新型聚苯并咪唑PBI的纳滤膜的分离硫酸铬的高碱卤水为促进氯碱 Process 工艺Word下载.docx

1、V V ersity of Singapore, 分校整形外科新加坡， 4 Engineering Dri 4工程直接还原铁 e 4, Singapore 117576 首页4，新加坡117576 The potential of employing nanofiltration for the removal of sulfate from concentrated chlor-alkali brine has 由于雇用了从集中硫酸纳滤膜去除氯的潜力已碱卤水 been investigated. 被调查。 Polybenzimidazole （PBI） was chosen to fabri

2、cate nanofiltration hollow-fiber membranes 聚苯并咪唑（PBI）的被选为编造纳滤中空纤维膜 through the dry-jet wet phase-inversion technique because of its robust mechanical strength and excellent 通过干湿相转化 ， 因为其具有强大的机械强度和优良的技术 chemical stability. 化学稳定性。 The feed solution was a concentrated brine consisting of 253.3 g L 饲料的解

3、决办法是集中卤水的二百五十三点三克蜇组成 - - 1 1 NaCl, 9.7 g L 氯化钠，九点七克孛 Na 钠 2 2 SO 苏 4 4 , and 9.5 g L ，和9.5国励 CrO 铬 with a pH value greater than 12.65. 以pH值大于12.65。 The PBI membranes showed high sulfate 在所涉方案预算膜表现出较高的硫酸盐 rejection （up to 98.4% at pH 13.25 and 25 bar） and low chloride rejection （less than 4.0%）, thus

4、 simultaneously 拒绝（高达98.4，在pH 13.25和25杆）和低氯抑制（小于4.0），从而同时 obtaining an extremely high di-/monovalent anion selectivity. 获得极高的di-/monovalent阴离子选择性。 In addition, the sulfate and chromate rejections 此外，硫酸铬拒绝 increased with increasing solution pH and/or operating pressure. 增加而增加溶液的pH值和/或工作压力。 The impres

5、sive separation performance can 令人印象深刻的分离性能 be attributed to the unique pore and charge characteristics and superior chemical stability of PBI NF membranes. 归功于独特的孔隙和收费的特点和优势所涉方案预算因子膜的化学稳定性。 It was found that the mean effective pore size of PBI membranes is around 0.30 nm in radius, which is close 结

6、果发现 ， 平均有效所涉方案预算膜孔径大小约为0.30纳米半径，接近 to the sizes of hydrated sulfate and chromate anions but much larger than chloride anion size, which contributes 对水合硫酸铬阴离子的大小 ， 但远远大于氯离子的大小，这有助于 to the high separation of divalent anions through size exclusion under high ionic strengths. 以二价阴离子的高分离 ， 通过规模高技术条件下的离子强

7、度排斥。Introduction 导言 In the chlor-alkali process, the electrolysis of a concentrated 在氯碱进程，集中电解 brine solution to produce chlorine and caustic soda takes place 盐水生产氯和苛性钠发生 simultaneously through electrolyzers using ion-exchange mem- 同时通过电解槽使用离子交换换液 branes. 布拉涅斯。 Depending on the nature of the raw mat

8、erials and the 根据对原材料的性质 production techniques, the sodium chloride （NaCl） used to 生产技术，氯化钠（NaCl），用于 prepare the brine for electrolysis generally contains impurities 准备电解卤水一般含有杂质 of SO 二氧化硫 and/or CrO 和/或铬 . 。 As a consequence, sulfate anions, 因此，硫酸负离子， present at low concentrations in the supplemen

9、tary brine stream, 在补充盐水流低浓度， gradually accumulate in the circuit and adversely affect elec- 逐步积累的电路 ， 影响利安达， trolysis, which can cause operating problems as a result of trolysis，这可能导致结果的经营问题 localized precipitation on the membrane. 局部降水的膜。 Because sulfate anions 由于硫酸阴离子 have a detrimental and irrev

10、ersible impact on the life of 对生命有害的和不可逆转的影响 expensive ion-exchange membranes, sulfate levels must be kept 昂贵的离子交换膜，硫酸水平必须保持 under control. 受到控制。A variety of approaches have been proposed 通过各种方法已经提出 for the removal of sulfate, including the induction of chemical 硫酸的搬迁，其中包括化学诱导 precipitation as BaSO

11、降水的硫酸钡 or CaSO 或硬石膏 , ion exchange, crystallization, ，离子交换，结晶， and purging. 和清除。These methods are capital-intensive and difficult 这些方法是资本密集型和困难 implement effectively in terms of techniques or environmental 有效地实施在技术或环境条件 constraints. 限制。 The removal of sulfate by means of nanofiltration 通过纳滤膜去除方法硫酸 （

12、NF） has recently emerged as an alternative approach to （NF）的最近成为一种替代办法 effectively handle the brine. 有效处理盐水。3 3 Nanofiltration is a pressure-driven, membrane-based separa- 纳滤膜是一种压力驱动膜的分色 tion technique that has been widely used for the separation of 重刑技术 ， 已广泛用于分离使用 small neutral and charged molecul

13、es in aqueous solutions 小中立和带电分子在水溶液中 through their active nanoscale pores, with estimated pore sizes 通过他们的积极纳米孔，孔径 ， 预计 of around 0.5 约0.5 2 nm in diameter. 在直径为2纳米。Separation mechanisms of 分离机制 nanofiltration involve steric （size-exclusion） effects, electrostatic 纳涉及立体（排阻）的影响，静电 （Donnan exclusion）

14、 partitioning interactions between the mem- 之间的号负责（唐南排除）分区相互作用 brane and the external solution, and dielectric exclusion. 膜和外部解决方案，和电介质排斥。5 5 8 8 Nanofiltration has become an effective means of removing 纳滤膜去除已经成为一种有效手段 heavy metals ions and divalent anions from wastewater. 重金属离子废水中的二价阴离子。9 9 The 那个 desirable NF membranes for liquid separation must have a robust 液体膜分离理想因子必须有一个强大的 mechanical strength to w