ABSTRACT Membrane separation processes have been widely applied in the treatment of wastewater. Polysulphone (PSF) membranes are the most common membranes used in ultrafiltration of wastewater due to its mechanical robustness and structural and chemical stability. Unfortunately these membranes are mostly hydrophobic by nature and therefore highly susceptible to fouling. Many studies have been conducted to increase the hydrophilic properties of the polysul-phone/ polyethersulfone membrane surface, more recently metal nanoparticles have been added to the polymer matrix in order to reduce fouling potential and increase membrane performance. TiO2 nanoparticles have proven successful in mitigating fouling of organic matter onto PES. Embedded Ag nanoparticles have improved virus removal from wastewater due to the bactericidal properties of silver. Al2O3 and most recently ZrO2 nanoparticles reduced the fouling rate of polyethersulfone membranes in wastewater, while the latter also showed lower flux decline of the composite membrane. These metal nanoparticles all impart specific properties onto the membrane surface. Scanning electron microscopy, steady state fouling rate and contact angle measurements are membrane characterisation techniques discussed in this review that reveal specific changes to membrane properties brought about by metal nanoparticles. This paper reviews the most recent developments and shortcomings of metal nanocomposite polysulfone and polyethersulfone (PES) membranes and strives to identify specific focus areas to consider in future research.
Cite this paper
H. Richards, P. Baker and E. Iwuoha, "Metal Nanoparticle Modified Polysulfone Membranes for Use in Wastewater Treatment: A Critical Review," Journal of Surface Engineered Materials and Advanced Technology, Vol. 2 No. 3, 2012, pp. 183-193. doi: 10.4236/jsemat.2012.223029.
 N. Savage and M. S. Diallo, “Nanomaterials and Water Purification: Opportunities and Challenges,” Journal of Nanoparticle Research, Vol. 7, No. 4-5, 2005, pp. 331- 342. doi:10.1007/s11051-005-7523-5
 E. M. V. Hoek and A. K. Ghosh, “Nanotechnology-Based Membranes for Water Purification,” In: N. Savage, M. Diallo, J. Duncan, A. Street and R. Sustich, Eds., Nano-technology Applications for Clean Water, William Andrew Publishing, Boston, 2009, pp. 47-58.
 P. Le-Clech, V. Che and T. A. G. Fane, “Fouling in Membrane Bioreactors Used in Wastewater Treatment,” Journal of Membrane Science, Vol. 284, No. 1-2, 2006, pp. 17-53. doi:10.1016/j.memsci.2006.08.019
 P. Xu, C. Bellona and J. E. Drewes, “Fouling of Nanofiltration and Reverse Osmosis Membranes during Municipal Wastewater Reclamation: Membrane Autopsy Results from Pilot-Scale Investigations,” Journal of Membrane Science, Vol. 353, No. 1-2, 2010, pp. 111-121.
 J. Zhang, H. C. Chua, J. Zhou and A. G. Fane, “Factors Affecting the Membrane Performance in Submerged Membrane Bioreactors,” Journal of Membrane Science, Vol. 284, No. 1-2, 2006, pp. 54-66.
 H.-H. Ngo and W. Guo, “Membrane Fouling Control and Enhanced Phosphorus Removal in an Aerated Submerged Membrane Bioreactor Using Modified Green Bioflocculant,” Bioresource Technology, Vol. 100, No. 18, 2009, pp. 4289-4291. doi:10.1016/j.biortech.2009.03.057
 Y. Shen, W. Zhao, K. Xiao and X. Huang, “A Systematic Insight into Fouling Propensity of Soluble Microbial Products in Membrane Bioreactors Based on Hydrophobic Interaction and Size Exclusion,” Journal of Membrane Science, Vol. 346, No. 1, 2010, pp. 187-193.
 H. K. Shon, S. Vigneswaran, I. S. Kim, J. Cho and H. H. Ngo, “Fouling of Ultrafiltration Membrane by Effluent Organic Matter: A Detailed Characterization Using Different Organic Fractions in Wastewater,” Journal of Membrane Science, Vol. 278, No. 1-2, 2006, pp. 232-238.
 J. Lee, W. Ahn and C. Lee, “Comparison of the Filtration Characteristics between Attached and Suspended Growth Microorganisms in Submerged Membrane Bioreactor,” Water Research, Vol. 35, No. 10, 2001, pp. 2435-2445.
