双极性膜电渗析法制备γ-氨基丁酸

通过对双极性膜电渗析转化γ-氨基丁酸(GABA)过程的研究,确定了三隔室电渗析工艺的可行性,并利用双极性膜电渗析装置,将γ-氨基丁酸钾盐转化为GABA和KOH.最终结果表明,经三隔室双极性膜电渗析转化和冷却结晶后,可以得到纯度为99%以上的γ-氨基丁酸结晶以及2.5%以上的粗氢氧化钾溶液,对于粗品γ-氨基丁酸溶液双极性膜电渗析转化过程,平均电流效率在60%以上,电耗为2kW.h/(kg GABA).     

二室双极膜电渗析器在低浓度二氧化硫净化工艺中应用的可行性

介绍了双权膜电渗析器在低浓度二氧化硫烟气净化中的应用，用国产双极膜和阴、阳离子交换膜组成二室双权膜电渗析器，考察了双极膜的性能，得出在高电流密度96．09mA/cm^2和1．2—1．7V的膜电压下，能获得较高的电流效率(80％一100％)和较快的转化速率．提出了国产双权膜存在的问题和今后研究的方向．     

双极膜电渗析质子渗漏相关因素的分析

采用恒流三室双极膜电渗析方式,利用同一种阴离子交换膜和两种不同型号的双极膜对Na2 SO4溶液再生H2 SO4和NaOH过程中酸室H+离子渗漏进行了研究,分析了双极膜及电渗透水通量与双极膜电渗析(BMED)再生酸碱中酸室H+离子渗漏的相互作用.实验结果表明:在相同电流密度条件下,双极膜的膜电阻越小,酸室电渗透水的通量越大,进而酸室质子渗漏的百分数越小.酸室H+渗漏携带的水量仅为酸室渗漏“逃水”水量的一部分.     

利用双极性膜电渗析分离丝氨酸和脯氨酸混合物

以丝氨酸和脯氨酸为例,探讨了使用双极性膜电渗析分离中性氨基酸混合物的理论问题和实施方法．在对混合氨基酸溶液中离子成分进行理论计算的基础上,预测了使用双极性膜电渗析分离丝氨酸和脯氨酸的可行性和操作方法,并且通过实验证明了理论预测的正确性．对于该体系,使用混合物中加适量碱的方式可以实现很高的单级分离效果,比如可以将50％的混合溶液分离为纯度90%以上的产品溶液．     

双极膜电渗析技术在有机酸生产中的应用进展

双极膜电渗析技术能直接将水解离为H 和OH-,因而能在不外加酸的情况下使有机酸盐转化为有机酸,且不产生任何废液.这一特殊的优势是传统工艺中的酸化沉淀法、离子交换法和普通电渗析无法比拟的.近年来,双极膜在柠檬酸和乳酸等有机酸生产中的应用研究进展迅猛.因此现谨就双极膜电渗析技术的原理、与传统工艺相比的优势、在实验和生产方面的研究进展和对未来的展望作一综述,以指导相关的研究工作.     

电渗析技术在零排放中的应用

零排放包含膜浓缩与蒸发结晶两个重点单元,而常用的膜浓缩技术包含高压反渗透、正渗透、电渗析.电渗析及双极膜电渗析技术以其在常温常压下可以达到高的浓缩终点和由盐制备酸碱的特性,在零排放膜浓缩中有很好的应用前景.在张家港工业园区的中试结果表明,电渗析可以有效降低进入热蒸发的水量,而双极膜电渗析可以将部分废盐溶液制成酸碱溶液在现场直接回用,实现了废盐资源化.     

均相离子交换膜在我国若干工业领域的应用

介绍了我国己批量生产的均相阴、阳离子交换膜的制造方法及其电化学性能指标，并且详细阐述了这些膜在填充床电渗析制造高纯水、造纸黑液的处理、甘氨酸的分离和纯化对及d-酒石酸钠生产d-酒石酸等若干工业领域的应用所取得的成果．我国已能生产用于上述领域的成套均相阴、阳膜组装的电渗析设备．     

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.     

