Microstructural optimization of a zeolite membrane for organic vapor separation

A seeded growth method for the fabrication of high-permeance, high-separation-factor zeolite (siliceous ZSM-5, [Si96O192]-MFI) membranes is reported. The method consists of growing the crystals of an oriented seed layer to a well-intergrown film by avoiding events that lead to a loss of preferred orientation, such as twin overgrowths and random nucleation. Organic polycations are used as zeolite crystal shape modifiers to enhance relative growth rates along the desirable out-of-plane direction. The polycrystalline films are thin (approximately 1 micrometer) with single grains extending along the film thickness and with large in-plane grain size (approximately 1 micrometer). The preferred orientation is such that straight channels with an open diameter of approximately 5.5 angstroms run down the membrane thickness. Comparison with previously reported membranes shows that these microstructurally optimized films have superior performance for the separation of organic mixtures with components that have small differences in size and shape, such as xylene isomers.     

Dispersible exfoliated zeolite nanosheets and their application as a selective membrane

Thin zeolite films are attractive for a wide range of applications, including molecular sieve membranes, catalytic membrane reactors, permeation barriers, and low-dielectric-constant materials. Synthesis of thin zeolite films using high-aspect-ratio zeolite nanosheets is desirable because of the packing and processing advantages of the nanosheets over isotropic zeolite nanoparticles. Attempts to obtain a dispersed suspension of zeolite nanosheets via exfoliation of their lamellar precursors have been hampered because of their structure deterioration and morphological damage (fragmentation, curling, and aggregation). We demonstrated the synthesis and structure determination of highly crystalline nanosheets of zeolite frameworks MWW and MFI. The purity and morphological integrity of these nanosheets allow them to pack well on porous supports, facilitating the fabrication of molecular sieve membranes.     

沸石培养基对大羽藓(Thuidium cymbifolium)配子体生长的影响

以大羽藓(Thuidium cymbifolium)的配子体为试验材料进行组织培养,通过观察外观变化并定期记录其一级分枝长度、一级分枝个数等指标,研究了沸石培养基对大羽藓配子体生长的影响。结果表明: 02%NaClO消毒60 s效果最好,以沸石为培养基7 d后污染率、死亡率均为0,存活率100%;沸石培养基促进大羽藓配子体的生长受沸石浓度、培养基pH值、琼脂浓度、蔗糖浓度的影响。沸石培养基促进大羽藓配子体生长的最适条件是: 沸石浓度20%、培养基pH值75、琼脂浓度10%。在此条件下,大羽藓30 d后一级分枝长度为344 cm、一级分枝数量达270个。     

农业增长方式转变与农业投资问题研究

论述了农业投资在推动农业增长方式的转变中的特殊地位和作用，以及农业投资规模，数量，结构和方向等对农业持续稳定增长的影响，并在此基础提出应确立有效的农业投资机制和正确的农业投资方向，对投资机制的确立和投资方向的调整提出了操作性较强的对策措施。     

改性沸石净化水中氮磷的研究进展

介绍了改性沸石在水处理领域中应用研究的现状,总结了天然沸石的改性方法、改性沸石对废水中的氨氮和磷的处理性能以及存在的问题,展望了改性沸石在废水处理尤其是微污染水源水处理中的应用前景。     

硫酸改性沸石中主要交换性阳离子动态变化研究

近年来天然沸石在农业中得到了广泛的应用.利用硫酸对天然沸石进行活化试验,通过对其1年的动态监测,分析沸石中对植物生长有重要影响的交换性K+、Ca2+、Mg2+、Na+以及阳离子交换量动态变化,以得到硫酸和沸石反应后各养分的动态变化,为改性后沸石生产农作物矿物肥提供理论依据.     

