氧化铈改性沸石脱氮的研究

用浸渍焙烧法制备稀土吸附剂,用于静态脱氮实验。结果表明,氧化铈改性的稀土吸附剂吸附性能优于氧化镧和氧化镧-氧化铈复合改性的稀土吸附剂;当吸附剂用量为2 g/L,进水pH为4~6,吸附时间为2.5 h,氧化铈改性稀土吸附剂对模拟废水氨氮浓度为20 mg/L的吸附率达到80.23%;吸附剂再生6次后氨氮的去除率下降不到7%,说明吸附剂具有较好的稳定性。     

硅藻土复合吸附剂的制备及其在废水中去氮除磷性能研究

针对水体富营养化现状,结合国内外相关研究,本论文采用硅藻土为基体材料,与沸石进行复合处理,处理后的复合吸附剂去氮能力达到59.76％,除磷能力达到了99.95％.最佳复合条件为:硅藻土∶沸石=6∶4,黏结剂15％,焙烧温度800℃,焙烧时间90min.经过5次再生和重复使用,复合吸附剂的除磷能力可以达到新鲜材料的99％,活性几乎完全恢复.通过对材料进行扫描电镜对比测试分析,可知在制备复合吸附材料的过程中,硅藻土与沸石的表面形貌、微观孔径大小、形状均发生了变化.     

沸石吸附处理含磷废水的实验研究

静态吸附状态下对人造沸石处理含磷模拟废水进行了实验研究,探讨了沸石用量、磷初始浓度、吸附时间、温度及pH对除磷效果的影响。结果表明,不同磷初始浓度,沸石除磷效果也不同,当废水含磷（以P20s汁）为16mg^-1。时,最佳除磷条件是：沸石质量浓度为18g,L,废水pH为6．8在右,吸附时间为20min,30℃条件下,磷去除率可达98％,沸石作为废水除磷吸附剂具有很好的发展前景。     

改性稀土沸石吸附剂的脱氮除磷性能研究

以沸石为载体、稀土元素为活性组分,通过浸渍、干燥、焙烧、筛分等工序后制成了污水脱氮除磷的稀土吸附剂。结果表明：稀土吸附剂对磷的吸附容量由沸石的2mg/g提高到25mg/g,而对氨氮的吸附容量提高较小（1～3mg/g）。当进水氨氮10mg/L、磷5mg/L、pH 4～7时,经稀土吸附剂处理后的出水pH 6～9、氮磷的去除率分别达到80%和99%。当稀土吸附剂再生10次时,脱氮效率是新鲜稀土吸附剂的90%,除磷效率则为80%。     

硅藻土-沸石复合吸附剂对水中磷的吸附性能研究

本文利用硅藻土和沸石为主要原料制备硅藻土-沸石复合吸附剂,采用傅里叶变换红外光谱法(FTIR)、X射线衍射(XRD)、SEM对其进行表征,研究了静态吸附过程中的复合吸附剂对溶液中磷的吸附动力学行为和吸附等温线.结果表明,硅藻土与沸石在复合过程中基本上完全参与了化学反应,可以增加复合吸附剂的活性;复合吸附剂对磷的吸附动力学特征更符合准二级反应动力学方程;等温吸附特征与Langmuir方程拟合较好.     

添加稀土镧对吸附分离乙烯/乙烷的影响

考察了添加稀土镧, 氧化镧、硝酸镧和氯化镧,对载铜活性炭吸附剂分离乙烯/乙烷的影响.测定了乙烯,乙烷40℃吸附等温线.乙烯选择性实验结果表明,氯化镧的添加效果最佳.合适的添加量在11.2%(wt)附近,可使乙烯的选择性提高到原来的两倍以上. 比表面及孔径分布数据表明, 添加适量稀土镧增大了吸附剂孔的比表面和孔体积, 特别是对微孔,因而更有利于提高吸附剂表面的利用率.通过SEM对稀土络合吸附剂的形貌观察可知,稀土分散于未被活性组分CuCl利用的活性炭表面.由于稀土对乙烷吸附量极小,从而极大抑制了活性炭载体对乙烷的物理吸附,这是此复合吸附剂提高乙烯乙烷分离性能的主要原因.     

