电去离子(EDI)过程水解离机理的研究(Ⅳ)ED和EDI过程水解离的差异性比较

ED和EDI过程中水的解离,在本质上均与高电势梯度有关,发生水解离时电势梯度的数量级为108V/m.在ED过程中,理论上阳膜先于阴膜发生浓差极化,但阳膜的极化与水解离在极化发生之后就受到膜面ζ-电位的制约,使得阳膜水解离反而远远滞后于阴膜.通过实验对EDI过程的水解离有了进一步的了解,并作了进一步分析,同时与ED过程的水解离现象作了对比.认为在EDI的淡水室内,填充的树脂使得不能形成具有抑制水解离效应的ζ-电位,从而阳膜先于阴膜发生水解离,且阴阳膜的水解离因更严重的浓差极化而更为剧烈.     

电去离子(EDI)过程水解离机理的研究(Ⅰ)特征曲线

系统研究了电去离子（EDI）过程非稳态开机阶段及稳定工况下的特征曲线,获得了若干区别于电渗析（ED）过程特征曲线的重要现象。研究表明,在开机阶段,淡水室中水的解离主要是在阳膜／阳树脂的表面发生;随着过程逐渐达到稳态,阴膜／阴树脂的表面也将发生程度不断加强的水的解离,浓差极化与水解离的可利用性是EDI与ED过程的最本质区别。     

电去离子过程水解离机理的研究(Ⅲ)阴膜和阴树脂的降解对水解离的影响

通过对离子交换树脂与膜的污染与降解的分析,认为在常规的ED（电渗析）过程中,导致阴膜电阻增大并进一步诱发阴膜异常极化和水解离的主要因素是膜污染;而在电去离子（EDI）过程中,导致膜对电阻增大的主要因素则是阴膜和阴树脂的持续降解．根据弱碱性的叔胺化合物对阴离子交换膜的催化效应理论,对EDI过程浓缩水pH的演变认为阴膜和阴树脂一定范围内的逐渐降解过程,对应着其催化水解离反应逐渐加强的过程．此外,实验测定了EDI过程中阴阳离子交换膜的面电阻的变化情况,确证了阴膜降解反应的存在。     

山东天维膜技术有限公司生产的荷电膜用于环保治理效益显著

<正>山东天维膜技术有限公司通过多年的科研公关,研发成功的电渗析膜、双极膜、扩散渗析阴膜、扩散渗析阳膜,实现了国内荷电膜产业化的重大突破.电渗析膜主要应用于海水和苦咸水淡化、天然水纯化、医药工业污水处理等领域;扩散渗析阴膜主要应用于钢铁、湿法冶     

SBS双极膜的制备及在成对电解合成乙醛酸中的应用

以SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)作为基膜材料,采用自由基接枝聚合反应,在SBS主链上引入丙烯酸(AA)链段和苯乙烯磺酸钠(StSO3Na)作为阳膜(记为SBS-g-(AA/StSO3Na));在SBS主链上接枝N,N-二甲胺基丙烯酸乙酯(DMAEMA)链段作为阴膜(记为SBS-g-DMAEMA),用流延法制备了SBS-g-(AA/StSO3Na)/SBS-g-DMAEMA双极膜(记为SBSBPM)。用红外光谱、热重和扫描电镜对膜成分与形态进行了表征,测定了SBS-g-(AA/StSO3Na)阳膜(接枝量40.0%)的含水率、接触角、离子交换容量分别为98.1%、32.7°、3.71mmol/g;SBS-g-DMAEMA(接枝量26.7%)阴膜的含水率、接触角、离子交换容量分别为71.1%、23.08°、1.42mmol/g。将SBSBPM作为阴阳两室隔膜,电流密度为16mA/cm2常温下电解,阴极电流效率最大可达83.2%,阳极电流效率最大可达80.3%,电压维持在3.4V。     

化学水处理问题之我见

本文对化学水处理的几个问题的进行了探讨：RO、ED等膜法水处理的浓盐水对环境产生污染，且不易处理。采用反渗透直接加混床的水处理方法，必须采取措施，保证混床的阳树脂和阴树脂每次都能充分混合。     

