界面聚合反渗透复合膜材料及其表面修饰

针对我国反渗透复合膜材料研究领域存在的膜材料品种单一、膜性能相对较差、膜产品缺乏核心竞争力等现状,重点开展了界面聚合反渗透复合膜材料及其表面修饰方面的研究工作.从功能单体与制备工艺入手,研究开发高性能反渗透复合膜材料;采用表面改性技术,对界面聚合反渗透复合膜材料进行表面功能化修饰,研究开发界面聚合反渗透复合膜材料的表面改性实用技术;以期为我国反渗透复合膜材料及其产业的发展提供核心材料和先进制备技术.     

聚酰胺纳滤膜制备过程中溶剂对膜性能的影响

以正己烷和甲苯的混合溶剂作为有机相溶剂,均苯三甲酰氯(TMC)和哌嗪(PIP)作为有机相和水相活性单体,采用界面聚合的方法在聚丙烯腈(PAN)超滤膜上制备得到一系列聚哌嗪酰胺纳滤复合膜.系统研究了不同正己烷与甲苯配比制备得到的纳滤复合膜活性分离层的表面化学组成、表面流动电位、平均孔径及表面形貌的变化规律,并解释了这些因素对纳滤复合膜分离性能的影响机理.结果表明:随着混合有机相溶剂中正己烷相对含量的增加,使得水相与有机相溶剂间界面张力增加,所制荷电纳滤复合膜活性分离层表面流动电位逐渐向负电转变,孔径逐渐变小,同时纳滤复合膜表面粗糙程度增加.复合膜表面粗糙度的增加使纳滤复合膜的透过性得到提高.     

静电喷雾辅助交联制备超薄复合膜及其性能研究

采用静电喷雾辅助交联聚合物制备了超薄聚乙烯亚胺(PEI)/戊二醛(GA)复合膜.考察了PEI浓度、电喷雾时间等对PEI/GA复合膜物理化学性质和分离性能的影响.通过SEM、AFM、FTIR、接触角和Zeta电位对复合膜的微观形貌、交联反应、亲水性和荷电性进行了表征.选用阳离子染料通过错流装置对复合膜的分离性能进行了测试.结果表明,采用静电喷雾辅助交联法成功制备出表面均匀致密、粗糙度小、亲水性得到明显改善的荷正电的PEI/GA复合膜,该膜对阳离子染料亚甲基蓝(MLB)和结晶紫(CV)的截留率分别达到95.1%和97.5%.通过改变PEI浓度和电喷雾时间可有效调控复合膜的分离性能,以满足更广泛的应用需求.     

新型耐高温聚芳酰胺复合膜的制备及性能

为了将反渗透技术在高温流体环境中使用,研究制备具有较高热稳定性的超滤膜以制备耐热性良好的复合膜,以杂萘联苯聚芳醚超滤膜为支撑层,通过间苯二胺与均苯三甲酰氯的界面聚合制备聚芳酰胺复合膜.研究了聚合反应中单体的浓度、反应温度和反应时间等与膜性能的关系.用原子力显微镜照片表征了膜表面形貌的变化,证明致密复合层的形成是膜性能变化的关键.考察了操作温度、压力对膜性能的影响.随着操作压力和温度的提高,膜的通量迅速增加,但对2000 mg·L-1的NaCl溶液的截留率则保持在99.0%左右,无明显变化.膜在1.6 MPa、80℃下重复测试30 d,性能无明显降低,说明其具有良好热稳定性.     

季铵盐壳聚糖/聚砜复合纳滤膜的制备及性能表征

通过涂敷交联法制备了一种新型荷正电纳滤膜,其中以三甲基壳聚糖酰氯（TMC）为膜材料配制铸膜液,以聚砜超滤膜为基膜,环氧氯丙烷为交联剂.试验在全面考察该复合纳滤膜制备工艺基础上,重点探讨了交联时间对复合纳滤膜性能的影响.结果显示:该方法极大地缩短了交联时间,最优交联时间仅为2 h;同时最优条件所制备纳滤膜的纯水透过系数为14.09L/（m²·h·MPa）,表面粗糙度约为4 nm;对无机盐的截留顺序符合以下规律:MgCl₂>NaCl>MgSO₄>Na₂SO₄,满足荷正电纳滤膜的Donnan平衡模型.     

