吸附介质结构参数对变压吸附性能的影响

通过对我们自行研制的产氧量为Q＝1－5L／min的双吸附柱的小型PSA分离空气制氧系统进行的吸附过程计算，分析了空气流经PSA多孔吸附介质填充床层时，多孔介质结构参数及操作参数对吸附性能的影响。结果表明：1.渗透率随介质颗粒直径的增大而增大，并且随颗粒直径的增加，其对渗透率的影响增加。而压降随多孔吸附介质颗粒直径的增大而减小。2.渗透率与空隙率基本成正抛物线关系，压降随空隙率的增大而减小。3.压降随着渗透率的增大而减小。4.在不同的毛细管截面形状条件下，空隙率和渗透率的影响较小，而颗粒直径对渗透率的影响较大，颗粒直径较大时，这种影响才比较明显，当吸附介质颗粒直径或空隙率一定时，细长条截面的填充方式具有最高的渗透率。5.对于较低流速范围（约＜0.1m/s），流速对压降的影响较小，否则，影响较大。     

适用于氢气和甲烷氢同位素测试的干燥剂性能研究

气体中的水蒸气会影响氢同位素比值的测试结果。为满足氢气和甲烷氢同位素测试的需要,筛选出合适的高效干燥剂,采用静态容量法和真空静态重量法分别测试了几种常用干燥剂对氢气、甲烷和低分压水蒸气的吸附性能。结果表明,CaCl₂具有较高的低分压水蒸气吸附量和较低的氢气、甲烷吸附量,水蒸气吸附速率较快,适用于氢气和甲烷氢同位素测试的除湿处理。     

胺基接枝介孔材料MCM-41对低放废水的净化处理研究

将合成的胺基接枝改性的介孔材料MCM-41用于吸附处理模拟低放废水中低浓度的Mn2＋和Co2＋,研究吸附时间和pH值对吸附容量的影响,相比三种吸附等温线模型对实验数据的拟合性能,结果表明,该吸附剂对低浓度金属离子的吸附足Sips等温线模型。吸附剂对Mn2＋和Co2＋的最大吸附容量分别为0．377mmol／g和0．384mmol／g。竞争吸附实验表明,吸附剂对Co2＋结合能力要大于Mn2＋。固定填充床的动态吸附实验表明,动态条件下的吸附容量小于静态条件。     

离子交换纤维除氯的动态试验的研究

比较静态交换与动态交换试验结果,发现在动态交换过程中,交换柱内纤维的利用率极低,吸附效率不到30%。通过模拟溶液在交换柱内扩散、吸附过程,得出由于交换柱内的纤维填充不均匀产生空隙,造成氯化钠溶液选择性流过交换柱从而降低了吸附效率。采用去离子水充满交换柱,然后用氯化钠溶液逐渐替换的方法,可以大大提高纤维利用率。     

非阻塞性微颗粒阻尼柱阻尼特性的实验研究

摘要：针对三个非阻塞性微颗粒阻尼空心柱,分别采用铁粉、铅粉和砂粒作为填充颗粒,通过自由振动实验,研究颗粒填充率、质量比、空腔结构形式、颗粒材料类型等因素对构件阻尼特性的影响,探索构件的合理空腔结构形式。实验结果表明：颗粒填充率和质量比是柱阻尼的显著影响因素,设计颗粒阻尼柱时选取合适的质量比或填充率可以获得最大程度的阻尼增大效果。另外,多空腔结构形式、多空腔填充颗粒方案以及选用合理的颗粒材料类型均有助于柱阻尼的提高。不管采用金属颗粒还是非金属颗粒,颗粒质量比宜控制在0.3~0.5的范围。当颗粒用量不大时,选用铅粉、铁粉等金属颗粒比采用非金属颗粒能获得更大的结构阻尼。实验结果可为非阻塞性微颗粒阻尼柱的合理设计提供依据。
     

水相中色氨酸分子印迹聚合物微球的合成、表征及其识别性能研究

分别以色氨酸、α-甲基丙烯酸或丙烯酸胺、三羟甲基丙烷丙烯酸酯、甲苯作为模板分子、功能单体、交联剂和致孔剂,在较佳工艺条件下水体系中合成了色氨酸分子印迹聚合物微球;其形貌、粒径分布以及模板分子与功能单体之间的相互作用分别通过SEM、激光粒度分析仪及紫外分光光度法进行表征.其吸附能力分别通过静态吸附法测定其分离因子(α)和相对分离因子(β)来确定.实验结果表明,该法合成的色氨酸分子印迹聚合物对底物具有较高的吸附选择性和较大的吸附容量.     

