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1.
TiO2光催化消除H2S的研究   总被引:2,自引:0,他引:2  
在TiO2上进行了气相H2S光催化氧化消除的研究.氧对H2S的光催化氧化消除过程是不可缺少的,对含量为560mg/m^3的H2S,,当加入的氧气与原料气中H2S的分子比为42:1,空速为28000h^-1时,去除率达到97%.在HiS光催化氧化消除过程中,单质硫的产生可使TiO2失活,经光照再生单质硫转化为SO4^2-后,TiO2活性恢复,而且SO4^2-的生成对催化剂的中毒有抑制作用.  相似文献   

2.
综述了以2-甲基萘为原料制备K类维生素中间体2-甲基萘醌的方法及其进展,总结了各种氧化方法及其优缺点,并针对当前工业生产中存在的问题,提出了合理的建议.  相似文献   

3.
介绍了2kt/a蒽醌法双氧水装置萃取塔的改造情况。改造后塔内物料返混现象消失,萃余液中双氧水含量低、夹带的水明显减少;工作液体积流量提高到25.5m^3/h,产量提高到7kt/a。  相似文献   

4.
Na-Ti-Si氧化物Ti元素的化学状态分析   总被引:1,自引:0,他引:1  
利用熔融方法制备了Na2O-TiO2-SiO2系统玻璃样品,用IR以及XPS等测试手段对系统玻璃样品结构进行了分析。结果表明:Na2O-SiO2-SiO2系统玻璃中Ti^4 离子可以部分地取代Si^4 离子的位置而以网络形成体的形式参与成玻。此外,通过对该系统玻璃的XPS钛元素的化学状态分析,认为该系统玻璃中Ti^4 离子存在[TiO4],[TiO6]等几种不同的微结构单元,并且随着玻璃中TiO2含量的增加,该系统玻璃中四方双锥结构的[TiO6]与正四面体结构的[TiO4]之比增大。  相似文献   

5.
Li2O-Na2O-K2O-CaO-MgO-Al2O3-SiO2系统乳浊釉的研究   总被引:1,自引:0,他引:1  
对Li2O-Na2O-K2O-CaO-MgO-Al2O3-SiO2系统釉进行了较全面的正交试验研究,找到了影响该系统釉乳浊及釉面质量的主次因素,获得了性能良好的乳浊釉及其较优乳浊釉配方.  相似文献   

6.
鲁军辉  李俊明 《化工学报》1951,73(9):3870-3879
不凝性气体制约换热设备安全和系统效率,为研究不凝性气体-蒸气于水平管外自然对流凝结换热机理和特性,实验测量了不凝性气体He、N2、CO2质量分数分别为1.16%~18.18%、7.56%~60.86%、11.39%~70.95%,壁面过冷度为5~25 K,总压力为5~101 kPa的H2O-He、H2O-N2、H2O-CO2自然对流条件下水平管外凝结换热特性,对比分析了H2O-He、H2O-N2、H2O-CO2的不凝性气体质量含量、壁面过冷度以及压力因素的影响。压力和壁面过冷度一定,相同质量分数时,实验凝结传热系数与Nusselt理论解的比值(Q/QNu)由大到小依次为:H2O-CO2、H2O-N2、H2O-He;相同摩尔分数时,Q/QNu由大到小依次为:H2O-He、H2O-N2、H2O-CO2。相同总压力和不凝性气体质量分数时,H2O-He的Q/QNu随着壁面过冷度的增加下降最为缓慢。相同不凝性气体质量分数和壁面过冷度时,H2O-He的Q/QNu值最小,其受压力影响最为显著。  相似文献   

7.
鲁军辉  李俊明 《化工学报》2022,73(9):3870-3879
不凝性气体制约换热设备安全和系统效率,为研究不凝性气体-蒸气于水平管外自然对流凝结换热机理和特性,实验测量了不凝性气体He、N2、CO2质量分数分别为1.16%~18.18%、7.56%~60.86%、11.39%~70.95%,壁面过冷度为5~25 K,总压力为5~101 kPa的H2O-He、H2O-N2、H2O-CO2自然对流条件下水平管外凝结换热特性,对比分析了H2O-He、H2O-N2、H2O-CO2的不凝性气体质量含量、壁面过冷度以及压力因素的影响。压力和壁面过冷度一定,相同质量分数时,实验凝结传热系数与Nusselt理论解的比值(Q/QNu)由大到小依次为:H2O-CO2、H2O-N2、H2O-He;相同摩尔分数时,Q/QNu由大到小依次为:H2O-He、H2O-N2、H2O-CO2。相同总压力和不凝性气体质量分数时,H2O-He的Q/QNu随着壁面过冷度的增加下降最为缓慢。相同不凝性气体质量分数和壁面过冷度时,H2O-He的Q/QNu值最小,其受压力影响最为显著。  相似文献   

8.
Zirconium oxide microcrystals were dispersed on SiO2 from methanol or toluene solution of corresponding zirconium compounds and the surface properties in terms of the acid-base concept was examined by means of a temperature-programmed-desorption technique. Though bulk zirconium dioxide exhibited both acidic and basic properties, surface zirconium oxide lost the basic properties.  相似文献   

9.
本文从热力学角度系统研究了CaO-MgO-SiO2-H2O体系及钢渣中钙镁硅矿物在水热条件下的反应特性,结果表明:在CaO-MgO-SiO2-H2O系统中,CaO优先与SiO2反应生成水化硅酸gO只能与剩余的SiO2反应生成水化硅酸镁:MgO固溶时,可促进托勃莫来石向硬硅钙石转化。而对白钙沸石向白钙镁沸石的转化影响不大,不固溶MgO时,低温型水化硅酸钙向高温型转化温度提高,钢渣鲁镁硅矿物中,镁蔷薇辉石活性最大,透辉石活性最差,钙镁橄榄石和镁黄长石介于前两者之间。  相似文献   

