不同硅铝比Y型沸石的稀土离子交换平衡

测定了4种不同硅铝比Y型沸石在303和333K下的N→Tb离子交换等温线,求得了热力学平衡常数,标准自由能、焓、熵三者的改变量以及沸石相中各组分的活度系数和超额自由能函数,研究了这些数值随硅铝比变化的规律。用双电层理论解释了所得的结果。     

高岭土原位晶化产品及全合成Y型沸石的稀土离子的交换平衡

本文测定了钠式高岭土原位晶化产品及全合成Ｙ型沸石与稀土离子铽Ｔｂ（Ⅲ）的离子交换等温线和平衡数据，采用了三种不同的热力学方法处理平衡数据，求得该离子交换反应Ｎｄ→Ｔｂ的选择系数、修正选择系数、热力学平衡常数以及标准自由能、热焓、熵的改变量。对这种离子交换剂的结果及三种热力学处理方法进行了对比及讨论。     

微波辐射下LaNaY沸石的水热交换反应

报道微波辐射应用于ＮａＹ沸石与Ｌａ（ＮＯ＿３）＿３溶液的离子交换反应,结果表明微波辐射可提高Ｌａ￣＋的交换度,缩短交换时间。     

Y型沸石和高岭土原位晶化产品的Tb／Tb同位素交换及NaTb,Tb／…

本文在前文＾［１］Ｙ型沸石和高岭土原位晶化产品上的Ｎａ／Ｔｂ离了交换平衡研究的基础上，进一步了这两种离了交换剂上Ｔｂ／Ｔｂ同位素交换及Ｎａ／Ｔｂ，Ｔｂ／Ｎａ正逆离子交换动力学，确定了反应机理，测得了铽的自扩散系数以及正逆交换的积分粒内互扩散系数。对这两种离交换剂所得结果进行了对比和讨论。     

沸石吸附钾离子的热力学研究

研究了沸石吸附钾离子的热力学行为,测定了不同温度下吸附等温线热力学性能的变化,对平衡常数及吸附热进行了计算.结果表明,Langmuir吸附等温式的曲线拟合能较好地描述不同温度下的实验数据,钾离子在K -Na 体系中的平衡常数与温度成负相关,△H为负值且较大,其吸附过程为自发的放热反应.     

钠改型天然斜发沸石对铵离子的交换性能

对分别来自国内三个产地和澳大利亚的沸石样品进行了铵离子交换性能的研究。在25℃下了样品的交换速率曲线。利用Verrmeulen's模型处理动力学数据，计算得到扩散系数，与文献报道的结果相一致，并发现不同样品的扩散系数与其致密程度相关。将粒度200mesh的沸石分别用三种不同方法聚集为颗粒，并测定了表观的扩散系数，均高于原颗粒的扩散系数，其中凝胶颗粒提高了一个数量级。     

蛋白质相互作用预测、设计与调控

蛋白质相互作用是生命活动在分子水平上的基本事件. 蛋白质相互作用的三维图像可以给出关键生命活动过程的分子细节. 了解蛋白质相互作用的原理有助于揭示生命活动的机制, 并在此基础上开展有重要价值的蛋白质设计. 本文对于蛋白质相互作用预测、设计和调控研究的近期进展进行了总结归纳, 介绍了作者实验室在相关领域的研究进展, 并对今后的研究方向进行了展望. 主要包括: (1) 蛋白质相互作用网络、蛋白质相互作用机制和蛋白质复合物结构计算分析; (2) 基于序列、结合位点以及复合物结构的蛋白质相互作用预测; (3)蛋白质相互作用设计方法; (4) 利用化学分子调控蛋白质相互作用的方法; (5) 针对蛋白质相互作用的蛋白质药物设计方法.     