Ce-Zn复合吸附剂的制备及除磷性能研究

以Ce(NO₃)₃·6H₂O和Zn(NO₃)₂·6H₂O为原料，采用共沉淀法制备Ce-Zn复合吸附剂，利用傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM)对其进行表征，对吸附过程进行动力学和热力学拟合，通过正交实验确定吸附除磷的最佳工艺条件，并对吸附剂进行再生处理，研究其可循环利用性能。结果表明，复合吸附剂表面生成了水合氧化铈和氧化锌颗粒，表面粗糙，呈多孔结构；磷酸盐离子取代复合吸附剂表面的金属羟基是吸附除磷的主要原因。除磷最佳工艺条件：磷初始质量浓度为5 mg/L,pH为4,Ce-Zn复合吸附剂投加量为0.07 g、反应时间为240 min；吸附过程符合Freundlich等温模型和准二级动力学方程，反应自发进行，且为吸热反应；利用碱液对吸附剂进行3次循环脱附再生，对磷的去除率保持在90%以上，证明该吸附剂可以循环使用。     

纳米复合吸附剂静态去除废水中磷

作者通过正交实验筛选出一种由纳米沸石分子筛和硅藻土组成的复合吸附剂,筛选试验以去除废水中的磷为基准对其组成、配比进行优化.静态试验考察了原水中磷的浓度、pH、搅拌时间对优化后的复合吸附剂去除污水中磷的性能的影响.     

己二酸锌钙皂纳米氧化铈/氧化镧对PVC/ASA的热稳定作用

合成了己二酸锌钙皂,并将纳米氧化铈和氧化镧分别作为共稳定剂制备了新型复合热稳定剂。采用刚果红法、热失重分析仪、动态力学分析仪等考查了复合热稳定剂对聚氯乙烯/丙烯酸酯苯乙烯丙烯腈接枝共聚物（PVC/ASA）共混材料的热稳定效果及动态力学性能。结果表明,稀土化合物作为共稳定剂可以提高己二酸锌钙皂对PVC/ASA共混材料的热稳定效果,氧化镧与己二酸锌钙皂的协同效果优于纳米氧化铈,而纳米氧化铈的加入可以提高材料的热变形温度。     

镧掺杂二氧化钛/沸石吸附对氨基酚的性能研究

以镧掺杂二氧化钛/沸石(La3+-TiO2/沸石)及沸石作为吸附剂,研究了两者吸附对氨基酚的性能。采用可见分光光度法,考察了吸附时间、吸附剂用量、对氨基酚浓度及温度等实验条件对吸附效率的影响。在吸附时间2 h、吸附剂用量0.02 g、对氨基酚初始浓度0.5 mg/L、实验温度20℃的条件下,La3+-TiO2/沸石吸附对氨基酚的能力明显优于未处理的沸石。对氨基酚在两种吸附剂上的吸附均符合准二级动力学模型。吸附过程为吸热过程,吸附等温线复合Langmuir和Freundlich方程。     

纳米氧化镧对吸收药热分解的催化作用

研究了纳米氧化镧对吸收药(硝化棉吸收硝化甘油的混合物,NC／NG)热分解反应的催化作用,并提出了形成过渡态配合物的反应机理。实验结果表明,纳米氧化镧能有效地催化吸收药的热分解。     

Preservation of the Activity of Supported Gold Catalysts for CO Oxidation

Procedures leading to the preservation of activity of supported gold catalysts for CO oxidation are reviewed. The inclusion of iron as Fe(OH)₃ in preparing catalysts using tin oxide, ceria and zirconia as supports gives better activity and much improved stability with time-on-stream. In the case of Au/Fe-SnO₂ (0.5–0.9% Au), the effect is maximal with ~4% Fe. The stability of catalysts based on ceria as support is also much better when small amounts of either iron or lanthanum during preparation of the support by thermal decomposition of nitrates. Au/SnO₂ catalysts often suffer initial deactivation followed by an increase in activity with time-on-stream; a period of refrigeration (7d) induces an excellent stability at high conversion.     

阴极材料含镧复合氧化物的电催化特性

中温固体氧化物燃料电池的研制是固体氧化物燃料电池商业圈的必然趋势，影响其发展的关键问题之一就是阴极材料的研制。钙钛矿结构稀土复合氧化物材料是最有前途的中低温固体氧化物燃料电池阴极材料。本文对钙钛矿结构含镧复合氧化物的电催化机理进行详尽的叙述，并提出了其发展方向。     

稀土镧改性PP流变性能的研究

以氧化镧为原料,利用化学沉淀法制备氢氧化镧,再以不同比例的氢氧化镧与苯甲酸合成了两种稀土化合物苯甲酸镧,将苯甲酸镧与聚丙烯(PP)共混,制得两种改性PP混合物。研究了苯甲酸镧对PP流变性能的影响。结果表明:苯甲酸镧加入到PP后,PP共混体系为非牛顿假塑性流体,其表观粘度随剪切速率增大而减小;随着苯甲酸铡含量的增加,PP共混体系的非牛顿指数降低,流变性能得到改善;2种PP共混物的粘流活化能分别达到58.60 kJ/mol和56.85 kJ/mol。     

