Influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite

Natural zeolite was first acid treated and then heat treated. The influences of acid and heat treatments on the structure and water vapor adsorption property of natural zeolite were investigated. X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), thermogravimetric analysis (TG), and Brunauer‐Emmett‐Teller (BET) surface areas were employed to investigate the structure changes of the zeolite samples. Water vapor adsorption property of the samples was investigated in order to determine wettability of the samples. The results showed that nitric acid treatment could remove Al from the structure, decrease relative crystallinity, and significantly increase specific surface area of the zeolite samples. Heat treatment could change or even destroy the structure, effectively remove water molecules from the surface/structure, and decrease the specific surface area of the zeolite samples. Water vapor adsorptions on the acid‐treated zeolite samples were significantly lower than that for the zeolite sample, and the adsorptions further reduced for the heat‐treated zeolite samples. The increase of Si/Al ratio, decreases of silanol groups, and specific surface area of the samples were major reasons related to the reductions of water vapor adsorptions on the zeolite samples.     

液-液萃取气相色谱法测定地表水中痕量苯酚

建立了液-液萃取气相色谱法测定地表水中痕量苯酚的方法。用盐酸调节水样至pH2左右,以二氯乙烷-乙酸乙酯(体积比为2∶1)混合溶液为萃取剂,以CD-5色谱柱进行分离,氢火焰离子化检测器检测苯酚的含量。苯酚的质量浓度在1.00~20.0μg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r=0.999 3,检出限为0.03μg/L。样品加标回收率为93.0%~97.0%,测定结果的相对标准偏差小于2%(n=7)。该方法检出限低,精密度和准确度高,操作简便,适用于地表水中微量苯酚的分析。     

表面富锡MCM-41分子筛的表面金属有机化学制备及其对苯酚羟基化催化反应性能研究

采用SnBu₄在MCM-41表面的接枝反应和后续处理制备出了一种只在表面含锡的MCM-41型介孔分子筛。通过与采用纳米SnO₂和MCM-41机械混合法、SnCl₄浸渍法、水热合成法等制备的具有相当硅锡比(Si/Sn≈100)的SnMCM-41分子筛进行结构和对苯酚羟基化反应催化性能的比较发现， 由该法所得分子筛的水热稳定性明显提高，并在苯酚羟基化反应中表现出优良的催化活性、选择性和过氧化氢利用率。本文还详细考察了该催化剂对苯酚羟基化反应的最佳反应条件。     

Nanocluster polyoxomolybdate supported on natural zeolite: a green and recyclable catalyst for epoxidation of alkenes

A heterogeneous catalyst for epoxidation of alkenes has been synthesized by introducing polyoxomolybdate into a natural zeolite as a solid and green support. The prepared catalyst was characterized by FT-IR, inductively coupled plasma optical emission spectrometry (ICP-OES), powder X-ray diffraction (XRD), N₂ absorption–desorption, field emission scanning electron micrograph (FE-SEM) and transmission electron microscopy (TEM). The catalytic investigations disclosed that nanocluster polyoxomolybdate supported on the surface is an active and recyclable catalyst in liquid phase alkene epoxidation in dichloroethane at 80 °C.     

腰果基表面活性剂的合成与表面性质

以腰果酚为起始原料,合成了中间体腰果酚聚氧乙烯醚（CPE）,进而在NaOH的催化作用下,由CPE和氯乙酸合成了系列腰果酚聚氧乙烯醚羧酸盐（CPEC）。 采用红外光谱和元素分析技术对产物的结构进行了表征,用表面张力法研究了CPEC的表面性能。 结果表明,该表面活性剂水溶液的临界胶束浓度(CMC）为9.30、8.50、8.10和7.71 mmol/L,相应的临界表面张力为28.38、28.60、30.40和30.00 mN/m。 根据Gibbs公式得出表面活性剂在溶液表面的最大吸附量为0.7087、0.7350、0.7195和0.7346 μmol/m²,表面活性剂的最小分子截面积为2.3439、2.2600、2.3087和2.2613 nm²。     

Evaluation of energy distribution on a heterogeneous surface from heat of adsorption and its application to the ammonia/Na-Y zeolite system

The— function (energy level function) which represents surface heterogeneity was derived from theq— function (experimental heat function) in the case of reversible adsorption. The Langmuir equation was extended and applied to the procedure of calculations. An iterative calculation led to the most probable— function by setting theq— function and adsorption temperature. As an example for actual cases, the— function of Na-Y zeolite was calculated from theq— function obtained by the measurement of heats of adsorption of ammonia at 373 K. The— function thus derived seemed to be consistent with the positional distribution of sodium ions.     

