含混合金属的羟基镍铝交联蒙托石的合成

用两种方法——取代法和共聚法合成了一系列羟基镍铝交联蒙托石(GNiAl-CLM和NiAl-CLM),首次利用两种方法,交联前和交联后高温老化处理,对交联蒙托石的热稳定性进行改进。结果表明:取代法合成的羟基镍铝交联蒙托石具有均一的(001)面衍射,底面间距d(001)值均为1.8nm左右,而共聚法合成的羟基镍铝交联蒙托石出现两个(001)面衍射,d(001)值分别为1.8nm和1.55nm;高温处理后,热稳定性得到明显改进,热稳定性可高达700℃以上。     

Synthesis and Property of H2La2Ti3O10/CdS Layered Nanocomposite Photocatalyst

H2La2Ti3O10/CdS nanocomposite with er photoactivity was synthesized by a stepwise exchange process from H2La2Ti3O10, which was obtained by H^＋ -exchanging reaction of H2La2Ti3O10 with HCl other than the normally used HNO3. The pillaring process was investigated by XRD, TEM, FT-IR and BET methods. The photocatalytic decomposition of aniline was used as the model system to evaluate the photochemical properties of H2La2Ti3O10/CdS,H2La2Ti3O10 and K2La2Ti3O10. It is found that the photoactivity of layered H2La2Ti3O10 is greatly improved by the intercalation of CdS in the interlayer. In general, the excellent photoactivity of the H2La2Ti3O10/CdS nanocomposite might be attributing to the extremely small particle size of incorporated CdS and good contact between CdS and La2Ti3O10^2- layers. On the other hand, the coupling of two semiconductor particles with different energy gap is useful to achieve effective charge separation. In H2La2Ti3O10/CdS, a photo-generated electron can transfer from CdS to the La2Ti3O10^2- layer, while the holes remain in the CdS particles. This helps to diffuse the electrons and holes before reaching the interface, and the holes and electrons can be effectively captured by the electrolyte in the solution. Simuhaneously, the optimal operating condition of photodecomposition aniline was investigated.     

Preparation and Properties of Pillared Montmorillonite by Polyhydroxyl-aluminum-manganese Cations

Al-Mn-pillared montmoriUonite ( AMPM ) was prepared by using the artificial Na-montmoril-lonite from the Qingfengshan bentonite mine as starting materials mixed with Al-Mn pillaring solutions at different Al / Mn molar ratios ( R ). The basal spacing and specific surface area of the materials were increased significantly compared with untreated c/ays. When R=0.5, the d(001) value and specific surface area of pillared montmoril-lonite were 1.8987 nm and 146.01 m^2 g^-1, respectively. The thermal stability was determined using calcined tests,X-ray diffraction( XRD ) analysis, thermal gravimetry and differential thermal analysis( TG- DTA ). The formed at initial R = 0. 5 exhibited a high stability, the basal interlayer spacing was stabilized at 1. 7859 nm after calcined for 2 h at 300℃. The adsorption behavior of the materials wets studied by adsorption experi-ments. The results show the AMPM and calcined AI-Mn-pilloTed montmoriUonite (CAMPM) exhibit a strong ca-pacity of adsorbing the Zn ( Ⅱ ) in aqueous solution at pH 10.0.     

Preparation and Microstructure of Al-pillared Interlayered Montmorillonite

Al-pillared interlayerad montmorillonite (Al-PILM) was prepared using the artifcial Na-mont-morillonite from the Qingfengshan betonite nime as a starting material mixed with Al-pillared solutions.The micorstructure of the materials was studied by an X-ray powder diffractometer and a Fourier transfomr infrared (FTIR) spectrometer,The results indicated that the basda spacing [d (001) value ] of the mateials was increased significantly to 1.9194 nm relative to Na-montmorillonite (1.2182 nm) ,After calcined for 2 h at 300 ℃ ,the significantly to 1.9194 nm relative to Na-montmorillonite (1.2182nm) ,After calcined for 2 h at 300℃,the basal spacing was stailized at 1.8394 nm and the layered structure of the materials not destroyed .Themal analysis was conduted by a thermal gravimetry and differential thermal analysis (TG-DTA) instrument,it showed that Al-PILM lost physically adsorbed water below 230.6℃ and water formed by dehydorxylation of the pillars at around 497.1℃,with a peak of the phase transformation at 903.0℃.     

