纳滤膜用于脱盐的实验研究
|
摘要
为了进一步了解纳滤膜的分离性能,在实验室研究选择透过膜分离性能。纳滤膜是一种新型的膜,其特性介于超滤和反渗透之间。它的应用范围也日益广泛。目前,纳滤膜的应用研究处于实验阶段,还有大量工作需要进行。本文在实验系统下考察了操作因素对纳滤膜的截留率及膜通量的影响。另外探究纳滤膜处理无机盐溶液时的分离性能。
首先本研究采用正交实验,把影响膜分离性能的操作因素分为操作压力、实验温度、料液浓度以及料液流速等四种,每种因素选用四个不同的工况。结果表明,操作压力和温度对膜通量的影响是最显著的两个因素,加大操作压力或升高实验温度,膜通量将增大。料液浓度对膜通量也有影响,料液浓度越高,膜通量越小,在本实验中,料液流速对膜通量的影响最不显著,料液流速的改变对膜通量基本没什么影响。对截留率影响显著的是压力因素,其它因素均不显著。提高压力,截留率升高,提高料液浓度,截留率降低,提高温度与流速,截留率有一定的波动,但都略呈上升之势。
对于单组分的无机盐溶液的纳滤膜分离性能已经有了很多研究,但是关于纳滤膜处理混合体系溶液的资料相对较少。本文利用纳滤膜处理双组分无机盐溶液,发现2价离子的竞争系数和溶液比成线性关系。利用这个关系建立起简单的去除率模型,用来模拟预测双组分无机盐溶液。
最后,本文还探讨了膜污染对膜通量的影响。实验发现利用纯水对纳滤膜进行清洗,基本不起作用。利用化学药剂对膜进行清洗,几乎使膜通量得到完全恢复。
通过实验研究,发现了操作因素对膜分离性能的影响各不相同,对以后建立膜分离模型提供理论,同时也发现了1价离子和2价离子在透过纳滤膜时的相互关系,为纳滤膜去除无机盐模型提供理论基础。
In order to predict NF membrane performance,a systematic study on the filtration performance of selected commercial NF membranes is presented in this paper. Nanofiltration(NF) membranes are new kinds of membranes that have properties between those of ultrafiltration(UF) and reverse osmosis(RO). The application of nanofiltration becomes increasingly popular. Up to now , the applications and researches of nanofiltration membranes have been still at experimental research stage, and many research efforts are needed.In this work, the efects of operation parameters on rejection and flux of permeate were tested with a lab rig . Investigations have revealed the permeation performance of electrolytes in the separation process by nanofiltration membranes in salt solutions.
The researches were carried out with the orthogonal experiment of 4 factors. The effect factors influencing separation performance of the membrane were operating pressure, temperature of experiment, concentration of feed solution, and velocity of flow. Each factor varied at four different condition levels. The experimental results show that operating pressure and temperature of experiment are two very prominent factors influencing flux of permeate. Increasing operating pressure or temperature of experiment, flux of permeate would increase. Concentration of feed solution also has influence on flux of permeate. The higher the concentration of feed solution is, the lower the flux of permeate. In the experiments, velocity of flow is the least prominent factor. Its change has little influence on flux of permeate. The prominent factor influencing rejection is operating pressure. The effects of other factors are not so significant. The rejection increases with increasing operation pressure. On the other hand, the higher the feed concentration is, the lower the rejection. And making temperature and flow velocity higher, respectively, would result in increasing rejection although rejection increases fluctuantly.
Investigations have revealed the permeation performance of electrolytes in the separation process by nanofiltration membranes in single salt solutions. However, there is still not much information about the separation process of mixed electrolyte solutions, and by now most of t he investigations have been on solutions containing three kinds of ions , in which anions are mostly Cl- and SO42- , and cations are mostly Na+, K+, Ca2+ and Mg2+. In this work, permeation experiments of nanofiltration membranes (NF90-2540) for binary electrolyte solutions (NaCl, Na2SO4; NaCl MgCl2; NaCl, CaCl2; Na2SO4, K2SO4) were carried out. The result showed that the ion with better permeation performance would permeate first, thus depressing the rejection of it self and enhancing the rejection of the co-ion with poor permeation performance.
