Fe/γ-Al_2O_3催化剂的制备及其在降解亚甲基蓝废水中的应用

利用等体积浸渍法制备了一系列Fe/γ-Al_2O_3催化剂。采用催化湿式氧化法考察了催化剂中Fe含量、催化剂焙烧温度、H_2O_2用量、反应温度、废水初始pH等对亚甲基蓝废水COD去除率的影响。结果表明,催化剂焙烧温度为300℃,Fe负载量为0.02 g时催化效果较好;其对应的反应条件为30%的H_2O_2的用量100μL,反应温度30℃,废水pH值4.5,反应时间1 h时,COD去除率最高达到80%。     

刚果红染料废水的Cu/γ-Al_2O_3催化降解

通过浸渍法制备了不同负载量的Cu/γ-Al_2O_3催化剂,对刚果红采用催化湿式过氧化氢法(CWPO)进行降解,并对其催化降解刚果红的性能进行了研究。分别考察了催化剂中Cu的负载量、催化剂用量、H_2O_2用量、温度、pH、降解时间对催化剂性能的影响。结果表明,对于30 mg/L的刚果红模拟废水,催化剂中Cu负载量为3%,催化剂用量为0.2 g,H_2O_2用量为1.5 u L,温度为30℃,pH为5,降解时间为1.5 h时催化剂的降解性能最好,刚果红的降解率可达90.1%。     

反应条件对Fe/γ-Al2O3催化剂去除苯酚废水COD的影响

利用等体积浸渍法制备了一系列Fe/γ-Al2O3催化剂。在温度为30℃时考察了催化剂中Fe含量对苯酚模拟废水COD去除率的影响,发现Fe0.01/γ-Al2O3具有较高的催化活性。研究了苯酚废水的初始pH,反应温度,是否添加H2O2以及是否通入空气时Fe0.01/γ-Al2O3催化剂的性能。结果表明,在反应初始pH为3,温度为30℃,加入100μL H2O2并通入空气的条件下,反应1 h后,苯酚废水COD的去除率最高,约为65%。给出了苯酚在催化剂表面的降解反应模型。     

超声波在γ-Al_2O_3载体制备中的应用

介绍了γ-Al2O3作为催化剂载体的优点和最新研究进展,同时介绍了超声波在化学合成领域中的发展过程以及超声波在γ-Al2O3载体制备过程中的作用机理。经过不同超声波反应条件制备的γ-Al2O3载体,其团聚程度,孔结构等性质均会发生不同程度的变化,能够对所制备载体的性质起到优化作用,从而提高催化剂的性能。     

MgO/γ-Al_2O_3烷氧基化催化剂制备及结构与性能研究

在γ Al2 O3 载体上浸渍Mg (NO3 ) 2 ·6H2 O ,然后分别经 40 0、45 0和 5 0 0℃焙烧制成MgO/γ Al2 O3 固体碱催化剂。结果表明 ,MgO在γ Al2 O3 载体表面具有单层分散性质 ,当MgO的负载量低于某一数值 (阈值 )时 ,从样品的X光粉末衍射谱图上观察不到MgO的特征衍射峰 ,负载量超过阈值时开始出现MgO的晶相 ,且MgO的XRD衍射峰强度随MgO的负载量的增加而增加 ,其单分散阈值为 0 0 80 gMgO/ 10 0m2 γ Al2 O3 。应用CO2 TPD技术测定了样品的碱性 ,结果表明 ,样品在接近阈值时其碱量大幅度增加 ,碱强度提高。样品的比表面最初随着MgO负载量的增加而下降 ,但达阈值后基本保持不变。     

Fe2O3/γ-Al2O3臭氧催化氧化催化剂的制备及性能研究

以γ-Al_2O_3为催化剂载体原料,Fe_2O_3为活性组分,制备Fe_2O_3/γ-Al_2O_3臭氧催化氧化催化剂。以苯胺为模拟废水探究催化剂活性。对催化剂强度、密度、孔隙率、比表面积进行表征。探究了催化剂最佳制备及应用条件。结果表明:制备的催化剂为粒径4～6 mm球型颗粒,在粘结剂为1%Na_2SiO_3溶液,成型转速为20～30 r·min~(-1),500℃煅烧时间为3 h条件下,催化剂强度可达186.4 N,密度为1.27 g/cm~3,孔隙率为58.71%,比表面积可达127.54 m~2/g。当臭氧通量为3 g·h~(-1),催化剂投加量为150 g·L~(-1),溶液pH值为9时,反应60 min后,COD去除率达81.40%。     

