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Mini-Reviews in Organic Chemistry

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ISSN (Online): 1875-6298

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Mini-Review Article

Recent Progress on the Development and Application of Polymeric Nanofiltration Membranes: A Mini-Review

Author(s): Fabiana Rodrigues de Almeida, Ivana Lourenço de Mello Ferreira* and Rodrigo Azevedo dos Reis

Volume 21, Issue 1, 2024

Published on: 06 September, 2022

Page: [3 - 21] Pages: 19

DOI: 10.2174/1570193X19666220623151653

Price: $65

Abstract

The inefficiency of conventional water treatment methods in terms of removing micropollutants is prompting research into other technologies. Among these, the process of separation by nanofiltration membranes is particularly promising because of the low operating cost, rapid implementation of the system, high selectivity and easy integration with other treatment processes. Studies in this area are recent and there are many avenues for future research. This mini-review describes the main characteristics of the polymeric membranes used for nanofiltration and the various methods and polymer materials under investigation. At the end, we report the result of a survey conducted on the ScienceDirect, Scopus and Web of Science platforms using different keywords, to depict a global panorama of the current research involving polymeric nanofiltration membranes. The results revealed a particular dearth of published studies involving application of these membranes to remove micropollutants with endocrine disruptive action. Furthermore, research involving nanofiltration membranes utilizing calcium alginate is very recent. This study provides an overview of the investigation of polymeric nanofiltration membranes.

Keywords: Polymeric membranes, separation process, nanofiltration, removal of micropollutants, hydrophilicity, calcium alginate.

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[1]
Bila, D.M.; Dezotti, M. Desreguladores endócrinos no meio ambiente: Efeitos e conseqüências. Quim. Nova, 2007, 30(3), 651-666.
[http://dx.doi.org/10.1590/S0100-40422007000300027]
[2]
Ali, S.; Rehman, S.A.U.; Luan, H-Y.; Farid, M.U.; Huang, H. Challenges and opportunities in functional carbon nanotubes for membrane-based water treatment and desalination. Sci. Total Environ., 2019, 646, 1126-1139.
[http://dx.doi.org/10.1016/j.scitotenv.2018.07.348] [PMID: 30235599]
[3]
Luo, Y.; Guo, W.; Ngo, H.H.; Nghiem, L.D.; Hai, F.I.; Zhang, J.; Liang, S.; Wang, X.C. A review on the occurrence of micropollutants in the aquatic environment and their fate and removal during wastewater treatment. Sci. Total Environ., 2014, 473-474, 619-641.
[http://dx.doi.org/10.1016/j.scitotenv.2013.12.065] [PMID: 24394371]
[4]
Bieber, S.; Greco, G.; Grosse, S.; Letzel, T. RPLC-HILIC and SFC with mass spectrometry: Polarity-extended organic molecule screening in environmental (Water) samples. Anal. Chem., 2017, 89(15), 7907-7914.
[http://dx.doi.org/10.1021/acs.analchem.7b00859] [PMID: 28650149]
[5]
Deeb, A.A.; Stephan, S.; Schmitz, O.J.; Schmidt, T.C. Suspect screening of micropollutants and their transformation products in advanced wastewater treatment. Sci. Total Environ., 2017, 601-602, 1247-1253.
[http://dx.doi.org/10.1016/j.scitotenv.2017.05.271] [PMID: 28605842]
[6]
Montes, R.; Aguirre, J.; Vidal, X.; Rodil, R.; Cela, R.; Quintana, J.B. Screening for polar chemicals in water by trifunctional mixed-mode liquid chromatography-high resolution mass spectrometry. Environ. Sci. Technol., 2017, 51(11), 6250-6259.
[http://dx.doi.org/10.1021/acs.est.6b05135] [PMID: 28457136]
[7]
Gago-Ferrero, P.; Krettek, A.; Fischer, S.; Wiberg, K.; Ahrens, L. Suspect screening and regulatory databases: A powerful combination to identify emerging micropollutants. Environ. Sci. Technol., 2018, 52(12), 6881-6894.
[http://dx.doi.org/10.1021/acs.est.7b06598] [PMID: 29782800]
[8]
Abtahi, S.M.; Marbelia, L.; Gebreyohannes, A.Y.; Ahmadiannamini, P.; Joannis-Cassan, C.; Albasi, C.; de Vos, W.M.; Vankelecom, I.F.J. Micropollutant rejection of annealed polyelectrolyte multilayer based nanofiltration membranes for treatment of conventionally-treated municipal wastewater. Separ. Purif. Tech., 2019, 209, 470-481.
[http://dx.doi.org/10.1016/j.seppur.2018.07.071]
[9]
Alves, T.; Girardi, R.; Pinheiro, A. Micropoluentes orgânicos: Ocorrência, remoção e regulamentação. Rev Gestão Água da América Lat., 2017, 14(1), 1-1.
[10]
CEDAE. CEDAE 2009, 1-6. Available from: https://cedae.com.br/Portals/0/ETA_Guandu.pdf
[11]
Rosso, T.C de A. Série Temática: Recursos Hídricos e Saneamento, 1st ed; Rosso, T.C de A.; Giordano, G., Eds.; Rio de Janeiro, 2012, 52. Available from: http://www.coamb.eng.uerj.br/download/coamb-RHS-Volume1.pdf
[12]
Abtahi, S.M.; Ilyas, S.; Joannis Cassan, C.; Albasi, C.; de Vos, W.M. Micropollutants removal from secondary-treated municipal wastewater using weak polyelectrolyte multilayer based nanofiltration membranes. J. Membr. Sci., 2018, 548, 654-666.
[http://dx.doi.org/10.1016/j.memsci.2017.10.045]
[13]
Morsch, P.; Möhlendick, L.; Süsser, M.; Nirschl, H. Elimination of micropollutants from municipal wastewater by adsorption on powdered activated carbon and separation by innovative precoat filtration. Separ. Purif. Tech., 2021, 277, 119444.
[http://dx.doi.org/10.1016/j.seppur.2021.119444]
[14]
Sher, F.; Hanif, K.; Rafey, A.; Khalid, U.; Zafar, A.; Ameen, M.; Lima, E.C. Removal of micropollutants from municipal wastewater using different types of activated carbons. J. Environ. Manage., 2021, 278(Pt 2), 111302.
