膜蒸馏海水淡化研究

研制了聚偏氟乙烯中空纤维微孔膜,并用减压膜蒸馏技术进行了海水淡化实验室试验及中间试验．海水温度在５５℃,经一次过程,脱盐率大于９９．７%,膜通量大于５ｋｇ/(ｍ２·ｈ)．试验数据表明,微孔膜的孔径与孔隙率,以及膜组件和膜装置的结构设计对膜蒸馏过程有重大影响．同时,研究了海水温度、真空度、流量等因素对膜蒸馏过程的作用．     

Synthesis and characterization of novel nanocomposite membrane of sodium titanate/Nafion

Novel nanocomposite membrane of sodium titanate/Nafion based on sodium titanate nanotubes with Nafion^® were prepared by solvent casting techniques. Nanotubes of sodium titanate were synthesized by hydrothermal method. TEM, XRD, and FTIR were employed to characterize the crystal phase, microstructure, and other physicochemical properties of the membrane and the nanotube samples. FTIR results showed us that the nanotube material of Na₂Ti₃O₇ has existed in the nanocomposite membrane of Na₂Ti₃O₇/Nafion. The existence of sodium titanate nanotubes in Nafion^® improves the methanol crossover and makes promising practical value of blocking methanol in direct methanol fuel cells.     

膜吸收法海水脱硫研究

实验采用疏水性聚丙烯中空纤维膜组件为膜接触器,以清水、海水以及与海水相同pH值的NaOH溶液作吸收液,比较了3种不同的吸收液对SO2与空气混合气体的脱硫效果.研究了气液压力差、吸收液流量、进气流量以及进气浓度等因素对脱硫效率的影响.结果表明,与清水及相同pH值的NaOH溶液相比,海水是一种对二氧化硫缓冲能力大,资源丰富,脱硫效率较高的吸收剂.在气液两相压力差保持在穿透压范围内时,以较低流量的海水吸收液处理较高流量的低浓度(SO2体积分数ψ为2 000×10-6以下)气体时,脱硫效率可达90%以上.因此膜吸收法海水脱硫技术在沿海地区具有广阔的应用前景.     

Pilot performance of Tokuyama Soda bipolar membrane in sodium chloride salt splitting

This paper was written by Cynthia Carmen of the Graver Water Division of the Graver Company, New Jersey, USA and presented at the Seventh International Forum on Electrolysis in the Chemical Industry, held from 7–11 November 1993 at Lake Buena Vista, Florida, USA.     

膜技术处理褐藻酸钠废水

介绍了采用预处理-超滤-纳滤工艺处理褐藻酸钠生产过程中排放的含钙废水的试验研究结果．结果表明，该废水经处理后，产水可作为生产工艺用水回用，回用率≥75％，浓缩液和废渣可制取海藻生物肥，实现清洁生产，环境效益和经济效益显著．     

纳滤膜在海水淡化中的应用研究

海水淡化是解决淡水危机的主要方法之一,但由于海水的硬度、浊度和总固溶物含量均非常高,因而导致淡化水的能耗量和成本较高.本文采用纳滤膜法处理海水,考察纳滤膜分离性能随操作压力、操作温度、时间、水回收率等变化的影响及纳滤膜运行的稳定性.结果表明,采用纳滤膜技术可以降低海水的硬度和总固溶物的含量,减少结垢与污染,提高水回收率,有望实现海水淡化成本的进一步降低.     

A mass spectrometer with a membrane interface for oil concentration monitoring in seawater

An immersion mass spectrometer with a membrane interface was used for oil detection and oil concentration measurements in seawater by measuring in situ the concentrations of three hydrocarbons: benzene, toluene, and xylene in the region of the specialized Primorsk oil loading seaport in the Gulf of Finland. The recorded mass spectra demonstrated the possibility of measuring the oil concentration in seawater and determining the grade of oil products. The use of a mass spectrometer with a membrane separator interface allows measurements of hydrocarbon concentration with high accuracy, which is currently not provided in commercially available monitors.     

