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排序方式: 共有8324条查询结果,搜索用时 62 毫秒
61.
Stakheev A. Yu. Gabrielsson P. Gekas I. Teleguina N. S. Bragina G. O. Tolkachev N. N. Baeva G. N. 《Topics in Catalysis》2007,42(1-4):143-147
Pt/Al2O3 and Pt/BaO/Al2O3 catalysts (1 wt% Pt, 10 wt%BaO) were sulfated under conditions simulating a real NSR catalyst operation. Comparative TPR
and XPS studies of sulfur removal from Pt/Al2O3 and Pt/BaO/Al2O3 catalysts indicate that the sulfur removal from Al2O3 surface precedes reductive decomposition of BaSO4 (250–400 °C). Barium sulfate decomposition started with further increase in desulfation temperature at the point of surface
atomic ratio Ba:S = 1 (~450o). Simultaneously, an intensive formation of sulfide species on the catalyst surface was observed. Thermodynamic analysis
of the desulfation process allows us to hypothesize that barium sulfide formation may hinder sulfur removal under reducing
conditions. 相似文献
62.
三盐基硫酸铅的生产工艺条件研究 总被引:2,自引:0,他引:2
介绍了氧化铅法中硝酸铅法生产三盐基硫酸铅两种生产工艺 ,对氧化铅法中硫酸的加入量、酸度、温度、时间等生产条件进行了研究 ,确定了最佳生产工艺条件 ,并对两种方法进行了简单对比 相似文献
63.
64.
Rakesh?Kumar?MahajanEmail author Inderpreet?Kaur Mandeep?Singh?Bakshi 《Journal of surfactants and detergents》2004,7(2):131-134
Poly(vinyl chloride) (PVC) membrane electrodes to determine monomer concentrations of tetradecyltrimethylammonium ion (TTA+) and hexadecylpyridinium ion (HPy+) based on neutral ion-pair carrier complexes of tetradecyltrimethylammonium dodecyl sulfate (TTA+-DS−) and hexadecylpyridinium dodecyl sulfate (HPy+-DS−), respectively, are reported here. The electrodes exhibit a Nernstian slope of 59 mV per decade for TTA+ and a sub-Nernstian slope of 34.5 mV per decade for HPy+ ions. The TTA+ ion-selective electrode (ISE) and the HPy+-ISE can determine the monomer units down to concentrations as low as 4.0×10−4M and 1.66×10−5 M, respectively. The effect of various additives, such as the anionic polyelectrolyte sodium dextran sulfate and macrocyclic
β-cyclodextrin, on the surface activity exhibited by the cationic surfactants TTA+-DS− and HPy+-DS−, in the presence of background concentrations of NaCl was also examined with surfactant-selective sensors. The Gibbs free
energy of micelle formation (ΔG
m
) of both surfactants in the presence of various additives was calculated and found to be less favorable with respect to an
increase in the amount of additives due to less availability of cationic surfactant monomer units. The ion-pair complexes
TTA+-DS− and HPy+-DS− were found to behave as selective carrier compounds in PVC membranes in determining the concentration of monomer units of
both TTA+ and HPy+, respectively. The proposed sensors worked well at a fairly acidic pH of 1–6.5 with response time of 60 s. The sensors responded
well to the surfactant ions even in the presence of additives at lower concentration. The lifetime of the sensors is 3 mon. 相似文献
65.
聚合硫酸铁处理制革废水 总被引:12,自引:0,他引:12
本文研究了几种常用的国产混凝剂处理制革废水的效果,得出聚合硫酸铁是一种比较经济有效的混凝剂,配合PAM助凝剂可以取得更好的效果。工艺上采用混凝气浮,可全部去除硫化物,出水总铬≤1mg/L,COD去除率可达70%-80%。 相似文献
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Previously obtained cloud point curves for mixtures of oligomeric poly(dimethyl siloxanes) (weight fraction W1) with oligomeric polyethylenes have been supplemented by the use of samples of higher molecular weight. Initial flat regions at low-medium W1 as well as a slight shoulder at extremely high W1 are now considered to be due to crystallization, since the temperatures at which they occur are the melting points of the oligoethylenes. The actual cloud point curves were of an unsymmetrical dome shape, the form of which could not be simulated by using a concentration-independent interaction parameter g in the Flory-Huggins equation. However, spinodals calculated by assuming a quadratic dependence of g on composition were of the same shape as the experimental cloud point curves. The critical compositions calculated on this basis were also close to the experimental ones. 相似文献
69.
70.
滴加法制备铁黄颜料工艺研究 总被引:1,自引:0,他引:1
采用滴加法制备铁黄颜料,即采用硫铁矿烧渣直接制得的硫酸亚铁及硫酸亚铁结晶母液为原料。用空气作氧化剂,用氨水作沉淀剂制品种;在二步氧化中滴加氨水和硫酸亚铁结晶母液。探讨了亚铁浓度、空气流量等对晶种形成的影响,以及晶种比、空气流量、溶液pH、硫酸铵浓度等因素对铁黄生成的影响。确定了晶种制备和二步氧化的最佳工艺条件,即二步氧化中溶液pH控制在2.5~3.5,亚铁浓度控制在0.18~0.25mol/L的范围。检测结果表明:铁黄各项指标均达到原化工部HG/T2249--1991一级品标准。 相似文献