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文章信息1Zhang Y X, Jia Y. Preparation of porous alumina hollow spheres as an adsorbent for fluoride removal from water with low aluminum residual[J]. Ceramics International, 2016, 42(15): 17472-17481.

推荐理由:作者介绍了一种多孔氧化铝空心球的制备方法及其对氟化物去除的应用。文章借助了扫描电镜、透射电镜、红外光谱、X射线衍射、热重分析等方法,对空心球的形成过程进行了分析,还从接触时间、初始浓度、pH值等方面对材料的吸附性能进行了评价。这种制备及性能表征方法对氧化铝类吸附剂的制备与应用具有借鉴作用。

Abstract: Amorphous aluminum hydroxide hollow spheres were synthesized and characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermal gravimetric analysis. The obtained amorphous aluminum hydroxide hollow spheres were an excellent precursor for the fabrication of porous alumina hollow spheres via a simple thermal transformation process. The influence of the calcination temperature on the fluoride removal performance and the concentration of the residual aluminum ions were investigated. With the calcination temperature of 800°C, the concentration of the residual aluminum ions was low than that of WHO guideline (0.2 mg·L−1), and the corresponding adsorption capacity towards fluoride at neutral pH was 16.77 mg·g−1. When the calcination temperature lower than 800°C, both of the fluoride adsorption capacity and the concentration of the residual aluminum ions were increased. Batch experiments were performed to study the influence of various experimental parameters such as contact time, initial concentration, pH value and the presence of competing anions on the adsorption of fluoride on porous alumina hollow spheres prepared with the calcination temperature of 800°C. The fluoride adsorption can be well described by the Langmuir model, and the kinetic data was well fitted to pseudo-second-order model. The co-existing carbonate and phosphate anions have great influence on fluoride removal. Furthermore, the regeneration and recyclability of the obtained porous alumina hollow spheres were evaluated.

下载地址http://www.sciencedirect.com/science/article/pii/S0272884216313554

 

文章信息2Guo Y, Yan K, Cui L, et al. Improved extraction of alumina from coal gangue by surface mechanically grinding modification[J]. Powder Technology, 2016, 302:33-41.

推荐理由:作者采用机械改性的方式对煤矸石进行有效的活化,并对其结构变化及氧化铝回收率进行分析。作者采用激光粒度分析、氮吸附/解吸等热分析,以及扫描电镜、x射线衍射等分析手段对经过磨削后的煤矸石粉体热活化机理进行研究。研究表明:在这种处理下,改进的煤矸石粒子尺寸减小,表面积增加,高岭石结构改变,促进了氧化铝的提取。这项研究对于分析煤矸石等固体废弃物的改性及提高活性具有借鉴指导作用。

Abstract: Coal gangue, a type of kaolinite clay in coal measures, is one of the largest categories of solid industrial wastes in China. Alumina extraction from coal gangue could offer an alternative to bauxite as a source of alumina. Mechanically modification by grinding is an effective activation method to improve alumina recovery from coal gangue. The effect of grinding on coal gangue, however, had not been investigated systematically. Present understanding regarding the effects of grinding on coal gangue is still restricted to that on kaolinite. Furthermore, the differences in the inherent mechanisms between grinding and thermal activation on coal gangue have not been investigated so far. This study aimed to clarify the differences among them. Changes in particle size, surface area, and morphology were followed by means of laser particle size analysis, nitrogen adsorption/desorption isotherms, and scanning electron microscopy (SEM). Possible modifications of the chemical structure, mineral phase and thermal behavior were monitored using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Infrared analysis (IR), and Thermogravimetry (TG). The results showed that the alumina dissolution from coal gangue increased with longer grinding time. Grinding followed by calcination further improved the alumina extraction. After the calcined coal gangue was ground for 20 h, the alumina extraction reached ~ 95%. The results of XRD, XPS, and IR analysis implied that grinding produced defects in the coal gangue kaolinite; however the main kaolinite layer structure (SiOAlVI) were unaffected in the absence of calcination. In this case, the improved activity might be due to reduced particle size, increased surface area, and aluminum enrichment at the surface. The primary structure of kaolinite in coal gangue was destroyed by calcination after grinding, and kaolinite was altered to amorphous metakaolinite with SiOAlIV structure, which facilitated alumina extraction.

下载地址:http://www.sciencedirect.com/science/article/pii/S0032591016305150

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