高硅去除率电去离子技术制备高纯水的研究

将BM引入到CEDI中,构建了BMEDI装置,研究其对弱电解质硅去除的改进效果,并将其与CEDI进行对比考察。结果表明,以一级RO水为进水,在膜堆电流低于0.08A时,BMEDI在产水水质上稍优于CEDI且其膜堆电阻较CEDI更低。进一步以人工添加进水Si含量的方式对BMEDI与CEDI进行考察,在进水Si的质量浓度分别为0.5、1.0、1.5、2.0 mg/L条件下,BMEDI的产水水质和除Si效果均优于CEDI;在上述的进水条件下继续运行25 h,当进水Si的质量浓度为1.5 mg/L时BMEDI的Si去除率和产水电阻率分别达到94.65%和15.0 MΩ·cm,而CEDI则已下降至61.25%和10MΩ·cm。研究表明BMEDI能够适应较高的原水Si含量而稳定制取高纯水,对工业及实验室超纯水的制备具有应用前景。     

制备纯水用电去离子工艺的进展

制备纯水用电去离子(EDI)工艺在工业上已应用近20 a了.为了改善EDI装置的性能、增加可靠性和降低系统的总费用,已先后推出了第一代"薄室"、第二代"厚室"和第三代"圆盘式"结构EDI装置的种种系列产品,EDI工艺已在发电、电子、制药等行业得到愈来愈多地应用.作者通过对这三代EDI装置发展历程的讨论,重点阐述圆盘式新型EDI装置的结构和特点.还讨论了EDI装置的出水水质标准方面的问题.     

电去离子纯水制备技术

EDI作为一种先进的纯水、高纯水生产技术,已经越来越受到人们的关注,该文主要介绍EDI过程的原理、工艺及关键技术,展望了EDI的发展前景。     

电去离子（EDI）高纯水新技术及其研究进展

介绍了EDI过程的脱盐机理,分析并提出了过程的主要强化途径。阐述了EDI的V-I、pH-I特征及“树脂电再生”等特征及其与电渗析（ED）过程的区别。介绍了国内外EDI的研究进展与应用概况。     

回收重金属废水用电去离子技术研究进展

电去离子(EDI)技术是由电渗析和离子交换相互有机结合的膜分离脱盐技术.其具有连续运行、不用酸碱、环境友好等显著优点.作者介绍了国内外采用电去离子技术回收含铜和含镍废水的研究进展,针对重金属废水的特点,设计了以阳树脂为主的阴、阳树脂分层填充的电去离子装置,采用该技术代替传统的离子交换技术,可实现重金属废水的回收和利用.达到闭路循环、零排放、无污染的目的.     

水净化用电去离子装置

美国专利披露了一种大容量的超纯电去离子装置，该装置由很多放置在阴极和阳极间的去离子水和浓水隔室组成，产水或浓水流经这些隔室，每个隔室含几个充填有适宜的离子交换介质的流道。在此隔室中间流动的废水和产水流是并行的(即，“同时的”)；通过流道的水流是“串联”的(即，“顺序”的)。在该装置中，电流是通过使用了分段的电极(阴极或阳极)的隔室产生的。此电去离子装置具有快速、有效和坚固耐用的优点，其结构易于放大至较大容量。     

回收重金属废水用电去离子技术研究进展

回收重金属废水用电去离子（EDI）技术,是一项电渗析和离子交换相互有机结合的膜分离脱盐技术。具有连续运行、无人值守、不用酸碱、环境友好等显著优点。介绍了国内外几项用于回收含铜和含镍废水的研究进展,针对重金属废水的特点,设计了以阳树脂为主的阴、阳树脂分层填充的装置,采用这种技术,代替传统的离子交换技术,可实现重金属废水的回收和利用,达到闭路循环,零排放,无污染。     

碳钢在高温高纯水中腐蚀与成膜规律研究

本文从理论上分析了碳钢在高温高纯水中的腐蚀机理,推导了碳钢在高温高纯水中的腐蚀与成膜规律。并用失重法等实验验证了这一规律的存在。本文还应用表面测试技术,研究了碳钢表面膜组成的变化规律。结果对了解碳钢——水热管的内部腐蚀规律、制定解决碳钢——水热管相容性措施提供了依据。     