高温质子交换膜燃料电池用Nafion／SiO2复合膜研究进展

传统的质子交换膜燃料电池在高温下工作时，质子膜会因温度升高而发生脱水和膜电阻升高的现象，这对提高燃料电池的工作性能是一个致命的阻碍．由于Nafion／SiO2复合膜具有较好的吸水和保水性能和较好的阻止甲醇渗透的能力，人们通过溶胶一凝胶法或重铸法合成了Nafion／SiO2复合膜，并于高温(80～140℃)下应用在质子交换膜燃料电池和直接甲醇燃料电池中．简单介绍了Nafion／SiO2复合膜的制备方法、结构性能及研究情况，并分析了存在的问题和其广阔的应用前景．     

Synthesis and characterization of Nafion/TiO2 nanocomposite membrane for proton exchange membrane fuel cell

In this study, the syntheses and characterizations of Nafion/TiO2 membranes for a proton exchange membrane fuel cell (PEMFC) were investigated. Porous TiO2 powders were synthesized using the sol-gel method; with Nafion/TiO2 nanocomposite membranes prepared using the casting method. An X-ray diffraction analysis demonstrated that the synthesized TiO2 had an anatase structure. The specific surface areas of the TiO2 and Nafion/TiO2 nanocomposite membrane were found to be 115.97 and 33.91 m2/g using a nitrogen adsorption analyzer. The energy dispersive spectra analysis indicated that the TiO2 particles were uniformly distributed in the nanocomposite membrane. The membrane electrode assembly prepared from the Nafion/TiO2 nanocomposite membrane gave the best PEMFC performance compared to the Nafion/P-25 and Nafion membranes.     

钨酸钠溶液膜电解体系的阳极选择研究

通过测定钨酸钠溶液电解体系中的多种材料的电极极化曲线和强化电解寿命试验,筛选出了钨酸钠溶液膜电解过程中不同阶段的合适的阳极材料;并通过考察不同形状的阳极对电解的影响,得出了网状阳极更适合钨酸钠溶液电解的结论。     

Nafion/silane nanocomposite membranes for high temperature polymer electrolyte membrane fuel cell

The polymer electrolyte membrane fuel cell (PEMFC) has been studied actively for both potable and stationary applications because it can offer high power density and be used only hydrogen and oxygen as environment-friendly fuels. Nafion which is widely used has mechanical and chemical stabilities as well as high conductivity. However, there is a drawback that it can be useless at high temperatures (> or = 90 degrees C) because proton conducting mechanism cannot work above 100 degrees C due to dehydration of membrane. Therefore, PEMFC should be operated for long-term at high temperatures continuously. In this study, we developed nanocomposite membrane using stable properties of Nafion and phosphonic acid groups which made proton conducting mechanism without water. 3-Aminopropyl triethoxysilane (APTES) was used to replace sulfonic acid groups of Nafion and then its aminopropyl group was chemically modified to phosphonic acid groups. The nanocomposite membrane showed very high conductivity (approximately 0.02 S/cm at 110 degrees C, <30% RH).     

Electrochemical chloride removal for reinforced concrete with steel rebar cage using auxiliary electrodes

In this paper, a new approach of electrochemical chloride removal (ECR) using the auxiliary electrodes was proposed and the performances of this method were investigated by experiments. Two kinds of electrode setups were investigated: the radial type and the layer type. The results showed no matter which setup was used the chloride removal percentage all exceeded 70% after 8-week treatment. The chloride enclosed by the steel rebar cage could be successfully pushed out from concrete using auxiliary electrodes. The half cell potentials of rebars after 8-week treatment were all higher than −270 mV(CSE) and the corrosion rates were lower than 0.05 mpy, it indicated that after ECR treatment the corrosion risk of rebars was low. In addition, after ECR the surface hardness was enhanced via the results of rebound strength test. The pH value of concrete was also enhanced during the ECR process.     

膜生物反应器脱氮除磷工艺处理城市污水的工程应用

为强化城市污水脱氮除磷,研发了厌氧/缺氧/好氧/缺氧-膜生物反应器(A2/O/A-MBR)新工艺,并建设了设计处理规模为2万m3/d实际工程.对该工程的长期监测表明,出水C()D、TN、NH4+-N和TP的平均浓度分别为20.6、6.67、1.05、0.19 mg/L,优于《城镇污水处理厂污染物排放标准》中的一级A标准...     