Flash cosintering of a lanthanum strontium cobalt ferrite nanofibre/Gd-doped ceria bilayer structure

For solid oxide fuel cells, an important structural requirement is that the electrolyte layer needs to be dense and the electrode layer porous, which is difficult to obtain by conventional cosintering. In this work, flash cosintering of a double layer structure consisting of a Gd-doped ceria substrate with a lanthanum strontium cobalt ferrite nanofibre coating is investigated. Experimental and finite element modelling results reveal that when the LSCF layer is connected to the electrode, the heat is concentrated in the LSCF layer, which leads to a huge temperature gradient and introduces severe cracking. When the LSCF layer is electrically isolated from the electrode, the heat is concentrated in the GDC layer, and the temperature gradient is dramatically reduced. In this situation, the density of GDC can reach 92.86% while a high porosity of 52.26% is maintained in the LSCF layer, which is higher than that of the conventional cosintered sample.     

Compilation of mechanical properties for the structural analysis of solid oxide fuel cell stacks. Constitutive materials of anode-supported cells

The mechanical failure of one cell is sufficient to lead to the end of service of a solid oxide fuel cell (SOFC) stack. Therefore, there is growing interest in gaining knowledge on the mechanical properties of the cell materials for stress analysis.This study compiles available data from the literature on the mechanical properties of the most common materials used in intermediate-temperature anode-supported cells: nickel and yttria-stabilized zirconia (Ni–YSZ) anodes, YSZ electrolytes, yttria (YDC) or gadolinia-doped ceria (GDC) compatibility layers and lanthanum strontium manganite (LSM) or lanthanum strontium cobalt ferrite (LSCF) cathodes. The properties for the simulation of stresses, i.e. coefficient of thermal expansion (CTE), Young's modulus, Poisson's ratio, creep behaviour and strength are reported, with an emphasis on temperature and porosity dependence and the evolution upon aging or cycling when available. Measurements of our Ni(O)–YSZ anode material includes the CTE (oxidised and reduced state), Young's modulus and strength at room temperature (oxidised and reduced) and 1073 K (oxidised).     

Effect of NiO content on structural, surface and catalytic characteristics of nano-crystalline NiO/CeO2 system

The NiO/CeO₂ nano-composite catalysts containing different nickel content prepared by impregnation method have been characterized by XRD and TEM. The surface and catalytic properties of Ni/Ce mixed oxide solids were determined by nitrogen adsorption at −196 °C and catalytic conversion of isopropanol at different temperatures. These composites can be described as a mixture of nickel oxide and ceria modified by the insertion of a part of nickel in the ceria lattice. The size of the nickel oxide varies considerably from clusters to a crystallized material, depending on the amount of nickel oxide. From the characterization of the composites, it was concluded: at low Ni loading, the ceria surface is gradually covered with the dispersed NiO species. At higher loading, highly dispersed NiO, well crystalline nickel oxide and Ni-Ce-O solid solution coexist.It was verified that the structural, morphological, surface and catalytic properties could be influenced by nickel loading. This treatment led to a slightly increase in the crystallite size of ceria particles. On the other hand, the augmentation in the nickel content brought about an increase in the crystallite size, lattice constant and unit cell volume of nickel oxide. The nickel loading brought about an increase in the formation of Ni-Ce-O solid solution with subsequent creation of oxygen vacancies.     

改性磁铁矿的制备及其对水中磷的吸附

用硝酸钙和氯化镧对磁铁矿进行改性,考察不同初始浓度、pH、作用时间对含磷废水的吸附效果,进而分析其吸附等温线及动力学特性。结果表明:Langmuir等温吸附方程能很好地描述其等温吸附特性,未改性、硝酸钙改性、氯化镧改性的磁铁矿对磷的吸附饱和量分别为0.068、0.409、2.157 mg/g;未改性、硝酸钙改性、氯化镧改性的磁铁矿分别在pH为12、pH为8~12、pH为4~10时,对磷的吸附效果较好;氯化镧改性磁铁矿对磷的去除率达95%以上且其吸附过程符合二级吸附动力学方程。     

Catalytic oxidation of organic compounds in aqueous media

Ru, Pt and Rh catalysts supported on titania, ceria or active carbon and a Mn/Ce composite oxide catalysts were prepared and their catalytic behavior in Wet Air Oxidation ( 20 bar O₂) of phenol and acetic acid were investigated. Phenol was found to be an easily oxidizable compound as 170°C, while acetic acid was a very refractory molecule, even at 200°C. Ru(5 wt.-%)/C is a very efficient catalyst for the WAO of acetic acid without any leaching of noble metal.