10.
Mixed oxide coatings consisting of varying proportions of RuO2 and TiO2 have been prepared on titanium and silica substrates. Development of the microstructure was examined by X-ray diffraction and also monitored by resistivity measurements. The X-ray results suggest that the mixed oxide coatings prepared at 400° C are best described as a metastable solid solution of the two components. The resistivity-composition relationship however is more indicative of a finely interdispersed mixture of conducting and insulating particles. Coatings fired at higher temperatures (700–800° C) exhibit separate X-ray diffraction peaks corresponding to almost pure RuO2 and TiO2 phases with no evidence of significant solid solubility.  相似文献   

11.
Interaction of small ( 5 nm) CeO2 particles with silica catalyst carrier in hydrogen at 570–970 K was studied by XRD and TEM. It was found that, at 770 K, CeO2 began to redisperse and spread onto silica and at 970 K its complete amorphization occurred. Addition of 0.4 wt% Pd had a small promoting effect on the process.  相似文献   

12.
氧氮化硅结合碳化硅窑具材料研究   总被引:4,自引:2,他引:2  
利用热力学分析了氧氮化硅结合相的生成机理。探讨了硅粉加入量对氧氮化硅生成量、材料的各项理化性能以及抗氧化性能的影响。结果表明:氧氮化硅的含量随Si含量的增加而增加,制品的常温耐压强度和荷重软化温度相应提高  相似文献   

13.
ZrO2-SiO2复合氧化物因具有较好的热稳定性和化学稳定性、较大的比表面积和较强的表面酸碱性等优点,已受到广泛关注.本文主要对ZrO2-SiO2复合氧化物的常用制备方法及其影响因素进行了总结,并综述了该复合氧化物在催化反应中的应用.  相似文献   

14.
《Journal of Catalysis》1999,181(1):155-159
Ultraviolet light dramatically increases the rate of isotope exchange between gas-phase O2and water adsorbed on TiO2at room temperature, but it does not affect the rate of CO2–water exchange. Both ethanol and acetaldehyde, when coadsorbed with H218O, dramatically decrease the rate of O2exchange, but not CO2exchange, with adsorbed H218O. This decrease is attributed to a combination of competition for adsorbed oxygen between exchange and photocatalytic oxidation of the adsorbed organic and blocking of the oxygen adsorption sites by the organic. The same oxygen species participate in O2-H218O exchange and photocatalytic oxidation.  相似文献   

15.
阐述了TiO2在Al2O3-SiO2系耐火材料,特别是高铝矾土中的分布和存在方式,并通过分析Al2O3-SiO2系耐火原料的煅烧过程和Al2O3-SiO2系制品的使用过程中TiO2、Al2O3和SiO2三者之间的化学反应,介绍了TiO2对Al2O3-SiO2系耐火材料结构和性能的影响。  相似文献   

16.
以Al2TiO5微细粉、SiO2-Al2O3微细粉为原料,外加6%(质量分数,下同)PVA结合剂,100 MPa压力成型,1400 ℃保温1 h烧成,制备出低热膨胀系数,抗热震性能优于SiO2-Al2O3材料的Al2TiO5-SiO2-Al2O3复合材料.对复合材料的性能测定分析,研究不同的Al2TiO5含量、烧结温度等对Al2TiO5-SiO2-Al2O3复合材料性能的影响,获得了制备性能优良的Al2TiO5-SiO2-Al2O3复合材料的最佳工艺参数.  相似文献   

17.
《Ceramics International》2017,43(15):11676-11685
The higher melting temperature and longer soaking time during conventional glass melting route promoted the search for alternative in developing new bioactive glass (BG) composition with improved in fabrication temperature and melting time. The current project involved fabrication of new BG compositions based on SiO2-CaO-Na2O-P2O5 system via melt derived route. It was confirmed that all bioactive glass composition can be melted at temperature lower than 1400 °C. Formation of Si-O-Si (tetrahedral) functional group highlighted that silicate based glass was established as detected by Fourier transform infrared spectroscope (FTIR). BG bioactivity was performed by incubating the BG powder in Tris-buffer solution (pH 8) for 7, 14 and 21 days. In vitro test confirmed the apatite formation on the bioactive glass surface upon soaking in Tris-buffer solution with characteristic of carbonate group (C-O) and P-O band noticed from FTIR and present of crystalline peak observed in X-ray diffraction (XRD). Morphology of apatite formation on BG surface was observed using scanning electron microscope (SEM).  相似文献   

18.
19.
氧传感器用CeO_2和TiO_2复合材料的研究   总被引:1,自引:0,他引:1  
氧传感器的发展方向之一是向复合化的方向发展。CeO2和TiO2都是半导体氧化物。CeO2具有半导体特性、抗侵蚀性能和催化特性;TiO2的半导体特性因研究广泛而趋于成熟。将两种氧化物复合的氧传感器可望有更好的性能。  相似文献   

20.
Proton NMR line width and spin-lattice relaxation time T 1 for the ferroelectric (CH 3 ) 2 NH 2 H 2 AsO 4 have been measured at the temperature range between 77 K and 300 K. The temperature dependence of T 1 is well described by the expressions based on rotation of the methyl group using the value of activation energy E a = 99 meV and elementary correlation time τ0 = 1.5 ×10 -13 sec. Moreover, a sharp dip of T 1 near ferrroelectric phase transition temperature ( T c = 274.5 K) results from the ordering of protons. In addition, the temperature dependence of T 1 deviates from the expression for molecular rotation above around 200 K. It is deduced that the deviation is caused by the suppression of some kind of proton motion.  相似文献   

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