政府主导下环境导向型农业技术扩散研究

环境导向型技术扩散的原动力来自于政府推动和农户对利润的追逐,技术扩散的难点在农村基层组织（乡村）中农户采纳。将环境导向型技术在乡村的扩散分为示范和模仿两阶段,分析了不同阶段技术扩散的特点和规律,建立了政府主导的环境导向型技术基层组织扩散模型,并从政府扩散动力、中介桥梁、技术转换管理机制、扩散渠道和农民生态环境意识等方面提出了促进环境导向型技术的扩散的措施。     

沸石对犬生长和血液生化指标的影响

将18只5月龄左右中华田园犬随机分成3组,每组6只,分别饲喂在基础日粮中添加0％(对照组)、3％(试验组Ⅰ)、5％(试验组Ⅱ)沸石的饲料.研究不同添加量的沸石对犬生长及血液生化指标的影响.结果表明,3％的沸石添加量具有降低犬料肉比的趋势(P＞0.05);5％的沸石添加量具有提高犬平均日增重和降低犬料肉比的趋势(P＞0.05).3％和5％的沸石均能显著降低血清中尿素氮含量(P＜0.05),且具有提高血清中总蛋白含量和血清碱性磷酸酶活性的趋势(P＞0.05).     

不同土壤改良剂在皖南酸性红黄壤油菜上的效应

针对皖南红黄壤酸且瘠的特点,采用田间试验方法,以油菜为试验作物研究了沸石、石灰、白云石单施以及配合施用对红黄壤的改良效果.结果表明:施用沸石、石灰和白云石均能够明显地促进油菜的生长发育,改善经济性状,显著地提高油菜产量.沸石、石灰、沸石+石灰和白云石处理分别比施用氮磷钾肥的对照增产19.5%、53.5%～209.7%、72.7%～229.3%和204.9%.说明了沸石、石灰和白云石单施及配合施用对皖南酸性红黄壤有很好的改良效果.     

Extra-large-pore zeolites with two-dimensional channels formed by 14 and 12 rings

Stable zeolites that have larger pore apertures and a three-dimensional pore topology are of interest because they could be used to adsorb larger molecules, particularly for application in oil refining. Several large-pore zeolitic materials with channels formed by openings of more than 12 rings are known, but all of them have a one-dimensional channel system that limits their use in catalysis. We report the synthesis and some characterizations of IM-12, a thermally stable germanium-containing zeolite that contains the first two-dimensional channel system with extra-large pores formed by 14- and 12-ring channels.     

改性沸石对氨氮去除效果与机理研究

[目的]研究改性沸石对废水中氨氮的去除效果及吸附机理。[方法]采用脱磷尿液作为试验废水,比较了不同改性沸石(NaCl沸石、HCl沸石、HCl-焙烧沸石和HCl-焙烧-微波沸石)对试验废水中氨氮的去除效果,并探讨了其吸附机理。[结果]在粒径为0.5～1.0 mm,投加量为200 g/L时,天然沸石和4种改性沸石对氨氮的平衡吸附量依次为天然沸石饱和NaCl改性沸石5.0%HCl改性沸石5.0%HCl-400℃焙烧改性沸石5.0%HCl-400℃焙烧-微波改性沸石。沸石扫描电镜影像和质量损失揭示吸附差异的主要原因是不同改性方法导致沸石孔隙大小和数量的差异。[结论]5.0%HCl-400℃焙烧-微波改性沸石对氨氮具有较高吸附能力,平衡吸附量为17.9 mg/g,是天然沸石的2.6倍。     

A cationic cesium continuum in zeolite x

A cesium continuum that fills the channels and cavities of zeolite X has been prepared, and its structure has been determined by single-crystal x-ray crystallography. The three-dimensional continuum is cationic to balance the negative charge of the zeolite framework. Its valence electrons, only 0.3 per Cs(+) ion, are widely delocalized over 95 percent of the cesium ions in the crystal. The continuum has a unit cell formula of (Cs(122))(86+) and contains Cs(13) and Cs(14) clusters (one per supercage) arranged like the atoms in diamond, with one Cs(2) appendix (in the sodalite cavity) per cluster.     

