酰腙功能化MCM-41吸附尾矿废水中镉离子研究

在碱性条件下,以十六烷基三甲基溴化(CTAB)和正硅酸乙酯(TEOS)为主要原料,采用水热合成法制备出MCM-41分子筛。通过物理浸渍法对MCM-41分子筛进行表面功能化,制备出2-羰基丙酸邻羟基苯甲酰腙修饰MCM-41孔分子筛。研究了修饰分子筛对尾矿废水中镉离子的吸附性能,考察了吸附时间、pH值、温度、分子筛用量等因素对功能化分子筛吸附性能的影响。结果表明:2-羰基丙酸邻羟基苯甲酰腙修饰MCM-41分子筛在吸附时间为30 min,pH为8.02,温度为40℃,吸附剂用量为0.08 g的条件下吸附性能最佳,最大去除率为95.6%。     

MCM-41和HMS孔内组装[Eu(bpy)2]3+及其光致发光性质

采用浸渍的方法在MCM-41和HMS介孔材料孔内组装[Eu(bpy)2]3 (bpy:2,2-联吡啶).所得介孔复合材料经XRD、ICP等离子发射光谱、IR、N2吸附实验及光致发光谱进行了表征.实验结果表明:与介孔材料母体相比,组装稀土配合物后的介孔复合材料的BET比表面积、孔径和孔容均有所下降;组装稀土配合物的介孔复合材料在氙光源激发下,均发射出特征的Eu3 光致发光谱;与组装稀土配合物的HMS介孔复合材料相比,组装后的MCM-41介孔复合材料具有较高的光致发光效率.MCM-41介孔材料是一种比HMS合适的载体,有助于增强介孔材料孔内组装稀土配合物的光致发光效率.     

介孔分子筛MCM-41对铅离子吸附性能研究

采用十六烷基三甲基溴化铵(CTAB)作模板剂,正硅酸乙脂(TEOS)为硅源,氨水(NH3.H2O)为碱性介质的条件下在常温下快速合成出了介孔分子筛MCM-41。采用X射线衍射(XRD)对合成样品进行了表征,XRD结果表明合成的MCM-41具备高的结构规整度。将该MCM-41作为吸附剂,对水中铅离子的吸附进行了研究。实验结果表明:MCM-41用量、吸附时间、吸附温度和pH值均影响其对铅离子的吸附率;其吸附动力学符合准二级动力学方程式;其等温吸附行为可以用Langmuir等温线来描述。     

商业介孔SiO_2对水体中Cd、Hg污染物的净化

针对受Cd、Hg重金属污染的水体,研究了添加商业介孔SiO_2(MCM-41)对Cd~(2+)、Hg~(2+)的净化效果及其影响因素。模拟实验表明:适量的MCM-41对Cd~(2+)、Hg~(2+)具有良好的净化效果,特别是对于低Cd~(2+)、Hg~(2+)污染物浓度的水体,净化效率超过90%;而过量的MCM-41颗粒间易发生团聚现象影响吸附效率;降低水体温度、提高pH有利于提高MCM-41对Cd~(2+)、Hg~(2+)污染物的净化效率;吸附过程以物理吸附为主,吸附速率较快,净化体系短时间内即可达到吸附饱和,可作为填料应用于饮用水净化装置。     

介孔分子筛富集-紫外可见分光光度法测定废水中微量镍

利用MCM-41介孔分子筛对废水中微量镍进行富集,并运用紫外可见分光光度法对富集后镍的含量进行测定。以三嵌段共聚物P123(PEO-PPO-PEO)为模板,正硅酸乙酯(TEOS)为硅源,在酸性条件下用水热法合成MCM-41分子筛,并对其进行相关表征。实验结果表明:在酸度为p H=6.00,富集时间为35min时,对废水中微量镍的富集效率达到93.40%;以丁二酮肟(20g·L-1)为显色剂,CTMAB为增敏剂,在λmax=535nm,酸度为p H=9.0的条件下,镍在1mg·L-1⁸0mg·L-1范围内符合比尔定律,线性方程为Y=0.03675X+1.44186,R=0.9966。     

