低温等离子体与MnO_x/γ-Al_2O_3协同催化降解正己醛

研究了在低温等离子体和催化剂共同作用下低浓度正己醛的降解反应.结果表明,等离子体与γ-Al2O3之间产生了很好的催化协同作用,在低放电功率(2.8W)和低温(80℃)下,干燥空气气氛中,γ-Al2O3对0.12%正己醛的去除率为87.1%;当γ-Al2O3负载7.5%MnOx后,正己醛去除率达到96.5%,其效果与Pt/γ-Al2O3相当.7.5%MnOx/γ-Al2O3在实验条件下连续使用50h,其催化活性未见下降.     

Removal of Hexanal by Non-thermal Plasma and MnOx/y-Al2O3 Combination

研究了在低温等离子体和催化剂共同作用下低浓度正己醛的降解反应.结果表明,等离子体与γ-Al2O3之间产生了很好的催化协同作用,在低放电功率(2.8W)和低温(80 ℃)下,干燥空气气氛中,γ-Al2O3对0.12％正己醛的去除率为87.1％;当γ-Al2O3负载7.5％MnOx后,正己醛去除率达到96.5％,其效果与Pt/γ-Al2O3相当.7.5％MnOx/γ-Al2O3在实验条件下连续使用50h,其催化活性未见下降.     

用TPR技术研究脱铝天然丝光沸石催化性能

本文应用程序升温反应(TPR)技术研究了盐酸脱铝天然丝光沸石的催化性能。通常,由于结晶条件的差别,天然丝光沸石的孔径较合成的小得多。我们用盐酸脱铝来增大孔径;从而改进了天然丝光沸石的催化性能,增加了B酸强度,增大的孔径对邻二甲苯异构化有较好的适应性。这样,脱铝天然丝光沸石有可能在其些方面代替合成丝光佛石用于石油化学工业。还用X射线衍射、比表面测定和热重分析等方法考察了催化剂的性能和结构。     

天然丝光沸石多步脱铝-钛化制备钛硅分子筛

以优选的天然丝光沸石为原料, 采用多步脱铝-钛化法合成钛硅分子筛, 利用 X 射线粉末衍射、紫外-可见光谱、电感耦合等离子体原子发射光谱、N2 吸附-脱附法以及氨程序升温脱附等手段对其进行了表征, 并考察了它在苯乙烯氧化反应中的催化性能. 结果表明, 该方法可成功地将 Ti 同晶取代到天然丝光沸石的骨架中, 其 Si/Ti 达到 79, 且能稳定地保持天然丝光沸石的结构. 该钛硅分子筛在以 H2O2 水溶液为氧化剂的苯乙烯氧化反应中表现有良好的催化活性, 是商业 TS-1 催化剂的 75%, 具有一定的应用前景.     

Ag-AgBr/RGO光催化性能研究

以石墨烯为载体,通过化学沉积与光还原法制备了具有等离子体共振效应的Ag-AgBr/RGO可见光催化剂。采用XRD及UV-Vis吸收光谱对催化剂进行结构与性能表征,并考察其降解甲基橙溶液的光催化性能。研究结果表明,在可见光下照射60min,催化剂对10 mg·L-1甲基橙溶液的降解率达91%。由于表面金属的等离子体共振效应和石墨烯的协同作用,石墨烯为载体的催化剂的可见光催化活性比氧化铝为载体时高。     

动态法测定丝光沸石的吸附系数和有效扩散系数

本文用动态法研究丝光沸石的吸附和扩散性能。以氮气作示踪剂,在经改装的色谱仪上分别测定了氮气在天然和合成丝光沸石上的吸附平衡常数和有效扩散系数。实验结果表明,氮气在合成丝光沸石上具有较大的吸附平衡常数和有效扩散系数。把天然丝光沸石的微粒磨细至5—9μm可改善其吸附和扩散性能。     

具有表面等离子体效应的Ag-AgBr/Al2O3光催化性能研究

以介孔γ-Al2O3为载体,通过化学沉积与光还原法制备了Ag-AgBr/Al2O3等离子体诱导可见光催化材料。采用SEM、TEM、XRD及UV-Vis吸收光谱对复合材料进行结构与性能表征,并通过降解亚甲基蓝溶液对其光催化性能进行考察。研究结果表明,在可见光下照射1 h,催化材料对5 mg/L亚甲基蓝溶液的降解率达95%以上,总有机碳去除率为70%。由于表面金属的等离子体共振效应和介孔材料的吸附性能,催化剂具有很高的可见光催化活性和良好的稳定性,在开发新型等离子体诱导可见光催化剂方面应用前景广阔。     

正己醇(氧化)脱氢制正己醛的研究

制备尖晶石型复合氧化物CuAl2O4以及将其负载化,并进行正己醇制正己醛反应催化性能的评价.应用XRD及N2低温吸附等技术对其进行表征.研究结果表明,无论是在正己醇脱氢或氧化脱氢反应中,非负载型及氧化铝负载型CuAl2O4在280℃和LHSV(hexanol)=14.4mL·g-1·h-1时均有较好的催化性能.催化剂的预处理方法不同,对催化剂的氧化脱氢性能影响很大.     

