微滤技术在处理地表原水中的应用探讨

微滤(MF)膜在各种水处理分离膜中应用最广，在世界膜技术总产值中占50％以上，应用前景十分广阔。在概述了MF技术及其在国内外的应用和发展概况的基础上，介绍了高分子有机微滤膜、陶瓷微孔膜、动态形成膜等形态MF膜，探讨了不同形态MF膜技术在地表原水直接过滤应用中的优缺点，指出无机膜相对有机膜而言具有过滤精度高、能适应比较恶劣的操作运行环境、微生物不能降解等优点，而动态形成膜技术虽然还有待完善，但作为一项新型技术，亦存在研究价值。     

纳滤膜特性及对水中微污染物的控制

随着膜技术的发展与应用,20世纪80年代出现的纳滤膜充分弥补了反渗透与超滤之间的空白。介绍了纳滤膜的特性及其独特分离特点,阐述了纳滤膜在处理饮用水中有机污染物的必要性和合理性。最后指出了它的应用前景。     

膜分离技术在垃圾渗滤液处理中的应用

垃圾渗滤液是一种重污染的有毒有机废水,对生态环境造成了严重的威胁。本文综述了垃圾渗滤液现有的膜处理技术,与传统处理工艺相比,膜技术具有低能高效等优点,是未来渗滤液处理技术的重要发展方向。由于垃圾渗滤液组成的复杂性,根据不同处理目的,微滤膜(MF)、超滤膜(UF)、纳滤膜(NF)和反渗透膜(RO)4种膜在垃圾渗滤液处理中都得到了一定的应用。总结发现,其中MF和UF对渗滤液的处理效果较差,一般作为渗滤液的预处理技术;NF和RO对渗滤液的处理效果较好,主要作为其深度处理技术。然而,膜污染阻碍了膜技术在渗滤液处理方面的发展与应用,为此可通过研究开发新型膜材料、有效的预处理技术和膜分离工艺优化等方面来防止膜污染的发生,以便膜技术在渗滤液及其他水处理方面得到更加广泛的应用。     

纳滤膜在废水处理中的应用

本文着重介绍了纳滤膜在国内外废水处理中的应用及研究进展。纳滤膜技术与传统的废水处理方法相比具有处理效果好,可实现废水回用和有用物质的回收等特点。并展望了将纳滤膜技术应用与废水处理,膜技术的集成以及与传统的废水处理过程相结合均将产生较大的社会效益和经济效益。     

纳滤膜分离技术及其进展

纳滤技术是一种介于超滤和反渗透之间的新型分离技术。作者介绍了纳滤膜的特性及其独特的分离特点。高分子纳滤膜的几种主要制备方法的制备原理、制备要点,国内外纳滤膜在生产研究方面的进展,以及当前已商品化的几种主要的纳滤膜的材质。最后简单介绍了纳滤膜在水处理、食品、生化、医药、染料和化工等领域的应用进展,指出今后的发展将着重于传质机理、新的膜材料及集成工艺开发等方面。     

纳滤膜及其在饮用水处理中的应用研究

系统论述了纳滤膜的主要特点及其在饮用水处理中的主要性能,举例介绍了纳滤膜在饮用水处理中的应用与研究现状,并对纳滤膜的发展做了展望,纳滤膜在优质饮用水生产中具有广泛的应用前景.     

膜技术在废水处理中的应用

本文介绍了膜技术处理废水的基本原理及其特点，综述了反渗透、微滤、超滤、液膜和电渗析等传统膜技术在废水处理的应用，以及纳滤膜、充气膜、膜生物反应器、渗透蒸发和胶团强化超滤法等新型膜技术在废水处理的发展及其应用，指出了膜技术在处理废水中存在的主要问题，并对膜技术处理废水的发展前景作了展望。     

压力驱动膜分离蛋白质技术的研究进展

膜技术在蛋白质的分离与纯化产品中发挥着关键作用,通过膜分离技术有可以效的提高蛋白质生产的效率和品质。本文围绕近年来压力驱动膜分离蛋白质技术的最新进展进行了综述,主要对微滤膜、超滤膜和纳滤膜在分离蛋白质技术中的应用进行了论述,并对比了不同附加场强(电场、磁场和超声场)下对膜性能的改善程度;重点分析了膜污染现象中的机理和膜污染的影响因素,并对未来的膜法分离蛋白质技术发展进行了展望。     

基于两性离子的纳滤膜抗污染改性方法研究进展

纳滤膜对水中污染物的分离截留性能优异,膜污染控制和抗污染强化是该技术发展的研究热点。纳滤膜改性是强化纳滤膜抗污染性能的方法之一,基于两性离子材料的改性纳滤膜凭借两性离子材料静电作用与水分子结合的特性,在渗透性和抗污性方面表现优秀。系统综述了强化抗污染的两性离子纳滤膜的改性方法,包括涂覆法、接枝法、界面聚合法、自组装和共混掺杂法等,并阐释了各方法所制备纳滤膜的抗污效能和适用条件,最后对各改性方法做出了展望,以期为两性离子材料在纳滤膜改性和实际应用中的研究提供参考。     