Synthesis of metatungstate pillared layered double hydroxides with variable layer composition. Effect of the Mg:Al ratio on the microporous structure

A series of layered double hydroxides (LDHs) pillared with the Keggin ion H₂W₁₂O₄₀⁶⁻ has been synthesized with final Mg:Al ratios of 1.75:1, 2.31:1 and 3.51:1 by ion exchange reaction of the LDH-hydroxide and LDH-adipate precursors. In each case, the pillared product was characterized by specific BET N₂ surface areas of more than 110 m² g⁻¹ and micropore volumes in excess of 0.026 ml g⁻¹. The micropore size distribution plots obtained from the argon adsorption isotherms indicate that the micropore diameters become smaller as the surface charge density of the LDH increases. A study was also performed on each of the LDH precursors in order to determine any problematic steps in the overall synthesis. Significant differences were noticed in the POXRD patterns of the LDH-adipate precursor; these are believed to be due to differences in the orientation and degree of order of the adipate anions in the gallery space of the LDH. It was found that adipate anions orientated with the long axis perpendicular to the inorganic layers were easier to exchange than those where the long axis was aligned parallel to the inorganic layers.     

羟基铝-铬复合柱撑蒙脱石的制备与表征

以辽宁某地的钙基膨润土为原料，钠化改型后采用共聚法合成Al-Cr柱化剂，制备了羟基Al-Cr复合柱撑蒙脱石，并运用X－射线衍射分析（XRD）、化学分析、比表面积测定等手段研究了材料的微结构变化和特性。结果表明：n(Cr^3 ):(Al^3 )为0.10时,可得到层间距d(001)值与比表面积分别为1.9194nm和165.7m^2/g的产物,500℃煅烧后其层间距稳定在1.7313nm,具有较强的热稳定性;钠基膨润土经柱撑反应后,柱化剂主要以离子交换方式进入蒙脱石层间。     

介孔型硅柱撑蒙脱石的制备及表征

利用溶剂化作用,将辛胺和正硅酸四乙酯同时插层进入十六烷基三甲基有机阳离子型蒙脱石层间,在辛胺的碱性催化作用下,正硅酸四乙酯在蒙脱石层间原位水解得到硅酸及有机物混合插层蒙脱石.将此混合插层化合物在550℃煅烧后得到硅柱撑蒙脱石.用TG-DTA、XRD、TEM和N_2吸附-脱附等技术对所制备的硅柱撑蒙脱石进行了表征.结果表明:蒙脱石经硅柱撑后其比表面积由原始的80m~2/g增大到667m~2/g,孔容达到0.7413cm~3/g,具有介孔结构.     

层间模板剂导向合成新型多孔蒙脱石材料的研究

采用提纯后天然蒙脱石为原料,经十六烷基三甲基溴化铵和十八烷基三甲基氯化铵改性后,分别以C8～C14中性伯胺为结构导向剂,蒙脱石/胺/正硅酸乙酯摩尔比为1:20:150,搅拌反应时间为8h,经分离、干燥、焙烧,成功制备出新型多孔氧化硅/蒙脱石复合材料.用XRD、TG、FT-IR、N_2等温吸附-脱附和酸催化烷基化探针反应等表征了其结构和性能.结果表明,合成材料具有高比表面积、大层间通道、孔径分布较窄且依据模板导向剂分子尺寸可调,其酸催化活性和选择性较普通的酸活化蒙脱石有较大的提高.     

Polyhydroxyl-aluminum pillaring improved adsorption capacities of Pb^2＋ and Cd^2＋ onto diatomite

In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities （qe） of Pb^2＋ and Cd^2＋ was synthesized with the following conditions： Addition of pillaring solution containing Al3＋-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na＋-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2＋ and Cd^2＋ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.     

层状新型纳米复合功能材料研究进展

综述了新型层状功能材料的特点、研究现状及其制备方法，以及利用层间嵌入反应制备纳米复合材料的方法和应用。着重强调了超细层状材料的制备方法，层状材料的改性思路及最新研究热点，并对该类新型材料在光催化领域的研究和应用提出了一些展望。