压力驱动膜去除中低水平放射性废水中的钴
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摘要
我国核电业的快速发展产生了大量的放射性废水,给环境保护带来巨大压力,其中以中低水平放射性废水居多。核废物的处理本着高效、节能的原则一般采用暂存后排放;对于中低水平的放射性废物,在采用适当的处理方法后,将大部分的放射性转移到小体积的浓缩物中,加以贮藏,对于大体积废物中剩余的放射性低于允许排放浓度时,将其排于环境中进行稀释、扩散。
本文研究用两种压力驱动膜纳滤,反渗透的方式处理模拟中低放废水。通过对核电站废水的特点、来源及危害程度的介绍确定了将~(60)Co作为处理对象。考察在压力、pH值、无机离子干扰和投加有机络合剂等情况下对膜通量和钴离子去除率的影响,同时涵盖纳滤、反渗透分离模型、参数的探索性介绍及得到相关计量关系帮助实际操作中实现运行决策。实验原水中Co~(2+)浓度为400ug/L,通过研究得到如下结果:
(1)纳滤膜对模拟水溶液中Co~(2+)的截留率一般可以维持在90%以上,膜通量高于80 L·m~(-2)·h~(-1)。反渗透膜的截留效果比纳滤膜要高,一般在95%以上,但膜通量很低,不到30 L·m~(-2)·h~(-1)。
(2)Co~(2+)在酸性水溶液中以金属离子形式存在的浓度是一定的,在弱碱性条件下则出现钴-水化学平衡的氢氧化钴沉淀,实验表明在弱碱性pH≈10,纳滤和反渗透均有最好的截留效果,NF约95.4%,RO约98.02%。
(3)干扰离子的存在对纳滤法截留效果的影响很大,且不同价态离子的影响也不同。如Na~+,Ca~(2+)的加入使膜对Co~(2+)的截留率分别产生了增大和减小两种不同的变化。此现象启发我们选择性透过膜不仅有应用于特殊放射性核素去除的优越性,还有达到从稀溶液中“挤出”贵重组分的目的。
(4)在选择了合适的pH值和Co~(2+)/络合剂装载量比后,纳滤膜对Co~(2+)的截留效果进一步提升,达到了98.06%。这说明络合剂的加入是可行、有效的,但高聚物对膜表面的浓差极化现象影响巨大,所以在对络合剂的选择方面还需要进一步研究。
(5)纳滤、反渗透级联使Co~(2+)有效截留率达98.68%,由于受到浓差极化和连续时间运行的影响,理想级联的效果应该更好。根据溶解扩散模型估算,一级纳滤,反渗透最终对Co~(2+)截留率可以达到99.7%,化学法无法检测。
The rapidly development of nuclear power industry in our country result in plenty of radioactive wastewater, most of which was at the low and medium radioactive level and bring a potent effect on environmental protection. With principle of higher efficiency and lower energy, nuclear waste comes from nuclear power plant is stored first and then discharged if it reaches standard; for example, low and medium radioactive level waste should be compressed or divided into two part, the part of high radioactive level will be sealed storage forever, the other part which radioactive level reach discharge standard will be sent to dilute in environment.
In this thesis, we use two types of pressure driving membrane: nanofiltration and reverse osmosis to treat the low and medium radioactive wastewater, considering the characteristic, source and harming degree of wastewater from nuclear power plants, we choose cobalt ions (~(60)Co) as research object. It studies the flux and removal rate of cobalt ions in several conditions such as pressure, pH, competing ions and complex agent. It also includes the illustrations of Physical model to make the interpretation of experimental results easily.
The concentration of Co~(2+) in raw water is 400ug/L. The following experimental conclusions can be obtained:
(1)In nanofiltration experiments, membrane flux is over 80L·m~(-2)·h-1, which is much more than reverse osmosis. And general removal rate of Co~(2+) is over 90%, that is lower about 5 percentage to reverse osmosis.
(2)The concentration of Co~(2+) will be constant in acid solution especially the solution is at especial pH. In the condition of weakly basic solution, there is cobalt-water balance and produce a certain amount of Co(OH)2 precipitation. Due to the experimental results, both nanofiltration and reverse osmosis have a good effect on retention at pH 10, the retention of nanofiltration is 95.4%, reverse osmosis is 98.02%.