Adsorption properties of low-silica zeolite ZK-5

Water vapor, methanol, and argon adsorption isotherms, as well as the heat of adsorption of ammonia, methanol, and carbon dioxide have been determined on zeolite types A, ZK-4, and ZK-5. The results are explained by the distribution and the bond lengths of cations in the zeolite crystal lattice. It was shown that the exchange of 10–15% of the Na⁺ ions with Li⁺ in zeolite ZK-5 leads to a deformation of the 8-membered ring impeding the diffusion of adsorbed molecules. Cations contained in the 8-membered ZK-5 zeolite ring are bound more strongly to the framework, than in zeolite NaA, resulting in their smaller adsorption capacity.I. V. Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, 199164 St. Petersburg, Russia. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2494–2500, November, 1992.     

杂原子钛对TiY分子筛性能的影响

采用水热晶化法合成了含骨架杂原子的TiY分子筛,通过X射线粉末衍射（XRD）、傅里叶变换红外光谱(FT-IR)、差示扫描量热、吡啶吸附红外光谱等方法考察了杂原子Ti进入Y分子筛骨架后对分子筛各项性能的影响。结果表明,TiY分子筛具有典型的Y型分子筛晶体结构;随着Ti添加量的增加,TiY分子筛晶化所需的时间延长,晶胞常数增大,分子筛的热稳定性和水热稳定性均有所增强。与Y分子筛相比, TiY分子筛的L酸中心数量明显增加,同时B酸中心强度增加,TiY分子筛的裂化反应活性提高,催化剂上的积炭量明显减少。     

丽水市地表水体铅污染的控制对策与成效

通过多点的普监和连续的定点跟踪监测,明确了丽水市地表水体铅污染的基本状况和主要污染源,提出了相应的对策措施,取得了显著的控制成效,为区域水环境治理提供了参考依据.     

A general synthetic method for the formation of arylaminotetrazoles using natural natrolite zeolite as a new and reusable heterogeneous catalyst

An efficient method for preparation of arylaminotetrazoles is reported using natrolite zeolite as a natural catalyst. Generally, isomer of 5-arylamino-1H-tetrazole can be obtained from arylcyanamides carrying electron-withdrawing substituent on aryl ring and as the electropositivity of substituent is increased, the product is shifted toward the isomer of 1-aryl-5-amino-1H-tetrazole. This method has the advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields.     

铜配合物在Y型分子筛超笼中的组装及其催化苯酚羟化活性

 详尽介绍了通过分步法，在Y型分子筛超笼中制备铜（II）- 1，10菲咯啉和8-羟基喹啉配合物（简称CuPhen/Y，CuOx/Y）的过程；活性评价结果显示同Cu/Y相比，以H2O2为氧化剂，CuPhen/Y，CuOx/Y具有特殊的催化苯酚羟化功能。     

Changes in the acidic properties of the zeolite H-ZSM-11 under the influence of hydrogen and water

The nature of the effect of hydrogen and water on the spectrum of acidity of H-ZSM-11 zeolite has been studied. An explanation of the observed changes is proposed and a prognosis has been made on the relative effect of transformation of the functional groups of the surface on the catalytic properties of H-ZSM-11 in various reactions of acid type. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 4, pp. 258–261, July–August, 2006.     

表面金属有机化学:SnMe4在HY沸石超笼表面的接枝反应

研究了高真空条件下SnMe4在HY沸石超笼的接枝反应,并用元素分析,ICP, GC, XRD, FTIR, DTG, DTA, UV-vis, DRS, N2吸附等方法对产物的组成、结构和性质进行了详细表征.研究结果表明,两者可以定量地、有选择性地进行化学反应,将确定数目的三甲基锡基团接枝在沸石的超笼中.反应可以在非常低的温度下快速进行,表观活化能为10.4 kJ·mol-1.经SnMe4改性后的HY沸石分子筛BET比表面积降低,孔体积变小,对不同尺寸的烃分子表现出明显的吸附择形性.     

Application of the thermal frequency response method and of pulsed field gradient NMR to study water diffusion in zeolite NaX

The thermal frequency response and pulsed field gradient NMR methods are applied in a comparative study of water diffusion in zeolite NaX under non-equilibrium and equilibrium conditions. The obtained results are found to be in satisfactory agreement with each other, indicating that by applying the thermal frequency response method, complications due to uncontrolled water adsorption at the chamber walls inherent in conventional frequency response measurements may be circumvented.     