高盐废水制取高纯水工艺研究

基于高盐废水制取高纯水,对2级反渗透(RO)+电去离子(EDI)工艺和膜蒸馏(MD)+EDI工艺进行了试验研究。结果表明,当原水电导率为3 310μS/cm时,2级RO的产水电导率为6.5~7.3μS/cm,总除盐率99.78%,MD产水电导率2.6~3.7μS/cm,除盐率99.89%,都可满足EDI进水水质要求,后续EDI产水水质相近,电导率稳定在0.077~0.083μS/cm。2级RO+EDI工艺技术成熟,能耗较低,但对原水含盐量适应性差,回收率较低(小于60%);MD+EDI工艺对原水含盐量适应性强,回收率高(大于90%),但膜通量较低,还处于开发阶段。综合考虑,MD+EDI工艺更具优越性,进一步完善膜蒸馏技术,应用前景广阔。     

电去离子水软化技术的实验研究

阐述了电去离子水软化技术的原理,并对超滤/电去离子(UF/EDI)工艺用于常规自来水脱硬,制备常低压工业锅炉软化水进行了实验研究.EDI水软化过程的特征曲线表明,该过程工况与传统电渗析过程相似,但分离效率显著提高.对于电导率627μS/cm的UF原水,实验条件下EDI软化过程的总脱盐率达到65%,而Ca2 、Mg2 的去除率则分别达到99.7%和99.97%,产品水硬度＜0.05 mg/L.研究表明,EDI工艺有望发展成为继纳滤之后的又一高效膜软化水新技术.     

Production of ultrapure water by continuous electrodeionization

The process of continuous electrodeionization (CEDI) has now been in commercial use for over twenty years and has gained widespread acceptance in the production of ultrapure process water for industrial use. Likely the chief reason for its commercial success is that CEDI is a green process. It substitutes electricity for the hazardous chemicals normally used to regenerate ion exchange resins, and thereby eliminates the waste stream associated with resin regeneration. This paper describes the mechanisms of operation, types of device construction, and principal industrial applications of this relatively new water purification technology.     

吸附法去除水中胶硅的研究

选用大孔吸附树脂作吸附剂,氢氧化钠溶液作脱附剂,对水体中的胶体硅进行去除试验,取得了令人满意的效果,处理量大于100倍树脂床体积,处理后水中的胶硅含量小于0．5mg/L,符合化工生产工艺要求,这项技术为水处理中除胶技术探索了一条新途径。     

Development of an electrodeionization process for removal of nitrate from drinking water Part 1: Single-species testing

A bench-scale study was performed to develop and evaluate the use of electrodeionization as a technology for the removal of nitrate from drinking water. Electrodeionization is an emerging technology that combines electrodialysis and ion exchange. Treatment of distilled water that was dosed with sodium nitrate was studied. The impact of design and operating conditions on nitrate flux and energy consumption for nitrate removal was evaluated. Increasing the voltage applied to the unit resulted in an increased nitrate flux out of the water stream but resulted in an increased energy consumption per equivalent of nitrate removed. Increasing the membrane spacing resulted in decreased fluxes and increased energy consumption. The type of resin employed in the process clearly had an impact on the fluxes, and the presence of any anion-exchange resin resulted in an improved performance compared to operation in the electrodialysis mode. Increasing the number of membrane pairs in the unit resulted in a decreased nitrate flux but appeared to have little impact on the energy consumed. Nitrate fluxes increased with nitrate concentration but appeared to approach a maximum flux at very high concentrations. At lower nitrate concentrations there was an increased energy consumption that likely resulted from the electrolysis of water at the lower ionic strength. Increasing the process flow rate appeared to have little impact on nitrate flux but resulted in higher energy consumption. Operation in recycle mode produced similar results to the once-through mode when conditions of similar outlet water composition were compared.     

超纯水制备

采用预处理+2级反渗透+ED I+混床工艺制备超纯水。实验结果证明,出水Ca2+质量浓度小于2μg/L,Na+质量浓度小于5μg/L,S iO2质量浓度小于5μg/L,电阻率稳定在17 MΩ.cm,能满足生产要求。     

Cr(VI) removal by continuous electrodeionization: Study of its basic technologies

The capabilities of continuous electrodeionization process (CEDI) and its basic technologies (electrodialysis (ED) and ion exchange (IX)) were analyzed in order to remove hexavalent chromium from synthetic solutions at pH 5. A cell with two chambers (dilute and concentrate) was used. Two cation exchange membranes (CM-1) and one anion exchange membrane (AFN) (40 cm² effective area) were employed in the experimental setup. IX technology was single evaluated using an IRA-67 anionic resin to know its independent performance from the other technologies, whereas ED was studied in the cell; I_lim determination was done by I vs. U plots and factors of 0.7 I_lim and 0.85 I_lim were applied to ED process. Finally, EDI process was studied at the same conditions that ED in order to know the resin bed role. During IX the removal reached was 50%; ED 98% after 6.25 h operation with an energy consumption of 1.21 kW h/m³; EDI (anionic bed) accomplishing 97.55% chromium removal (energy consumption of 0.91 kW h/m³). Finally EDI with mixed bed removed 99.8% in 1.3 h and of 0.167 kW h/m³ of energy consumption.     