新型分盐纳滤膜的制备与表征

设计界面聚合反应单体结构,调节界面聚合反应参数,是实现纳滤膜结构和性能调控的有效手段.针对Na_2SO_4/NaCl高效分离需求,以高哌嗪(HPIP)为水相单体、均苯三甲酰氯(TMC)为有机相单体,通过界面聚合反应制备了具有高Na_2SO_4/NaCl选择性的中空纤维纳滤膜.通过优化HPIP质量浓度、调节分离层的结构,可以实现对纳滤膜分离性能的有效调控.当HPIP质量浓度为3 g/L时,纳滤膜具有最佳的Na_2SO_4/NaCl选择性,该纳滤膜对Na_2SO_4和NaCl的截留率分别为98.0%和14.2%,Na_2SO_4/NaCl选择性为6.9,NaCl水溶液的渗透通量为39.7 L/(m~2·h).     

无机添加剂对磺化杂环共聚醚砜复合膜性能的影响

以磺化联苯型杂萘联苯共聚醚砜(SPPBES)为涂层材料,分别加入LiCl、NaCl、KCl作为无机添加剂配制浸涂稀溶液,在联苯型杂萘联苯共聚醚砜(PPBES)超滤底膜上,采用涂覆方法制备磺化杂萘联苯共聚醚砜复合纳滤膜(SPPBES-LiCl、SPPBESNaCl和SPPBES-KCl)。考察了无机添加剂对复合膜的分离性能的影响,复合膜对不同无机盐的脱盐率顺序均为Na_2SO_4NaClMg SO_4MgCl_2,表现出荷负电纳滤膜的分离特征,以LiCl为添加剂所制备的SPPBES-LiCl复合纳滤膜的脱盐率最高,通量最小。研究了复合膜的耐热性能和耐氧化性能,当操作温度从20℃升至95℃时,SPPBES-LiCl复合膜的通量由46 L·m~(-2)·h~(-1)增加到130 L·m~(-2)·h~(-1),而脱除率下降约3%,相比于SPPBES-NaCl和SPPBES-KCl,SPPBES-LiCl复合膜分离性能随操作温度升高变化最小。在0.2 g·L~(-1)的NaCl O溶液中浸泡8 d,SPPBES-LiCl复合膜通量增大2%左右,而SPPBES-NaCl与SPPBES-KCl的通量增幅小于8%;相比于SPPBES-NaCl和SPPBES-KCl膜,SPPBES-LiCl复合膜具有更好的耐氧化稳定性。此外,3种磺化杂萘联苯共聚醚砜复合纳滤膜均表现出了较好的耐酸碱稳定性。     

耐氯性能优良的磺化杂萘联苯共聚醚砜复合纳滤膜

以耐高温和耐氧化性能较好的磺化杂萘联苯共聚醚砜(SPPBES)为涂层材料制备了3种复合纳滤.通过考察次氯酸钠浓度、浸泡时间、次氯酸钠溶液pH对复合纳滤膜分离性能的影响,详细研究复合纳滤膜的耐氯性能.实验结果表明,随着次氯酸钠浓度的提高,复合膜的脱盐率逐渐降低;3种复合膜在质量分数300×10-6次氯酸钠溶液浸泡30天,膜性能没有显现变化,表现出良好的耐氯性能;与在次氯酸钠溶液(pH为4、12)浸泡的复合膜相比,在次氯酸钠(pH7)溶液中浸泡的复合膜性能变化较小,SPPBES复合膜在pH为4～12范围内具有很好的耐氯性能.     