(3) Competing ions in raw water make a potent effect on removal rate of Co~(2+), Competing ions with different valence states generate different functions, such as Na+ and Ca~(2+) will make the removal rate of Co~(2+) lower and higher. This result implies us that selective membrane can not only be applied in removal of particular ions, but also can squeeze valuable metal ions from dilute solution.
(4)At a suitable pH and the radio of cobalt to complex agent, the retention of cobalt ions by nanofiltration membrane reaches 98.06%. It available and effective to plunge into complex agent, but high polymer induces serious concentration polarization and makes membrane flux rather low. So how to choose complex agent should study further.
(5)In the experiment of nanofiltration- reverse osmosis cascade, the retention of cobalt ions reaches 98.68%. It is relatively poor than anticipated results because of concentration polarization. In accordance with Physical model of reverse osmosis membrane we shall obtain the retention of cobalt ions more than 99.7%, which can not test by Chemistry method.
本文研究用两种压力驱动膜纳滤,反渗透的方式处理模拟中低放废水。通过对核电站废水的特点、来源及危害程度的介绍确定了将~(60)Co作为处理对象。考察在压力、pH值、无机离子干扰和投加有机络合剂等情况下对膜通量和钴离子去除率的影响,同时涵盖纳滤、反渗透分离模型、参数的探索性介绍及得到相关计量关系帮助实际操作中实现运行决策。实验原水中Co~(2+)浓度为400ug/L,通过研究得到如下结果:
(1)纳滤膜对模拟水溶液中Co~(2+)的截留率一般可以维持在90%以上,膜通量高于80 L·m~(-2)·h~(-1)。反渗透膜的截留效果比纳滤膜要高,一般在95%以上,但膜通量很低,不到30 L·m~(-2)·h~(-1)。
(2)Co~(2+)在酸性水溶液中以金属离子形式存在的浓度是一定的,在弱碱性条件下则出现钴-水化学平衡的氢氧化钴沉淀,实验表明在弱碱性pH≈10,纳滤和反渗透均有最好的截留效果,NF约95.4%,RO约98.02%。
(3)干扰离子的存在对纳滤法截留效果的影响很大,且不同价态离子的影响也不同。如Na~+,Ca~(2+)的加入使膜对Co~(2+)的截留率分别产生了增大和减小两种不同的变化。此现象启发我们选择性透过膜不仅有应用于特殊放射性核素去除的优越性,还有达到从稀溶液中“挤出”贵重组分的目的。
(4)在选择了合适的pH值和Co~(2+)/络合剂装载量比后,纳滤膜对Co~(2+)的截留效果进一步提升,达到了98.06%。这说明络合剂的加入是可行、有效的,但高聚物对膜表面的浓差极化现象影响巨大,所以在对络合剂的选择方面还需要进一步研究。
(5)纳滤、反渗透级联使Co~(2+)有效截留率达98.68%,由于受到浓差极化和连续时间运行的影响,理想级联的效果应该更好。根据溶解扩散模型估算,一级纳滤,反渗透最终对Co~(2+)截留率可以达到99.7%,化学法无法检测。
The rapidly development of nuclear power industry in our country result in plenty of radioactive wastewater, most of which was at the low and medium radioactive level and bring a potent effect on environmental protection. With principle of higher efficiency and lower energy, nuclear waste comes from nuclear power plant is stored first and then discharged if it reaches standard; for example, low and medium radioactive level waste should be compressed or divided into two part, the part of high radioactive level will be sealed storage forever, the other part which radioactive level reach discharge standard will be sent to dilute in environment.
In this thesis, we use two types of pressure driving membrane: nanofiltration and reverse osmosis to treat the low and medium radioactive wastewater, considering the characteristic, source and harming degree of wastewater from nuclear power plants, we choose cobalt ions (~(60)Co) as research object. It studies the flux and removal rate of cobalt ions in several conditions such as pressure, pH, competing ions and complex agent. It also includes the illustrations of Physical model to make the interpretation of experimental results easily.
The concentration of Co~(2+) in raw water is 400ug/L. The following experimental conclusions can be obtained:
(1)In nanofiltration experiments, membrane flux is over 80L·m~(-2)·h-1, which is much more than reverse osmosis. And general removal rate of Co~(2+) is over 90%, that is lower about 5 percentage to reverse osmosis.