Development of an electrodeionization process for removal of nitrate from drinking water Part 2: Multi-species testing

A series of bench-scale experiments was performed with a novel electrodeionization (EDI) process to determine its capacity to remove NO₃⁻ from water in the presence of competing species. Experiments were performed with deionized water that was dosed with selected anionic and cationic species and with two natural waters that contained differing concentrations of dissolved solids. Extended duration experiments were performed to assess the ability of the process to sustain NO₃⁻ removal over a longer period of time. It was found that the use of ion-selective resins in the EDI unit resulted in a process that was more nitrate selective and energy efficient that when a general anion-exchange resin was employed. Operation in EDI mode was found to be superior to operation without resins (ED mode). The most highly selective and energy-efficient operation was at the lowest applied voltage of 2 V per membrane pair. The impact of competing species on NO₃⁻ flux was independent of the competing species when expressed on an equivalence basis. At elevated concentrations of multiple competing species the flux of NO₃⁻ was reduced. The removal of NO₃⁻ from two natural water streams revealed the significance of the water composition on the performance of the EDI unit with respect to the selectivity of NO₃⁻ removal and energy consumption. When treating the Manotick well water, the EDI unit required more energy per equivalence of NO₃⁻ removed and was less selective than when treating the Ottawa potable water that was lower in dissolved solids. Extended duration experiments with the dosed Ottawa water over a period of 48 h did not reveal any decline in fluxes.     

高硅水镁石钠化焙烧法除硅工艺研究

以高硅水镁石为原料、氢氧化钠为钠化剂,研究了高硅水镁石钠化焙烧除硅过程中氢氧化钠用量、焙烧温度、焙烧时间等对焙烧水洗产物中硅含量的影响,对不同温度条件下的焙烧产物和焙烧后水洗产物的结构和谱学特征进行分析和表征,以揭示高硅水镁石钠化焙烧除硅机理。结果表明：在焙烧温度为650 ℃、氢氧化钠用量为理论量3倍、焙烧时间为3 h的最优条件下,钠化焙烧过程中Na⁺会与蛇纹石热分解产物Mg₂SiO₄中的Mg²⁺发生置换反应,最终形成可溶性盐Na₄SiO₄,从而水洗除去,水洗产物中硅质量分数为1.89%,硅提取率达90.1%。     

湿法冶金去除太阳能级硅中硼的研究

湿法提纯作为冶金法制备太阳能级硅的前处理工序,可以去除大部分金属和硼杂质。研究了以氢氟酸-硫酸混合酸为浸出剂,有机溶剂甲醇作为后处理剂,去除硅粉中硼杂质的方法。采用电感耦合等离子体发射光谱仪（ICP）等对产品进行表征。酸浸过程优化工艺条件：硫酸质量分数为55%,氢氟酸质量分数为7%,酸浸温度为70 ℃、酸浸时间为4 h、液固质量比为8∶1。酸浸后可使硅粉中的硼杂质质量分数由6.893×10^-6降至3.867×10^-6,去除率为41.9%。在酸浸基础上采用有机溶剂甲醇作为后处理剂,杂质硼质量分数降至3.84×10^-6,去除率为44.29%。从硼酸浸后形成的产物入手探索提高硼去除率的方法,实验验证了该方法的可行性,为研究湿法冶金预处理太阳能级硅提供了新的参考。     

附加电场超滤膜去除水中有机污染物的研究

研究了附加电场超滤膜工艺去除水中有机污染物的性能,结果表明:原水中的腐殖酸在电场中发生电泳迁移,减少了向膜表面的移动,同时发生凝聚现象,沉积在膜表面形成疏松的滤饼层,有效减缓了膜污染。附加电场后对腐殖酸和4-MBC的去除率均有很大提高。同时发现,吸附是大孔径低压膜去除小分子4-MBC的主要作用,水中腐殖酸的存在对超滤去除4-MBC有很大的促进作用。