1,3-丙二醇发酵液电渗析脱盐中离子膜影响的实验研究

电渗析法可以有效去除1,3-丙二醇发酵液中存在的有机酸盐,保证下游处理过程的顺序进行,为了选取适于该脱盐过程的离子膜种类,采用4种离子交换膜分别进行了发酵液电渗析实验,通过对脱盐效果的综合评价着重探讨了离子交换膜性能的影响、实验研究表明,对于有机酸盐电渗析脱除过程,阴膜的选取至关重要;当阴、阳膜导电能力较强时,脱盐效果良好,此外,进行了中性溶质在不同离子膜中的模拟扩散实验,在综合比较脱盐效果和中性溶质扩散损失的基础上,获得了针对1,3-丙二醇发酵液电渗析脱盐的较优阴、阳离子膜种类。     

树脂分层填充EDI膜堆实验研究

介绍了阴、阳离子交换树脂分层填充EDI膜堆的特征,考察了一级两段式膜堆每段填充层数对EDI过程的影响.实验表明:每段填充2和16层的膜堆,在稳态条件下运行的电压一电流密度曲线呈现出一定的规律性;EDI膜堆浓水pH值随电流密度增加先下降后升高,最后稳定在碱性范围;两个膜堆均能在一定条件下持续、稳定生产17 MΩ·cm以上高纯水.最终,当两个膜堆在120 V下达到稳态运行时,填充的阴、阳树脂均具有一定的再生程度.     

XDLVO理论解析有机物在膜蒸馏过程中的膜污染行为机制

采用XDLVO(Extended Derjagu-Landau-Verwey-Overbeek)理论对商用微孔疏水膜(PVDF膜)与自制超疏水膜(SH-PVDF膜)在膜蒸馏(MD)处理高盐有机(腐殖酸(HA)、海藻酸钠(SA))废水过程中的膜污染行为机制进行定量解析,评价不同界面相互作用能(范德华(LW)作用能、静电(EL)作用能、路易斯酸碱(AB)作用能)对膜污染的影响程度,并采用气隙式膜蒸馏(AGMD)进行对比验证.结果表明：LW与EL作用能为正值,AB作用能为负值且在几种作用能中起主导作用、导致总界面相互作用能为负值,污染物与膜界面间表现为吸引作用,说明所考察的几种有机物都会对2种膜材料产生一定程度的污染;膜的受污染程度与膜和污染物的极性性质有关;对于同一种污染物,PVDF膜更容易受到污染;对于同一种膜而言,HA比SA更容易造成膜污染;另外,Ca²⁺的加入会加重膜污染.AGMD运行实验与计算结果一致,表明XDLVO理论对于有机物在膜蒸馏过程中的膜污染行为解析具有指导意义.     

操作条件对双极膜电渗析性能和膜污染的影响

采用正交试验设计法研究双极膜电渗析处理味精等电母液时的过程性能和膜污染,连续5批试验,考察了操作电流、流速、温度和酸室初始浓度对电渗析性能(硫酸根的平均再生率、能耗总和)和膜污染(膜湿重及能耗增加量)的影响.通过极差分析和方差分析确定操作电流是极显著影响因素,流速和温度是显著影响因素.其最佳操作条件为电流4.0 A,流速10cm/s,温度35℃,酸室初始浓度0.05 mol/L.     

Calcinable Polymer Membrane with Revivability for Efficient Oily‐Water Remediation

Fouling of polymeric membranes remains a major challenge for long‐term operation of oily‐water remediation. The common reclamation methods to recycle fouled membranes have the issues of either incomplete degradation of organic pollutants or damage to filter membranes. Here, a calcinable polymer membrane with effective reclamation after fouling is reported, which shows full recovery of the original oil/water separation efficiency. The membrane is made of polysulfonamide/polyacrylonitrile fibers by emulsion electrospinning, followed by hydrothermal decoration of TiO₂ nanoparticles. The bonding structured fibrous membrane displays outstanding thermal stability in air (400 °C), strong acid/alkali resistance (at the pH range from 1 to 13), and robust tensile strength. As a result, the chemically fouled polymeric membrane can be easily reclaimed without decreasing in separation performance and mechanical properties by annealing treatment. As a proof‐of‐concept, the as‐prepared membrane is integrated into a wastewater separation tank, which achieves a high water flux over 3000 L m^?2 h^?1 and oil rejection efficiency of 99.6% for various oil‐in‐water emulsions. The presented strategy on membrane fabrication is believed to be an effective remedy for membrane fouling, and should apply in a wider field of filtration industry.     