Electrochemical sample matrix elimination for trace-level potentiometric detection with polymeric membrane ion-selective electrodes

Potentiometric sensors are today sufficiently well understood and optimized to reach ultratrace level (subnanomolar) detection limits for numerous ions. In many cases of practical relevance, however, a high electrolyte background hampers the attainable detection limits. A particularly difficult sample matrix for potentiometric detection is seawater, where the high saline concentration forms a major interfering background and reduces the activity of most trace metals by complexation. This paper describes for the first time a hyphenated system for the online electrochemically modulated preconcentration and matrix elimination of trace metals, combined with a downstream potentiometric detection with solid contact polymeric membrane ion-selective microelectrodes. Following the preconcentration at the bismuth-coated electrode, the deposited metals are oxidized and released to a medium favorable to potentiometric detection, in this case calcium nitrate. Matrix interferences arising from the saline sample medium are thus circumvented. This concept is successfully evaluated with cadmium as a model trace element and offers potentiometric detection down to low parts per billion levels in samples containing 0.5 M NaCl background electrolyte.     

膜脱气技术脱除盐酸的工艺研究

针对酸液中盐酸的脱除与回收,提出以中空纤维疏水微孔膜为核心环节的膜脱气工艺,并考察了脱气组件的膜面积、原液流速、原液中盐酸浓度等因素对HCl脱除效率的影响.研究结果表明:该工艺可行,随着膜面积的增大、原液流速的升高,HCl的脱除率均有所上升;随着原液盐酸浓度的降低HCl的脱除率下降.在膜面积为1.0 m2,流速为0.12 m/min,真空度为0.090 MPa的条件下,从浓度为6mol/L的盐酸溶液中脱除HCl,其脱除率最高可达85%.     

High efficiency removal of 2-chlorophenol from drinking water by a hydrogen-based polyvinyl chloride membrane biofilm reactor

A continuously stirred hydrogen-based membrane biofilm reactor (MBfR) with polyvinyl chloride (PVC) hollow fiber membrane was investigated for removing 2-chlorophenol (2-CP) from contaminated drinking water. The bioreactor startup was achieved by acclimating the microorganisms from a denitrifying and sulfate-reducing MBfR to the drinking water contaminated by 2-CP. The effects of some major factors, including 2-CP loading, H(2) pressure, nitrate loading, and sulfate loading, on the removal of 2-CP by the MBfR were systematically investigated. Although the effluent 2-CP concentration increased with its increasing influent loading, the removing efficiency of 2-CP by the MBfR could be up to 94.7% under a high influent loading (25.71 mg/L d). The removing efficiency of 2-CP by the MBfR could be improved by higher H(2) pressure, and lower influent nitrate concentration and sulfate concentration. A high H(2) pressure can assure enough available H(2) as the electron donor for 2-CP degradation. The competition in the electron donor made nitrate and sulfate inhibit the degradation of 2-CP in the MBfR. The electron flux analyses indicated that the degradation of 2-CP only accounted for a small part of electron flux, and the autohydrogenotrophic bacteria in the MBfR were highly efficient for the 2-CP removal.     

高温质子交换膜燃料电池用Nafion(R)/SiO2 复合膜研究进展

传统的质子交换膜燃料电池在高温下工作时,质子膜会因温度升高而发生脱水和膜电阻升高的现象,这对提高燃料电池的工作性能是一个致命的阻碍.由于Nafion(R)/SiO2复合膜具有较好的吸水和保水性能和较好的阻止甲醇渗透的能力,人们通过溶胶-凝胶法或重铸法合成了Nafion(R)/SiO2复合膜,并于高温(80～140℃)下应用在质子交换膜燃料电池和直接甲醇燃料电池中.简单介绍了Nafion(R)/SiO2复合膜的制备方法、结构性能及研究情况,并分析了存在的问题和其广阔的应用前景.