共查询到20条相似文献,搜索用时 158 毫秒
1.
2.
3.
Fe修饰Mn-Ce/Al2O3-TiO2催化剂对NO氧化性能的实验研究 总被引:1,自引:0,他引:1
采用溶胶凝胶法制备了TiO_2与Al_2O_3摩尔比为1∶4的Al_2O_3-TiO_2复合氧化物载体,使用共浸渍法制备了Mn,Ce质量分数分别为10%和2%的Mn-Ce/Al_2O_3-TiO_2催化剂,并通过添加不同质量分数的Fe对催化剂进行修饰。在固定床反应装置上进行了催化剂氧化性能的实验。结果表明:在空速为15 000 h~(-1),氧气体积分数为8%时,Fe的添加能够显著提升Mn-Ce/Al_2O_3-TiO_2催化剂的NO催化氧化性能,并在Fe质量分数为4%时,Mn-Ce-Fe(4)/Al_2O_3-TiO_2催化剂的NO催化氧化活性最优,280℃时NO的转化率达到86%。H_2-TPR实验结果显示,Fe的修饰使Mn-Ce/Al_2O_3-TiO_2催化剂的还原峰大幅向低温方向移动,改善了催化剂的氧化还原活性。 相似文献
4.
5.
6.
以γ-Al_2O_3为载体,采用浸渍硝酸铁的方法,经过静置、干燥、焙烧,制备了Fe/γ-Al_2O_3催化剂。以甲基橙溶液作为模拟印染废水进行湿式催化氧化实验。考察了湿式催化氧化反应条件pH、催化剂投加量、催化反应时间、氧化剂投加量等对甲基橙废水处理效果的影响。实验结果表明:粒度为40~60目的γ-Al_2O_3经过0.1 mol/L的硝酸铁溶液浸渍,静置12 h,80℃的恒温干燥箱中干燥2 h,于350℃马弗炉中焙烧3 h,制备的Fe/γ-Al_2O_3催化剂,在湿式催化氧化反应温度为27℃、pH为7、催化剂投加量为300 mg、氧化剂30%过氧化氢溶液5 mL、反应时间90 min时,甲基橙溶液模拟废水降解率达到83.49%。 相似文献
7.
采用浸渍法制备了CuO/Al_2O_3催化剂,并将其用于催化臭氧氧化降解酸性红B,研究了CuO负载量、催化剂投加量、臭氧流量等因素对COD去除率的影响。通过加入羟基自由基抑制剂叔丁醇,判断CuO/Al_2O_3催化臭氧氧化降解酸性红B的途径。运用XRD、XPS、SEM、EDS、BET等表征手段对催化剂的结构和性能进行表征,实验结果表明,载体上的铜物种均为CuO,且均匀地分布在载体上。CuO/Al_2O_3催化剂的加入能够促进臭氧分解羟基自由基降解酸性红B,当CuO负载量为1.0%,催化剂投加量为5.56 g/L,臭氧流量为15 L/min时,具有较好的COD去除率。 相似文献
8.
以自制Fe2O3-Ce O2/γ-Al2O3为催化剂,采用催化湿式过氧化氢氧化法(CWPO)预处理有机磷农药废水,通过单因素和正交试验研究了过氧化氢投加量、起始p H、反应温度和反应时间对COD的去除效果及影响规律。结果表明,反应最优条件为H2O2投加量2 m L、起始p H=5、反应温度80℃、反应时间40 min,在此条件下COD的去除率可达85.8%,可生化性提高到B/C=0.43。运用一级动力学模型和Arrhenius经验公式,建立了催化湿式过氧化氢氧化降解COD的动力学方程。 相似文献
9.
高浓度有机废水具有极大危害,湿式催化氧化法(CWO)是如今常用的方法。本文简单的介绍了湿式催化氧化法的机理及其潜在价值和未来应用。实验结果表明:Fe OOH纳米催化剂的量、H_2O_2浓度、pH值,反应时间都对COD的值有很大影响。我们对新疆独山子炼油厂的汽油碱渣废水进行了研究,确定了由预处理和湿式催化氧化法组成的最佳处理工艺。通过实验得到处理该废水的最佳工艺条件:催化剂的用量为0.05将10000 mg/L的COD值可被降到1000 mg/L。 相似文献
10.
11.