 H. Hua, N. Li, L. Wu, H. Zhong, G. Wu, Z. Yuan, X. Lin and L. Tang, “Anti-Fouling Ultrafiltration Membrane Prepared from Poly-sulfone-Graft-Methyl Acrylate Copoly- mers by UV-Induced Grafting Method,” Journal of Environmental Sciences, Vol. 20, No. 5, 2008, pp. 565-570.
 H. Ivnitsky, D. Minz, L. Kautsky, A. Preis, A. Ostfeld, R. Semiat and C. G. Dosoretz, “Biofouling Formation and Modeling in Nanofiltration Membranes Applied to Waste- water Treatment,” Journal of Membrane Science, Vol. 360, No. 1-2, 2010, pp. 165-173.
 M. Herzberg, D. Berry and L. Raskin, “Impact of Micro-filtration Treatment of Secondary Wastewater Effluent on Biofouling of Reverse Osmosis Membranes,” Water Research, Vol. 44, No. 1, 2010, pp. 167-176.
 Y. Yanan, Z. Huixuan, W. Peng, Z. Qingzhu and L. Jun, “The Influence of Nano-Sized TiO2 Fillers on the Morphologies and Properties of PSF UF Membrane,” Journal of Membrane Science, Vol. 288, No. 1-2, 2007, pp. 231-238.
 N. Maximous, G. Nakhla, W. Wan and K. Wong, “Preparation, Characterization and Performance of Al2O3/PES Membrane for Wastewater Filtration,” Journal of Membrane Science, Vol. 341, No. 1-2, 2009, pp. 67-75.
 Z. G. Wu, M. Munoz and O. Montero, “The Synthesis of Nickel Nanoparticles by Hydrazine Reduction,” Advanced Powder Technology, Vol. 21, No. 2, 2009, pp. 165-168.
 F. Guo, H. Zheng, Z. Yang and Y. Qian, “Synthesis of Cobalt Nanoparticles in Ethanol Hydra-zine Alkaline System (EHAS) at Room Temperature,” Materials Letters, Vol. 56, No. 6, 2002, pp. 906-909.
 J. Mulder, “Basic Principles of Membrane Technology,” 2nd Edition, Kluwer Academic Publishers, Dordrecht, 1996, p. 584. doi:10.1007/978-94-009-1766-8
 A. Rahimpour, “UV Photo-Grafting of Hydrophilic Mono-mers onto the Surface of Nano-Porous PES Membranes for Improving Surface Proper-ties,” Desalination, Vol. 265, No. 1-3, 2011, pp. 93-101.
 A. Rahimpour, S. S. Madaeni, M. Jahanshahi, Y. Mansourpanah and N. Mortazavian, “Development of High Performance Nano-Porous Polyethersulfone Ultrafiltration Membranes with Hydrophilic Surface and Superior Antifouling Properties,” Applied Surface Science, Vol. 255, No. 22, 2009, pp. 9166-9173.
 H. Susanto, N. Stahra and M. Ulbricht, “High Performance Polyethersulfone Micro-filtration Membranes Having High Flux and Stable Hydrophilic Property,” Journal of Membrane Science, Vol. 342, No. 1-2, 2009, pp. 153-164. doi:10.1016/j.memsci.2009.06.035
 K. Zodrow, L. Brunet, S. Mahendra, D. Li, A. Zhang, Q. Li and P. J. J. Alvarez, “Polysulfone Ultrafiltration Membranes Impregnated with Silver Nanoparticles Show Improved Biofouling Resistance and Virus Removal,” Water Research, Vol. 43, No. 3, 2009, pp. 715-723.
 J. Kim and B. Van der Bruggen, “The Use of Nanoparticles in Polymeric and Ceramic Membrane Structures: Review of Manufacturing Procedures and Performance Im- provement for Water Treatment,” Environmental Pollution, Vol. 158, No. 7, 2010, pp. 2335-2349.
 H. Omidian, J. G. Rocca and K. Park, “Advances in Superporous Hydrogels,” Journal of Controlled Release, Vol. 102, No. 1, 2005, pp. 3-12.
 N. Maximous, G. Nak-hla, W. Wan and K. Wong, “Performance of a Novel ZrO2/PES Membrane for Wastewater Filtration,” Journal of Membrane Science, Vol. 352, No. 1-2, 2010, pp. 222-230.