偕胺肟水热碳对U(VI)-CO3/Ca-U(VI)-CO3的吸附性能研究

水热碳吸附材料具有制备工艺简单、合成条件温和、表面易改性等优点。本研究以可溶性淀粉为碳源, 在硝酸铈铵催化作用下, 将丙烯腈开环接枝到淀粉分子上, 通过水热反应和盐酸羟胺还原制备偕胺肟化水热碳(AO-HTC)。结合静态和动态吸附实验, 重点研究了溶液pH、碳酸根和钙离子浓度对AO-HTC吸附铀性能的影响, 通过Thomas和Yoon-Nelson模型探究AO-HTC吸附铀的动态过程。结果表明: 随着pH、碳酸根浓度和钙浓度的增加, AO-HTC吸附铀的容量逐渐降低; 掺杂5wt%AO-HTC土壤柱的穿透点和饱和点体积也随之减小。与纯土壤柱相比, 掺杂5wt%AO-HTC土壤柱的最大吸附容量(q_o)和吸附质穿透50%所需的时间(τ)增大了数倍。由此可见, AO-HTC是一种性能优异的可渗透性反应墙(PRB)介质, 有望用于修复铀污染土壤和地下水。     

弱酸离子交换纤维对含镍废水的吸附性能研究

系统研究了自制羧基离子交换纤维对电镀废水中Ni 2+的吸附性能。结果表明钠型羧酸纤维的平衡吸附容量远高于相应氢型纤维;静态条件下纤维对Ni 2+的吸附容量可达220mg/g以上;溶液初始浓度、pH值以及温度越高,钠型羧酸纤维的平衡吸附量越大。100～300mg/L范围内的含镍电镀废水经柱吸附后可达国家规定排放浓度(≤0.5mg/L),吸附Ni 2+后的纤维可用2mol/L盐酸溶液解吸,纤维重复使用100次后吸附性能基本不变。     

螯合树脂填充膜的制备及其对铜（Ⅱ）的吸附研究

采用相转化法制备了D418螯合树脂填充聚砜（PS）平板滤膜,考察了聚合物含量、凝固浴的组成以及制膜液温度等工艺参数对膜结构性能的影响;研究了膜对Cu^2 的选择性吸附性能,进行了静态和动态测试。在静态测试中,研究了膜厚、树脂粒径、吸附反应条件等对吸附速率与吸附容量的影响;在动态测试过程中,验证了该膜对Cu^2 萃取－反萃取同级进行的传递模式。     

高比表面积SiO_2为基质的含N复合分离材料的制备及其吸附性能

制备了PEI/SiO2复合分离材料,用红外光谱鉴定了其-N基团的存在,用SEM观察了其表面结构,并且用树脂吸附铜离子量来表征了其结合PEI的量.结果表明,复合分离材料对于铜离子的吸附速率很快,在0.5～0.7h就已经达到了饱和,静态最大吸附容量为47.1mg/g树脂;同时树脂具有再生性能,经过10次的解吸-吸附试验后,其吸附容量降至42.5mg/g树脂.     

Ion-implanted polytetrafluoroethylene enhances Saccharomyces cerevisiae biofilm formation for improved immobilization

The surface of polytetrafluoroethylene (PTFE) was modified using plasma immersion ion implantation (PIII) with the aim of improving its ability to immobilize yeast. The density of immobilized cells on PIII-treated and -untreated PTFE was compared as a function of incubation time over 24 h. Rehydrated yeast cells attached to the PIII-treated PTFE surface more rapidly, with higher density, and greater attachment strength than on the untreated surface. The immobilized yeast cells were removed mechanically or chemically with sodium hydroxide and the residues left on the surfaces were analysed with Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). The results revealed that the mechanism of cell attachment on both surfaces differs and a model is presented for each. Rapid attachment on the PIII-treated surface occurs through covalent bonds of cell wall proteins and the radicals on the treated surface. In contrast, on the untreated surface, only physisorbed molecules were found in the residue and lipids were more highly concentrated than proteins. The presence of lipids in the residue was found to be a consequence of damage to the plasma membrane during the rehydration process and the increased cell stress was also apparent by the amount of Hsp12 in the protein residue. The immobilized yeast cells on PIII-treated PTFE were found to be as active as yeast cells in suspension.     