In this study, a novel bifunctional catalyst IrFe/Al2O3, which is very active and selective for preferential oxidation of CO under H2-rich atmosphere, has been developed. When the molar ratio of Fe/Ir was 5/1, the IrFe/Al2O3 catalyst performed best, with CO conversion of 68% and oxygen selectivity towards CO2 formation of 86.8% attained at 100 °C. It has also been found that the impregnation sequence of Ir and Fe species on the Al2O3 support had a remarkable effect on the catalytic performance; the activity decreased following the order of IrFe/Al2O3 > co-IrFe/Al2O3 > FeIr/Al2O3. The three catalysts were characterized by XRD, H2-TPR, FT-IR and microcalorimetry. The results demonstrated that when Ir was supported on the pre-formed Fe/Al2O3, the resulting structure (IrFe/Al2O3) allowed more metallic Ir sites exposed on the surface and accessible for CO adsorption, while did not interfere with the O2 activation on the FeOx species. Thus, a bifunctional catalytic mechanism has been proposed where CO adsorbed on Ir sites and O2 adsorbed on FeOx sites; the reaction may take place at the interface of Ir and FeOx or via a spill-over process. 相似文献
12.
以γ-Al2O3为载体,采用等体积分步浸渍法制备了以Ni为活性组分,La、Ce、Fe、Cr、Co为助剂的催化剂M/γ-Al2O3,在固定床管式反应器中研究了M/γ-Al2O3催化剂的性能,考察了反应温度、水碳比和空速对氢产率的影响,并对催化剂进行XRD、SEM和BET表征。结果表明,NiLaCeFeCrCo/γ-Al2O3催化剂具有较好的催化性能,在反应温度700 ℃、水碳物质的量比10和空速6 min-1的条件下,氢产率达到27.335 mol·mol-1,并在300 min内表现出较好的活性,平均氢产率为21.966 mol·mol-1。 相似文献
13.
氧化石墨烯负载纳米Fe3O4类芬顿处理制药废水 总被引:1,自引:0,他引:1
采用改进Hummer法制备了氧化石墨烯(GO)负载纳米Fe3O4磁性催化剂(Fe3O4/GO),对其进行了X射线衍射仪、扫描电子显微镜和能量-色散光谱表征,并将其应用于多相类芬顿处理高浓化学原料药生产废水。结果表明,Fe3O4颗粒成功负载在GO表面,且没有出现明显的团聚现象。当废水的pH为3,双氧水(H2O2的质量分数30%)投加量10 mL/L,催化剂投加量2 g/L,反应120 min后COD去除率达78%,UV254去除率高达81%。三维荧光光(3D-EEM)分析可知,芳香类和富里酸类物质在催化降解过程中得到有效去除。 相似文献
14.
通过浸渍法制备了Al_2O_3负载的Pd和Pt催化剂,考察催化剂的甲烷、乙烷和丙烷催化燃烧活性,以及助剂Ba对催化性能的影响。对于Pd/Al_2O_3催化剂,加入Ba使活性物种PdO颗粒变大和还原温度升高,形成更稳定的PdO活性物种,是Pd-Ba/Al_2O_3催化剂活性提升的主要原因。对于Pt/Al_2O_3催化剂,加入Ba助剂使活性物种Pt0含量降低,PtO_x与Al_2O_3载体相互作用增强,使PtO_x物种更难被还原为Pt~0,导致Pt-Ba/Al_2O_3催化剂活性降低。Pd和Pt催化剂催化烷烃氧化反应活性规律一致:丙烷乙烷甲烷。Pd/Al_2O_3催化剂有利于C—H键活化,Pt/Al_2O_3催化剂有利于C—C键活化。Pt/Al_2O_3催化剂对C1-C3烷烃氧化活性的差别明显大于Pd/Al_2O_3催化剂。Pt/Al_2O_3催化剂对碳比例高的烷烃活性更高。 相似文献
15.
The selective catalytic reduction (SCR) of NO by C3H6 in excess oxygen was evaluated and compared over Ag/Al2O3 and Cu/Al2O3 catalysts. Ag/Al2O3 showed a high activity for NO reduction. However, Cu/Al2O3 showed a high activity for C3H6 oxidation. The partial oxidation of C3H6 gave surface enolic species and acetate species on the Ag/Al2O3, but only an acetate species was clearly observed on the Cu/Al2O3. The enolic species is a more active intermediate towards NO + O2 to yield—NCO species than the acetate species on the Ag/Al2O3 catalyst. The Ag and Cu metal loadings and phase changes on Al2O3 support can affect the activity and selectivity of Ag/Al2O3 and Cu/Al2O3 catalysts, but the formation of enolic species is the main reason why the activity of the Ag/Al2O3 catalyst for NO reduction is higher than that of the Cu/Al2O3 catalyst. 相似文献
16.
