纳米水滑石结构表征及其对氯离子吸附性能

以天然菱镁矿为原料,采用尿素法制备纳米Mg-Zn-Al水滑石、Zn-Mg-Al-Fe水滑石,用XRD、SEM对水滑石的结构特征、晶粒尺寸进行表征,并利用水滑石的层间阴离子交换性及结构“记忆效应”,来研究焙烧态水滑石对溶液中氯离子的吸附性能.结果表明:Zn-Mg-Al水滑石的结晶度比Mg-Al水滑石、Zn-Mg-Al-Fe水滑石的高,同时Zn-Mg-Al水滑石的粒径非常均匀,尺寸在20 nm左右,为层片状结构,而且其晶体形貌呈现花瓣状结构;在Mg-Al水滑石中,随着n(Mg)∶n(Al)的增加,溶液中Cl-的去除率逐渐提高,且在n(Mg)∶n(Al) =4时去除率最大,为85.96％;当n(M2+)∶n(M3+)固定为2时,Zn-Mg-Al水滑石对Cl-的去除率要比Mg-Al水滑石对Cl-的去除率高13.25％,但Zn-Mg-Al-Fe水滑石对Cl-的去除率却比Mg-Al水滑石低32.53％.     

水滑石除磷的吸附动力学研究

采用共沉淀法制备了Mg/Al水滑石,研究了不同Mg/Al物质的量比、材料用量、不同pH条件下Mg/Al水滑石吸附除磷的动力学特征,从而对吸附速率的控制过程进行分析。结果表明水滑石对磷的吸附能较好地符合准二级动力学方程、Elovich动力学方程和内扩散模型。n(Mg)/n(Al)=3是水滑石最理想配比,水滑石投加量越大,外扩散过程越慢;一定范围内pH的升高能促进水滑石对磷吸附速率和吸附容量的提升。     

NiMgAl类水滑石制备条件研究

采用共沉淀法合成了不同摩尔投料比的NiMgAl类水滑石化合物.测定了Ni、Mg、Al单盐以及不同摩尔比的混合硝酸盐溶液的滴定曲线,考察了加料方式、晶化温度、晶化时间、原料配比对类水滑石合成的影响.通过XRD、IR对合成物进行表征,结果表明,在恒定pH值为8～9,n(Mg Ni)/n(Al)=1～3,n(Mg)/n(Ni)=8～16,晶化温度为65℃,晶化时间6h的条件下即得到晶相单=的NiMgAl-HTLcs;随n(Mg Ni)/n(Al)的增加,类水滑石结构的规整性提高,n(Mg)/n(Ni)比增加,层间距略有减小.     

二元金属类水滑石的合成及其作为前驱体对NOx的吸附性能研究

用共沉淀法合成了多种二元金属类水滑石化合物,对其进行了XRD、IR表征,并测试了焙烧产物对NOx的吸附性能.结果表明,合成的样品都具有典型的水滑石层状结构;二元金属类水滑石化合物MAl-HTlcs(M=Cu,Mg,Zn,Co,Ni)对NOx均具有良好的吸附性能,其中锌铝型类水滑石(摩尔比Zn/Al=3)对NOx的吸附速率及饱和吸附量最大,饱和吸附量为1851mg/g.     

Mg/Al水滑石对腐殖酸的去除性能研究

采用共沉淀法制备了 Mg/Al 水滑石,并在不同温度下煅烧。探究了煅烧温度、材料投加量、pH 值、腐殖酸初始浓度对水滑石去除腐殖酸的影响。结果表明,当金属物质的量比为3的 Mg/Al 水滑石投加量为0.5 g/L, pH 值为8.5,温度为25℃时,水滑石对10 mg/L 的腐殖酸的去除率能达到96.64%,此时,水滑石的饱和吸附量为19.33 mg/g。Mg/Al 水滑石经3次再生后,对腐殖酸的去除率仍然高达95%以上,表明 Mg/Al 水滑石的可重用性好。     

二维层状磁性镁铝水滑石的制备与表征

采用共沉淀法将磁性基质与镁铝水滑石组装制备二维层状磁性镁铝水滑石,考察了在一定的pH值、沉淀生成温度及陈化时间下,不同n(Mg2 )/n(Al3 ),n(Fe2 )/n(Mg2 )比值及焙烧温度对合成磁性镁铝水滑石结构的影响,并借助HRTEM、XRD、VSM、TG-DSC、FT-IR等手段对其晶型结构、磁学性能及结晶度等进行表征,结果表明镁铝水滑石在赋予磁性后,并没有改变其典型的层状结构,证实了将磁性基质与层状材料组装合成的可行性.     

