尔比为3的铁镍双氢氧化物(NiFe-LDH)。在400°C 煅烧后,铁镍双氢氧化物转变为铁镍双氧化物(NiFe-LDO)。制备的样品通过X-射线衍射仪、场发射扫描电子显微镜,X-射线分光光谱,氮气吸附−脱附,傅里叶变换红外光谱分析仪进行表征。煅烧以及未煅烧的NiFe-LDH被用作吸附剂从水溶液中去除刚果红染料(CR)。NiFe-LDH 和NiFe-LDO 样品的吸附平衡数据可以被Langmuir模型拟合,拟合出最大的理论吸附量分别为205 和 330 mg/g。二级动力学和分子内扩散模型很好的描述了动力学数据。潜在的吸附机理在研究后被定义为离子交换及结构重建。 (2)通过简单的水热法制备出了ZnO-AlOOH纳米片组装的花状结构。制备的样品通过各种表征手段进行表征。花状ZnO-AlOOH复合材料以及纯的ZnO和AlOOH作为吸附剂去除水溶液的刚果红(CR)的染料。二级动力学很好描述样品吸附染料的动力学。ZnO–AlOOH样品的吸附平衡数据用Langmuir拟合的很好。ZnO–AlOOH样品具有杰出的吸附能力(524 mg/g),这高于纯的AlOOH 和 ZnO的吸附量。ZnO–AlOOH样品优越的去除效果是由于其分等级多孔结构和高的比表面积。这项工作为制造高效去除废水中阴离子染料的吸附剂提供了新的见解。 (3)采用简单的水热法及后续的煅烧工艺成功地制备了分等级多孔ZnO/NiO复合金属氧化物微球。制备的样品通过各种表征手段进行表征。同时,研究了其从水溶液中去除刚果红(CR)的能力。合成的分等级多孔ZnO/NiO复合材料对刚果红染料表现出优越的吸附性能(518 mg/g),其明显高于纯的NiO (397 mg/g) 和ZnO (304 mg/g)样品。ZnO/NiO复合材料优越的吸附性能主要是由于它独特的分等级多孔结构及较高的比表面积(130 m2/g),这能够为CR分子提供大量的活性位点。吸附动力学和等温线数据很好的符合二级动力学和Langmuir等温模型。这些结果表明,所制备的分等级多孔ZnO/NiO复合金属氧化物微球可以被视为一个高效的吸附剂,以除去从废水中的有机染料。 With the development of human life andindustrial activities, water pollution has become a global environmental issueand received wide attention. Among the common contaminants in the aqueous mediainclude dyes, organic matters, heavy metals, pesticides and pharmaceuticals. Inthe recent decades, dyes are widely used in textile, leather, dyeing, cosmeticsand food industries. These dyes have brought serious threats to human healthand environmental ecosystems due to its high toxicity, hard to degrade and mayaffect photosynthesis in aquatic environments by inhibiting light penetration.For the sustainable development of human society and ecological environment, itis necessary to develop an effective technology to remove dyes from wastewater.At present, the dye wastewater treatment methods mainly consist of biologicalmethod, physical method, chemical method and some combination technology and soon.Along with the composition of dye wastewater isbecoming more and more complex and the improved requirements of environmentalprotection, processing difficulty is also growing. Adsorption is considered tobe one of the best methods because of its advantages such as high efficiency,low cost and easy operation. Therefore, it is a very meaningful work to developefficient and environmentally friendly adsorbent to remove dye pollutants fromwater. In this paper, the preparation of hierarchical porous metal oxidecomposites and their adsorption properties for organic dyes in water werestudied. The main contents and conclusions are as follows: (1) Hierarchically porousnickel–iron-layered double hydroxide (NiFe-LDH) with a Ni2+/Fe3+ molar ratio of3 was successfully synthesised through a simple hydrothermal route. Aftercalcination at 400 °C, NiFe-LDH transformed into nickel–iron-layered doubleoxides (NiFe-LDO). The as-prepared samples were characterised through X-raypowder diffraction, field emission scanning electron microscopy, energydispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-rayphotoelectron spectroscopy and nitrogen adsorption. The calcined and uncalcinedNiFe-LDH was used as adsorbents to remove Congo red (CR) dye in an aqueoussolution. The equilibrium adsorption data of NiFe-LDH and NiFe-LDO samples werewell fitted to Langmuir model and were characterised by excellent adsorptioncapacities of 205 and 330 mg/g, respectively. Pseudo-second-order kinetic andintra-particle diffusion models indicated that CR was well adsorbed on theadsorbent. The underlying adsorption mechanism was investigated and observed asanion exchange and reconstruction. (2) ZnO–AlOOH nanoflakes assembled inflower-like structures were produced through a simple hydrothermal route. Thesynthesized composites were characterised by X-ray powder diffraction,field-emission scanning electron microscopy, energy-dispersive X-rayspectroscopy, transmission electron microscopy, nitrogen adsorption−desorption, Fourier-transform infrared spectroscopy and X-rayphotoelectron spectroscopy analyses. The flower-like ZnO–AlOOH composites wereused as adsorbents to remove Congo Red (CR) dye from aqueous solution andcompared with pure AlOOH and ZnO adsorbents. The adsorption kinetics of the dyeon the synthesised samples was described by a pseudo-second-order model. The equilibriumadsorption data of CR on the ZnO–AlOOH samples fitted well with the Langmuirmodel. The ZnO–AlOOH samples possessed excellent adsorption capacity (524mg/g), which was higher than those of pure AlOOH and ZnO samples. The superiorCR removal efficiency of the ZnO-AlOOH samples could be attributed to theirhierarchical porous structures and high specific surface areas, which areconducive to the diffusion and adsorption of the CR molecules. This workprovides new insights into the fabrication of efficient adsorbents for anionicdye removal from wastewater. (3) ZnO–AlOOH nanoflakes assembled inflower-like structures were produced through a simple 关键词:金属氧化物;分等级多孔;刚果红;吸附;工业废水; metal oxide; Hierarchical porous; Congored; adsorption; industrial effluent |