Last , the effects of membrane fouling on separation performance of nanofiltration membrane were discussed. The cleaning efficiency and the fouling mechanism were thus investigated. In the cleaning experiment of nanofiltration membrane, the flux was almost recovered after cleaning with chemical medicine, which is a strong chelating agent for calcium.
This research shows the different factors influence the nanofiltration in different way. It offer the theories for building the membranes model. A new rejection model was built up to predict the rejection of binary electrolyte solutions.
首先本研究采用正交实验,把影响膜分离性能的操作因素分为操作压力、实验温度、料液浓度以及料液流速等四种,每种因素选用四个不同的工况。结果表明,操作压力和温度对膜通量的影响是最显著的两个因素,加大操作压力或升高实验温度,膜通量将增大。料液浓度对膜通量也有影响,料液浓度越高,膜通量越小,在本实验中,料液流速对膜通量的影响最不显著,料液流速的改变对膜通量基本没什么影响。对截留率影响显著的是压力因素,其它因素均不显著。提高压力,截留率升高,提高料液浓度,截留率降低,提高温度与流速,截留率有一定的波动,但都略呈上升之势。
对于单组分的无机盐溶液的纳滤膜分离性能已经有了很多研究,但是关于纳滤膜处理混合体系溶液的资料相对较少。本文利用纳滤膜处理双组分无机盐溶液,发现2价离子的竞争系数和溶液比成线性关系。利用这个关系建立起简单的去除率模型,用来模拟预测双组分无机盐溶液。
最后,本文还探讨了膜污染对膜通量的影响。实验发现利用纯水对纳滤膜进行清洗,基本不起作用。利用化学药剂对膜进行清洗,几乎使膜通量得到完全恢复。
通过实验研究,发现了操作因素对膜分离性能的影响各不相同,对以后建立膜分离模型提供理论,同时也发现了1价离子和2价离子在透过纳滤膜时的相互关系,为纳滤膜去除无机盐模型提供理论基础。
In order to predict NF membrane performance,a systematic study on the filtration performance of selected commercial NF membranes is presented in this paper. Nanofiltration(NF) membranes are new kinds of membranes that have properties between those of ultrafiltration(UF) and reverse osmosis(RO). The application of nanofiltration becomes increasingly popular. Up to now , the applications and researches of nanofiltration membranes have been still at experimental research stage, and many research efforts are needed.In this work, the efects of operation parameters on rejection and flux of permeate were tested with a lab rig . Investigations have revealed the permeation performance of electrolytes in the separation process by nanofiltration membranes in salt solutions.
The researches were carried out with the orthogonal experiment of 4 factors. The effect factors influencing separation performance of the membrane were operating pressure, temperature of experiment, concentration of feed solution, and velocity of flow. Each factor varied at four different condition levels. The experimental results show that operating pressure and temperature of experiment are two very prominent factors influencing flux of permeate. Increasing operating pressure or temperature of experiment, flux of permeate would increase. Concentration of feed solution also has influence on flux of permeate. The higher the concentration of feed solution is, the lower the flux of permeate. In the experiments, velocity of flow is the least prominent factor. Its change has little influence on flux of permeate. The prominent factor influencing rejection is operating pressure. The effects of other factors are not so significant. The rejection increases with increasing operation pressure. On the other hand, the higher the feed concentration is, the lower the rejection. And making temperature and flow velocity higher, respectively, would result in increasing rejection although rejection increases fluctuantly.
Investigations have revealed the permeation performance of electrolytes in the separation process by nanofiltration membranes in single salt solutions. However, there is still not much information about the separation process of mixed electrolyte solutions, and by now most of t he investigations have been on solutions containing three kinds of ions , in which anions are mostly Cl- and SO42- , and cations are mostly Na+, K+, Ca2+ and Mg2+. In this work, permeation experiments of nanofiltration membranes (NF90-2540) for binary electrolyte solutions (NaCl, Na2SO4; NaCl MgCl2; NaCl, CaCl2; Na2SO4, K2SO4) were carried out. The result showed that the ion with better permeation performance would permeate first, thus depressing the rejection of it self and enhancing the rejection of the co-ion with poor permeation performance.