不同接种方法对发酵料栽培平菇的影响

[目的]筛选发酵料栽培平菇适宜的接种方法。[方法]用塑料袋栽培平菇,采用两端开放式接种、菌袋三道接种和菌料拌匀接种3种接种方法,在相同培养条件下,观察其菌丝生长情况和污染率。[结果]两端开放式接种栽培平菇,菌丝长势和子实体的形成都表现出较明显的优势,且污染率极低(7%)。菌料拌匀接种栽培平菇,菌丝生长情况明显比两端开放式接种差,而且污染率较高(21%);菌袋三道接种与两端开放式接种无明显差别。[结论]用塑料袋栽培平菇,两端开放式接种效果较好,菌丝生长快、长势好、周期短、污染率低。     

Vertical aluminophosphate molecular sieve crystals grown at inorganic-organic interfaces

Tubular aluminophosphate molecular sieve crystals were grown at an organic interface with their channels (7 angstroms in cross section) vertical to the substrate. To induce surface nucleation and oriented growth of AIPO(4)-5 crystals, organophosphonate layers cross-linked with Zr(IV) were assembled on a gold substrate and the modified substrate was immersed in a hydrothermal bath containing reagents for the synthesis of the molecular sieve. Reflection-absorption infrared studies demonstrated the stability of the phosphonate layers under these conditions. Drastic changes in the morphology of the surface-grown crystals from spherical agglomerates to vertical needles to thin tilted needles could be achieved by adjusting the water content of the synthesis bath. Nitrogen sorption in these structures on a piezoelectric device confirmed the presence of zeolitic microporosity.     

The Framework Topology of ZSM-18, a Novel Zeolite Containing Rings of Three (Si,Al)-O Species

ZSM-18 is the first known aluminosilicate zeolite to contain rings of three (Si,Al)-O species (3-rings). Its framework topology has been determined by hypothetical model building, subsequent constrained distance and angle least-squares refinements of atomic coordinates, and x-ray powder diffraction pattern simulations. Its channel structure is characterized by a linear unidimensional 12-ring channel, with an approximate pore opening of 7.0 angstroms. In addition, the channels are lined with pockets that are capped by 7-rings with dimensions of 2.8 angstroms by 3.5 angstroms. An intraframework packing model of the organic moiety used in the synthesis suggests that a strong templating effect may be responsible for the formation of this unusual zeolite structure.     

一类倒向随机微分方程解的Levi定理

在生成元g关于y连续、单调、一般增长,且关于z一致连续的条件下,用单调取极限的方法提出并证明了此类倒向随机微分方程解的Levi定理、Fatou定理、Lebesgue定理,推广了经典概率理论中的相应结论.     

Antibody-mediated bacteriorhodopsin orientation for molecular device architectures

A rational method for constructing highly oriented films of purple membrane (PM) has been established by using two kinds of bispecific antibodies with different antigen-binding sites, one binding to a specific side of bacteriorhodopsin and the other to a phospholipid hapten. A hapten monolayer deposited on a metal electrode was treated with a bispecific antibody solution and incubated with a PM suspension to produce a highly oriented PM film, as confirmed by electron microscopy in which an immunogold labeling technique was used. This antibody-mediated PM monolayer was then used in the construction of a light-sensing photoelectric device. A comparison of the two incorporated PM monolayers showed that highly efficient photocurrents were produced by the PM monolayer whose unidirectionally oriented cytoplasmic surface faces the electrode.     

Cu-Zn/ZSM-5催化剂催化湿式氧化H-酸

以萘系染料中间体中具有代表性的H-酸(1-氨基-8-萘酚-3,6-二磺酸,分子式为C10H9O7S2N)的水溶液为研究对象,分别采用以等体积浸渍法制备的不同负载量的Cu-Zn/ZSM-5催化剂、以共沉淀法制得的Cu-Zn-Al催化剂对H-酸水溶液进行湿空气催化氧化降解。研究结果表明:对于处理H-酸水溶液,Cu-Zn/ZSM-5系列催化剂的COD去除率更高,这主要是由于催化活性中心在分子筛上获得了更优的分散性;最佳的CuO负载量为3.41%,ZnO负载量为1.16%,此时H-酸COD去除率为88.18%。     

不同育秧基质对水稻秧苗素质的影响

为解决水稻机插秧育秧取土难的问题,对沸石、稻壳灰、珍珠岩、腐熟秸秆、营养土五种育秧基质对水稻机插秧苗素质的影响进行了研究。结果表明：沸石基质和稻壳灰基质培育的秧苗生长速率快,叶龄、株高适宜,叶绿素含量高,不定根数多,最长根长大,地上干重和根干重大,适合水稻机插秧的需要。沸石基质和稻壳灰基质是理想的育秧基质。     

Biomimetic Pathways for Assembling Inorganic Thin Films

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities.