排序方式: 共有24条查询结果,搜索用时 67 毫秒
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大孔树脂孔结构的测定 总被引:11,自引:0,他引:11
介绍了大孔树脂比表面积,孔容,平均孔径及孔径分布等孔结构参数的测定方法,对各参数的不同测定方法进行了分析,比较。通过作者的工作,对大孔树脂的孔结构测定及测定中需要注意的问题进行了讨论,对各种方法的特点进行了总结。 相似文献
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煤焦气化过程中比表面积和孔容积变化规律及其影响因素研究 总被引:11,自引:3,他引:8
煤焦的孔隙结构是影响气化反应的重要因素之一,本文通过测定部分气化焦样的比表面积及其孔隙结构,详细地研究了烟煤焦的孔隙结构在气化过程中的变化规律及其影响因素,结果表明,煤焦的孔隙结构在气化过程中的变化不但取决于原煤的性质,而且还取决于气化介质与气化温度;在相同条件下气化至相同气化率时总比表面积和孔体积大小顺序为彬县>神木>王封煤焦,总比表面积与微孔比表面积均随温度的升高而降低,在反应的前期CO2与H2O两种气氛下产生的总比表面积与微孔比表面积相当,但在反应后期CO2气氛下能够产生更多的总比表面积与微孔比表面积。 相似文献
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提出了一种纳米自组装大孔容介孔氧化铝固体材料的制备方法.提出了二级纳米自组装机理和框架式大孔容介孔固体材料形成机理.在一级纳米自组装体,超增溶胶团中,氢氧化铝沉淀与VB值小于1的表面活性剂原位自组装成线状、棒状二级纳米自组装体.二级纳米自组装氢氧化铝焙烧形成棒状纳米氧化铝.对于大孔容介孔固体材料的形成,我们提出了没有外表面要求限制,纳米氧化铝组成没有连续外表面的框架式介孔固体材料机理.采用二级纳米自组装体为模板剂合成出适用于渣油加氢处理催化剂的大孔容介孔固体材料,物理性质为1.8~2.7mL·g^-1的孔容、180~429m^2·g^-1比表面、17~57nm的平均孔径、大于10nm的孔为81%~94%、87%~93%的孔隙率和7.7~25N/mm的强度. 相似文献
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采用由环己烷、聚乙二醇辛基苯基醚(TritonX-100)、正丁醇与水溶液构成的反相微乳液体系, 合成了纳米Al2O3粉体. 采用X射线衍射、扫描电子显微镜、透射电子显微镜、比表面积分析仪等表征手段, 分别对产物的结构、形貌、比表面积和孔容进行了表征, 该纳米Al2O3比表面积约450 m2·g-1(随反应参数不同发生变化), 均属γ-Al2O3, 粒径均匀, 颗粒直径小于10 nm. 考察了微乳液体系中水与表面活性剂的物质的量之比r0、表面活性剂与助表面活性剂的体积比φ、焙烧温度等关键因素对产物比表面积等物理性质的影响. 结果表明, 当r0=20, φ=0.5, 焙烧温度为500 ℃时, 可以得到大比表面积、高孔容、分散性好及粒径分布均匀的γ-Al2O3粉体. 相似文献
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用二硫化碳-N-甲基-2-吡咯烷酮(CS2-NMP)(1:1,V/V)混合溶剂、丙酮和吡啶对南桐烟煤逐级萃取,得到各级残余物。通过比表面积及孔快速测试仪和扫描电镜,对煤及各萃取残余物的氮气吸附行为、粒度进行测试,考察了溶剂萃取对煤的BET比表面积与BJH孔容、孔面积随孔径分布规律以及粒度的影响。结果表明通过“溶解”小分子物质,溶剂萃取能够有效地改善煤的吸附性、比表面积和孔隙结构,降低其粒度,但不能破坏其基本结构单元,在本质上仍属于物理作用。根据最可几孔径计算出南桐烟煤胶态分子团结构模型中基本结构单元的粒径在3.5nm左右,证实了煤分子胶态团结构模型的假设。 相似文献
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Comparative analysis of methods for determination of structural characteristics of carbon adsorbents
A. A. Pribylov L. G. Shekhovtsova I. A. Kalinnikova 《Russian Chemical Bulletin》2005,54(10):2290-2298
Experimental data on the equilibrium adsorption of sulfur hexafluoride, methane, carbon dioxide, and benzene on carbon adsorbents
of different porosity obtained in a wide pressure range at 298–408 K were analyzed. The adsorption volumes, surface areas,
and sizes of slit-shaped pores of the carbons were determined using several independent methods. A method for determination
of the adsorption volume from the experimental isotherm of excessive adsorption of gases and the total content equation was
proposed. The resulting values are similar to the adsorption volumes calculated from the data for vapors. A new method for
the calculation of the adsorbent surface area is described. The method is based on the dependence of the adsorption volume
of adsorbent pores on the effective size of adsorbate molecules. A possibility to determine the average size of narrow slit-shaped
carbon pores from the difference of the initial heats of adsorption of the gas under study on the carbon black and porous
carbon adsorbent is considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2219–2227, October, 2005. 相似文献
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Chuan Lin Shaheen A. Al-Muhtaseb James A. Ritter 《Journal of Sol-Gel Science and Technology》2003,28(1):133-141
Very fine nickel hydroxide and oxide xerogel powders were prepared using a new sol-gel synthesis procedure in which nickel ethoxide was produced through the reaction of nickel chloride, as a precursor, with sodium ethoxide in dehydrated ethanol, followed by the hydrolysis of nickel ethoxide with ammonia and drying the resulting hydrogel under subcritical pressures to form the xerogel. The effects of thermal treatment on the surface area, pore volume, crystallinity and particle structure of the resulting xerogels were investigated and found to have significant effects on all of these properties. Overall, the xerogel remained amorphous as Ni(OH)2 space up to 200°C, with little change in the surface area and pore volume. At 250°C, the Ni(OH)2 began to decompose and form crystalline NiO with the uniformity of the crystals increasing with an increase in temperature. The surface area and pore volume decreased sharply when increasingthe temperature beyond 250°C; this was the temperature where maximums of about 270 m2/g and 0.33 cm3/g were exhibited by this composite amorphous Ni(OH)2 and crystalline NiO xerogel powders. At the higher calcination temperatures, very uniform NiO crystals with average crystallite sizes of 1.7 nm and 14.5 nm were obtained at 400 and 600°C, respectively. 相似文献