【作者】 陈玉洁；

【导师】 陈雪明；

【作者基本信息】 浙江大学 ， 环境工程， 2017， 硕士

【摘要】 无膜电去离子技术(MFEDI)是一种新型绿色的去离子技术。前面的研究采用下层弱酸强碱树脂、上层强酸强碱树脂的双层床MFEDI制备高纯水存在再生电压过高、处理流速过小等问题,限制了其在工业上的应用。本论文以双层床MFEDI为研究对象,对其树脂层结构进行改进,提高MFEDI制备高纯水的效能。研究内容主要包括:MFEDI强酸强碱层树脂配比改进、MFEDI强酸强碱层树脂种类改进、MFEDI系统在改进后的树脂层结构下长期运行的稳定性与经济性考察。研究结果表明:将MFEDI强酸强碱树脂层由单一配比1:1.75改为1:1、1:2、1:3的不同配比,能有效抑制阳离子逆向迁移,降低再生电压。改进后的MFEDI拥有更好的制备高纯水的处理能力与电再生性能。系统连续运行30个周期,MFEDI出水保持在0.058-0.060μs/cm,平均再生电压为620V,再生液的平均电导率保持在69.5μs/cm,pH维持在6.8-7.0,再生能耗仅为0.39 kWh/m3。对MFEDI强酸强碱层树脂的种类进行改进,在配比为1:1的树脂层中添加少量的弱型树脂,能有效促进强型树脂的电再生,提高系统制备高纯水的效能。再生操作参数的优化结果表明:处理流速50m/h,再生时长20min时,-选择再生流速40m/h,再生电流密度175 A/m2,MFEDI系统的电再生性能最优,树脂中吸附的阴阳离子均能得到很好地再生,此时MFEDI系统拥有最低再生能耗0.20kWh/m3以及较高的水回收率93.3%。经测试,改进后的MFEDI系统具有很强的稳定性。系统持续运行700小时,产水电导率始终稳定在0.057-0.059 μs/cm;pH保持在6.8-7.0,接近中性。电极和树脂的稳定性良好,树脂破损量很少,对系统整体的影响可忽略不计。与目前工业上应用的RO/RO/EDI工艺相比,MFEDI系统再生能耗低,且无需离子交换膜,装置结构简单,具有明显的经济优势。因此,MFEDI技术有着强大的市场竞争力与广泛的工业应用前景。更多还原

【Abstract】 Membrane-free electrodeionization(MFEDI)is a novel deionization for high purity water production.MFEDI in previous research using double layers filed with mixed weak-acid and strong-base resins in the lower,strong-acid and strong-base resins in the upper was restricted due to the poor performance and high regeneration voltage.This thesis was aimed at improving the resin layer structure of MFEDI with double layers and increasing its purification and regeneration performance.Major research works were:improvement on the ratio of the strong-acid and strong-base resin layer;improvement on the variety of the strong-acid and strong-base resin layer;stability and economy of improved MFEDI in long last running.The results showed that changing the ratio of strong-acid and strong-base resin from single 1:1.75 into 1:1,1:2,1:3 could effectively inhibit cationic reverse migration and decrease regeneration voltage.MFEDI with improved layers had better performance for high purity water production.Examined in 30 operational cycles,the effluent conductivity of improved MFEDI was 0.058～0.060ps/cm,the average regeneration voltage was 620V,the concentrate conductivity kept in 69.5μs/cm,pH maintained at 6.8-7.0,and the system energy consumption was only 0.39 kWh/m3.Changing the variety of the strong-acid and strong-base resin layers of MFEDI by adding some of weak resins into the strong resin layer of the ratio 1:1 could effctiveiy promote the regeneration of strong resin and improve its performance for high purity water production.By investigating their influence on the performance of MFEDI,the optimal regeneration parameters were obtain:processing velocity at 50 m/h,regeneration duration 20min,regeneration velocity of 40 m/h,regeneration current density of 175 A/m2,cation and anion of resin absorbed both got good regeneration,MFEDI system had the lowest energy consumption of 0.20 kWh/m3 and the highest water recovery rate at 93.3%.The improved MFEDI system had strong operation stability by testing.Running continuously for 700 hours,the effluent conductivity maintained at 0.057～0.059μs/cm,pH was kept from 6.8 to 7.0,near to neutral.Electrodes and resin also had good stability,the breakage rate of resin was sharely short,their impact on the overall system can be neglected.Compared to RO/RO/EDI,MFEDI system had obvious economic advertange in industrial application with the lower energy consumption,none of ion exchange membrane,simple device,easy for automation control.Therefore,MFEDI system had a stronger market competiviveness and a bright industrial prospect.更多还原