分步浸渍法制备CoMoAg/γ-Al_2O_3催化剂及其脱硫性能的研究

以γ-Al2O3为载体,以Co、Mo、Ag为主要活性组分,采用浸渍法制备了负载型催化剂CoMoAg/γ-Al2O3,并对其进行了XRD表征;利用加氢原理,考察了MoCoAg/γ-Al2O3催化剂在不同工艺条件下处理模拟汽油的脱硫效果。结果表明,在反应温度164.5℃、反应压力1.0 MPa、γ-Al2O3∶Co∶Ag∶Mo（质量比）为1∶1∶2∶1的条件下,催化剂对模拟汽油的脱硫效果较好。     

Ni对Cu-Ni/γ-Al_2O_3苯羟基化催化剂的影响

通过程序升温还原方法合成了Cu/γ-Al2O3和Cu-Ni/γ-Al2O3催化剂,使苯直接羟基化制苯酚。该反应过程中,温度和溶剂对Cu-Ni/γ-Al2O3催化剂的反应性能影响进行了探讨。采用H2-TPR、XRD、EDS等表征技术考察了Ni对催化剂结构和性质的影响。结果表明,Ni使催化剂前驱体还原温度增加、活性组分Cu单晶粒度降低、催化剂表面Cu原子数增加;当反应温度为70°C、以水作反应溶剂时,Cu-Ni/γ-Al2O3比Cu/γ-Al2O3催化剂有较高反应活性和选择性,苯转化率为32.4%,苯酚选择性为93.3%,苯酚收率为30.2%。     

Fe_3O_4-H_2O_2类Fenton法降解亚甲基蓝

以Fe Cl_3·6H_2O和Fe SO_4·7H_2O为原料,氢氧化钠溶液为沉淀剂,制备了磁性Fe_3O_4粒子。采用XRD、SEM方法表征,并研究了Fe_3O_4粒子对亚甲基蓝的降解作用。结果表明,Fe_3O_4粒子平均粒径为5μm,以Fe_3O_4-H_2O_2组成类Fenton反应体系降解10 mg/L的亚甲基蓝溶液,当溶液p H值为3,浓度3%的H_2O_2用量为4 m L和0.2 g Fe_3O_4粉末,9 h内亚甲基蓝的降解率可达98.69%。     

不同前驱体CNX-CS催化剂的构筑及其性能

分别以三聚氰胺、尿素、硫脲为前驱体,采用高温焙烧法制备出不同的g-C_3N_4(CNX)材料,通过共混交联法将g-C_3N_4与壳聚糖(CS)进行复合,制得易再生、高稳定性的CNX-CS催化剂材料。采用扫描电镜(SEM)、X射线衍射图谱(XRD)、傅里叶变换红外(FTIR)等进行了表征,并对其进行了光催化性能评价。结果表明,来自于不同前驱体的g-C_3N_4均匀的分散在CS基质表面,复合过程中各自的结构得到了保持。以硫脲为前驱体的CNT-CS催化剂材料表现出最佳的吸附性能和催化性能协同作用,在5次循环实验之后降解率仍能达到95%,质量损失不超过10%。反应后的催化剂可通过简单加入氢氧化钠和过氧化氢进行再生。该研究对于易再生g-C_3N_4基催化剂的设计和水处理方面应用提供了良好基础。     

Characterization and activity of Pt-Sn/Al2O3 catalysts of different preparation: coimpregnation and new Pt-Sn precursor

A new bimetallic Pt-Sn compound [Pt(NH₃)₄][SnCl₆] has been used as precursor for the preparation of supported Pt-Sn/Al₂O₃ catalysts. A comparison of a dried sample with that prepared by coimpregnation displays different behaviour in TPR, chemisorption. The initial catalytic activity properties were checked in the reactions of cyclohexane dehydrogenation and cyclopentane ring opening, whilen-hexane skeletal reactions were used to probe the quasisteady-state activity. The catalyst prepared via the Pt-Sn complex precursors exhibited some-what lower specific activity. This fact, together with enhanced olefin formation fromn-hexane was taken as an indication of lower amount of contiguous Pt atoms and some electronic interaction between Pt and Sn in that catalyst.On leave from Fachhochschule Ostfriesland, D-26723 Emden, Germany.     

直接还原法制备纳米金催化剂及其对甲醛氧化的活性研究

选用典型的非活性载体MgO、γ-Al2O3和活性载体TiO2、CeO2,采用硼氢化钠直接还原法制备4种负载型纳米金催化剂,催化甲醛氧化。结果表明,其对甲醛氧化的活性规律为Au/CeO2>Au/TiO2>Au/γ-Al2O3>Au/MgO,并对其进行了金含量、比表面测定和TEM形貌分析,为净化甲醛污染提供了有效依据。     

Preparation,characterization and activity of wet-proofed Pt/silicalite catalysts

A procedure for wet-proofing Pt/silicalite catalysts with polytetrafluoroethylene fibres is described. The procedure yielded catalysts with stable and high activities for the exchange of hydrogen isotopes between liquid water and hydrogen gas. Characterization of the catalysts by hydrogen chemisorption and scanning electron microscopy showed that the wet-proofing procedure can produce catalysts in which most of the Pt surface in the Pt/silicalite before wet-proofing can remain accessible. Hydrogen chemisorption was found to be a valuable tool for prescreening of wet-proofed catalysts.     