HAlMCM-41介孔分子筛催化1,3-苯并二噁茂烷合成的研究

研究了HAlMCM-41分子筛催化邻苯二酚与环己酮、丁酮、丙酮、丙醛、丁醛、异丁醛、戊醛、正己醛、正辛醛、苯甲醛、二苯甲酮等十余种醛(酮)的缩合反应. 考察了反应时间、酚与醛(酮)的配比、HAlMCM-41分子筛用量、硅铝比、催化剂重用次数等因素对邻苯二酚与醛(酮)反应的影响. 结果表明, 当邻苯二酚与醛(酮)物质的量比为1∶1.4, 催化剂用量为3.5 g/mol邻苯二酚, 反应4 h, 分子筛n(SiO₂)/n(Al₂O₃)为15时, 选择性一般在99.4%以上, 转化率也一般在85.6%以上, 因此, HAlMCM-41分子筛对邻苯二酚与醛(酮)的反应有较好的催化性能.     

HMAS-5分子筛催化合成缩醛(酮)

研究了HMAS_5分子筛催化乙二醇与环己酮、丁酮、丙酮、丙醛、丁醛、异丁醛、戊醛、异戊醛、正己醛、正辛醛、苯甲醛等醛(酮)的缩合反应。考察了反应时间、醛(酮)与醇的配比、HMAS_5分子筛用量等因素对醛(酮)与醇缩合反应的影响。结果表明,HMAS_5分子筛对醛(酮)与醇的缩合反应有较好的催化性能,选择性一般在98%以上,转化率也一般在90%以上。     

Removal of gadolinium ions from solutions using granulated zeolites

The possiblity of the use of granulated zeolites for the removal of gadolinium ions from solutions has been investigated. Measurements of gadolinium ion concentrations in solutions and of the distribution of gadolinium ions in column filligns (granulated zeolites), after passing the solution through columns filled with various granulated zeolites (zeolite 4A, zeolite 13X and synthetic mordenite), have shown that gadolinium ions can be effectively removed from nearly neutral or acidic solutions using granulated mordenite. The influency of pH, column filling and the flow rate of the solution through the column on the efficiency of gadolinium ion removal and on the distribution of gadolinium ions in the columns has been investigated. On the basis of the results obtained, the conditions for the most efficient removal of gadolinium ions from solutions have been obtained.     

Differential Response of Pentanal and Hexanal Exhalation to Supplemental Oxygen and Mechanical Ventilation in Rats

High inspired oxygen during mechanical ventilation may influence the exhalation of the previously proposed breath biomarkers pentanal and hexanal, and additionally induce systemic inflammation. We therefore investigated the effect of various concentrations of inspired oxygen on pentanal and hexanal exhalation and serum interleukin concentrations in 30 Sprague Dawley rats mechanically ventilated with 30, 60, or 93% inspired oxygen for 12 h. Pentanal exhalation did not differ as a function of inspired oxygen but increased by an average of 0.4 (95%CI: 0.3; 0.5) ppb per hour, with concentrations doubling from 3.8 (IQR: 2.8; 5.1) ppb at baseline to 7.3 (IQR: 5.0; 10.8) ppb after 12 h. Hexanal exhalation was slightly higher at 93% of inspired oxygen with an average difference of 0.09 (95%CI: 0.002; 0.172) ppb compared to 30%. Serum IL-6 did not differ by inspired oxygen, whereas IL-10 at 60% and 93% of inspired oxygen was greater than with 30%. Both interleukins increased over 12 h of mechanical ventilation at all oxygen concentrations. Mechanical ventilation at high inspired oxygen promotes pulmonary lipid peroxidation and systemic inflammation. However, the response of pentanal and hexanal exhalation varies, with pentanal increasing by mechanical ventilation, whereas hexanal increases by high inspired oxygen concentrations.     

Contribution of UV light to the decomposition of toluene in dielectric barrier discharge plasma/photocatalysis system

The contribution of UV light from plasma and an external UV lamp to the decomposition of toluene in a dielectric barrier discharge (DBD) plasma/UV system, as well as in a plasma/photocatalysis system was investigated. It was found that UV light from the DBD reactor was very weak. Its contribution to the removal of toluene in the plasma/photocatalysis system could be ignored. Whereas, the introduction of external UV light to the plasma significantly improves the removal efficiency of toluene by 20%. The removal efficiency of toluene in the plasma/photocatalysis system increased about 22% and 16% when compared with a plasma only system and plasma driven photocatalyst system, respectively. The increased toluene removal efficiency was mostly attributed to the contribution of the synergy between plasma and UV light, but not to the synergy between plasma and photocatalysis. The synergetic effect between plasma and photocatalysis was not significant.     