双极膜电渗析烟气脱硫技术经专家评议通过

<正>2014年,由北京廷润膜技术开发有限公司出资,与浙江大学和哈尔滨哈投投资股份有限公司合作,在哈投热电厂进行了双极膜电渗析烟气脱硫中试,试验经过3个月连续运行,整套装置运行稳定,填料式喷淋吸收塔和双极膜电渗析装置的性能均达到预期效果,经处理后的烟气均达标排放.2014年10月22日,中国膜工业协会专门对"双极膜电渗析烟气脱硫技术"在哈投热电厂组织召开了"双极膜电渗析烟气脱硫技术评议会",针对该中试项目进行了现场综合评议.由中国膜工业协会秘书长尤金德邀请了高从堦院士、侯立安院士,     

双极膜电渗析由葡萄糖酸钠制备葡萄糖酸的实验研究

采用装配自产双极膜和阳膜的两隔室双极膜电渗析装置,研究了将10%(质量分数)葡萄糖酸钠溶夜转化为葡萄糖酸的实验过程.双极膜电渗析过程可使葡萄糖酸钠溶液电导率降低到3mS/cm,实现超过95%转化率;随着料液中葡萄糖酸钠浓度的逐渐降低,电流密度、电流效率、产酸量均逐渐下降,而产酸能耗逐渐升高.随着膜对电压的升高,电流密度和产酸量均增加,产酸能耗也增加;膜对电压分别为1.3、1.5和1.8V时对应的电流密度为206、278和340A/m~2,对应的产酸量为56、73和98 mol/(m~2·h),对应的产酸直流能耗为48、55和62kW·h/kmol;膜对电压的升高导致了较低的资本支出和较高的运营支出,最佳的膜对电压取决于总支出的最小化;当采用膜对电压为1.5V时第1年的总支出最小,但随后年份中膜对电压1.3V时的总支出最小.     

双极性膜电渗析技术在硅溶胶生产中的应用

报道了双极性膜电渗析取代行工艺中泡花碱转化成硅溶胶的酸化过程的研究,转化得到硅溶胶中SiO2含量达到6％－105,pH值在3以下,平均电流效率在55％－75％范围内,平均耗电低于1kW.h/kg(每千克硅溶胶）,制得的硅溶胶产品符合工业要求。     

双极性膜电渗析法连续处理酚钠的工业实验研究

介绍了利用双极性膜电渗析法连续处理酚钠溶液使之转化为苯酚的工业实验情况,分别进行了长周期运行小试和扩大实验,长周期小试实验中膜面积为0.03 m2(膜的有效面积为0.0147 m2)的膜器,运行1000 h,考查各种实验参数及膜的耐久性.扩大实验中单张膜膜面积为0.5 m2.实验结果表明:酚钠转化率接近100%,电流效率大于50%;所得碱液浓度能保持在3%~6%,能够循环回碱洗工段使用.     

Concentration and purification of chromate from electroplating wastewater by two-stage electrodialysis processes

A designed two-stage electrodialysis system is proposed to concentrate and purify chromate from a low pH electroplating wastewater using monovalent selective electrodialysis membranes. With low pH of the raw water (pH 2.2) in the first stage, chromate was presented as HCrO(4)(-) and monovalent ions (HCrO(4)(-), NH(2)SO(3)(-), Na(+) and Cl(-)) were able to pass through the membrane thus chromate was concentrated up to 191%. Higher current density, flowrate and more membrane area all increased the chromium recovery. When pH was adjusted to 8.5 before entering the second stage, the chromate species was presented as divalent CrO(4)(2-) and retained in the concentrated stream, and the rest monovalent ions (NH(2)SO(3)(-), Na(+) and Cl(-)) were separated by passing through the membrane. For example, 45% of the chlorides were separated in this study. The separation efficiencies in the second stage were also increased when the current density, flowrate and membrane area were increased. Electron Spectroscopy for Chemical Analysis was used to examine the surface chromate species for stage 1, and anion exchange membrane showed more chromate fouling comparing to cation exchange membrane due to more adsorption and concentration polarization effects for the anion exchange membrane.     