甘氨酸-Mg_3Al水滑石的制备、剥离以及与蒙脱土的插层组装

用共沉淀法制备甘氨酸(简称Gly)插层Mg3Al水滑石(简称Gly-Mg3Al LDHs),利用甘氨酸等电点的性质实现了Mg3Al水滑石在pH=3~4水溶液中的剥离,并将剥离出的LDHs纳米片层与蒙脱土进行插层组装,制备出Mg3Al水滑石/蒙脱土层状复合材料。用X射线粉末衍射、红外光谱、N2吸附-脱附以及电泳仪等手段对样品进行了表征。结果表明,制备出的GlyMg3Al LDHs结构规整,晶相单一,甘氨酸以42°的倾角排列于水滑石层间。在nGly∶nNO3-=1∶2的条件下制备的Gly-Mg3Al LDHs剥离效果最好,剥离后形成的无机聚合粒子的zeta电位介于35 mV~40 mV之间,剥离液可以稳定存在72 h。所得层状复合材料的层间距为1.44nm,此值为单元LDHs片层与单元蒙脱土片层的厚度之和,证明LDHs纳米片层与蒙脱土进行了有序交叉叠层。     

镁铝水滑石纳米片可控制备及其吸附性能研究

在聚乙二醇(PEG)存在的条件下,通过一步水热法合成了晶相单一的六方片状镁铝水滑石层状双氢氧化物(LDH)。采用XRD、SEM、TEM、FT-IR、N2吸附、UV-Vis紫外-分光光度计和zeta电位仪等对产物进行了表征。考察了PEG活性剂对水滑石形貌及性能的影响。结果表明,添加活性剂改性后制备的六边形水滑石纳米片形貌规整均一,宽约几微米,厚度约为100~200 nm,纳米片间易形成交叉支撑结构,分散性好,比表面积为203.5 m2/g。在室温,焙烧后的Mg AlLDO对浓度为100 mg/L的刚果红30 min内去除率可达97%,饱和吸附量为243.5 mg/g。     

MgAl-LDH吸附甲基橙性能研究

在水热反应温度为180℃,反应溶液pH值=9～10,反应时间为4h,反应总物质浓度为0.1mol/L的实验条件下,探索Mg/Al的摩尔比对MgAl-LDH吸附甲基橙性能的影响,并考察了材料再生后的吸附性能。研究结果表明,Mg/Al摩尔比为2.5∶1时的MgAl-LDH吸附甲基橙性能最优;在最佳吸附条件下,MgAl-LDH对甲基橙吸附量高达83.33mg/g;并对吸附材料循环利用焙烧温度进行探讨,可再生循环焙烧温度在400℃达到最佳,循环使用3次吸附性能保持良好。此外,对Mg/Al-LDH及其各个温度焙烧产物进行TG-DTA和SEM表征,显示其片状构型及对甲基橙进行的离子交换吸附和表面静电吸附作用。     

纳米晶镁铝水滑石制备机理及抗毒性研究

以尿素为沉淀剂制备纳米晶镁铝水滑石,考察不同镁铝比制备的纳米晶镁铝水滑石催化剂对大豆油酯交换的影响以及催化剂的抗水抗酸性和使用寿命,并探讨纳米晶镁铝水滑石的合成机理.随镁铝摩尔比增加,酯交换反应所需时间减少,当m(Mg2 ):m(Al3 )=3:1时,转化率高达94.2%;当m(Mg2 ):m(Al3 )=4:1时,使用寿命最长,可重复使用5次.纳米晶镁铝水滑石具有较强抗水抗酸性,故在进行酯交换反应中无须脱水脱酸.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.