钠改型天然斜发沸石的铵离子交换平衡

对分别来自国内三个产地和澳大利亚的天然斜发沸石样品进行了铵离子交换性能的研究,在25℃下测定了样品的总交换容量和平衡等温线,根据测定的平衡等温线,提出了表示沸石平衡情况的双孔道组合模型,并用文献报道的结果对模型进行检验,此模型不仅与实验结果较好地符合而且也适用于文献报道的结果。     

蛋白质相互作用的研究方法

生物体的生理功能主要由细胞中的蛋白质控制和调节。其中,多数蛋白质是通过与配体结合或是作为蛋白质复合物中的一部分参与细胞的代谢过程。因此,研究蛋白质间的相互作用是理解生命活动的基础。本文对现有蛋白质相互作用的研究方法和技术进行了评述。     

纳米颗粒与蛋白质分子的相互作用

纳米技术的快速发展和广泛应用前景,引起了人们对纳米生物效应和安全性问题的普遍关注。为保证纳米技术的健康持续发展,纳米颗粒与生物体的相互作用以及产生的生物学效应不容忽视。为充分了解纳米颗粒物产生的生物学效应,阐明纳米颗粒如何进入生物体以及与生物体相互作用的分子过程至关重要。在总结国内外相关研究的基础上,本文介绍了纳米颗粒进入机体的主要途径,并系统综述了纳米颗粒与蛋白质分子的相互作用及其表征方法,以及纳米颗粒与蛋白质相互作用对蛋白质结构功能和纳米颗粒生物效应的影响。     

NaA沸石离子交换过程的介电弛豫谱研究

在40 Hz~110 MHz频率段对不同Ca²⁺交换度的NaA沸石堆积体系进行了介电测量, 并利用Cole-Cole公式及Hanai方法对介电参数和相参数进行拟合与解析. 结果表明, 随着Ca²⁺交换度的不断增高, 堆积体系的介电增量、弛豫频率、弛豫分布系数以及粒子的电导率均有不同程度的降低, 而粒子的介电常数保持不变. 通过综合分析弛豫变化规律与离子交换度的内在联系发现, 离子交换后Ca²⁺选择六元环占位, 同时六元环和八元环位置的相邻2个Na⁺被置换; 占据六元环的Ca²⁺与八元环位置的Na⁺对沸石粒子的极化贡献等价; Ca²⁺的进入导致沸石孔道内微观电场多样化.     

Chromium uptake from tricomponent solution in zeolite fixed bed

Removal of Cr³⁺,Ca²⁺,Mg²⁺ and K⁺ in equilibrium isotherms and in tricomponent solutions (Cr/Ca/K, Cr/Ca/Mg and Cr/Mg/K) were investigated in NaX and NaY packed beds at 30^∘C. The equilibrium selectivity was obtained as Cr⁺³ > Mg²⁺ > Ca²⁺≈K⁺ for zeolite NaY and Ca^{2 +}≫Cr^{3 +} > Mg^{2 +}≈K⁺ for zeolite NaX. The breakthrough curves showed sequential ion exchange where chromium ions are able to replace the competing cations. Some mass transfer parameters, such as length of unused bed and overall mass transfer coefficient, were investigated. Chromium retention was also investigated through a mass balance. Based on the breakthrough results, it was concluded that chromium-uptake mechanism was hardly influenced by the competition and interaction between the entering ions. NaY showed a higher affinity towards Cr³⁺ for both equilibrium and dynamic systems and its sites were more efficiently used in the ion exchange process. Chromium was less retained in NaX due to the high selectivity towards calcium ions.     