Removal of cesium radioisotopes from solutions using granulated zeolites

The influence of type of zeolite and the flow rate of solution through the column on the removal efficiency of radioactive cesium ions from solution has been investigated. The analysis of the change in the concentration of cesium ions in the solutions and distribution of cesium ions in the column fillings (granulated zeolites), after passing the solutions through the columns filled with various granulated zeolites (zeolite 4A, zeolite 13X, synthetic mordenite) was performed. On the basis of the results of this study, the conditions for the most efficient removal of cesium ions from solutions have been discussed.     

Polymer monolith microextraction with in situ derivatization and its application to high-performance liquid chromatography determination of hexanal and heptanal in plasma

A simple, rapid and sensitive method for the determination of hexanal and heptanal in plasma by high-performance liquid chromatography (HPLC) has been developed, which is based on polymer monolith microextraction (PMME) with in situ derivatization. 2,4-dinitrophenylhydrazine (DNPH) as a derivatizing reagent was first adsorbed on a poly (methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith, and then microextraction was performed simultaneously with derivatization on the monolith. The several parameters affecting the in situ derivatization simultaneously with PMME were investigated, including the flow rate, pH, buffer concentration, and temperature. The whole pretreatment process can be accomplished within 8 min. The limits of detection for hexanal and heptanal were found to be 2.4 and 3.6 nmol/L, respectively. The recoveries in plasma sample were in the range of 83-87% with the inter- and intra-day precisions less than 6.8%. This method was successfully applied to the analysis of hexanal and heptanal in plasma samples from different cancer patients.     

High-resolution 27Al NMR study of the states of aluminum atoms in modified natural mordenite

High-resolution ²⁷Al NMR has been applied to the states of aluminum in modified natural mordenite. Acid treatment of the natural mordenite and heat treatment of the ammonium form alter the coordination state of 6–8% of the aluminum atoms from tetrahedral (in the framework) to octahecral (at the inner surfaces of the zeolite cavities). In that state, the aluminum can exchange with Na⁺, NH₄ ⁺, and other cations. This change in coordination state should have a considerable effect on the catalytic parameters of zeolites.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, No. 2, pp. 241–244, March–April, 1987.     

Investigation of catalytic degradation of high-density polyethylene by hydrocarbon group type analysis

Catalytic degradation of waste high-density polyethylene (HDPE) to hydrocarbons by ZSM-5, zeolite-Y, mordenite and amorphous silica–alumina were carried out in a batch reactor to investigate the cracking efficiency of catalysts by analyzing the oily products including paraffins, olefins, naphthenes and aromatics with gas chromatography/mass spectrometry (GC/MS). Catalytic degradation of HDPE with zeolite-Y, mordenite and amorphous silica–alumina yielded 71–82 wt.% oil fraction, which mostly consisted of C₆–C₁₂ hydrocarbons, whereas ZSM-5 yielded much lower 35% oil fraction, which mostly consisted of C₆–C₁₂ hydrocarbons. Both all zeolites and silica–alumina increased olefin content in oil products, and ZSM-5 and zeolite-Y particularly enhanced the formation of aromatics and branched hydrocarbons. ZSM-5 among zeolites showed the greatest catalytic activity on cracking waste HDPE to light hydrocarbons, whereas mordenite produced the greatest amount of coke. Amorphous silica–alumina also showed a great activity on cracking HDPE to lighter olefins in high yield, but no activity on aromatic formation.     

Influence of Plasma Regimes and Catalysts on Ethanethiol Oxidation

Plasma oxidation of ethanethiol in air was investigated using three plasma regimes: surface dielectric pulsed corona discharge, surface dielectric barrier discharge and pulsed corona discharge (PCD) in the plasma reactor. Catalytic plasma degradation of ethanethiol was also performed on the singular or binary metals doped ?èCAl₂O₃. The ethanethiol removal rate increased with increasing energy density but energy efficiency was first increased and then decreased with increasing energy density under three various types of discharges. PCD plasma required the lowest energy density at the similar ethanethiol removal performance compared with the other two plasma discharges. The main intermediate by-products of ethanethiol oxidation by plasma are CH₃CHO, HCHO, CO and CO₂. The sum of these intermediate products selectivities is 19?C43?%, implying that some other intermediates containing carbon were undetermined. When using PCD plasma combined with catalysts, ethanethiol removal rate and energy efficiency were all evidently improved. The maximum energy efficiency was achieved about 200?g kWh^?1 using Fe?CMn/?èCAl₂O₃ assisted PCD plasma, which was about 4.4 times when using PCD plasma alone. The mechanism of ethanethiol oxidation is also discussed.