[http://dx.doi.org/10.1016/j.jenvman.2020.111302] [PMID: 33152547]
[15]
Kooijman, G.; de Kreuk, M.K.; Houtman, C.; van Lier, J.B. Perspectives of coagulation/flocculation for the removal of pharmaceuticals from domestic wastewater: A critical view at experimental procedures. J. Water Process Eng., 2020, 34, 101161.
[http://dx.doi.org/10.1016/j.jwpe.2020.101161]
[16]
Simonič, M.; Lobnik, A. The efficiency of a hybrid flocculation/UF process for a real dye-house effluent using hydrophilic and hydrophobic membranes. Desalination, 2011, 271(1-3), 219-224.
[http://dx.doi.org/10.1016/j.desal.2010.12.028]
[17]
Sotelo, J.L.; Rodríguez, A.R.; Mateos, M.M.; Hernández, S.D.; Torrellas, S.A.; Rodríguez, J.G. Adsorption of pharmaceutical compounds and an endocrine disruptor from aqueous solutions by carbon materials. J. Environ. Sci. Health B, 2012, 47(7), 640-652.
[http://dx.doi.org/10.1080/03601234.2012.668462] [PMID: 22560026]
[18]
Kim, H-S.; Takizawa, S.; Ohgaki, S. Application of microfiltration systems coupled with powdered activated carbon to river water treatment. Desalination, 2007, 202(1-3), 271-277.
[http://dx.doi.org/10.1016/j.desal.2005.12.064]
[19]
Li, B.; Lei, Z.; Huang, Z. Surface-treated activated carbon for removal of aromatic compounds from water. Chem. Eng. Technol., 2009, 32(5), 763-770.
[http://dx.doi.org/10.1002/ceat.200800535]
[20]
Stefanello Cadore, J.; Fabro, L.F.; Garcia Maraschin, T.; de Souza Basso, N.R.; Rodrigues Pires, M.J.; Barbosa Brião, V. Bibliometric approach to the perspectives and challenges of membrane separation processes to remove emerging contaminants from water. Water Sci. Technol., 2020, 82(9), 1721-1741.
[http://dx.doi.org/10.2166/wst.2020.450] [PMID: 33201839]
[21]
Mailler, R.; Gasperi, J.; Coquet, Y.; Buleté, A.; Vulliet, E.; Deshayes, S.; Zedek, S.; Mirande-Bret, C.; Eudes, V.; Bressy, A.; Caupos, E.; Moilleron, R.; Chebbo, G.; Rocher, V. Removal of a wide range of emerging pollutants from wastewater treatment plant discharges by micro-grain activated carbon in fluidized bed as tertiary treatment at large pilot scale. Sci. Total Environ., 2016, 542(Pt A), 983-996.
[http://dx.doi.org/10.1016/j.scitotenv.2015.10.153] [PMID: 26571333]
[22]
Mailler, R.; Gasperi, J.; Coquet, Y.; Deshayes, S.; Zedek, S.; Cren-Olivé, C.; Cartiser, N.; Eudes, V.; Bressy, A.; Caupos, E.; Moilleron, R.; Chebbo, G.; Rocher, V. Study of a large scale powdered activated carbon pilot: Removals of a wide range of emerging and priority micropollutants from wastewater treatment plant effluents. Water Res., 2015, 72, 315-330.
[http://dx.doi.org/10.1016/j.watres.2014.10.047] [PMID: 25466636]
[23]
Mansas, C.; Mendret, J.; Brosillon, S.; Ayral, A. Coupling catalytic ozonation and membrane separation: A review. Separ. Purif. Tech., 2020, 236, 116221.
[http://dx.doi.org/10.1016/j.seppur.2019.116221]
[24]
Beltrán, F.J.; Aguinaco, A.; García-Araya, J.F. Application of ozone involving advanced oxidation processes to remove some pharmaceutical compounds from urban wastewaters. Ozone Sci. Eng., 2012, 34(1), 3-15.
[http://dx.doi.org/10.1080/01919512.2012.640154]
[25]
Maniero, M.G.; Bila, D.M.; Dezotti, M. Degradation and estrogenic activity removal of 17β-estradiol and 17α-ethinylestradiol by ozonation and O3/H2O2. Sci. Total Environ., 2008, 407(1), 105-115.
[http://dx.doi.org/10.1016/j.scitotenv.2008.08.011] [PMID: 18805570]
[26]
Yu, R.; Zhu, R.; Jiang, J.; Liang, R.; Liu, X.; Liu, G. Mussel-inspired surface functionalization of polyamide microfiltration membrane with zwitterionic silver nanoparticles for efficient anti-biofouling water disinfection. J. Colloid Interface Sci., 2021, 598, 302-313.
[http://dx.doi.org/10.1016/j.jcis.2021.04.040] [PMID: 33901854]
[27]
Park, M.; Snyder, S.A. Attenuation of contaminants of emerging concerns by nanofiltration membrane: Rejection mechanism and application in water reuse.Contaminants of Emerging Concern in Water and Wastewater; Elsevier, 2020, pp. 177-206.
[http://dx.doi.org/10.1016/B978-0-12-813561-7.00006-7]
[28]
Koyuncu, I.; Sengur, R.; Turken, T.; Guclu, S.; Pasaoglu, M.E. Advances in water treatment by microfiltration, ultrafiltration, and nanofiltration. Advances in Membrane Technologies for Water Treatment; Elsevier, 2015, pp. 83-128.
[http://dx.doi.org/10.1016/B978-1-78242-121-4.00003-4]
[29]
Ojajuni, O.; Saroj, D.; Cavalli, G. Removal of organic micropollutants using membrane-assisted processes: A review of recent progress. Environ. Technol. Rev., 2015, 4(1), 17-37.
[http://dx.doi.org/10.1080/21622515.2015.1036788]
[30]
Mulder, M. Basic Principles of Membrane Technology, 2nd ed; Springer Netherlands: Dordrecht, 1996.
[http://dx.doi.org/10.1007/978-94-009-1766-8]
[31]
Monsalvo, V.M.; McDonald, J.A.; Khan, S.J.; Le-Clech, P. Removal of trace organics by anaerobic membrane bioreactors. Water Res., 2014, 49, 103-112.