Protein adsorption and transport in dextran-modified ion-exchange media. I: Adsorption

Adsorption behavior is compared on a traditional agarose-based ion-exchange resin and on two dextran-modified resins, using three proteins to examine the effect of protein size. The latter resins typically exhibit higher static capacities at low ionic strengths and electron microscopy provides direct visual evidence supporting the view that the higher static capacities are due to the larger available binding volume afforded by the dextran. However, isocratic retention experiments reveal that the larger proteins can be almost completely excluded from the dextran layer at high ionic strengths, potentially leading to significant losses in static capacity at relevant column loading conditions. Knowledge of resin and protein properties is used to estimate physical limits on the static capacities of the resins in order to provide a meaningful interpretation of the observed static capacities. Results of such estimates are consistent with the expectation that available surface area is limiting for traditional resins. In dextran-modified media, however, the volume of the dextran layer appears to limit adsorption when the protein charge is low relative to the resin charge, but the protein–resin electroneutrality may be limiting when the protein charge is relatively high. Such analyses may prove useful for semiquantitative prediction of maximum static capacities and selection of operating conditions when combined with protein transport information.     

银离子交换分子筛的一氧化氮吸附性能

银离子交换分子筛上一氧化氮的吸附性能张文祥贾明君于剑锋吴通好（吉林大学化学系,长春１３００２３）八寻秀典岩本正和（北海道大学触媒研究中心,日本札幌０６０）关键词银,离子交换,分子筛,一氧化氮,吸附态分类号Ｏ６４７／Ｘ５氮氧化合物（ＮＯｘ）是酸雨和空...     

The effect of acidity behaviour of Y zeolites on the catalytic degradation of polyethylene

Thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses were used to investigate the effect of the acidity behaviour of Y zeolites on the catalytic degradation of polyethylene (PE). The acidity behaviour of these zeolites was modified by ion exchange treatments. Two Y zeolites with similar Si/Al atomic ratios were subjected to an ion exchange treatment using NaNO₃ for H-form (HY) and NH₄NO₃ for Na-form (NaY). The activity and the deactivation behaviour of the Y zeolites were determined in the samples by TGA measurements, using a polymer/catalyst ratio of 9:1. The sample residues obtained after an isothermic TGA, were analysed by DSC, in order to evaluate the crystallinity of each mixture. The HY zeolite, which has the strongest acidity, reduced the onset temperature resulting in more rapid degradation of the polymer. It is shown that the ion exchange treatment over Y zeolites enhances the selective catalytic degradation of polymer in detriment of the rapid deactivation.     

具有抗生物污染活性的分子筛膜用于高效油水分离

The development of the global economy has been accompanied by frequent oil spills caused by accidental leaks and industrial manufacturing, which have seriously threatened the aquatic environment and human health. Traditional methods for the treatment of oily wastewater include centrifugation, skimming, flotation, oil-absorbing technology, etc., which are limited by low separation efficiency as well as secondary pollution during the post-processing of oil absorption materials. Recently, separation technologies utilizing the special wettabilities of filtration membranes have been developed to enrich and recycle oils from wastewater. Among these, the fabrication of superhydrophilic/underwater superhydrophobic membranes have attracted intensive research interest, which can selectively allow the passage of water through the membrane while blocking the oils. However, microorganisms are more likely to breed on these hydrophilic surfaces, eventually leading to the blockage of the membranes. In this study, ZSM-5 zeolite crystals (MFI topological structure) were coated onto the stainless-steel meshes by means of seeding and secondary hydrothermal growth. Then, 70% of the total Na⁺ ions in the zeolite channels were substituted by Ag⁺ ions via an ion exchange process. The resultant membranes (Ag@ZCMFs) were superamphiphilic in air, with both water contact angle and oil contact angle of approximately 0°. However, they became superoleophobic when immersed in water, and the underwater oil contact angle reached 151.27° ± 4.34°. In terms of special wettability, Ag@ZCMF achieved efficient separation for various oil-water mixtures with separation efficiencies above 99%. The water flux and intrusion pressure of Ag@ZCMF depended on the diameter of pinholes in the membrane, which could be modulated by altering the time of secondary hydrothermal growth. For instance, the average diameter of pinholes in Ag@ZCMF with optimum secondary growth time of 14 h (Ag@ZCMF-14) reached approximately 21 μm, giving rise to the water flux and intrusion pressure of 54720 L·m^-2·h^-1 and 4357 Pa, respectively. The anti-corrosion test and rubbing test confirmed the high chemical and mechanical stability of Ag@ZCMF-14, respectively. The separation efficiency of Ag@ZCMF-14 remained stable during ten purification-regeneration cycles, and no obvious attenuation was observed, proving the high separation stability of Ag@ZCMF-14. Furthermore, the loaded Ag⁺ ions afforded the membrane excellent anti-biofouling activity, which could effectively inhibit the growth of both alga and bacteria in the operating environment, thus preventing membrane blockage during the oil-water separation process. In particular, the bacteriostatic rate of Ag@ZCMF-14 to Escherichia coli reached to 99.6%. These results demonstrate that Ag@ZCMFs with anti-biofouling activity has promising potential future applications in the removal of oil slicks from oily wastewater.     