Al掺杂对硅基介孔材料MCM-41结构的影响

以水玻璃为硅源,在无压体系中合成含Al的硅基MCM-41,并采用XRD、TEM、27Al MASNMR及N2吸附-脱附等表征手段,系统研究Al的引入对MCM-41结构的影响。研究结果表明:Al原子对MCM-41骨架Si进行同晶取代后,Al以四配位骨架和六配位骨架外Al的形式存在,Al-MCM-41仍能保持长程有序的一维孔道结构。并且随着Al掺杂量的增加,孔径和孔体积减小,当Si/Al=25时比表面积达最高值。     

载体对固载化Ru基催化剂CO2加H2活性的影响

将三种有机胺功能化的无机载体——气相法SiO2、Zr（OH）4和MCM-41介孔分子筛固载的Ru基催化剂用于CO2加H2合成HC00H反应,其中固载于气相法SiO,和MCM-41介孔分子筛上的催化剂所显示的活性要优于相应的均相催化剂,并且由于MCM-41的介孔分子筛特性,其活性明显优于其余两种无机载体,在温度80℃,总压16、OMPa反应条件下,产物甲酸转化频率达到1022h^-1。     

改性MCM-41分子筛负载钼钴系催化剂的TPS研究

本文采用程序升温硫化(TPS)技术研究了负载于MCM-41分子筛的钼钴系催化剂的性能。根据TPS结果可知:(1)载体和MoO_3相互作用强弱顺序如下:Al_2O_3>Al_2O_3-MCM-41>MCM-41>TiO_2-MCM-41,由此推断TiO_2具有削弱MCM-41和MoO_3作用的能力,而Al_2O_3则相反,它增强了MoO_3和MCM-41的相互作用;(2)助剂CoO对负载在未经改性的MCM-41载体上的MoO_3的硫化没有明显的促进作用,这和以Al_2O_3为载体的情况不同,TPS结果表明在Al_2O_3上MoO_3和CoO可能生成Co-Mo-O复合相从而促进了MoO_3的硫化;(3)助剂CoO对负载在经TiO_2和Al_2O_3改性的MCM-41上的MoO_3的硫化起促进作用。     

4(R)-N-正-十八氨基-5(R)-(1R，2S，5R)-孟氧基-3，3-二氢呋喃-2-酮的合成研究

以糠醛为原料通过光氧化反应生成4-羟基丁烯内酯,再与薄荷醇缩醛化制得手性合成砌块5(R)-(1R,2S,5R)-孟氧基-2(5H)-呋喃酮(1),然后使1与正十八胺进行不对称Michael加成反应,在十分温和的条件下得到标题化合物4(R)-N-正-十八氨基-5(R)-(1R,2S,5R)-孟氧基-3,3-二氢呋喃-2-酮(2)。并通过元素分析,IR,~1HNMR,~(13)CNMR和MS对其进行了结构表征。     

介孔分子筛富集紫外可见法测定废水中重金属汞

以十六烷基三甲基溴化铵为模板,正硅酸乙酯为硅源,在碱性条件下通过水热法先合成MCM-41分子筛.利用介孔分子筛的吸附性能对微量汞进行富集盐酸解脱,考察了富集条件对富集效果的影响.结果表明,温度、pH值对介孔分子筛的富集效果影响最为明显,在温度为25℃、pH值为4.5时,富集效率可达90%以上.在吐温-80增溶条件下,汞与罗丹明B、溴化物发生显色反应形成络合物,建立了测定络合物的分光光度法.络合物的最大吸收峰为530 nm,表观摩尔吸光系数为5.42×105L/mol/cm.在50 mL溶液中,汞(Ⅱ)浓度在2.000×10-4～1.800×10-1mg/L范围内符合比尔定律,线性回归方程Y=2.736 9X-0.000 1,相关系数R=0.9996.该方法灵敏度高,选择性好.     

固载杂多酸的合成、表征及催化异丙醇脱水反应的活性

采用浸渍法制备负载型HPA／MCM－41催化剂，用FT－IR，XRD表征了催化剂的骨架和晶体结构及性能。负载后HPA的酸强度得到了提高，其Keggin结构仍然保持。适量的杂多酸对MCM－41的介孔性质无影响。不同载体与HPA之间的作用不相同。固载化HPA应用于异丙醇气相脱水反应，得到了与表征完全一致的结果。     