Enhancing simultaneous electricity production and reduction of sewage sludge in two-chamber MFC by aerobic sludge digestion and sludge pretreatments

Batch tests were conducted to enhancing simultaneous electricity production and reduction of sewage sludge in two-chamber MFC by aerobic sludge digestion in cathode chamber and sludge pretreatments (sterilization and base pretreatment) prior to sludge addition to anode chamber, respectively. During the stable stage, The voltage outputs and power densities of MFC increased from 0.28-0.31 V to 17.3-21.2 mW/m(2) to 0.41-0.43 V and 36.8-40.1 mW/m(2), respectively, when aerobic sludge digestion occurred in the cathode chamber. When the sludge added to the anode chamber was sterilized or base pretreated, the voltage outputs and power densities of MFC increased from 0.30-0.32 V and 19.9-22.6 mW/m(2) (raw sludge) to 0.34-0.36 V and 25.5-28.6 mW/m(2) (sterilized sludge), 0.41-0.43 V and 37.1-40.8 mW/m(2) (base pretreated sludge), respectively. At the end of the test, the total suspended solids (TSS) and volatile suspended solids (VSS) reduction of sludge in the anode chambers increased from 33.9% and 36.8% to 34.5% and 38.7% with aerobic sludge digestion in the cathode chamber, respectively; while, those (TSS and VSS reduction) with sludge pretreatments prior to the sludge addition to the anode chambers increased from 25.1% and 22.8% (raw sludge) to 32.8% and 34.6% (sterilized sludge), and 25.5% and 26.7% (base pretreated sludge), respectively. The experimental results illuminated both aerobic sludge digestion in the cathode chamber and sludge pretreatments (sterilization and base pretreatment) prior to sludge addition to the anode chamber could enhance simultaneous electricity production from sludge and sludge reduction.     

Development of a two-chamber process for self-assembling a fluorooctatrichlorosilane monolayer for the nanoimprinting of full-track nanopatterns with a 35 nm half pitch

The technology of depositing a uniform and stable anti-adhesion layer on a wafer-scale nanostamp is a critical issue in the industrialized nanoimprinting process. The deposition of an anti-adhesion layer involves O2 plasma treatment to modify the stamp surface and the reaction of the monomers with the surface. Although an automated one-chamber system was developed for uniform and stable anti-adhesion layer coating, unwanted molecules are irregularly deposited on a sample during the O2 plasma treatment due to the contamination of the chamber, leading to the degradation of the anti-adhesion properties. In this paper, a two-chamber self-assembled monolayer (SAM) deposition system was proposed to prevent the degradation of the anti-adhesion properties due to contamination. To examine the effectiveness of the proposed system, the contact angles and chemical compositions of the SAM-coated silicon mold prepared using the one- and two-chamber systems were measured and compared. Finally, 4-in nanoimprinting of 35-nm-half-pitch full-track nanopatterns was conducted using a SAM-coated silicon nanomold prepared using the one- and two-chamber systems, and the replication quality was examined.     

Active dosimetry on recent space flights

The radiation exposure inside the spacecraft in low earth orbit was investigated with a telescope based on two silicon planar detectors during three NASA shuttle-to-MIR missions (inclination 51.6 deg, altitude about 380 km). Count and dose rate profiles were measured, as well as separate linear energy transfer (LET) spectra, for the galactic cosmic rays (GCR) and the trapped radiation encountered in the South Atlantic Anomaly (SAA). Effective quality factors are deduced from the converted LET spectra (in water) in the range 0.1-120 keV micrometer-1 according to ICRP 60. Measured mission averaged dose rates in silicon are in the range 98-108 microGy d-1 and 137-178 microGy d-1 for the GCR and SAA contributions, respectively. The deduced effective quality factors are 2.95-3.29 (GCR) and 1.18-1.25 (SAA), resulting in mission averaged dose equivalent rates of 631-716 microSv d-1 for the comparable three missions.     

电渗析器免拆洗剂研究

通过静态溶垢试验和静态模拟试验对电渗析器清剂进行了研究，研究表明：质量分数为2％，HCl,5%的多聚磷酸盐，HCl CaCO3可清洗掉常用电渗析器内垢物和污染物。