研究浓差极化和膜污染过程的方法与策略

简要综述了浓差极化和膜污染的研究方法和策略．利用超滤法处理印钞擦版废液实验说明研究思路和各种分析方法的应用．通过膜阻力模型实验,分析出各污染途径产生的阻力大小,讨论了应注意的问题．采用EDX,ICP,TOC,SEM,FTIR和MC对膜污染物、酸洗和碱洗液、清洗前后膜表面形貌分析鉴定,发现主要无机污染物是钙离子,主要有机污染物是磺化蓖麻油．模拟实验结果与上述结果一致,并引导出四步清洗方法,可对污染膜进行有效清洗;并发现对于严重污染的膜,采用三个以上清洗周期才能使膜通量得到完全恢复．最后提出一个浓差极化和膜污染的研究方法和策略框架图．     

Effective factors in the treatment of kerosene-water emulsion by using UF membranes

The effects of different parameters including membrane type (regenerated cellulose and polysulphone), transmembrane pressure (TMP), the content of oil in the feed, the flow velocity of the feed and pH on the ultrafiltration of an emulsion of kerosene in water were studied. It was found that the important factors affecting ultrafiltration were, in order, membrane type, pressure and oil concentration. The greatest flux at the optimum conditions here of 3 bar, an oil content of 3% (v/v) and with membrane type C30F was predicted as 108 L/(m(2)h) that was within the range of the confidence limit of the measured value of 106 L/(m(2)h). The normalised FTIR results of the virgin cellulosic membranes C30F and C100F showed more abundant OH groups. The bigger number of OH groups implies a greater hydrophilicity. The larger observed flux in the C30F is related to a higher number of pores as well (surface porosity) compared with the C100F membrane. In the "polarised regime" from 3 bar upwards, flux was independent of pressure for all membranes and was assumed to be determined by the back diffusion transport. Despite the fact that both the PS100H and C100F membranes had the same cut-off (100 kg/mol), the hydrophilic C100F showed a superior permeate flux. The strongest drop of flux with time due to oil fouling was observed for the C100F although it was hydrophilic. In the case of the PS100H, both FTIR and SEM showed that cake layer formation was not the cause of fouling. Meanwhile the SEM and FTIR results of fouled C100F provided evidence of adsorptive and gel formation fouling.     

脏污对道床剪切性能影响及评估指标的离散元分析

对国内外典型的道床脏污评估指标进行了综合分析。基于已有研究成果,提出了新的道床评估指标PFI。采用离散元法建立了基于精细道砟仿真单元的直剪数值模型,对不同脏污程度道床的剪切性能及PFI的合理性进行了研究,研究结果表明：脏污会显著降低道床的抗剪性能,其下降幅度与道床的脏污程度有关;脏污材料的粒径对道床剪切性能影响明显,且在材质相同的情况下,小粒径的脏污会引起道床剪切性能的进一步降低;相比于已有评估指标VCI,PFI能够考虑脏污材料粒径的影响,从而更准确的评估道床脏污情况。     

膜生物反应器运行中的膜污染及其控制

阐述了膜生物反应器(MBR)在水处理方面的优缺点及膜污染的主要影响因素,总结了国内外关于膜污染及其数学模型的研究进展,归纳出膜污染模型的几种形式,并从膜本身的理化性质改变、混合液理化特性改善、操作条件优化等方面论述了减缓膜污染的方法及措施,介绍了几种膜清洗的方法及设计和操作过程中应注意的问题,提出了今后研究的重点和方向．     

Effect of sand and clay fouling on the shear strength of railway ballast for different ballast gradations