膜在生物技术中的应用

综述了膜在生物技术方面的应用。概述了纳滤膜的基本原理。着重介绍了纳滤膜在食品工业，生物化工与制药工业，染料工业等方面的一些应用。     

Nanofiltration Membrane Process for the Removal of Arsenic from Drinking Water

The removal of arsenic from drinking water by nanofiltration membranes was investigated. Experiments were conducted with tap water to which arsenate and arsenite were added. Two types of nanofiltration membranes, i.e., NF‐90 and NF‐200, have been tested. The effect of various operating conditions, e.g., applied pressure, feed concentration, pH and temperature, were also investigated. The pH and arsenic concentration in the feed and the operating temperature are found to be decisive factors in determining the arsenic concentration remaining in the permeate. The level of removal of As(V) was higher than 98 % for both membranes, but that of As(III) was much lower. It can be concluded that by controlling the operating parameters, source water containing As(V) may be recovered as drinking water to EPA maximum contaminant level quality standards, but that water containing As(III) must undergo a pre‐oxidation treatment before passing through the nanofiltration membrane in order to maintain drinking water quality.     

Effect of Poly(vinyl pyrrolidone) on Antifouling Properties of Asymmetric Poly(ethylene‐co‐vinyl alcohol) Membranes

Poly(ethylene‐co‐vinyl alcohol)/poly(vinyl pyrrolidone) (EVAL/PVP) blend membranes with antifouling properties were prepared by nonsolvent induced phase separation. Residual PVP in the sample was calculated by infrared spectroscopic data and confirmed by thermogravimetric analysis. The effect of residual PVP on hydrophilicity and permeation characteristics of the membranes was evaluated. Porosity and equilibrium water content of the membranes were influenced by the addition of PVP. The effect of protein fouling on flux using bovine serum albumin as a model system was studied in detail. The residual PVP content could enhance the antifouling property of the membrane. All membranes proved to have sufficient mechanical strength to withstand pressure‐driven filtrations.     

Preparation of novel Polyvinylidene fluoride/boehmite composite membrane made using nonsolvent induced phase separation method for arsenate ion removal from water

Polyvinylidene fluoride/boehmite composite membranes with hydrophilic surfaces were prepared using the nonsolvent induced phase inversion technique (NIPS) method to remove arsenate ions from water. The nanoparticles were added with different boehmite filler content. The contact angle of the bare membrane is 85⁰, and it is reduced to 53⁰, imparting hydrophilicity due to the presence of boehmite nanoparticles. The mechanical characteristics of the membranes have significantly improved. The BET and SEM results have shown that the average pore diameter gets reduced with boehmite addition, and surface area increases. Additionally, the use of nanoparticles enhanced the membranes' thermal stability. The nanofiltration unit is used to filter the arsenic-contaminated water. The transmembrane pressure of ~4 bar is applied to all the membranes, and arsenic rejection; the flux of the membranes was calculated. The membrane has shown the highest rejection of 55% with a flux of 3.5659 L/m².h.     

Removal of arsenic from aqueous media using zeolite/chitosan nanocomposite membrane

In this work, the removal of arsenic (III) using zeolite/chitosan nanocomposite membranes was studied and characterized using scanning electron microscopy (SEM), atomic force microscope (AFM), etc. The water contact angle of the membrane decreased from 74.2 to 59.2° and the porosity of the prepared membranes increased from 20.38 to 45.81% with an increase in the concentration of zeolite. The rejection of arsenic (III) increases with increase in the zeolite loading for 500 and 1000 µg/L; but at 100 and 150 µg/L, the trend was opposite. The membrane with 1.0 [Chi-Z (1.0)] and 1.25 [Chi-Z (1.25)] wt% zeolite showed the highest rejection (>94%) for 1000 µg/L concentration of arsenic trioxide aqueous solution.     

Effect of operating conditions in removal of arsenic from water by nanofiltration membrane

The removal of arsenic from synthetic waters and surface water by nanofiltration (NF) membrane was investigated. In synthetic solutions, arsenic rejection experiments included variation of arsenic retentate concentration, transmembrane pressure, crossflow velocity and temperature. Arsenic rejection increased with arsenic retentate concentration. Arsenic was removed 93-99% from synthetic feed waters containing between 100 and 382 μg/L as V, resulting in permeate arsenic concentrations of about 5 μg/L. Under studied conditions, arsenic rejection was independent of transmembrane pressure, crossflow velocity and temperature. In surface water, the mean rejection of As V was 95% while the rejection of sulfate was 97%. The co-occurrence of dissolved inorganics does not significantly influence arsenic rejection. The mean concentration of As in collected permeated was 8 μg/L. The mean rejection of TDS, total hardness and conductivity were 75, 88 and 75% respectively.     