Properties and performance of novel high-resolution/high-permeability ion-exchange media for protein chromatography

There is continued interest in the development of stationary phases for protein chromatography that can provide high resolution at elevated flow rates of the mobile phase. When using porous particles, resolution and dynamic binding capacity decline rapidly as the flow rate is increased. Monolithic columns have been developed to overcome these limitations. However, there are difficulties in manufacturing homogeneous larger scale monoliths. In this paper we investigate the morphology and performance characteristics of columns based on new ion exchangers obtained by mechanically disrupting continuous beds of acrylamido-based polymeric media. Near colloidal suspensions of loose particles obtained with this procedure can be flow-packed in ordinary chromatography columns resulting in beds of unexpectedly high hydraulic permeability. Columns up to 2.2 cm in diameter were studied with both Q and S functionalized media. The hydraulic permeability and interparticle porosity of these columns were rather high. The permeabilities of the S and Q media were 1.5 x 10(-13) and 2.4 x 10(-13) m2, respectively, while the corresponding porosities were 60 and 70%. These porosity values are similar to those of monoliths, suggesting that these particles assemble under flow to give high-porosity bridged structures. The structure of these packed beds was further characterized by embedding small packed columns in resins and obtaining sections for microscopic observation. The sections reveal the presence of small aggregates of non-porous 1-3 microm particles, surrounded by flow channels several micrometers in size. The height equivalent to a theoretical plate under isocratic and gradient elution conditions and the dynamic binding capacity were determined for several proteins and were found to be virtually independent of flow.     

Protein adsorption and transport in agarose and dextran-grafted agarose media for ion exchange chromatography: Effect of ionic strength and protein characteristics

This work investigates the effects of ionic strength and protein characteristics on adsorption and transport of lysozyme, BSA, and IgG in agarose-based cation exchangers with short ligand chemistry and with charged dextran grafts. In all cases, the adsorption equilibrium capacity decreased with increasing salt. However, the adsorption kinetics was strongly influenced by the adsorbent structure and protein characteristics. For the smaller and positively charged lysozyme, the effective pore diffusivity was only weakly dependent on salt for the dextran-free media, but declined sharply with salt for the dextran-grafted materials. For this protein, the dextran grafts enhanced the adsorption kinetics at low salt, but the enhancement vanished at higher salt concentrations. For BSA, which was near its isoelectric point for the experimental conditions studied, the effective diffusivity was low for all materials and almost independent of salt. Finally, for the larger and positively charged IgG, the effective diffusivity varied with salt, reaching an apparent maximum at intermediate concentrations for both dextran-free and dextran-grafted media with the kinetics substantially enhanced by the dextran grafts for these conditions. Microscopic observations of the particles during protein adsorption at low ionic strengths showed transient patterns characterized by sharp adsorption fronts for all materials. A theory taking into account surface or adsorbed phase diffusion with electrostatic coupling of diffusion fluxes is introduced to explain the mechanism for the enhanced adsorption kinetics observed for the positively charged proteins.