(2)The concentration of Co~(2+) will be constant in acid solution especially the solution is at especial pH. In the condition of weakly basic solution, there is cobalt-water balance and produce a certain amount of Co(OH)2 precipitation. Due to the experimental results, both nanofiltration and reverse osmosis have a good effect on retention at pH 10, the retention of nanofiltration is 95.4%, reverse osmosis is 98.02%.
(3) Competing ions in raw water make a potent effect on removal rate of Co~(2+), Competing ions with different valence states generate different functions, such as Na+ and Ca~(2+) will make the removal rate of Co~(2+) lower and higher. This result implies us that selective membrane can not only be applied in removal of particular ions, but also can squeeze valuable metal ions from dilute solution.
(4)At a suitable pH and the radio of cobalt to complex agent, the retention of cobalt ions by nanofiltration membrane reaches 98.06%. It available and effective to plunge into complex agent, but high polymer induces serious concentration polarization and makes membrane flux rather low. So how to choose complex agent should study further.
(5)In the experiment of nanofiltration- reverse osmosis cascade, the retention of cobalt ions reaches 98.68%. It is relatively poor than anticipated results because of concentration polarization. In accordance with Physical model of reverse osmosis membrane we shall obtain the retention of cobalt ions more than 99.7%, which can not test by Chemistry method.
引文
[1]任建新.膜分离技术及其应用[M]北京:化学工业出版社,2002:6-12.
[2]王湛、周翀.膜分离技术基础(第二版)[M]北京:化学工业出版社,2006:163-167.
[3]李胤龙、杨晓松.纳滤去除模拟矿山废水中金属离子的研究[J].北京化工大学学报:自然科学版,2010,38(1)2.
[4] M Arous,F Zuki,N sulaiman.Removal of chromium ions from aqueous solutions by polymer-enhanced ultrafiltration[J].Journal of Hazardous Materials,2007,147:752-758.
[5]刘泉征,曾丽娥.纳滤膜分离技术最新研究进展[J].甘肃科技,2006,8,1.
[6]Grazyna Zakrzewska-Trznadel,Marian Harasimowicz,Andrzej G.Chmielewski.Membrance processes in nuclear technology-application for liquid waste treatment[J].Separation and Purification Technology 22-23(2001) 621.
[7]谢章旺.壳聚糖络合-超滤耦合工艺对溶液中重金属去除的的研究[D].上海:上海交通大学,2006.
[8] HJ 550-2009,水质总钴的测定5-氯-2-(吡啶偶氮)-1,3-二氨基苯分光光度法(暂行).
[9] B Spivakov,K Geckeler,E Bayer.Liquid-phass polymer-bassed retention the separation of metals by ultrafiltration on polychelatogens[J].NATURE,1985,315(23):313-315.
[10]王磊,福士宪.原水性质对纳滤膜透水性能的影响[J].中国给排水,2003:2-4.
[11]核电站水质工程.钱达中.中国电力出版社. 2008.8.
[12]张艳萍.污水深度处理与回用[M]化学工业出版社;2009.4 57-60.
[13]刘家祺.分离过程与模拟[M]清华大学出版社; 2007.4 101-120
[14]王晓琳,丁宁.反渗透和纳滤技术和应用[M]化学工业出版社; 2005.6 15-16.
[15] Dr Anil Kumar Pabby,Membrane techniques for trement in nuclear waste processing:global experience[J].Membrane Technology,2008;9-11.
[16] Markku Kuronen,Mark Weller,Ion exchange selectivity and structural changes inhighly aluminous zeolites[J].Reactive&Functional Polymers 66(2006)1350-1361.
[17]牟旭凤,白庆中.聚合物辅助纳滤技术处理模拟放射性废水给排水技术[J]2006,32,174-177.
[18] Peter Lukac,Maria Foldesova and Stefan Svetik.Synergistic Effcet of Chemical and Thermical Treament on the Structure and Sorption Properties of Natural and Chemically Modified Slovak Zeolite[J]. Petroleum&Coal 47(1),17-21,2005.
[19] Teresia Moller,Risto Harjula,Jukka Lehto.Ion exchange of 85Sr,134Cs and 57Co in sodium titanosilicate and effect of crystallinty on selectivity[J]. Separation and Purification Technology 28(2002)13-23.
[20]张宝宗.反渗透水处理应用技术[M]中国电力出版社2004.3 34-40.
