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排序方式: 共有620条查询结果,搜索用时 15 毫秒
1.
R. Dula R. Janik T. Machej J. Stoch R. Grabowski E.M. Serwicka 《Catalysis Today》2007,119(1-4):327-331
Mg/Mn/Al mixed oxide systems of similar atomic ratios close to 2/0.5/1 were obtained by calcination of Mg,Al layered double hydroxide (LDH) type precursors containing Mn either in the cationic form within the brucite layer or as permanganate anions in the interlayer. The materials were characterised with PXRD, thermal analysis, XPS, ESR, TPR and BET. In mixed oxides derived from interlayer-doped precursor PXRD identified MgO–MnO solid solution and poorly crystalline Al-rich spinel phase, while those obtained from layer-doped LDH contained a better crystalline Mn-rich spinel. Surface of both materials was covered with poorly crystalline and/or amorphous Mn4+-containing phases. Higher reducibility of this surface coat in calcined layer-doped catalyst, as compared to interlayer-doped one, was attributed to the differences in the nature of underlying crystalline phases, and was considered the chief reason for the higher catalytic activity of this catalyst in the total oxidation of toluene. 相似文献
2.
《中国稀土学报(英文版)》2022,40(6):897-905
A family of Ce-doped LaCoO3 perovskites are presented as possible catalysts for Cl–VOCs elimination. These materials with different contents of Ce were obtained through the citrate and the reactive grinding methods. The insertion of Ce in the original perovskite structure favours the presence of Co2+/Co3+ and Ce3+/Ce4+ redox pairs and a higher content of oxygen vacancies that enhances the catalytic performance in chlorobenzene combustion based on differential kinetics studies. The family obtained by the grinding method presents a performance as high as that synthesized by citrate method. Thus, the reactive grinding is a feasible green chemistry alternative to obtain a catalyst with the same performance as that obtained from traditional methods. Finally, the stability of samples was evaluated under total combustion reaction conditions showing an excellent activity during 45 h time on stream. 相似文献
3.
Baoqing Deng Shanshan Kong Chang Nyung Kim 《Korean Journal of Chemical Engineering》2007,24(4):577-582
In this paper, a mathematical model is presented to describe the photocatalytic degradation of VOCs in a packed bed reactor.
Here, the adsorption of VOCs on the wall of the reactor is taken into account and the diffusion of VOCs in the axial direction
is neglected. First-order kinetics is used to describe the photocatalytic oxidation of VOCs. The analytical solution of the
present model is obtained by traveling wave method. The solution shows that the reactor performance is totally dependent on
the inlet concentration of VOCs when the time is large enough. The present model is validated through the experimental result
of the photocatalytic oxidation of trichloroethylene in a packed bed and the predicted results accord well with the experimental
data. The influence of flow rate and inlet concentration on the performance of the reactor is discussed in detail. High flow
rate offers high reaction rate and low conversion efficiency. The different inlet conditions and different reaction patterns
are also investigated. The model would be useful to estimate the rate constant and help to the design of the reactor. 相似文献
4.
5.
蜂窝陶瓷型La0.8Sr0.2MnO3催化剂VOCs催化燃烧反应活性 总被引:2,自引:0,他引:2
以堇青石(CH)为第一载体,六铝酸盐(HA)为第二载体(washcoat),La0.8Sr0.2MnO3(LSM)为活性物种,制备了LSM/HA/CH催化剂.XRD表征发现,LSM具有完善的钙钛矿晶型.SEM观察表明,活性物种在涂层表面分散均匀.通过对苯、甲苯、二甲苯、乙酸乙酯、丙酮和乙醇六种有机物的性能测试,发现LSM/HA/CH对上述六种有机物均具有很好的催化活性,特别是对乙酸乙酯等含氧有机物表现出更好的燃烧性能,在10000 h-1空速下,反应温度为240℃时即可将含氧有机物完全燃烧. 相似文献
6.
7.