 S. Chen, R. Liou, C. Lai, M. Hung, M. Tsai and S. Huang, “Embedded Nano-Iron Polysulfone Membrane for Dehydration of the Ethanol/Water Mixtures by Pervaporation,” Desalination, Vol. 234, No. 1-3, 2008, pp. 221-231.
 T. Bae and T. Tak, “Effect of TiO2 Nanoparticles on Fouling Mitigation of Ultrafiltration Membranes for Activated Sludge Filtration,” Journal of Membrane Science, Vol. 249, No. 1-2, 2005, pp. 1-8.
 L. Y. Ng, A. W. Mohammad, C. P. Leo and N. Hilal, “Polymeric Membranes Incorporated with Metal/Metal Oxide Nanoparticles: A Comprehensive Review,” Desalination, 2010, in Press. doi:10.1016/j.desal.2010.11.033
 J. S. Taurozzi, H. Arul, V. Z. Bosak, A. F. Burban, T. C. Voice, M. L. Bruening and V. V. Tarabara, “Effect of Filler Incorporation Route on the Properties of Polysulfone-Silver Nanocomposite Membranes of Different Porosities,” Journal of Membrane Science, Vol. 325, No. 1, 2008, pp. 58-68. doi:10.1016/j.memsci.2008.07.010
 H. Li, Y. Cao, J. Qin, X. Jie, T. Wang, J. Liu and Q. Yuan, “Development and Characterization of Anti-Fouling Cellulose Hollow Fiber UF Membranes for Oil-Water Separation,” Journal of Membrane Science, Vol. 279, No. 1-2, 2006, pp. 328-335. doi:10.1016/j.memsci.2005.12.025
 H.-Y. Yu, M.-X. Hu, Z.-K. Xu, J.-L. Wang and S.-Y. Wang, “Surface Modification of Polypropylene Microporous Membranes to Improve Their Antifouling Property in MBR: NH3 Plasma Treatment,” Sepa-ration and Purification Technology, Vol. 45, No. 1, 2005, pp. 8-15.
 Q. Sun, Y. Su, X. Ma, Y. Wang and Z. Jiang, “Improved Antifouling Property of Zwitterionic Ultrafiltration Membrane Composed of Acry-lonitile and Sulfobetaine Co-polymer,” Membrane Science, Vol. 285, No. 1-2, 2006, pp. 299-305. doi:10.1016/j.memsci.2006.08.035
 N. A. Hashim, F. Liu and K. Li, “A simplified Method for Preparation of Hydrophilic PVDF Membranes from an Amphiphilic Graft Copolymer,” Journal of Membrane Science, Vol. 345, No. 1-2, 2009, pp. 134-141.
 H. Ju, B. D. McCloskey, A. C. Sagle, V. A. Kusuma and B. D. Freeman, “Preparation and Characterization of Cross-linked Ploy(Ethylene Glycol) Diacrylate Hydrogels as Fouling-Resistant Membrane Coating Materials,” Journal of Environmental Sciences, Vol. 330, No. 1-2, 2009, pp. 180-188.
 A. C. Sagle, H. Ju, B. D. Freeman and M. M. Sharma, “PEG-Based Hydrogel Membrane Coatings,” Polymer, Vol. 50, No. 3, 2009, pp. 756-766.
 J. A. Howell, V. Sanchez and R. W. Field, “Membranes in Bioprocessing: Theory and Application,” Chapman & Hall, Cambridge, 1993. doi:10.1007/978-94-011-2156-9
 T. Nomura, T. Fujii and M. Suzuki, “Application of the Ceramic Membrane with Hydrophobic Skin Layer to Separation of activated Sludge,” Water Science and Technology, Vol. 35, No. 8, 1997, pp. 137-144.
 K. H. Choo and C. H. Lee, “Understanding Membrane Fouling in Terms of Surface Free Energy Changes,” Colloid Interface Science, Vol. 226, No. 2, 2000, pp. 367-370.
 N. Maximous, G. Nakhla and W. Wan, “Comparative Assessment of Hydrophobic and Hydrophilic Membrane Fouling in Wastewater Applications,” Journal of Membrane Science, Vol. 339, No. 1-2, 2009, pp. 93-99.