共查询到8条相似文献,搜索用时 4 毫秒
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利用粉煤灰制备沸石分子筛是其高值化利用的重要方向之一.以循环流化床粉煤灰为原料,采用酸浸预处理-氢氧化钠碱熔活化-水热晶化法制备F型八面沸石,并用于吸附亚甲基蓝.考察酸浸温度、碱熔温度及碱灰质量比对粉煤灰结构的影响及碱熔温度、碱灰质量比、液固比及晶化时间对沸石的结构和形貌的影响.通过XRD和SEM对粉煤灰沸石的晶体结构和形貌进行表征.结果表明,利用循环流化床粉煤灰制备高纯F型八面沸石适宜条件为碱熔温度550℃,碱灰质量比1.5:1,液固比12 mL/g,晶体导向剂用量10;,晶化温度100℃,晶化时间20 h.其比表面积高达357 m2/g,且对亚甲基蓝的饱和吸附量高达178 mg/g. 相似文献
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采用经碱熔融-离心提取处理后的粉煤灰为原料,经水热反应研究两步法合成高纯度ZSM-5型沸石的过程,探讨了碱灰比、焙烧温度对硅铝溶出量的影响,研究了碱度、晶化时间、晶化温度与硅铝比对合成ZSM-5型沸石的影响.结果表明:碱灰比为2.3∶1,焙烧温度为680 ℃时可获得最高的硅铝溶出量;当SiO2/Na2O =7(摩尔比),SiO2/Al2O3=45(摩尔比),晶化时间为68 h,晶化温度为180 ℃时可获得高纯度的ZSM-5型沸石. 相似文献
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以粉煤灰为原料,采用固相法合成NaA型粉煤灰沸石.通过静态吸附实验,研究了吸附时间、pH值、溶液浓度以及吸附温度对粉煤灰沸石吸附脱除亚甲蓝性能的影响.通过SME、XRD对产品进行表征,探讨了亚甲蓝在粉煤灰沸石上的吸附行为.结果表明:经XRD分析,合成产物主要为NaA型沸石.SEM分析表明,产物分别具有纺锤体及NaA型沸石立方体骨架结构;在吸附温度25 ℃,pH值>5,粉煤灰沸石投加量8 g·L-1,吸附30 min时,NaA型沸石对初始浓度为50~100 mg·L-1的亚甲蓝去除率均可达90;以上,较粉煤灰提高了45;;与商品沸石的吸附性能相当.合成的粉煤灰沸石吸附亚甲蓝过程符合Langmuir模型,其为单分子层吸附. 相似文献
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Xu Hongyan Diwu Jiangtao Hai Zhenyin Gao Libo Zhang Qiang Tang Jun Zhang Binzhen Xue Chenyang 《Crystal Research and Technology》2016,51(2):123-128
Pure Co3O4 microcrystals were prepared by a hydrothermal method from Co(NO3)2·6H2O and urea solution, and the effect of thermal treatment time on the growth of Co3O4 microcrystals was studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), Raman and UV‐Vis absorption spectra. The results show that with the thermal treatment time increases from 2 h to 12 h, the shape of as‐prepared Co3O4 microcrystals changes from the hedgehog sphere‐like to the as‐cubic one that were stacked by lots of lamella, and finally cubes, and then longer time treatment will only lead to the size growth and agglomeration of particles. In conclusion, the cubic Co3O4 microcrystals of uniform size (∼6 μm) are synthesized via a 12‐h thermal treatment. Moreover, the synthesis mechanism has been studied. 相似文献
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Chaturaporn Nimjaroen Shigeki Morimoto Chaiyot Tangsathitkulchai 《Journal of Non》2009,355(34-36):1737-1741
The porous glasses were prepared by a conventional phase separation method using coal fly ash as a raw material, and the properties of these porous glasses were investigated. The composition of coal fly ash is basically composed of SiO2–Al2O3–Fe2O3–CaO system and the SiO2–B2O3–Al2O3–CaO–Na2O system of glass was chosen as base glass composition. The pore diameter increases proportional to cube root of heating time (t1/3), however, the early stage of phase separation is not clear. It is estimated that the rate determining step may be the diffusion process of structural units involving oxygen ions and the phase separation may take place by the nucleation and growth mechanism, and the relatively larger pores of above 1 μm can be obtained easily. The chemical composition of porous glasses is SiO2–B2O3–Al2O3(–CaO–Na2O). A relatively large amount of fly ash (>40%) can be used successfully for the preparation of porous glass. 相似文献
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Xiande Yang Yongqian Wang Zhengshu Wang Qun Ma Junhan Kong Hanxiang Jia Meihua Yu 《Crystal Research and Technology》2015,50(8):658-667
In this article, flower‐like CdS structures have been prepared by a hydrothermal method with SDBS as surfactant. The influences of different experimental conditions on the morphologies, UV‐Vis and fluorescence properties of CdS have been investigated. The performances of CdS have been analyzed by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet‐visible (UV–Vis) and room‐temperature photoluminescence (PL). The XRD result indicates that the flower‐like CdS structures are of hexagonal phase. The FESEM results indicate that the main role of SDBS is to make the CdS crystals assemble together to form the flower‐like structures. The UV–Vis results show CdS has a strong absorption in the ultraviolet region and visible‐light region. The PL results show CdS has two emission peaks, respectively at 461 nm and 553 nm. The growth mechanism for the formation of flower‐like CdS structures is also described. 相似文献
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Fei Huang Ai‐Hua Yan Zheng‐Yi Fu Fan Zhang Yue‐Hua Wang Shi‐Bin Yin Ying‐Huai Qiang 《Crystal Research and Technology》2014,49(5):331-337
Hollow dipyramid titanium dioxide with truncated structure was synthesized by a facile hydrothermal approach in an aqueous solution of hydrofluoric acid and hydrogen peroxide. The critical oxygen from the decomposition of hydrogen peroxide has been investigated in detail. X‐ray diffraction and Raman measurements show that the main phase is anatase titanium dioxide, accompanied by a small amount of rutile titanium dioxide. The formation mechanism is proposed based on oxygen release, oxidation, etching and hydrolyzation. The sensing properties of such a hollow dipyramid titanium dioxide sensor show that the desirable sensing characteristics with a sensitivity of about 2.1 towards 5 ppm ethanol gas at 200 °C could be obtained. 相似文献