Ballast contamination by fine materials such as sand and clay in railway track at arid regions is an important issue that causes track instability problems and settlement due to reduction of shear strength of ballast. In this paper, the results of direct shear box test conducted on clean ballast, sand-fouled ballast and clay-fouled ballast for different ballast gradations are reported and discussed. For this purpose, three different fouling amounts according to fouling index are added to clean ballast. Test results show that by increasing the fouling percentage, the ballast shear strength always decreases both for sand and clay fouled ballast. However, the amount of shear strength reduction is low at high normal stresses. Clay contamination has more adverse effect on the shear strength of ballast compared with sand contamination. Also, the results of tests for evaluation of gradation effect on shear strength of fouled ballast which are conducted on various gradations according to American Railway Engineering and Maintenance-of-Way Association, show that the maximum particle size as well as uniformity coefficient affect the shear strength of ballast. Also, an empirical equation is presented to observe the effect of ballast gradation on reduction of shear strength with regard to amount of fouling material and normal stress.     

Preparation of lamellar hybrid inorganic–organic films of layered titanate and cationic or anionic surfactants

Hybrid inorganic–organic films were fabricated from aqueous colloidal solutions of a layered titanate salt and cationic and anionic surfactants. Cetyltrimethylammonium bromide and dodecyl phosphate were used as cationic and anionic surfactants, respectively. When the substrates dip-coated with mixtures of the titanate salt colloids and the surfactants were treated with steam in a closed vessel, hybrid inorganic–organic films with a lamellar structure were fabricated. Although the titanate layers have a negative charge, the hybrid inorganic–organic films consisting of the titanate layer and the anionic surfactant could be obtained, as well as the ones including the cationic surfactants.     

Sensitive and Versatile Detection of the Fouling Process and Fouling Propensity of Proteins on Polyvinylidene Fluoride Membranes via Surface-Enhanced Raman Spectroscopy

Membrane fouling is the major drawback of membrane-based technologies because it will lead to severe flux declines and the need to clean or replace the fouled membrane. A technique capable of early diagnosis, process monitoring, and evaluation of the role of different foulants playing in the fouling process is crucial for the fouling control. We develop surface-enhanced Raman spectroscopy (SERS) as a new and versatile tool to investigate the fouling process of protein on PVDF (polyvinylidene fluoride) membranes as well as the fouling propensity of three different proteins. We optimized the aggregation level and volume of SERS-active Ag sol and the spectra acquisition method combined with a statistical analysis method to ensure a high detection sensitivity, signal uniformity, and stability. We then used SERS for the early diagnosis of the fouling process and determining when the membrane pores would be blocked. The fouled area was visualized by a combination of the silver staining and Raman mapping. The fouling propensity of different proteins was studied by comparing the relative SERS band intensities of different proteins on a glass slide and after membrane filtration. Compared with fluorescence-based techniques, the narrow, well-resolved Raman band, especially the use of the same excitation line and laser power, endows SERS the ability to compare the fouling propensity in a very simple way.     

复合膜反渗透装置微生物污染的防治

简述了反渗透（ＲＯ）装置被微生物污染的情况及其危害．提出了防治复合膜反渗透装置微生物污染的方法，包括：ＲＯ前的预处理工艺的选择，采用紫外线杀菌器及电子除菌器；ＲＯ膜阻垢剂及抑菌剂的选择；ＲＯ系统停运时防止微生物污染的方法；ＲＯ系统被微生物污染后用杀菌剂药液清洗ＲＯ膜及系统．     

微滤膜上污染的蛋白质的定量方法

蛋白质对膜的污染是限制微滤效率的关键因素之一。迄今为止虽然已就膜污染的机理进行了广泛研究,但是,还没有一种比较完善的方法直接对污染的微滤膜上的蛋白质进行定量。文章建立了一种简便的测定微滤膜上污染的蛋白质量的方法。被蛋白污染的膜首先用氨基黑10B染色,再在脱色液中脱色,最后用洗脱液洗脱结合到膜上的染料。在620nm处测定洗脱液的吸光度。根据吸光度计算膜上蛋白的量。并就3种膜（纤维素膜,Druapore GVWP膜和核孔膜）和4种蛋白质（牛血清白蛋白,牛血红蛋白,溶菌酶和卵清蛋白）进行实验,测定了点样、堆积和吸附3种条件下洗脱液吸光度和膜上蛋白量的关系,均呈较好线性。但不同蛋白质之间存在一定差异。