加成型硅橡胶铂催化剂的制备及其活性研究

合成了几种不同的铂催化剂 (氯铂酸二乙烯基四甲基二硅氧烷 ,氯铂酸 -异丙醇 ,氯铂酸 -邻苯二甲酸二乙酯 )。考察了其对于有机硅橡胶加成聚合反应的催化活性 ,并从催化机理的角度初步探讨了催化剂不同活性差异的原因     

The influence of the precursor form on the ammonia synthesis activity of ruthenium zeolite catalysts

At temperatures ranging from 300 to 450°C and under atmospheric pressure, Ru₃/KY and Ru₃/NaY catalysts prepared from sorbing Ru(CO)₅ generated by Ru₃(CO)₁₂ on KY and NaY zeolites were found to be much more active for ammonia synthesis than Ru/KY and Ru/NaY prepared from cation exchange with Ru(NH₃)₆Cl₃. Dynamic secondary ion mass spectrometric and X-ray photoelectron spectroscopic studies disclosed that the reduced Ru metal particles were mainly entrapped within the zeolite framework and that their nature is related to the precusor forms.     

Preparation of Cu-MgO catalysts with different copper precursors and precipitating agents for the vapor-phase hydrogenation of furfural

This article presents the effects of three copper precursors and four precipitating agents on the catalytic performance of the corresponding co-precipitated Cu-MgO catalysts in the vapor-phase hydrogenation of furfural. The chemical and physical properties were analyzed by means of XRD, BET, SEM, and EDX techniques. The nitrate precursor provided the highest performance (conversion of ~89%). Whereas, the catalyst prepared with NaOH was the most efficient (furfuryl alcohol yield of >90%) during 240 min; the most durable conversion (~95%) was assured with Na_2-CO₃, and the highest selectivity to furfuryl alcohol (>97%) was achieved with K₂CO₃ as the precipitating agent. The least efficient catalyst (prepared with ammonium carbonate) led to 5-methylfurfural and 2,2-methylenebisfuran as the main byproducts. The major byproducts over the rest of the catalysts included tetrahydrofurfuryl alcohol, furfuryl ether, 1-pentanol, and 2-methylfuran. An increasing trend of furfuryl alcohol selectivity with time-on-stream was evident for all of the catalysts.     

Preparation of silica-immobilized titanium-containing silsesquioxane catalysts and activity for the epoxidation of alkenes

Silsesquioxanes containing tetrapodal titanium species and alkenylsilyl groups were immobilized onto dimethylsilyl-functionalized silica having mesopores by chemical tethering via hydrosilylative reaction in the presence of a Pt catalyst. The immobilized catalysts showed higher activity than their corresponding homogeneous catalyst towards the epoxidation of cyclooctene by tert-butylhydroperoxide, probably because of the improvement of the micro-environment around the titanium center. The reaction was found to be truly heterogeneous, since no further reaction proceeded after the separation of the catalyst by filtration. These catalysts also showed excellent catalytic activity for the epoxidation using hydrogen peroxide as an oxidant, while the parent homogeneous catalysts did not show any activity at all.     

MoP/TiO2-ZrO2催化剂制备及加氢脱氮性能考察

采用溶胶-凝胶法制备了TiO₂-ZrO₂复合载体,并用共浸渍法制备负载型MoP/TiO₂-ZrO₂催化剂,通过原位还原技术对催化剂进行还原处理后,在连续固定床反应器上进行活性评价。结果表明, TiO₂和ZrO₂物质的量比以及Mo负载量对催化剂活性有较大影响,当n(Ti)∶n(Zr)=4∶1和Mo负载质量分数为20%时,MoP/TiO₂-ZrO₂催化剂的加氢脱氮效果最好,并且TiO₂-ZrO₂复合载体比TiO₂-Al₂O₃复合载体的活性提高12.4个百分点。     

Hydrogenation of hexanoic acid with different catalysts

Hexanoic (or caproic) acid was hydrogenated, using three different catalysts. Copper chromite was used at different temperatures, and partially with added water. Nickel and platinum catalysts were investigated for comparison. Programs for thermodynamics and kinetic calculations were developed, which allowed a detailed evaluation. With copper chromite ester, small amounts of alcohol and hexane are formed directly. Alcohol is mainly formed via the ester by hydrolysis; its amount cannot be increased by addition of water. Ni and Pt catalysts are more active, which leads to direct formation also of alcohol and undecane.