[http://dx.doi.org/10.1016/j.watres.2013.11.026] [PMID: 24321247]
[32]
Boonnorat, J.; Techkarnjanaruk, S.; Honda, R.; Prachanurak, P. Effects of hydraulic retention time and carbon to nitrogen ratio on micro-pollutant biodegradation in membrane bioreactor for leachate treatment. Bioresour. Technol., 2016, 219, 53-63.
[http://dx.doi.org/10.1016/j.biortech.2016.07.094] [PMID: 27475331]
[33]
Subtil, E.L.; Hespanhol, I.; Mierzwa, J.C. Submerged Membrane Bioreactor (sMBR): A promising alternative to wastewater treatment for water reuse. Ambient e Agua - An Interdiscip. J. Appl. Sci., 2013, 8(3)
[34]
Khanzada, N.K.; Farid, M.U.; Kharraz, J.A.; Choi, J.; Tang, C.Y.; Nghiem, L.D.; Jang, A.; An, A.K. Removal of organic micropollutants using advanced membrane-based water and wastewater treatment: A review. J. Membr. Sci., 2020, 598, 117672.
[http://dx.doi.org/10.1016/j.memsci.2019.117672]
[35]
Alzahrani, S.; Mohammad, A.W.; Abdullah, P.; Jaafar, O. Potential tertiary treatment of produced water using highly hydrophilic nanofiltration and reverse osmosis membranes. J. Environ. Chem. Eng., 2013, 1(4), 1341-1349.
[http://dx.doi.org/10.1016/j.jece.2013.10.002]
[36]
Andrade, L.H.; Mendes, F.D.S.; Espindola, J.C.; Amaral, M.C.S. Nanofiltration as tertiary treatment for the reuse of dairy wastewater treated by membrane bioreactor. Separ. Purif. Tech., 2014, 126, 21-29.
[http://dx.doi.org/10.1016/j.seppur.2014.01.056]
[37]
Teychene, B.; Chi, F.; Chokki, J.; Darracq, G.; Baron, J.; Joyeux, M.; Gallard, H. Investigation of polar mobile organic compounds (PMOC) removal by reverse osmosis and nanofiltration: Rejection mechanism modelling using decision tree. Water Sci. Technol. Water Supply, 2020, 20(3), 975-983.
[http://dx.doi.org/10.2166/ws.2020.020]
[38]
Zielińska, M.; Bułkowska, K.; Cydzik-Kwiatkowska, A.; Bernat, K.; Wojnowska-Baryła, I. Removal of bisphenol A (BPA) from biologically treated wastewater by microfiltration and nanofiltration. Int. J. Environ. Sci. Technol., 2016, 13(9), 2239-2248.
[http://dx.doi.org/10.1007/s13762-016-1056-6]
[39]
Yüksel, S.; Kabay, N.; Yüksel, M. Removal of bisphenol A (BPA) from water by various nanofiltration (NF) and reverse osmosis (RO) membranes. J. Hazard. Mater., 2013, 263(Pt 2), 307-310.
[http://dx.doi.org/10.1016/j.jhazmat.2013.05.020] [PMID: 23731784]
[40]
Ebrahimzadeh, S.; Wols, B.; Azzellino, A.; Martijn, B.J.; van der Hoek, J.P. Quantification and modelling of organic micropollutant removal by reverse osmosis (RO) drinking water treatment. J. Water Process Eng., 2021, 42, 102164.
[http://dx.doi.org/10.1016/j.jwpe.2021.102164]
[41]
Vergili, I. Application of nanofiltration for the removal of carbamazepine, diclofenac and ibuprofen from drinking water sources. J. Environ. Manage., 2013, 127, 177-187.
[http://dx.doi.org/10.1016/j.jenvman.2013.04.036] [PMID: 23708199]
[42]
Zhang, H.; Zhu, G.; Jia, X.; Ding, Y.; Zhang, M.; Gao, Q.; Hu, C.; Xu, S. Removal of microcystin-LR from drinking water using a bamboo-based charcoal adsorbent modified with chitosan. J. Environ. Sci. (China), 2011, 23(12), 1983-1988.
[http://dx.doi.org/10.1016/S1001-0742(10)60676-6] [PMID: 22432328]
[43]
Fenyvesi, É.; Barkács, K.; Gruiz, K.; Varga, E.; Kenyeres, I.; Záray, G.; Szente, L. Removal of hazardous micropollutants from treated wastewater using cyclodextrin bead polymer-A pilot demonstration case. J. Hazard. Mater., 2020, 383, 1-10.
[44]
van Gijn, K.; Chen, Y.L.; van Oudheusden, B.; Gong, S.; Wilt, H.A.; Rijnaarts, H.H.M.; Langenhoff, A.A.M. Optimizing biological effluent organic matter removal for subsequent micropollutant removal. J. Environ. Chem. Eng., 2021, 9(5), 1-7.
[45]
Fu, H.; Huang, J.; Gray, K. Crumpled graphene balls adsorb micropollutants from water selectively and rapidly. Carbon, 2021, 183, 958-969.
[http://dx.doi.org/10.1016/j.carbon.2021.07.081]
[46]
Escalona, I.; de Grooth, J.; Font, J.; Nijmeijer, K. Removal of BPA by enzyme polymerization using NF membranes. J. Membr. Sci., 2014, 468, 192-201.
[http://dx.doi.org/10.1016/j.memsci.2014.06.011]
[47]
Sadmani, A.H.M.H.M.A.; Andrews, R.C.; Bagley, D.M. Impact of natural water colloids and cations on the rejection of pharmaceutically active and endocrine disrupting compounds by nanofiltration. J. Membr. Sci., 2014, 450, 272-281.
[http://dx.doi.org/10.1016/j.memsci.2013.09.017]
[48]
Dai, R.; Guo, H.; Tang, C.Y.; Chen, M.; Li, J.; Wang, Z. Hydrophilic selective nanochannels created by metal organic frameworks in nanofiltration membranes enhance rejection of hydrophobic endocrine-disrupting compounds. Environ. Sci. Technol., 2019, 53(23), 13776-13783.
[http://dx.doi.org/10.1021/acs.est.9b05343] [PMID: 31689090]
[49]
Sanches, S.; Rodrigues, A.; Cardoso, V.V.; Benoliel, M.J.; Crespo, J.G.; Pereira, V.J. Comparison of UV photolysis, nanofiltration, and their combination to remove hormones from a drinking water source and reduce endocrine disrupting activity. Environ. Sci. Pollut. Res. Int., 2016, 23(11), 11279-11288.