Last , the effects of membrane fouling on separation performance of nanofiltration membrane were discussed. The cleaning efficiency and the fouling mechanism were thus investigated. In the cleaning experiment of nanofiltration membrane, the flux was almost recovered after cleaning with chemical medicine, which is a strong chelating agent for calcium.
This research shows the different factors influence the nanofiltration in different way. It offer the theories for building the membranes model. A new rejection model was built up to predict the rejection of binary electrolyte solutions.
引文
[1]Philip C S.Control of disifection by-product in drinking water[J].Water Environment Research,1998,70(4):727-734
[2]张绍园,王菊恩.膜生物反应器水力停留时间的确定及其影响因素分析[J].环境科学,1997,18(6):35-38
[3]桂平.膜一生物反应器运行条件对膜过滤特性的影响[J].环境科学,1999,20(5):38-41
[4]刘忠洲,续曙光,李锁定.微滤、超滤过程中的膜污染与清洗[J].水处理技术,1997,23(4):187-193
[5]Takeshi Matsuura.Progress in membrane science and technology for seawater desalination- a review[J].Desalination,2001,134:47-54
[6]Pepper DRO-fraction membranes[J]. Desalination,1988,70(2):89-93
[7]Rautenbach R,Groschl A.Separation potential of nanofiltration membranes[J] Desalination,1990,77(2):73-84
[8]Ikeda K,Nakano T,Ito H,et al. New composite charged reverse osmosis membrane[J]. Desalination,1988,68(3):109-119
[9]王晓琳,纳滤膜分离技术最新进展[J].天津建设学院学报,2003,9(2):82-89
[10]王晓琳,张澄洪,赵杰等.纳滤膜的分离机理及其在食品和医药行业中的应用[J].膜科学与技术,2000,20(3):29-35
[11]Wang X L, Tsuru T,Nakso S,et al. The electrostatic and sterie-hindrance model for the transport of charged solutes through nanofiltration membranes[J].J. Membr.Sci.,1997,135:19-32
[12]Wang X L,Tsuru T,Togoh M ,et al. Transport of organic electrolytes with electrostatic and steric-hindrance effects through nanofiltration membranes[J]. Chem.Eng.Japan,1995,28(3):372-380
[13]Wang X L,Tsuru T,Togoh M,et al.Evaluation of pore structure and electrical properties of nanofiltration membranes[J].Chem.Eng. Japan, 1995,28(4):186-192.
[14]唐受印,戴友芝.水处理工程师手册[M].北京:化学工业出版社,2000
[15]邵刚.膜法水处理技术及其工程实例[M].北京:化学工业出版社,2002
[16]Hassan A M,Al-Soli M A,AI-Amoudi A S,et al .A new approach to membrane and thermal seawater desalination processes using nanofiltration membranes[P]. Desalination,1998,118(4):35-51
[17]张显球,王力友,张玉清.纳滤软化锅炉用水的试验研究[J].南京师范大学学报(工程技术版),2004,4(2):19-21
[18]A Gaid,G Bablon,G Turner,et al .Pe rformance of 3 year's of nanofiltration plants[J]. Water Supply,1999,17(4):65-74
[19]Zaidi A.Ultra-and nanofiltration in advanced effluent treatment schemes for 263-271
[20]刘梅红、姜坪.膜法染料废水处理工艺研究[J].膜科学与技术,2002,22(3):43-45
[21]Gahr F,Hermanutz F,Oppermann W.Ozonation-an important technique to comply with new German law for textile wastewater treatment[J]. Wat Sci.Tech.,1994,30(4):255-263
[22]Schaefer T,Gross R,Janitza J,et al.Nanofiltration of dye waste water[J]. F&S Fihr,1999,13(2):9-16