新型家用除砷氟净水器研制与试验研究

针对我国部分地区饮用水砷、氟含量超标问题,设计出一种分散型的家用净水器,以预氧化—吸附—膜处理为技术路线,以曝气—改良活性炭—活性氧化铝—反渗透膜为实际组成单元,分别对单独除砷、单独除氟、砷氟共除效果进行实验测定。实验结果表明,单砷浓度1.994 mg/L,单氟浓度（以F-计）4.925 mg/L,及砷氟共存砷浓度2.128 mg/L,氟浓度（以F-计）5.293 mg/L时,出水砷氟浓度均符合《生活饮用水卫生标准》（GB 5749-2006）。砷氟共除时,浓水砷氟含量符合《污水综合排放标准》（GB 8978-1996）,可以安全排放。说明此净水器方法可行,有实用价值。     

紫外光强化钛柱撑型蒙脱土除砷吸附剂的研制

制备了对水体中的砷具有良好吸附效果的柱撑蒙脱土.研究了在紫外光照射的强化作用下的除砷效果,并确定了适宜的吸附砷工艺条件.结果表明经过压力溶弹处理的钛柱撑蒙脱土,Ti元素有效地替换了蒙脱土层间的Al元素,形成锐钛矿型TiO2柱撑结构,晶型发育比较完全,可以有效地去除水体中的砷.     

Fabrication of a pilot scale module of thin film composite hollow fiber membrane for osmotic pressure‐driven processes

Polyamide thin film composite hollow fiber membranes have advantages in their unique structure compared to flat sheet membranes. This study examined interfacial polymerization methods for fabricating pilot scale hollow fiber membranes (membrane area: 1.2 m², number of hollow fiber strands: 1200). For use in osmotic pressure‐driven processes, a one‐pot hydrophilic interfacial polymerization procedure was developed simultaneously to modify the surface property and synthesize polyamide thin film. With the procedure, a pilot scale module has a water flux of 13 LMH using a draw solution of 0.6M NaCl and a feed solution of distilled water through the design of the module configuration. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46110.     

沉淀法制备氢氧化镁及其对砷溶液的吸附特性

以蛇纹石制备的硫酸镁为镁源,以氨气为沉淀剂,常压下采用一步法制备氢氧化镁。对氢氧化镁吸附处理含砷(Ⅴ)废水进行了研究,考察了氢氧化镁用量、pH值、吸附时间及砷初始浓度等因素对砷(Ⅴ)去除效果的影响,并探讨了吸附作用机理。结果表明:氢氧化镁对废水中砷(Ⅴ)的去除率为76.45%,氢氧化镁对水溶液中砷(Ⅴ)的吸附量随吸附时间的变化规律符合Langmuir吸附等温模式,而吸附量随砷起始浓度的变化则符合Freundlich吸附等温模式。     

Use of ArsenXnp,a hybrid anion exchanger,for arsenic removal in remote villages in the Indian subcontinent

Many of the arsenic removal units operating in remote villages of West Bengal, India now use a hybrid anion exchanger (HAIX) which are essentially spherical anion exchange resin beads containing dispersed nanoparticles of hydrated ferric oxide (HFO). HAIX, now commercially available as ArsenX^np, offers a very high selectivity for sorption of oxyanions of arsenic due to the Donnan membrane effect. The sorption columns used in the field for removal of arsenic are either single column or split-column design. The sorption columns allow flow of atmospheric oxygen, thereby promoting oxidation of dissolved Fe(II) species of arsenic-contaminated raw water to insoluble Fe(III) oxides or HFO particulates. Apart from the usual role played by the sorbents like ArsenX^np or activated alumina towards arsenic removal, HFO particulates also aid in the treatment process. Each unit is attached to a hand-pump driven well and capable of providing arsenic-safe water to three hundred (300) households or approximately one thousand villagers. No chemical addition, pH adjustment or electricity is required to run these units. On average, every unit runs for more than 20,000 bed volumes before a breakthrough of 50 μg/L of arsenic, the maximum contaminant level in drinking water in India, is reached. In addition to arsenic removal, significant iron removal is also achieved throughout the run. Upon exhaustion, the media is withdrawn and taken to a central regeneration facility where 2% NaCl and 2% NaOH solution are used for regeneration. Subsequently, the regenerated resin is reloaded into the well-head sorption column. Following regeneration, the spent solutions, containing high arsenic concentration, are transformed into solids residuals and contained in a way to avoid any significant arsenic leaching. Laboratory investigations confirmed that the regenerated ArsenX^np is amenable to reuse for multiple cycles without any significant loss in capacity.