[http://dx.doi.org/10.1007/s11356-016-6325-x] [PMID: 26924700]
[50]
Mamo, J.; Insa, S.; Monclús, H.; Rodríguez-Roda, I.; Comas, J.; Barceló, D.; Farré, M.J. Fate of NDMA precursors through an MBR-NF pilot plant for urban wastewater reclamation and the effect of changing aeration conditions. Water Res., 2016, 102, 383-393.
[http://dx.doi.org/10.1016/j.watres.2016.06.057] [PMID: 27393963]
[51]
Miralles-Cuevas, S.; Oller, I.; Agüera, A.; Ponce-Robles, L.; Pérez, J.A.S.; Malato, S. Removal of microcontaminants from MWTP effluents by combination of membrane technologies and solar photo-Fenton at neutral pH. Catal. Today, 2015, 252, 78-83.
[http://dx.doi.org/10.1016/j.cattod.2014.11.015]
[52]
Ho, H.L.; Chan, W.K.; Blondy, A.; Yeung, K.L.; Schrotter, J. Experiment and modeling of advanced ozone membrane reactor for treatment of organic endocrine disrupting pollutants in water. Catal. Today, 2012, 193(1), 120-127.
[http://dx.doi.org/10.1016/j.cattod.2012.03.059]
[53]
Liu, M.; Wang, S.; Wang, T.; Duan, M.; Su, Y.; Han, H.; Lin, X.; Li, Z. Application of microfiltration-nanofiltration combined technology for drinking water advanced treatment in a large-scale engineering project. J. Water Supply, 2021, 70(4), 619-636.
[http://dx.doi.org/10.2166/aqua.2021.020]
[54]
Chon, K.; Cho, J.; Shon, H.K. A pilot-scale hybrid municipal wastewater reclamation system using combined coagulation and disk filtration, ultrafiltration, and reverse osmosis: Removal of nutrients and micropollutants, and characterization of membrane foulants. Bioresour. Technol., 2013, 141, 109-116.
[http://dx.doi.org/10.1016/j.biortech.2013.03.198] [PMID: 23611699]
[55]
Yangali-Quintanilla, V.; Sadmani, A.; McConville, M.; Kennedy, M.; Amy, G. Rejection of pharmaceutically active compounds and endocrine disrupting compounds by clean and fouled nanofiltration membranes. Water Res., 2009, 43(9), 2349-2362.
[http://dx.doi.org/10.1016/j.watres.2009.02.027] [PMID: 19303127]
[56]
Ravikumar, Y.V.L.; Sridhar, S.; Satyanarayana, S.V. Development of an electrodialysis-distillation integrated process for separation of hazardous sodium azide to recover valuable DMSO solvent from pharmaceutical effluent. Separ. Purif. Tech., 2013, 110, 20-30.
[http://dx.doi.org/10.1016/j.seppur.2013.02.031]
[57]
Akbari, A.; Aliyarizadeh, E.; Mojallali Rostami, S.M.; Homayoonfal, M. Novel sulfonated polyamide thin-film composite nanofiltration membranes with improved water flux and anti-fouling properties. Desalination, 2016, 377, 11-22.
[http://dx.doi.org/10.1016/j.desal.2015.08.025]
[58]
Shen, M.; Song, B.; Zhu, Y.; Zeng, G.; Zhang, Y.; Yang, Y.; Wen, X.; Chen, M.; Yi, H. Removal of microplastics via drinking water treatment: Current knowledge and future directions. Chemosphere, 2020, 251, 126612.
[http://dx.doi.org/10.1016/j.chemosphere.2020.126612] [PMID: 32443234]
[59]
Wang, Y.; Ju, L.; Xu, F.; Tian, L.; Jia, R.; Song, W.; Li, Y.; Liu, B. Effect of a nanofiltration combined process on the treatment of high-hardness and micropolluted water. Environ. Res., 2020, 182, 109063.
[http://dx.doi.org/10.1016/j.envres.2019.109063] [PMID: 31896469]
[60]
Chen, Y.; Sun, H.; Zhang, H.; Chen, K.; Chai, D.; Li, P.; Hou, Y.; Niu, Q.J. Fabrication of high performance nanofiltration membranes based on the interfacial polymerization regulated by the incorporation of dextran nanoparticles. Desalination, 2021, 519, 1-12.
[http://dx.doi.org/10.1016/j.desal.2021.115308]
[61]
Lan, H.; Zhai, Y.; Chen, K.; Zhai, Z.; Jiang, C.; Li, P.; Hou, Y.; Jason Niu, Q. Fabrication of high performance nanofiltration membrane by construction of Noria based nanoparticles interlayer. Separ. Purif. Tech., 2022, 290, 120781.
[http://dx.doi.org/10.1016/j.seppur.2022.120781]
[62]
Waheed, A.; Baig, U.; Ansari, M.A. Fabrication of CuO nanoparticles immobilized nanofiltration composite membrane for dye/salt fractionation: Performance and antibiofouling. J. Environ. Chem. Eng., 2022, 10(1), 106960.
[http://dx.doi.org/10.1016/j.jece.2021.106960]
[63]
Chen, Y.; Sun, H.; Tang, S.; Feng, H.; Zhang, H.; Chen, K.; Li, P.; Niu, Q.J. Nanofiltration membranes with enhanced performance by constructing an interlayer integrated with dextran nanoparticles and polyethyleneimine coating. J. Membr. Sci., 2022, 654, 120537.
[64]
Dadari, S.; Rahimi, M.; Zinadini, S. Novel antibacterial and antifouling PES nanofiltration membrane incorporated with green synthesized nickel-bentonite nanoparticles for heavy metal ions removal. Chem. Eng. J., 2022, 431, 134116.
[http://dx.doi.org/10.1016/j.cej.2021.134116]
[65]
Purushothaman, M.; Arvind, V.; Saikia, K.; Vaidyanathan, V.K. Fabrication of highly permeable and anti-fouling performance of Poly(ether ether sulfone) nanofiltration membranes modified with zinc oxide nanoparticles. Chemosphere, 2022, 286(Pt 1), 131616.
[http://dx.doi.org/10.1016/j.chemosphere.2021.131616] [PMID: 34325268]
[66]
Baker, R.W. Membrane Technology and Applications. Second. Baker RW; Technology, M., Ed.; John Wiley & Sons, Ltd: Chichester, UK, 2004.