[23]Guohua Chen,Xijun Chai,Po-Lock Yue,et al.Treatment of textile desizing wastewater by pilot scale nanofiltration membrane separation[J]. J. Membr.Sci.,1997,127(4):93-99
[24]周金盛,陈观文.纳滤膜技术的研究进展[J].膜科学与技术,1999,19(3):1-10
[25]Gaubert E,Barnier H ,I Maurel A,et al. Selective strontium removal from a sodium nitrate aqueousme dium by nanofilrtation-complexation [J]. Sep.Sci.Technol.1997,32(4):585-597
[26]李丽,李萍,杨旭等.石油废水处理技术[J].化工时刊,2005,19(2):59-61
[27]熊蓉春,雷晓东,魏刚等.纳米TiO2与纳滤膜在水处理中的应用[J].机械给排水,2002,2(4):29-33
[28]国家环保局编.水和废水监测分析方法(第三版),北京:中国环境科学出版社,1989:354-358
[29]《正交实验法》编写组.正交实验法[M].北京:国防工业出版社,1976,202
[30]楼永通,陈益棠,王寿根.膜分离技术在电镀镍漂洗水回收中的应用[J].膜科学与技术,2002,22(2):46
[31]蔡惠如,高从凯.纳滤膜对染料去除行为的研究[J].膜科学与技术,2002,22 (3):3-4
[32]朱安娜,祝万鹏,张玉春.纳滤过程的污染问题及纳滤膜性能的影响因素[J]膜科学与技术,2003,23(1):45-46
[33]刘东方,陈璐,纪涛.纳滤膜处理高浓度工业废液浓差极化与膜污染[J].城市环境与城市生态,2003,16(1):16-17
[34]Moritz T,Benfer S,Arki P,et al. Influence of the surface charge on the permeate flux in the dead-end filtration with ceramic membranes[J]. Separation and Purification Technology,2001(25):503-511
[35]Pontie′M,Diawar C K,Rumeau M, P,et al.(2003)Seawater nanofiltration (NF): fiction or reality? Desalination, 158(3):277-280
[36]Pontie′M,Lhassani A, Diawara C K,et al.(2004) Seawater nanofiltration for the elaboration of usable salty waters. Desalination,167(4):347-355
[37]Hilal N,Al-Zoubi H,Darwish N A,et al.(2005) Nanofiltration of highly concentrated salt solutions up to seawater salinity. Desalination,184(5):1295-1306
[2]张绍园,王菊恩.膜生物反应器水力停留时间的确定及其影响因素分析[J].环境科学,1997,18(6):35-38
[3]桂平.膜一生物反应器运行条件对膜过滤特性的影响[J].环境科学,1999,20(5):38-41
[4]刘忠洲,续曙光,李锁定.微滤、超滤过程中的膜污染与清洗[J].水处理技术,1997,23(4):187-193
[5]Takeshi Matsuura.Progress in membrane science and technology for seawater desalination- a review[J].Desalination,2001,134:47-54
[6]Pepper DRO-fraction membranes[J]. Desalination,1988,70(2):89-93
[7]Rautenbach R,Groschl A.Separation potential of nanofiltration membranes[J] Desalination,1990,77(2):73-84
[8]Ikeda K,Nakano T,Ito H,et al. New composite charged reverse osmosis membrane[J]. Desalination,1988,68(3):109-119
[9]王晓琳,纳滤膜分离技术最新进展[J].天津建设学院学报,2003,9(2):82-89
[10]王晓琳,张澄洪,赵杰等.纳滤膜的分离机理及其在食品和医药行业中的应用[J].膜科学与技术,2000,20(3):29-35
[11]Wang X L, Tsuru T,Nakso S,et al. The electrostatic and sterie-hindrance model for the transport of charged solutes through nanofiltration membranes[J].J. Membr.Sci.,1997,135:19-32
[12]Wang X L,Tsuru T,Togoh M ,et al. Transport of organic electrolytes with electrostatic and steric-hindrance effects through nanofiltration membranes[J]. Chem.Eng.Japan,1995,28(3):372-380
[13]Wang X L,Tsuru T,Togoh M,et al.Evaluation of pore structure and electrical properties of nanofiltration membranes[J].Chem.Eng. Japan, 1995,28(4):186-192.