[21]杨座国.膜科学技术过程与原理[M]华东理工大学出版社2009.3 10-14.
[22]侯立安.特殊废水处理技术及工程实例[M]化学工业出版社2003.6 157-158.
[23] N.V.Elizondo,E.Ballesteros,B.I.Kharisov Cleaning of liquid radioactive wastesusing natural zeolites[J].Applied Radiation and Isotopes 52(2000)27-30.
[24]于波,陈靖.从酸性高放废液中去除137Cs的研究进展[J]原子能科学技术,2002,32(1);52-57.
[25] Antonian P.Kryvoruchko,Boris Yu.Kornilovich,Water deactivation by reverse osmosis[J]. Desalination 157(2003)403-407.
[26] M.sancho,J.M.Arnal,G.Verdu,J.Lora,J.I.Villaescusa. Ultrafiltration and reverse osmosis performance in the treatment of radioimmunoassay liquid wastes[J]. Desalination 201(2006)207-215.
[27]云桂春,成徐州.压水反应堆水化学编著[M]哈尔滨工程大学出版社2009.1 101-105.
[28]吴伟民.放射性废液的处理和处置的现状与发展[D] China Academic Journal ElectronicPublishing House 2009;8-15.
[29] O.Korkuna,R.Leboda,J.Rycskowski.Structural and physicochemical properties of natural zeolites:clinoptilolite and mordenite[J]. Microporous and Mesoporous Materials 87(2006)243-254.
[30]熊忠华,模拟放射性废水的超滤+反渗透处理工艺[J]核化学与放射化学,Vol30,No30,2008.6,142-145.
[31]陈良,田湾核电站放射性废液处理系统介绍[D]2007年核化工三废处理处置学术交流会(厦门)论文集,84-87.
[32]顾忠茂.核废物处理技术[M]原子能出版社2005.9.
[33] Szabolcs Szoke,Gyorgy Patzay,Laszlo Weiser,Cobalt(Ⅲ)EDTA complex removal from aqueousalk aline borate solutions by nanofiltration[J].Desalination 175(2005)179-185.
[34]杨庆等,中低水平放射性废水处理技术研究进展[J]环境科学与管理.2007(9) 104.
[35]顾景智,大亚湾核电站辐射源项控制的实践[J]辐射防护,Vol.24,No.3-4,2004.5,227-232.
[36] Murat Akgul,Abdulkerim Karabakan,Removal of silver(I)from aqueous solutionswith clinoptilolite[J].Microporous and Mesoporous Materials (2006)99-104.
[37]陈红盛等,聚合物辅助陶瓷膜处理重金属废水[J]膜科学与技术, Vol25,No6,2005,45-50.
[38]侯立安,左莉,纳滤膜分离技术处理放射性污染废水的试验研究[J]给水排水,Vol30,No10,2004,47-49.
[2]王湛、周翀.膜分离技术基础(第二版)[M]北京:化学工业出版社,2006:163-167.
[3]李胤龙、杨晓松.纳滤去除模拟矿山废水中金属离子的研究[J].北京化工大学学报:自然科学版,2010,38(1)2.
[4] M Arous,F Zuki,N sulaiman.Removal of chromium ions from aqueous solutions by polymer-enhanced ultrafiltration[J].Journal of Hazardous Materials,2007,147:752-758.
[5]刘泉征,曾丽娥.纳滤膜分离技术最新研究进展[J].甘肃科技,2006,8,1.
[6]Grazyna Zakrzewska-Trznadel,Marian Harasimowicz,Andrzej G.Chmielewski.Membrance processes in nuclear technology-application for liquid waste treatment[J].Separation and Purification Technology 22-23(2001) 621.
[7]谢章旺.壳聚糖络合-超滤耦合工艺对溶液中重金属去除的的研究[D].上海:上海交通大学,2006.
[8] HJ 550-2009,水质总钴的测定5-氯-2-(吡啶偶氮)-1,3-二氨基苯分光光度法(暂行).
[9] B Spivakov,K Geckeler,E Bayer.Liquid-phass polymer-bassed retention the separation of metals by ultrafiltration on polychelatogens[J].NATURE,1985,315(23):313-315.
[10]王磊,福士宪.原水性质对纳滤膜透水性能的影响[J].中国给排水,2003:2-4.