生物过滤塔在挥发性有机物和恶臭气体处理方面具有良好的应用前景,但生物量过度累积是影响其运行稳定性的主要问题。为了探讨利用臭氧控制生物量过度累积的可行性,该研究系统考察了连续投加臭氧对于生物过滤塔甲苯去除性能、填料层压降及空隙率、生物量增长以及碳平衡的影响。研究结果表明,臭氧浓度为0~220mg/m3时,投加臭氧不会降低生物过滤塔的甲苯去除性能;臭氧浓度为100~220mg/m3时,投加臭氧可以显著控制生物量过度累积、优化填料层结构和控制压降快速升高。进一步研究表明,提高甲苯的矿化率是臭氧控制生物量快速累积的主要途径。 相似文献
8.
室内丙酮气体的TiO2/UV光催化氧化 总被引:4,自引:1,他引:4
以波长为253.7nm的9W紫外灯为光源,锐钛型二氧化钛为催化剂,考察了室内空气中丙酮气体不同的起始质量浓度、二氧化钛用量、空气循环流量以及光照时间对丙酮光催化降解过程的影响.用Langmuir-Hinshelwood方程讨论了二氧化钛光催化氧化丙酮的动力学模式.研究表明,TiO2/UV光催化氧化室内丙酮气体效果较好,可用于室内的循环空气处理;在一定初始质量浓度范围内,TiO2/UV光催化氧化丙酮表现为一级反应动力学规律. 相似文献
9.
室内材料中释放的挥发性有机化合物是造成室内空气污染的主要原因之一.文章采用常用室内装饰材料-细木工板,模拟室内装修中进行油漆常规涂刷,对经油漆板材释放出的甲醛、氨、苯、甲苯、二甲苯进行了连续研究和测定.结果表明,木制板材在油漆施工大约七天之后,释放的污染物浓度下降且趋于稳定,油漆等涂料对板材中有毒有害污染物向外释放有一定的抑制和封闭作用. 相似文献
10.
Eveline Santos da Silva Michel Kohnen Georges Gilson Therese Staub Victor Arendt Christiane Hilger Jean-Yves Servais Emilie Charpentier Olivia Domingues Chantal J. Snoeck Markus Ollert Carole Seguin-Devaux Danielle Perez-Bercoff 《International journal of molecular sciences》2022,23(14)
SARS-CoV-2 variants raise concern because of their high transmissibility and their ability to evade neutralizing antibodies elicited by prior infection or by vaccination. Here, we compared the neutralizing abilities of sera from 70 unvaccinated COVID-19 patients infected before the emergence of variants of concern (VOCs) and of 16 vaccine breakthrough infection (BTI) cases infected with Gamma or Delta against the ancestral B.1 strain, the Gamma, Delta and Omicron BA.1 VOCs using live virus. We further determined antibody levels against the Nucleocapsid (N) and full Spike proteins, the receptor-binding domain (RBD) and the N-terminal domain (NTD) of the Spike protein. Convalescent sera featured considerable variability in the neutralization of B.1 and in the cross-neutralization of different strains. Their neutralizing capacity moderately correlated with antibody levels against the Spike protein and the RBD. All but one convalescent serum failed to neutralize Omicron BA.1. Overall, convalescent sera from patients with moderate disease had higher antibody levels and displayed a higher neutralizing ability against all strains than patients with mild or severe forms of the disease. The sera from BTI cases fell into one of two categories: half the sera had a high neutralizing activity against the ancestral B.1 strain as well as against the infecting strain, while the other half had no or a very low neutralizing activity against all strains. Although antibody levels against the spike protein and the RBD were lower in BTI sera than in unvaccinated convalescent sera, most neutralizing sera also retained partial neutralizing activity against Omicron BA.1, suggestive of a better cross-neutralization and higher affinity of vaccine-elicited antibodies over virus-induced antibodies. Accordingly, the IC50: antibody level ratios were comparable for BTI and convalescent sera, but remained lower in the neutralizing convalescent sera from patients with moderate disease than in BTI sera. The neutralizing activity of BTI sera was strongly correlated with antibodies against the Spike protein and the RBD. Together, these findings highlight qualitative differences in antibody responses elicited by infection in vaccinated and unvaccinated individuals. They further indicate that breakthrough infection with a pre-Omicron variant boosts immunity and induces cross-neutralizing antibodies against different strains, including Omicron BA.1. 相似文献