电渗析苦咸水淡化技术研究进展

电渗析苦咸水淡化技术具有脱盐效果好、成本较低、绿色环保等优点,但存在制膜工艺繁琐、传质模型不够精确、能效有待提升等问题。本文首先分析了苦咸水电渗析用离子交换膜的制备及改性方法,对膜材料存在的问题进行了探讨。综述对比了苦咸水电渗析在简化模型、理论模型、半经验模型方面的原理及最新进展,系统总结了常规苦咸水电渗析过程的运行方式和工艺优化策略,并进一步介绍了以新型电去离子、冲击电渗析、可再生能源驱动电渗析为代表的新型电渗析过程在苦咸水淡化方面的原理及应用。在此基础上,提出了今后的研究方向集中于降低制膜成本、优化传质模型、探究集成膜法淡化工艺以及新型电渗析过程等方面。     

离子交换水软化技术研究与应用进展

离子交换法是目前最常见的水软化技术之一,其基于可逆的离子交换反应将溶液中的硬度离子选择性去除,属于典型的特种分离过程。本文介绍并总结了离子交换水软化的基本原理、水软化用离子交换树脂的结构和分类、离子交换水软化技术研究和应用,并针对离子交换水软化存在的问题提出了相应的解决思路。     

电去离子(EDI)过程的水解离动力学分析

基于Nernst-Planck方程建立了EDI过程的传质动力学微分方程.根据此传质模型方程获知,EDI过程中在阴阳离子交换膜/树脂表面与溶液接触的界面层中发生的水解离的差异性,是在于离子交换界面电势梯度的差异,而这种差异又与膜和树脂的结构、性能以及阴阳离子在水溶液中的迁移数的差异有关.     

电去离子集成过程分级浓缩与纯化电镀镍漂洗废水

Successive concentration and purification of simulated nickel-electroplating rinsing wastewater was carried out by integrating membrane process with electrodeionization. The concentrate compartments were filled with ion exchange resins to enhance the separation. The concentrate stream of the primary EDI procedure was operated in closed circuit circulation. The influence of the volumetric ratio of resins in concentrate compartments on the separation was examined. It was found that the best performance could be achieved when anion to cation resin ratio of 6∶4 was adopted. With feed Ni²⁺ concentration of 50 mg·L^-1 and pH of 4.25,the Ni²⁺ concentration of effluent dilute stream could reach 2.78 mg·L^-1 while that of the effluent concentrate stream was as high as 11171 mg·L^-1,which gave a concentration ratio of higher than 220. The effluent dilute stream of the primary EDI was then sent to the second EDI stack for deep desalting. Dilute product with resistivity of 1.6—2.0 MΩ·cm was then obtained,which could be recovered as pure water for electroplating. The membrane process integrated with EDI could find its potent role for zero emission and resource reuse of heavy metal wastewater.     

纳滤膜技术浓缩分离含镍离子溶液

采用纳滤膜法对较高浓度含Ni2+离子溶液进行了高倍数浓缩,考察了操作压力、进料液流量、原水Ni2+离子质量浓度和pH等因素对分离过程性能的影响.结果表明,纳滤膜对Ni2+的截留率随操作压力、进料液流量和原水Ni2+质量浓度的增加而增大,膜通量则随进水Ni2+的质量浓度增加而减小.对于Ni2+质量浓度为3900 mg·L-1,pH为3的NiSO4溶液原水,在操作压力1.4MPa条件下,经截留液全循环工艺运行,纳滤淡化出水Ni2+的截留率均保持在99.6%以上,浓缩液中Ni2+质量浓度最高可能达到23 510mg·L-1,浓缩倍数超过6.研究表明,选择适宜的纳滤膜用于重金属废水的高倍数浓缩,实现有价金属的资源化回收具有良好的技术可行性.     

HIGH—PURITY WATER PRODUCTION BY RO／EDI SYSTEM

Electrodeionization(EDI),also known as continuous deionization(CDI)and packed-cell electrodialysis,is a novel hybrid separation process combining ion-exchange resin with ion-exchange membrane in one unit.The EDI process was discovered in the 1950's［1，2］in laboratory,the first commercial apparatus for the production of high-purity water was available in 1987［3］.Now the EDI technology has been found and will be continuously found its great applications in many engineering fields. In EDI,the dilute compartments are filled with mixed-bed ion-exchange resins,which enhance the transport to the membranes under the force of a direct current.The ion transport is almost entire through the ion-exchange resins and is not effected through the water.Under certain conditions,water-splitting reaction occurs in the dilute chambers and then the relative high concentrations of H+ and OH- are able to regenerate the resins continuously, With the unique “electroregeneration",the EDI unit can be considered as a mixed-bed ion-exchange column with continuous regeneration.and therefore is capable of deep deionization.Comparing with electrodialysis and ion exchange respectively,EDI has put up much superiority in water desalination. In our experiments,the processes for production of high-purity water from tap water are consisted of pretreatment (with ultrafiltration,active carbon and 10 μm-filtration),RO and EDI.     

EDI过程处理低浓度重金属离子废水的研究

为处理低浓度重金属离子废水,对常规的用于超纯水生产的EDI内部构造进行了适应性改进.以模拟的低浓度含镍废水为研究对象,研究了填充树脂类型对过程分离性能的影响.结果表明,使用大孔型强酸强碱性混床树脂较凝胶型树脂能有效强化过程传质.     

双极膜电渗析解离NaCl清洁制备酸碱的实验研究

采用国产双极膜、均相阴、阳离子交换膜交替排列构成的三隔室双极膜电渗析(BMED)构型,以NaCl为原料制备NaOH和HCl.研究了电流密度、原料液浓度和电极液浓度对BMED操作性能的影响,并对两种不同的均相阳膜进行了对比考察.结果表明:在电流密度30mA/cm2,NaCl原料液浓度为1.5 mol/L的条件下,实验范围内NaOH的收率可达80.19%,其收率和能耗随电流密度的增大而增加;电流密度恒定时,较高的原料液浓度利于保持更小的膜堆电阻,过程能耗相应降低;本实验条件下,极室Na2SO4溶液在1%~2%的低浓度范围内时,过程运行效果较3%~4%的高浓度更优.采取进一步向原料室持续补充10%NaCl的操作时,5h后产品NaOH浓度可提高至10%左右,较间歇式操作时的4%水平有显著提高.     

浅水钻探工作平台的改进与推广应用

为了更好地满足水域、沼泽和水陆交互带的地震勘探需要,研制开发了10套浅水钻探工作平台。针对该平台存在的体积和质量较大、下药困难等问题,从平台自航能力、搬迁和运输及提高下药准确率等方面加以改进,形成了浅水钻探工作平台系列,推广应用证明,平台增加了自航能力,提高了工作效率和安全性,减轻了工人劳动强度,一次性下药合格率也得以提高。     

电去离子技术同步纯化和浓缩含镍离子溶液的研究

采用自制微型电去离子膜堆装置,以模拟电镀镍漂洗水为处理对象,基于特征曲线考察确定了工作膜堆电压,并重点研究了淡水室中的树脂比例对过程分离性能的影响.结果表明,阴阳树脂比存在最优值,任一树脂所占比例过高,均会导致膜堆内部结垢,而阴树脂过量时尤为明显.对于含Ni2+质量浓度52mg/L、pH=3的NiSO4溶液,在优选的膜堆电压下,所用阴阳树脂(体积)比为4:6时,淡化出水和浓缩水的Ni2+质量浓度分别达到0.28mg/L和3 407mg/L,浓差大于12 000倍,且过程具有良好的稳定性.