[11]核电站水质工程.钱达中.中国电力出版社. 2008.8.
[12]张艳萍.污水深度处理与回用[M]化学工业出版社;2009.4 57-60.
[13]刘家祺.分离过程与模拟[M]清华大学出版社; 2007.4 101-120
[14]王晓琳,丁宁.反渗透和纳滤技术和应用[M]化学工业出版社; 2005.6 15-16.
[15] Dr Anil Kumar Pabby,Membrane techniques for trement in nuclear waste processing:global experience[J].Membrane Technology,2008;9-11.
[16] Markku Kuronen,Mark Weller,Ion exchange selectivity and structural changes inhighly aluminous zeolites[J].Reactive&Functional Polymers 66(2006)1350-1361.
[17]牟旭凤,白庆中.聚合物辅助纳滤技术处理模拟放射性废水给排水技术[J]2006,32,174-177.
[18] Peter Lukac,Maria Foldesova and Stefan Svetik.Synergistic Effcet of Chemical and Thermical Treament on the Structure and Sorption Properties of Natural and Chemically Modified Slovak Zeolite[J]. Petroleum&Coal 47(1),17-21,2005.
[19] Teresia Moller,Risto Harjula,Jukka Lehto.Ion exchange of 85Sr,134Cs and 57Co in sodium titanosilicate and effect of crystallinty on selectivity[J]. Separation and Purification Technology 28(2002)13-23.
[20]张宝宗.反渗透水处理应用技术[M]中国电力出版社2004.3 34-40.
[21]杨座国.膜科学技术过程与原理[M]华东理工大学出版社2009.3 10-14.
[22]侯立安.特殊废水处理技术及工程实例[M]化学工业出版社2003.6 157-158.
[23] N.V.Elizondo,E.Ballesteros,B.I.Kharisov Cleaning of liquid radioactive wastesusing natural zeolites[J].Applied Radiation and Isotopes 52(2000)27-30.
[24]于波,陈靖.从酸性高放废液中去除137Cs的研究进展[J]原子能科学技术,2002,32(1);52-57.
[25] Antonian P.Kryvoruchko,Boris Yu.Kornilovich,Water deactivation by reverse osmosis[J]. Desalination 157(2003)403-407.
[26] M.sancho,J.M.Arnal,G.Verdu,J.Lora,J.I.Villaescusa. Ultrafiltration and reverse osmosis performance in the treatment of radioimmunoassay liquid wastes[J]. Desalination 201(2006)207-215.
[27]云桂春,成徐州.压水反应堆水化学编著[M]哈尔滨工程大学出版社2009.1 101-105.
[28]吴伟民.放射性废液的处理和处置的现状与发展[D] China Academic Journal ElectronicPublishing House 2009;8-15.
[29] O.Korkuna,R.Leboda,J.Rycskowski.Structural and physicochemical properties of natural zeolites:clinoptilolite and mordenite[J]. Microporous and Mesoporous Materials 87(2006)243-254.
[30]熊忠华,模拟放射性废水的超滤+反渗透处理工艺[J]核化学与放射化学,Vol30,No30,2008.6,142-145.
[31]陈良,田湾核电站放射性废液处理系统介绍[D]2007年核化工三废处理处置学术交流会(厦门)论文集,84-87.
[32]顾忠茂.核废物处理技术[M]原子能出版社2005.9.
[33] Szabolcs Szoke,Gyorgy Patzay,Laszlo Weiser,Cobalt(Ⅲ)EDTA complex removal from aqueousalk aline borate solutions by nanofiltration[J].Desalination 175(2005)179-185.
[34]杨庆等,中低水平放射性废水处理技术研究进展[J]环境科学与管理.2007(9) 104.
[35]顾景智,大亚湾核电站辐射源项控制的实践[J]辐射防护,Vol.24,No.3-4,2004.5,227-232.
[36] Murat Akgul,Abdulkerim Karabakan,Removal of silver(I)from aqueous solutionswith clinoptilolite[J].Microporous and Mesoporous Materials (2006)99-104.
[37]陈红盛等,聚合物辅助陶瓷膜处理重金属废水[J]膜科学与技术, Vol25,No6,2005,45-50.
[38]侯立安,左莉,纳滤膜分离技术处理放射性污染废水的试验研究[J]给水排水,Vol30,No10,2004,47-49.