[http://dx.doi.org/10.1002/0470020393]
[67]
Chen, Y.; Liu, F.; Wang, Y.; Lin, H.; Han, L. A tight nanofiltration membrane with multi-charged nanofilms for high rejection to concentrated salts. J. Membr. Sci., 2017, 537, 407-415.
[http://dx.doi.org/10.1016/j.memsci.2017.05.036]
[68]
Zhang, H.; Luo, J.; Wan, Y. Regenerable temperature-responsive biocatalytic nanofiltration membrane for organic micropollutants removal. iScience, 2021, 25(1), 103671.
[http://dx.doi.org/10.1016/j.isci.2021.103671] [PMID: 35028540]
[69]
Liu, Y.; Zhao, Y.; Wang, X.; Wen, X.; Huang, X.; Xie, Y.F. Effect of varying piperazine concentration and post-modification on prepared nanofiltration membranes in selectively rejecting organic micropollutants and salts. J. Membr. Sci., 2019, 582, 274-283.
[http://dx.doi.org/10.1016/j.memsci.2019.04.018]
[70]
Hoover, L.A.; Schiffman, J.D.; Elimelech, M. Nanofibers in thin-film composite membrane support layers: Enabling expanded application of forward and pressure retarded osmosis. Desalination, 2013, 308, 73-81.
[http://dx.doi.org/10.1016/j.desal.2012.07.019]
[71]
Mänttäri, M.; Pihlajamäki, A.; Nyström, M. Effect of pH on hydrophilicity and charge and their effect on the filtration efficiency of NF membranes at different pH. J. Membr. Sci., 2006, 280(1-2), 311-320.
[http://dx.doi.org/10.1016/j.memsci.2006.01.034]
[72]
Bhaskar, V.V.; Kaleekkal, N.J. Next-generation thin-film composite nanofiltration membranes for water remediation: A review; Emergent Mater, 2021.
[http://dx.doi.org/10.1007/s42247-021-00273-8]
[73]
Comerton, A.M.; Andrews, R.C.; Bagley, D.M.; Hao, C. The rejection of endocrine disrupting and pharmaceutically active compounds by NF and RO membranes as a function of compound and water matrix properties. J. Membr. Sci., 2008, 313(1-2), 323-335.
[http://dx.doi.org/10.1016/j.memsci.2008.01.021]
[74]
Do, V.T.; Tang, C.Y.; Reinhard, M.; Leckie, J.O. Degradation of polyamide nanofiltration and reverse osmosis membranes by hypochlorite. Environ. Sci. Technol., 2012, 46(2), 852-859.
[http://dx.doi.org/10.1021/es203090y] [PMID: 22221176]
[75]
Do, V.T.; Tang, C.Y.; Reinhard, M.; Leckie, J.O. Effects of chlorine exposure conditions on physiochemical properties and performance of a polyamide membrane--mechanisms and implications. Environ. Sci. Technol., 2012, 46(24), 13184-13192.
[http://dx.doi.org/10.1021/es302867f] [PMID: 23214945]
[76]
Idil Mouhoumed, E.; Szymczyk, A.; Schäfer, A.; Paugam, L.; La, Y.H. Physico-chemical characterization of polyamide NF/RO membranes: Insight from streaming current measurements. J. Membr. Sci., 2014, 461, 130-138.
[http://dx.doi.org/10.1016/j.memsci.2014.03.025]
[77]
Amy, G.; Kim, T-U.; Yoon, J.; Bellona, C.; Drewes, J.; Pellegrino, J.; Heberer, T. Removal of micropollutants by NF/RO membranes. Water Sci. Technol. Water Supply, 2005, 5(5), 25-33.
[http://dx.doi.org/10.2166/ws.2005.0035]
[78]
Darvishmanesh, S.; Buekenhoudt, A.; Degrève, J.; Van der Bruggen, B. General model for prediction of solvent permeation through organic and inorganic solvent resistant nanofiltration membranes. J. Membr. Sci., 2009, 334(1-2), 43-49.
[http://dx.doi.org/10.1016/j.memsci.2009.02.013]
[79]
Kim, S.; Chu, K.H.; Al-Hamadani, Y.A.J.; Park, C.M.; Jang, M.; Kim, D-H.; Yu, M.; Heo, J.; Yoon, Y. Removal of contaminants of emerging concern by membranes in water and wastewater: A review. Chem. Eng. J., 2018, 335, 896-914.
[http://dx.doi.org/10.1016/j.cej.2017.11.044]
[80]
Marchetti, P.; Jimenez Solomon, M.F.; Szekely, G.; Livingston, A.G. Molecular separation with organic solvent nanofiltration: A critical review. Chem. Rev., 2014, 114(21), 10735-10806.
[http://dx.doi.org/10.1021/cr500006j] [PMID: 25333504]
[81]
Verliefde, A.R.D.; Cornelissen, E.R.; Heijman, S.G.J.; Verberk, J.Q.J.C.; Amy, G.L.; Van der Bruggen, B.; van Dijk, J.C. The role of electrostatic interactions on the rejection of organic solutes in aqueous solutions with nanofiltration. J. Membr. Sci., 2008, 322(1), 52-66.
[http://dx.doi.org/10.1016/j.memsci.2008.05.022]
[82]
Volpin, F.; Fons, E.; Chekli, L.; Kim, J.E.; Jang, A.; Shon, H.K. Hybrid forward osmosis-reverse osmosis for wastewater reuse and seawater desalination: Understanding the optimal feed solution to minimise fouling. Process Saf. Environ. Prot., 2018, 117, 523-532.
[http://dx.doi.org/10.1016/j.psep.2018.05.006]
[83]
Mo, Y.; Tiraferri, A.; Yip, N.Y.; Adout, A.; Huang, X.; Elimelech, M. Improved antifouling properties of polyamide nanofiltration membranes by reducing the density of surface carboxyl groups. Environ. Sci. Technol., 2012, 46(24), 13253-13261.
[http://dx.doi.org/10.1021/es303673p] [PMID: 23205860]
[84]
Zhang, X.; Lin, B.; Zhao, K.; Wei, J.; Guo, J.; Cui, W.; Jiang, S.; Liu, D.; Li, J. A free-standing calcium alginate/polyacrylamide hydrogel nanofiltration membrane with high anti-fouling performance: Preparation and characterization. Desalination, 2015, 365, 234-241.