采用等体积浸渍法制备一系列Co负载量不同的Co/Al2O3催化剂,用于乙酰丙酸液相催化加氢制γ-戊内酯反应。采用X射线衍射仪和透射电镜对Co/Al2O3催化剂进行表征,考察Co负载量、反应温度、反应压力和催化剂用量等对乙酰丙酸液相催化加氢反应的影响。结果表明,在Co负载质量分数15%、反应温度140 ℃、反应压力4.0 MPa和催化剂用量为反应物总质量的20%条件下,以甲醇为溶剂,反应6 h,乙酰丙酸转化率100%,γ-戊内酯选择性80.4%。催化剂重复使用6次仍具有较好的催化性能。 相似文献
17.
18.
采用吸附-沉淀法制备负载Ru质量分数为1.0%的Ru/Al_2O_3催化剂,以马来酸二甲酯催化加氢合成丁二酸二甲酯为探针反应,详细考察预处理条件对Ru/Al_2O_3催化剂加氢性能的影响,并对其进行XRD、TEM和H2-TPR表征。结果表明,焙烧温度越高,催化剂催化活性越低;直接还原活化所得催化剂活性高于空气中焙烧后还原活化所得催化剂。以甲醇为溶剂,在70℃和1.0 MPa条件下,直接还原活化所得Ru/Al_2O_3催化剂上马来酸二甲酯转化率达100%,丁二酸二甲酯选择性约100%。相同时间内,空气焙烧后还原活化所得Ru/Al_2O_3催化剂上马来酸二甲酯转化率接近25%,继续延长反应时间,马来酸二甲酯转化率几乎不变。经高温焙烧还原后,活性组分Ru烧结;直接还原活化后,活性组分Ru高度分散。 相似文献
19.
Ag-based catalysts supported on various metal oxides, Al2O3, TiO2, and TiO2–Al2O3, were prepared by the sol–gel method. The effect of SO2 on catalytic activity was investigated for NO reduction with propene under lean burn condition. The results showed the catalytic activities were greatly enhanced on Ag/TiO2–Al2O3 in comparison to Ag/Al2O3 and Ag/TiO2, especially in the low temperature region. Application of different characterization techniques revealed that the activity enhancement was correlated with the properties of the support material. Silver was highly dispersed over the amorphous system of TiO2–Al2O3. NO3− rather than NO2− or NOx reacted with the carboxylate species to form CN or NCO. NO2 was the predominant desorption species in the temperature programmed desorption (TPD) of NO on Ag/TiO2–Al2O3. More amount of formate (HCOO−) and CN were generated on the Ag/TiO2–Al2O3 catalyst than the Ag/Al2O3 catalyst, due to an increased number of Lewis acid sites. Sulfate species, resulted from SO2 oxidation, played dual roles on catalytic activity. On aged samples, the slow decomposition of accumulated sulfate species on catalyst surface led to poor NO conversion due to the blockage of these species on active sites. On the other hand, catalytic activity was greatly enhanced in the low temperature region because of the enhanced intensity of Lewis acid site caused by the adsorbed sulfate species. The rate of sulfate accumulation on the Ag/TiO2–Al2O3 system was relatively slow. As a consequence, the system showed superior capability for selective adsorption of NO and SO2 toleration to the Ag/Al2O3 catalyst. 相似文献
20.
以Al_2O_3为载体,RuCl_3·xH_2O和FeCl_3·6H_2O为活性组分前驱体,采用吸附-沉淀法制备了Ru-Fe/Al_2O_3和Ru/Al_2O_3催化剂,以马来酸二甲酯加氢合成丁二酸二甲酯为探针反应,结合H_2-TPR和XRD表征技术,考察Fe改性Ru基催化剂的氧化-还原性能及催化活性。经氧化-还原循环处理后,催化剂Ru-Fe/Al_2O_3上马来酸二甲酯加氢活性高于Ru/Al_2O_3。XRD结果显示,经处理的Ru-Fe/Al_2O_3上未见金属Ru的特征衍射峰,而Ru/Al_2O_3上出现了金属Ru的特征衍射峰。结合H_2-TPR结果推断,Ru与Fe之间发生了相互作用,这种协同作用可以改善Ru/Al_2O_3催化剂的热稳定性。 相似文献