Lifetime and regeneration of immobilized titania for photocatalytic removal of aqueous hexavalent chromium

Immobilized titania (TiO2) batch reactors reduced hexavalent chromium (Cr(VI)) in the form of potassium dichromate (K2Cr2O7) to trivalent chromium (Cr(III)) in aqueous solution at pH 3 under 171 W/m2 light intensity. The light source was a 125-W ultraviolet (UV) lamp. The Cr(VI) reduction showed zero-order kinetics (k0), while the Cr(VI) adsorption fitted with first-order kinetics (k(1st)). Adsorption capacity increased with increasing initial Cr(VI) concentration, and the area of immobilized TiO2 limited the reduction efficiency. The lifetime of fresh immobilized TiO2 was approximately 14 h. In addition, the regeneration of TiO2 with 3M sodium hydroxide (NaOH) was necessary to improve adsorption reaction.     

交联海藻酸钠磁性微球的制备及固定化胰蛋白酶研究

制备了交联海藻酸钠磁性微球,并以磁性微球为载体,戊二醛为交联剂,将胰蛋白酶固定化;利用透射电镜、粒度分析、红外分析对交联海藻酸钠磁性微球进行了表征;探讨给酶量、戊二醛浓度和pH值对固定化酶活性的影响;与自由酶比较,考察了固定酶的酶学性质.结果表明:交联海藻酸钠磁性微球是固定化胰蛋白酶的良好载体,固定化酶最适宜的条件是吸附时间12h,给酶量为100mg/0.1g磁性载体、交联剂戊二醛浓度为5%、溶液pH值为6,同时将酶固定化后,酶的稳定性和催化性能均有所提高.     

Control of colloidal behavior of polystyrene latex nanoparticles and their cytotoxicity toward yeast cells using water-soluble polymers

Positively charged polystyrene latex (PSL) nanoparticles (NPs) dispersed in physiological saline (154?mM NaCl solution) are taken up by yeast cells. However, in low ionic strength solutions, the yeast cells are covered with the NPs, leading to cell death. The environmental conditions under which NPs are taken up are therefore limited. In this study, we attempted to control the uptake of positively charged PSL NPs by Saccharomyces cerevisiae in 5?mM NaCl solution using a water-soluble polymer. Addition of a small amount of anionic sodium carboxymethylcellulose (CMC), which has a carboxyl group, to 5?mM NaCl solution allowed the uptake of PSL NPs by living yeast cells. In contrast, non-ionic methylcellulose did not affect the NP behavior. This is because the negatively charged CMC adhered to the positively charged PSL NP surfaces and the surface charge changed from positive to negative. Atomic force microscopy using a single-NP probe consisting of one NP immobilized on the flattened end of the silicon nitride tip showed that CMC significantly reduced the interaction force between a negatively charged living yeast cell and a positively charged PSL NP.     

细胞固定化方法对酶活稳定性的影响

本文以大肠杆菌为转化菌,研究了海藻酸钠包埋法细胞固定化技术,初步探讨了细胞固定化方法对产天冬氨酸酶活稳定性的影响。将固定化细胞放置于不同条件下保存,对比研究保存前后的酶活力,结果表明：海藻酸钠浓度4％,细胞浓度5％,温度40℃时保存的固定化细胞酶活稳定性最高。     

有机介质中固定化面包酵母催化苯甲醛加氢反应

研究了活化时间、摇床转速、缓冲液的pH值、反应温度等因素对海藻酸钙固定化面包酵母在有机介质中催化苯甲醛加氢生成苯甲醇的反应活性的影响,并对固定化酵母的重复利用性进行了探讨.结果表明,在pH为10的缓冲液中制备的固定化面包酵母的催化加氢能力最强;活化时间对催化加氢能力有较大的影响;在不同的有机溶剂中,最适的反应温度也不同.     

灭活酵母对Sr2+的吸附行为及其受γ辐照的影响

以灭活面包酵母为原料,利用原子吸收光谱(AAS)、X射线能谱仪(EDS)等手段,研究吸附剂加入量、pH值等因素对其吸附效果的影响,并分析了γ辐照条件下灭活面包酵母菌对Sr2+的吸附动力学过程。结果显示,不同温度下酵母菌对Sr2+的吸附均是快速进行的反应过程,整个吸附过程中单位吸附量qt均存在30℃>20℃>10℃。不同温度下面包酵母菌对Sr2+的动力学二级吸附速率方程拟合程度非常好(R>0.999),其吸附反应过程中限速步骤是化学吸附过程。EDS分析进一步证明Sr2+被吸附到面包酵母细胞上。辐照后酵母菌对Sr2+的吸附效果要比相同温度条件下辐照前实验组略好。     