MCM-41中孔分子筛的全微波法合成及其表征

中孔分子筛的合成已进入了一个全新的时期,合成方法日新月异。本文首次在不需任何助表面活性剂的条件下,用全微波的合成方法（即ＭＣＭ－４１的合成和模板剂的烧除均在微波辐射的条件下完成）合成了ＭＣＭ－４１中孔分子筛,并应用ＸＲＤ、ＩＲ、ＴＧ和ＳＥＭ等方法对样品进行了表征。结果显示,此法比以往常规水热合成法具有合成时间短,晶化时间１０－１５ｍｉｎ,焙烧模板剂１ｈ左右。所得产品晶粒分布均匀,晶形以球状为主,晶粒大小约１０μｍ等优点。全微波合成法工艺简单,操作方便,产品收得率高,它将为ＭＣＭ－４１中孔子筛的快速合成探索出新的途径     

MCM-41分子筛负载磷钨酸催化H2O2氧化环已酮/环已醇合成己二酸

在无溶剂、无相转移催化剂条件下,用磷钨酸做为催化剂。先用MCM-41分子筛作为催化剂载体,30%H2O2作氧源,在一定条件下可以将环已醇/环己酮混合物氧化成己二酸。讨论了30%H2O2的量、反应时间、反应温度、催化剂用量、草酸对己二酸产量的影响,以及催化剂回收重复利用。结果表明：用MCM-41分子筛负载80%的磷钨酸作催化剂反应7h,己二酸的最大产率高达89.17%。具有很好的应用价值。     

介孔分子筛MCM-41的合成及其合成机理研究

文章综述了国内外对介孔分子筛MCM-41合成的最新研究，以及合成机理研究的新进展，包括液晶模板机理、协同作用机理和电荷匹配机理．     

四进制以及数制转换的研究

单转换猜想:设二种数制N1、N2的基数分别为R1、R2,i为大于等于2的整数,如果R1=Ri2,则这两种进制之间存在着比较简单的转换关系;N进制的最大数码为(N-1),那么,加法猜想:(N-1) (N-1)是一个二位数,其高位为1,低位为(N-2);乘法猜想:(N-1)*(N-1)是一个二位数,其高位为(N-2),低位为1。     

Effects of method and format on subjects' responses to a control of variables reasoning problem

Excessive time and training demands have rendered Piaget's clinical method of reasoning assessment impractical for researchers and science teachers who work with large numbers of students. The published literature

1 See: Lawson, A. E. Journal of Research in Science Teaching, 1978, 15 (1), 11-24; Shayer, M., Adey, P., & Wylam, H. Journal of Research in Science Teaching, 1981, 18 (2), 157-168; Staver, J. R., & Gabel, D. L. Journal of Research in Science Teaching, 1979, 16 (6), 534-544; Tobin, K. G., & Capie, W. Educational and Psychological Measurement, 1981, 41 (2), 413-424.

indicates that reliable, valid alternatives to clinical assessment are feasible. However, the overestimate/underestimate of reasoning for different methods and formats remains unresolved through research. The objective of this study was to determine the effects of various methods and formats on subjects' responses to a Piagetian reasoning problem requiring control of variables. The task chosen for this investigation was the Mealworm problem.

2 See: Karplus, R., Lawson, A., Wollman, W., Appel, M., Bernoff, R., Howe, A., Rusch, J., & Sullivan, F. Science teaching and the development of reasoning. Berkeley, CA: University of California, 1977.

The task was presented by three methods: (1) individual clinical interview; (2) group presentation of task followed by paper-and-pencil problem with illustration; and (3) group administration of paper-and-pencil instrument with illustration. Each method included four formats: (1) completion answer with essay justification; (2) completion answer with multiplechoice justification; (3) multiple-choice answer with essay justification; and (4) multiple-choice answer with multiple-choice justification. Two hundred and fifty-three (253) students who were enrolled in a freshman level biological science class participated in the study. The research design was a 3 × 4 factorial design with method and format of assessment as the main effects. The participants were in 12 randomly selected laboratory or discussion sections, and each section was randomly assigned to a cell in the research design. Regression analysis with the individual as the unit of analysis showed that format but not method of assessment accounted for a significant amount of variance in student performance. The overall interaction was nonsignificant. Regression analysis with sections as the unit of analysis revealed nonsignificant findings for both method and format. The interrater agreement in the scoring of the Mealworm task was 82.1%. The principal conclusion is that format but not method of task administration influenced the performance of subjects, and the influence is similar for various combinations of method and format. Discussion is focused on the relative importance of the nonsignificant and significant findings for using alternative methods of Piagetian assessment. The results are also discussed with respect to earlier work, and suggestions for future research as well as implications for teachers are set forth.