[http://dx.doi.org/10.1016/j.desal.2015.03.015]
[85]
Valladares Linares, R.; Yangali-Quintanilla, V.; Li, Z.; Amy, G. Rejection of micropollutants by clean and fouled forward osmosis membrane. Water Res., 2011, 45(20), 6737-6744.
[http://dx.doi.org/10.1016/j.watres.2011.10.037] [PMID: 22055122]
[86]
Nghiem, L.; Schäfer, A.; Elimelech, M. Nanofiltration of hormone mimicking trace organic contaminants. Sep. Sci. Technol., 2005, 40(13), 2633-2649.
[http://dx.doi.org/10.1080/01496390500283340]
[87]
Li, F.; Meng, J.; Ye, J.; Yang, B.; Tian, Q.; Deng, C. Surface modification of PES ultrafiltration membrane by polydopamine coating and poly(ethylene glycol) grafting: Morphology, stability, and anti-fouling. Desalination, 2014, 344, 422-430.
[http://dx.doi.org/10.1016/j.desal.2014.04.011]
[88]
Yeom, C.K.; Kim, C.U.; Kim, B.S.; Kim, K.J.; Lee, J.M. Recovery of anionic surfactant by RO process. Part II. Fabrication of thin film composite membranes by interfacial reaction. J. Membr. Sci., 1999, 156(2), 197-210.
[http://dx.doi.org/10.1016/S0376-7388(98)00352-4]
[89]
Alturki, A.A.; McDonald, J.A.; Khan, S.J.; Price, W.E.; Nghiem, L.D.; Elimelech, M. Removal of trace organic contaminants by the forward osmosis process. Separ. Purif. Tech., 2013, 103, 258-266.
[http://dx.doi.org/10.1016/j.seppur.2012.10.036]
[90]
Heidari, A.A.; Mahdavi, H. Thin film composite solvent resistant nanofiltration membrane via interfacial polymerization on an engineered polyethylene membrane support coated with polydopamine. J. Membr. Sci., 2021, 634, 1-17.
[91]
Ren, L.; Chen, J.; Lu, Q.; Wang, C.; Han, J.; Huang, K.; Pan, X.; Wu, H. Construction of high selectivity and antifouling nanofiltration membrane via incorporating macrocyclic molecules into active layer. J. Membr. Sci., 2020, 597, 1-13.
[92]
Tang, Y.; Zhang, L.; Shan, C.; Xu, L.; Yu, L.; Gao, H. Enhancing the permeance and antifouling properties of thin-film composite nanofiltration membranes modified with hydrophilic capsaicin-mimic moieties. J. Membr. Sci., 2020, 610, 118233.
[http://dx.doi.org/10.1016/j.memsci.2020.118233]
[93]
Cao, X-L.; Zhou, F-Y.; Cai, J.; Zhao, Y.; Liu, M-L.; Xu, L.; Sun, S-P. High-permeability and anti-fouling nanofiltration membranes decorated by asymmetric organic phosphate. J. Membr. Sci., 2021, 617, 1-9.
[94]
Paseta, L.; Luque-Alled, J.M.; Malankowska, M.; Navarro, M.; Gorgojo, P.; Coronas, J.; Téllez, C. Functionalized graphene-based polyamide thin film nanocomposite membranes for organic solvent nanofiltration. Separ. Purif. Tech., 2020, 247, 1-9.
[http://dx.doi.org/10.1016/j.seppur.2020.116995]
[95]
Kong, F.; Yang, Z-Y.; Yue, L-P.; Chen, J.; Guo, C. Nanofiltration membrane with substrate incorporated amine-functionalized graphene oxide for enhanced petrochemical wastewater and shale gas produced water desalination. Desalination, 2021, 517, 1-12.
[http://dx.doi.org/10.1016/j.desal.2021.115246]
[96]
Tian, B.; Hu, P.; Zhao, S.; Wang, M.; Hou, Y.; Niu, Q.J.; Li, P. Nanofiltration membrane combining environmental-friendly polycarboxylic interlayer prepared from catechol for enhanced desalination performance. Desalination, 2021, 512, 1-9.
[http://dx.doi.org/10.1016/j.desal.2021.115118]
[97]
Dai, R.; Han, H.; Zhu, Y.; Wang, X.; Wang, Z. Tuning the primary selective nanochannels of MOF thin-film nanocomposite nanofiltration membranes for efficient removal of hydrophobic endocrine disrupting compounds. Front. Environ. Sci. Eng., 2022, 16(4), 1-13.
[http://dx.doi.org/10.1007/s11783-021-1474-7]
[98]
Dai, R.; Han, H.; Wang, T.; Li, X.; Wang, Z. Enhanced removal of hydrophobic endocrine disrupting compounds from wastewater by nanofiltration membranes intercalated with hydrophilic MoS2 nanosheets: Role of surface properties and internal nanochannels. J. Membr. Sci., 2021, 628, 1-9.
[99]
Jin, P.; Yuan, S.; Zhang, G.; Zhu, J.; Zheng, J.; Luis, P. Van der B. Polyarylene thioether sulfone/sulfonated sulfone nanofiltration membrane with enhancement of rejection and permeability via molecular design. J. Membr. Sci., 2020, 608, 1-12.
[100]
Sun, Y.; Sun, T.; Pang, J.; Cao, N.; Yue, C.; Wang, J.; Han, X.; Jiang, Z. Poly(aryl ether ketone) membrane with controllable degree of sulfonation for organic solvent nanofiltration. Separ. Purif. Tech., 2021, 273, 1-9.
[101]
Kim, J.H.; Choi, Y.; Kang, J.; Choi, E.; Choi, S.E.; Kwon, O.; Kim, D.W. Scalable fabrication of deoxygenated graphene oxide nanofiltration membrane by continuous slot-die coating. J. Membr. Sci., 2020, 612, 1-8.
[102]
Sadmani, A.H.M.A.; Andrews, R.C.; Bagley, D.M. Influence of naturally occurring dissolved organic matter, colloids, and cations on nanofiltration of pharmaceutically active and endocrine disrupting compounds. Chemosphere, 2014, 117, 170-177.
[http://dx.doi.org/10.1016/j.chemosphere.2014.06.027] [PMID: 25016429]
[103]
Sadmani, A.H.M.A.; Andrews, R.C.; Bagley, D.M. Rejection of pharmaceutically active and endocrine disrupting compounds by nanofiltration as a function of source water humic substances. J. Water Process Eng., 2014, 2, 63-70.