O-MoS_2改性PMIA疏松纳滤膜的制备及其性能

为考察氧化二硫化钼(O-MoS_2)对聚间苯二甲酰间苯二胺(PMIA)膜结构和分离性能的影响,采用相转化法制备了PMIA平板疏松纳滤膜,进行了O-MoS_2添加量对膜的形貌结构、膜表面电势、分离性能及抗污染性能的影响分析.结果表明,与PMIA原膜相比,复合PMIA/O-MoS_2膜表面光滑无缺陷;随着复合膜中O-MoS_2质量分数由0增加至0.5%,膜表面接触角由原膜的61.8°降低至35.0°;复合膜表面的荷负电性能增强.纳滤实验结果表明,在O-MoS_2质量分数为0.3%条件下制备的复合膜,在0.2 MPa操作压力下,纯水通量为361.5 L/(m~2·h),是原膜通量的1.5倍.同时O-MoS_2的添加增强了复合膜的抗污染性能,在染料废水处理等领域展现了潜在的应用前景.     

渗透汽化分离芳烃/烷烃的聚芳醚腈酮复合膜的制备

采用耐高温的杂萘联苯聚芳醚腈酮(PPENK)超滤膜为底膜,聚(乙二醇)甲基丙烯酸酯(PEO500OHMA)为单体,通过常压介质阻挡放电(DBD)等离子同步辐照接枝技术,成功制备了芳烃/烷烃渗透汽化分离复合膜.以甲苯/正庚烷为模型体系,考察了单体浓度对复合膜的芳烃/烷烃渗透汽化分离性能的影响规律,并利用分子模拟技术初步探索了其内在机制.结果表明,单体浓度为0.45 mol/L时,PPENK复合膜的甲苯/正庚烷分离系数和渗透通量分别为5.6和2.66 kg/(m~2·h).随单体浓度增大,所制备PPENK复合膜的甲苯/正庚烷分离系数先增大后减小,与溶液中单体的扩散系数的变化趋势一致.这或许说明扩散是制备"孔填充"复合膜需要调控的参数.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K₂SO₄, and relative amounts of fluorine and SO₄ groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb₃Zr₂F₉SO₄ · 2H₂O, Cs₂ZrF₂(SO₄)₂ · 2H₂O, Cs₈Zr₄F₂(SO₄)₁₁ · 16H₂O, and Cs₂ZrF₄SO₄ offer the most efficient RL.     

Heat and Mass Transfer and Modeling and Prediction of Environmental Catastrophes

Basic definitions and concepts of the physicomathematical theory of natural catastrophes are given. Possibilities of mathematical modeling of natural and technogenic catastrophes are discussed in the context of the theory of heat and mass transfer and the mechanics of reacting media. The importance of taking into account conjugate heat and mass exchange in modeling catastrophes is emphasized. A formula for evaluating the probability of a collisional catastrophe is given.     

Multi-ferroic and magnetoelectric materials and interfaces

The existence of multiple ferroic orders in the same material and the coupling between them have been known for decades. However, these phenomena have mostly remained the theoretical domain owing to the fact that in single-phase materials such couplings are rare and weak. This situation has changed dramatically recently for at least two reasons: first, advances in materials fabrication have made it possible to manufacture these materials in structures of lower dimensionality, such as thin films or wires, or in compound structures such as laminates and epitaxial-layered heterostructures. In these designed materials, new degrees of freedom are accessible in which the coupling between ferroic orders can be greatly enhanced. Second, the miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and storage increase, without further size reduction, is to use multi-functional materials that would enable new device capabilities. Here, we review the field of multi-ferroic (MF) and magnetoelectric (ME) materials, putting the emphasis on electronic effects at ME interfaces and MF tunnel junctions.     

CellML and associated tools and techniques

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.     

The shape and stability of wall-bound and wall-edge-bound drops and bubbles

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.