固定化植物酯酶-TPPS_1纳米传感膜的制备与表征

为了检测神经毒剂类似物甲基膦酸二甲酯（DMMP）,制备了一种新型的固定化植物酯酶-单磺酸基四苯基卟啉（TPPS1）纳米传感膜.首先对膜材制备的影响因素,如戊二醛浓度、活化时间和吸附时间等进行了优化研究.再通过原子力显微镜（AFM）和UV-Vis光谱对在优化条件下制备的膜材的表面形貌和对DMMP的传感性能分别进行了表征和分析.结果表明,当戊二醛浓度为0.43mol/L,活化时间为80min,吸附时间为170min时,固定化植物酯酶的活力较高.该膜材的纳米结构增加了其对DMMP的敏感性,降低了检测限.TPPS1与固定化植物酯酶作用后会在422nm处形成一特征峰.把固定化植物酯酶-TPPS1表面暴露于DMMP中,由于DMMP可以把卟啉从酶的活性位点上置换下来,所以引起422nm处吸光度的降低.并且,在DMMP浓度低于9×10^-7mol/L的范围内,422nm处吸光度的变化与DMMP的浓度呈线性相关.该纳米传感膜可以检测浓度低至4.5×10^-10mol/L的DMMP.     

Selective elimination of lead(II) ions by alginate/polyurethane composite foams

A new type of adsorbent which is capable of selectively adsorbing lead(II) ions (Pb(2+)) was developed. The adsorbent was generated by reaction of sodium alginate with NB-9000B, a polyisocyanate type of prepolymer of polyurethane. The adsorbent was a hydrophilic and flexible alginate/polyurethane composite foam (ALG/PUCF) with the alginate chemically immobilized in the cell walls of the foam. Acid-base titration was used to quantify the concentration of carboxyl groups, which are present on the alginate molecules of the ALG/PUCF, functioning as the essential sites for binding Pb(2+). For the optimized ALG/PUCF, the carboxyl was found to be 38.2+/-1.2mumol/g of dry weight. The capacity for adsorbing Pb(2+) ions in 1.0g of dry weight of the optimized ALG/PUCF was found to be 16.0+/-2.1mumol, indicating that ion exchange was the essential mechanism for adsorbing Pb(2+) ions. The adsorption capacity was found to be highly sensitive to the pH of the sample solution; lower pH (<3) significantly decreased the adsorption. Competing ions such as Mg(2+), Ca(2+), and Cd(2+) also caused a decrease in selectivity and capacity for Pb(2+) adsorption, although the effect was less pronounced than the effect of pH. The ALG/PUCF is highly stable, flexible and easy to use. ALG/PUCF is also reusable after regeneration with ethylenediamine-N,N,N',N'-tetraacetic acid, disodium salt (EDTA-2Na). Due to these features, this adsorbent may be highly useful for elimination of Pb(2+) ions from contaminated water.     

Polymerase chain reaction coupling with magnetic nanoparticles-based biotin-avidin system for amplification of chemiluminescent detection signals of nucleic acid

A novel method was established through the detection of chemiluminescent signals of nucleic acid hybridization based on magnetic nanoparticles (MNPs) and PCR. 5' amino- modified specific probes were immobilized on the surface of silanized MNPs by Schiff reaction between amino and aldehyde group. The probes were used to capture the synthetic biotin-dUTP-labeled DNA fragments which were obtained by polymerase chain reaction (PCR). Then these complexes were bonded with streptavidin-modified alkaline phosphatase (SA-AP). Finally the chemiluminescent signals were detected by adding 3-(2'-spiroadamantane)- 4-methoxy -4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane (AMPPD) which was the substrate reagent of AP. The concentration of probes which were immobilized on the surface of MNPs was studied, how to reduce the adsorption of SA-AP on the surface of MNPs was also researched. It was shown that 12.5 pmol of probes were immobilized on 1 mg of MNPs. Aldehyde-MNPs modified with probes could adsorb SA-AP, affecting the sensitivity of chemiluminescene consequently. Reduction of aldehyde group by sodium borohydride and blocking the bare position of MNPs with bovine serum albumin (BSA) could decrease the background of chemiluminescence, and this method has good specificity in detection of chloramphenicol acetyltransferase (CAT) gene.