NiMo/Al_2O_3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel

Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)activities of fluid catalytic cracking(FCC)diesel.They were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and HRTEM.The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y.The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed.The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite.     

Basic zeolite and zeolite-type catalysts for the oxidative methylation of toluene with methane

The oxidative methylation of toluene with methane is used as a test reaction for determining the activity, selectivity and yield of C₈ hydrocarbons (ethylbenzene and styrene) over different zeolite and zeolite-type catalysts, viz., X, Y, mordenite, ZSM-5, silicalite and AlPO₄-5. Selectivity and basicity increase with decreasing Si/Al atomic ratio within the series of the same structural type. The basicity, surface structure and structural integrity are characterized by TPD of CO₂, XPS and IRS, respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effects of natural zeolite and silane coupling agents on melting and crystallization behaviour of polypropylene

The thermal characterization of polypropylene (PP) composites containing untreated and treated zeolite with different silane coupling agents was carried out using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) to investigate the effects of natural zeolite and surface modifiers on melting, crystallization and degradation behaviour of PP. 3-aminopropyltriethoxysilane (AMPTES), methyltriethoxysilane (MTES) and 3-mercaptopropyltrimethoxysilane (MPTMS) were used as surface modifiers at four different concentrations (0.5–2.0 mass%). Thermal analyses indicated that silane treatment and 2–6 mass% zeolite addition have no significant effect on the melting and degradation temperatures of the composites. The crystallization temperatures of the composites were increased due to the nucleating effect of the zeolite. The influence of the modifiers on the interactions between PP and zeolite was determined by the activities of untreated and treated zeolite. The maximum interactions leading to good adhesion were observed in the AMPTES treated composites. Also, non-isothermal crystallization kinetics of the composites was analyzed using Avrami and Kissinger models.     

Hydrogen production by conversion of methane over nickel-supported USY-type zeolite catalysts

Hydrogen production by conversion of methane over Ni-supported zeolite catalysts was investigated, and Ni-supported USY-type zeolite (Si/Al₂ = 14.0, 360) was found to have longer catalytic lifetime than Ni-supported silica (Cab-O-Sil) catalyst, which had been reported to have the longest catalytic lifetime for this reaction.     

Study of the grafting reaction of SnMe4 on the surface of ZSM‐5 zeolite

The grafting reaction of tetramethyltin on the surface of ZSM‐5 zeolite (Si:Al = 55.0) was studied under vacuum conditions, and the chemical compositions, structure and properties of the resulting solid were characterized by in situ FTIR, ICP, XRD, XPS, UV–vis DRS, temperature programmed decomposition (TPD) and N₂ adsorption. The results show that the reaction occurs on the surface of ZSM‐5 zeolite at 223 K without destroying the zeolite framework. The BET surface area and the pore volume of the zeolite decrease and the surface properties change; however, the microporous structure is retained during the reaction and post treatment. Copyright © 2006 John Wiley & Sons, Ltd.     

析氧反应铁镍基预催化剂的表界面调控与进展

析氧反应（OER）是水分解中重要的半反应, 为提高其催化性能,开发高效非贵金属催化剂已成为当前的研究重点。铁镍（FeNi）基材料被认为是最好的预催化剂, 在催化过程中,它们的表面将转变成高价态金属氧化物或氢氧化物作为真正的活性物质。FeNi基预催化剂的结构和形貌在很大程度上影响了其催化性能, 因此, 优化和调整FeNi基预催化剂的结构和化学环境可以提高电催化性能。基于我们的研究工作, 我们撰写了FeNi基预催化剂的表面结构调控促进电化学析氧反应的研究进展。我们首先介绍了碱性OER的反应机理, 然后从杂原子掺杂、表面成分改性、选择性结构转变、表面化学状态调节、异质结构构建和载体效应等方面讨论了FeNi基预催化剂表面调控对析氧反应性能的影响。尽管在OER反应中FeNi都被认为转变成高价态的金属活性物质, Fe/Ni体系的表面结构、形貌和化学状态仍然能够显著影响其最终的催化性能, 即FeNi基预催化剂的性质会影响析氧反应的催化性能。通过精细设计并尽量提高Fe和Ni的协同作用将有利用提升氧析出的催化性能。我们希望本综述能够对FeNi基预催化剂的制备和表界面性质调控与电催化析氧反应性能的理解有所帮助。