[http://dx.doi.org/10.1016/j.jwpe.2014.05.004]
[104]
Zhao, Y.; Kong, F.; Wang, Z.; Yang, H.; Wang, X.; Xie, Y.F.; Waite, T.D. Role of membrane and compound properties in affecting the rejection of pharmaceuticals by different RO/NF membranes. Front. Environ. Sci. Eng., 2017, 11(6), 20.
[http://dx.doi.org/10.1007/s11783-017-0975-x]
[105]
Guo, H.; Deng, Y.; Yao, Z.; Yang, Z.; Wang, J.; Lin, C.; Zhang, T.; Zhu, B.; Tang, C.Y. A highly selective surface coating for enhanced membrane rejection of endocrine disrupting compounds: Mechanistic insights and implications. Water Res., 2017, 121, 197-203.
[http://dx.doi.org/10.1016/j.watres.2017.05.037] [PMID: 28535433]
[106]
El-Aassar, A.M. Polysulfone/Polyvinyl alcohol thin film nano-composite membranes: Synthesis, characterization and application for desalination of saline groundwater. J. Appl. Sci. Res., 2012, 8(7), 3811-3822.
[107]
Huang, S.; McDonald, J.A.; Kuchel, R.P.; Khan, S.J.; Leslie, G.; Tang, C.Y.; Mansouri, J.; Fane, A.G. Surface modification of nanofiltration membranes to improve the removal of organic micropollutants: Linking membrane characteristics to solute transmission. Water Res., 2021, 203, 1-10.
[108]
Hu, M.; Wu, Q.; Chen, C.; Liang, S.; Liu, Y.; Bai, Y.; Tiraferri, A.; Liu, B. Facile preparation of antifouling nanofiltration membrane by grafting zwitterions for reuse of shale gas wastewater. Separ. Purif. Tech., 2021, 276, 119310.
[http://dx.doi.org/10.1016/j.seppur.2021.119310]
[109]
Trivedi, J.S.; Bera, P.; Bhalani, D.V.; Jewrajka, S.K. In situ amphiphilic modification of thin film composite membrane for application in aqueous and organic solvents. J. Membr. Sci., 2021, 626, 119155.
[http://dx.doi.org/10.1016/j.memsci.2021.119155]
[110]
Zhang, X.; Chen, T-H.; Chen, F-F.; Wu, H.; Yu, C-Y.; Liu, L-F.; Gao, C-J. Structure adjustment for enhancing the water permeability and separation selectivity of the thin film composite nanofiltration membrane based on a dendritic hyperbranched polymer. J. Membr. Sci., 2021, 618, 118455.
[http://dx.doi.org/10.1016/j.memsci.2020.118455]
[111]
Ren, D.; Jin, Y.T.; Liu, T.Y.; Wang, X. Phenanthroline-based polyarylate porous membranes with rapid water transport for metal cation separation. ACS Appl. Mater. Interfaces, 2020, 12(6), 7605-7616.
[http://dx.doi.org/10.1021/acsami.9b22086] [PMID: 31968159]
[112]
Xiong, S.; Han, C.; Phommachanh, A.; Li, W.; Xu, S.; Wang, Y. High-performance loose nanofiltration membrane prepared with assembly of covalently cross-linked polyethyleneimine-based polyelectrolytes for textile wastewater treatment. Separ. Purif. Tech., 2021, 274, 119105.
[http://dx.doi.org/10.1016/j.seppur.2021.119105]
[113]
Wieczorek, J.; Ulbricht, M. Amphiphilic poly(arylene ether sulfone) multiblock copolymers with quaternary ammonium groups for novel thin-film composite nanofiltration membranes. Polymer (Guildf.), 2021, 217, 123446.
[http://dx.doi.org/10.1016/j.polymer.2021.123446]
[114]
Badiger, H.; Shukla, S.; Kalyani, S.; Sridhar, S. Thin film composite sodium alginate membranes for dehydration of acetic acid and isobutanol. J. Appl. Polym. Sci., 2014, 131(6), 1-9.
[115]
Chen, X.; Wang, D.; Wang, W.; Su, Y.; Gao, C. A novel composite nanofiltration (NF) membrane prepared from sodium alginate/polysulfone by epichlorohydrin cross-linking. Desalination Water Treat., 2011, 30(1-3), 146-153.
[http://dx.doi.org/10.5004/dwt.2011.1941]
[116]
Huang, R.Y.M.; Pal, R.; Moon, G.Y. Characteristics of sodium alginate membranes for the pervaporation dehydration of ethanol-water and isopropanol-water mixtures. J. Membr. Sci., 1999, 160(1), 101-113.
[http://dx.doi.org/10.1016/S0376-7388(99)00071-X]
[117]
Yeom, C.K.; Lee, K. Characterization of sodium alginate membrane crosslinked with glutaraldehyde in pervaporation separation. J. Appl. Polym. Sci., 1998, 67(2), 209-219.
[http://dx.doi.org/10.1002/(SICI)1097-4628(19980110)67:2<209:AID-APP3>3.0.CO;2-Y]
[118]
Nigiz, F.U.; Dogan, H.; Hilmioglu, N.D. Pervaporation of ethanol/water mixtures using clinoptilolite and 4A filled sodium alginate membranes. Desalination, 2012, 300, 24-31.
[http://dx.doi.org/10.1016/j.desal.2012.05.036]
[119]
Wang, D.; Aarstad, O.A.; Li, J.; McKee, L.S.; Sætrom, G.I.; Vyas, A.; Srivastava, V.; Aachmann, F.L.; Bulone, V.; Hsieh, Y.S. Preparation of 4-Deoxy-L-erythro-5-hexoseulose Uronic acid (DEH) and guluronic acid rich alginate using a unique exo-alginate lyase from Thalassotalea crassostreae. J. Agric. Food Chem., 2018, 66(6), 1435-1443.
[http://dx.doi.org/10.1021/acs.jafc.7b05751] [PMID: 29363310]
[120]
Garcia-Cruz, C.H.; Foggetti, U.; da Silva, A.N. Alginato bacteriano: Aspectos tecnológicos, características e produção. Quim. Nova, 2008, 31(7), 1800-1806.