[14]唐受印,戴友芝.水处理工程师手册[M].北京:化学工业出版社,2000
[15]邵刚.膜法水处理技术及其工程实例[M].北京:化学工业出版社,2002
[16]Hassan A M,Al-Soli M A,AI-Amoudi A S,et al .A new approach to membrane and thermal seawater desalination processes using nanofiltration membranes[P]. Desalination,1998,118(4):35-51
[17]张显球,王力友,张玉清.纳滤软化锅炉用水的试验研究[J].南京师范大学学报(工程技术版),2004,4(2):19-21
[18]A Gaid,G Bablon,G Turner,et al .Pe rformance of 3 year's of nanofiltration plants[J]. Water Supply,1999,17(4):65-74
[19]Zaidi A.Ultra-and nanofiltration in advanced effluent treatment schemes for 263-271
[20]刘梅红、姜坪.膜法染料废水处理工艺研究[J].膜科学与技术,2002,22(3):43-45
[21]Gahr F,Hermanutz F,Oppermann W.Ozonation-an important technique to comply with new German law for textile wastewater treatment[J]. Wat Sci.Tech.,1994,30(4):255-263
[22]Schaefer T,Gross R,Janitza J,et al.Nanofiltration of dye waste water[J]. F&S Fihr,1999,13(2):9-16
[23]Guohua Chen,Xijun Chai,Po-Lock Yue,et al.Treatment of textile desizing wastewater by pilot scale nanofiltration membrane separation[J]. J. Membr.Sci.,1997,127(4):93-99
[24]周金盛,陈观文.纳滤膜技术的研究进展[J].膜科学与技术,1999,19(3):1-10
[25]Gaubert E,Barnier H ,I Maurel A,et al. Selective strontium removal from a sodium nitrate aqueousme dium by nanofilrtation-complexation [J]. Sep.Sci.Technol.1997,32(4):585-597
[26]李丽,李萍,杨旭等.石油废水处理技术[J].化工时刊,2005,19(2):59-61
[27]熊蓉春,雷晓东,魏刚等.纳米TiO2与纳滤膜在水处理中的应用[J].机械给排水,2002,2(4):29-33
[28]国家环保局编.水和废水监测分析方法(第三版),北京:中国环境科学出版社,1989:354-358
[29]《正交实验法》编写组.正交实验法[M].北京:国防工业出版社,1976,202
[30]楼永通,陈益棠,王寿根.膜分离技术在电镀镍漂洗水回收中的应用[J].膜科学与技术,2002,22(2):46
[31]蔡惠如,高从凯.纳滤膜对染料去除行为的研究[J].膜科学与技术,2002,22 (3):3-4
[32]朱安娜,祝万鹏,张玉春.纳滤过程的污染问题及纳滤膜性能的影响因素[J]膜科学与技术,2003,23(1):45-46
[33]刘东方,陈璐,纪涛.纳滤膜处理高浓度工业废液浓差极化与膜污染[J].城市环境与城市生态,2003,16(1):16-17
[34]Moritz T,Benfer S,Arki P,et al. Influence of the surface charge on the permeate flux in the dead-end filtration with ceramic membranes[J]. Separation and Purification Technology,2001(25):503-511
[35]Pontie′M,Diawar C K,Rumeau M, P,et al.(2003)Seawater nanofiltration (NF): fiction or reality? Desalination, 158(3):277-280
[36]Pontie′M,Lhassani A, Diawara C K,et al.(2004) Seawater nanofiltration for the elaboration of usable salty waters. Desalination,167(4):347-355
[37]Hilal N,Al-Zoubi H,Darwish N A,et al.(2005) Nanofiltration of highly concentrated salt solutions up to seawater salinity. Desalination,184(5):1295-1306