[http://dx.doi.org/10.1590/S0100-40422008000700035]
[121]
Sun, L.; Fugetsu, B. Graphene oxide captured for green use: Influence on the structures of calcium alginate and macroporous alginic beads and their application to aqueous removal of acridine orange. Chem. Eng. J., 2014, 240, 565-573.
[http://dx.doi.org/10.1016/j.cej.2013.10.083]
[122]
McHugh, D.J. Production and utilization of products from commercial seaweeds, 288th ed; FAO Fish.Tech.Pap: Australia, 1987.
[123]
Olivas, G.I.; Barbosa-Cánovas, G.V. Alginate-calcium films: Water vapor permeability and mechanical properties as affected by plasticizer and relative humidity. Lebensm. Wiss. Technol., 2008, 41(2), 359-366.
[http://dx.doi.org/10.1016/j.lwt.2007.02.015]
[124]
de Mello Ferreira, I.L.; de Araújo, L.S.; da Silva, M.R. Superparamagnetic nanocomposite based on alginate/maghemite/montmorillonite clay: Evaluation of thermal, morphological and magnetic properties. Sci. Adv. Mater., 2016, 8(5), 956-965.
[http://dx.doi.org/10.1166/sam.2016.2659]
[125]
da Costa, M.P.M.; Delpech, M.C.; de Mello Ferreira, I.L.; de Macedo Cruz, M.T.; Castanharo, J.A.; Cruz, M.D. Evaluation of single-point equations to determine intrinsic viscosity of sodium alginate and chitosan with high deacetylation degree. Polym. Test., 2017, 63, 427-433.
[http://dx.doi.org/10.1016/j.polymertesting.2017.09.003]
[126]
Costa, M.P.M.; Prates, L.M.; Baptista, L.; Cruz, M.T.M.; Ferreira, I.L.M. Interaction of polyelectrolyte complex between sodium alginate and chitosan dimers with a single glyphosate molecule: A DFT and NBO study. Carbohydr. Polym., 2018, 198, 51-60.
[http://dx.doi.org/10.1016/j.carbpol.2018.06.052] [PMID: 30093029]
[127]
Lourenço de Mello Ferreira, I.; Ferreira Bittencourt, R.; Sousa Júnior, C. Nanomagnetic polymeric absorbent based on alginate and gamma-maghemite synthesized in situ for wastewater treatment from metallurgical industry. Properties and Applications of Alginates, 1st ed; Deniz, I.; Imamoglu, E.; Gundogdu, T.K., Eds.; IntechOpen: Londres, 2022, pp. 1-15.
[http://dx.doi.org/10.5772/intechopen.98611]
[128]
Kashima, K.; Imai, M. Selective diffusion of glucose, maltose, and raffinose through calcium alginate membranes characterized by a mass fraction of guluronate. Food Bioprod. Process., 2017, 102, 213-221.
[http://dx.doi.org/10.1016/j.fbp.2016.11.003]
[129]
Daemi, H.; Barikani, M. Synthesis and characterization of calcium alginate nanoparticles, sodium homopolymannuronate salt and its calcium nanoparticles. Sci. Iran., 2012, 19(6), 2023-2028.
[http://dx.doi.org/10.1016/j.scient.2012.10.005]
[130]
Rezende Barbosa Turbiani, F.; Guenter Kieckbusch, T. Propriedades mecânicas e de barreira de filmes de alginato de sódio reticulados com benzoato de cálcio e/ou cloreto de cálcio. Braz. J. Food. Technol., 2011, 14(02), 82-90.
[http://dx.doi.org/10.4260/BJFT2011140200011]
[131]
Santana, A.A.; Kieckbusch, T.G. Physical evaluation of biodegradable films of calcium alginate plasticized with polyols. Braz. J. Chem. Eng., 2013, 30(4), 835-845.
[http://dx.doi.org/10.1590/S0104-66322013000400015]
[132]
da Silva, M.A.; Bierhalz, A.C.K.; Kieckbusch, T.G. Influence of drying conditions on physical properties of alginate films. Dry. Technol., 2012, 30(1), 72-79.
[http://dx.doi.org/10.1080/07373937.2011.620727]
[133]
Turbiani, F.R.B.; Kieckbusch, T.G.; Gimenes, M.L. Liberação de benzoato de cálcio de filmes de alginato de sódio reticulados com íons cálcio. Polímeros, 2011, 21(3), 175-181.
[http://dx.doi.org/10.1590/S0104-14282011005000034]
[134]
Bierhalz, A.C.K.; da Silva, M.A.; Braga, M.E.M.; Sousa, H.J.C.; Kieckbusch, T.G. Effect of calcium and/or barium crosslinking on the physical and antimicrobial properties of natamycin-loaded alginate films. Lebensm. Wiss. Technol., 2014, 57(2), 494-501.
[http://dx.doi.org/10.1016/j.lwt.2014.02.021]
[135]
Zactiti, E.M.; Kieckbusch, T.G. Release of potassium sorbate from active films of sodium alginate crosslinked with calcium chloride. Packag. Technol. Sci., 2009, 22(6), 349-358.
[http://dx.doi.org/10.1002/pts.860]
[136]
Cisneros-Zevallos, L.; Krochta, J.M. Internal modified atmospheres of coated fresh fruits and vegetables: Understanding relative humidity effects. J. Food Sci., 2002, 67(6), 1990-1995.
[http://dx.doi.org/10.1111/j.1365-2621.2002.tb09490.x]
[137]
Chen, M.; Zhang, X.; Zhao, K.; Wang, X.; Zhang, Z.; Wei, J. Removal of heavy metal ions from water by calcium alginate hydrogel nanofiltration membrane with high anti-fouling performance. Polym. Mater. Sci. Eng., 2016, 32(8), 99-103.
[138]
Bano, S.; Mahmood, A.; Kim, S.J.; Lee, K-H. Chlorine resistant binary complexed NaAlg/PVA composite membrane for nanofiltration. Separ. Purif. Tech., 2014, 137(1), 21-27.
[http://dx.doi.org/10.1016/j.seppur.2014.09.024]
[139]
Chen, X.; Gao, X.; Wang, W.; Wang, D.; Gao, C. Study of sodium alginate/polysulfone composite nanofiltration membrane. Desalination Water Treat., 2010, 18(1-3), 198-205.
[http://dx.doi.org/10.5004/dwt.2010.1771]

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