Fouling mitigation and cleanability of TiO2 photocatalyst-modified PVDF membranes during ultrafiltration of model oily wastewater with different salt contents
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In the present study, TiO2-coated ultrafiltration membranes were prepared and used for oily water filtration (droplet size < 2 μm). The aim of this work was to investigate the effect of different salt contents on fouling and filtration properties of neat and TiO2-coated membranes during oil-in-water emulsion filtration. The effect of the TiO2 coating on the flux, surface free energy, and retention values was measured and compared with the neat membrane values. The cleanability of the fouled TiO2-coated membranes by UV irradiation was also investigated by measuring flux recovery and contact angles, and the chemical changes during cleaning were characterized by ATR-IR. It was found that increasing the salt content of the model wastewaters, oil-in-water emulsions, increased the zeta potential and the size of the droplets. The presence of the TiO2 coating decreases the membrane fouling during oily emulsion filtration compared to the neat membrane, due to the hydrophilicity of the coating regardless of the salt content of the emulsions. The neat and coated membrane oil retention was similar, 96 ± 2%. The coated membrane can be effectively cleaned with UV irradiation without additional chemicals and a significant flux recovery can be achieved. Monitoring of the cleaning process by following the membrane surface wettability and ATR-IR measurements showed that the recovery of flux does not mean the total elimination of the oil layer from the membrane surface.
KeywordsTiO2-coated membrane PVDF Salt content Oil-in-water emulsion Ultrafiltration Fouling
This project was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. The authors received financial support from the project Hungarian Scientific Research Fund (NKFI contract number K112096).
- Bellobono IR, Stanescu R, Costache C, Canevali C, Morazzoni F, Scotti R, Bianchi R, Mangone ES, de Martini G, Tozzi PM (2005) Laboratory-scale photomineralisation of n-alkanes in aqueous solution, by photocatalytic membranes immobilising titanium dioxide. Int J Photoenergy 7(2):79–85. https://doi.org/10.1155/S1110662X05000127 CrossRefGoogle Scholar
- Kolltweit Y (2016) Relationship between crude oil composition and physical-chemical properties, Master Thesis, Department of Chemistry, Faculty of Mathematics and Natural Science, University of Bergen, June 2016Google Scholar
- Low ZX, Wang Z, Leong S, Razmjou A, Dumée LF, Zhang X, Wang H (2015) Enhancement of the antifouling properties and filtration performance of poly(ethersulfone) ultrafiltration membranes by incorporation of nanoporous titania nanoparticles. Ind Eng Chem Res 54(44):11188–11198. https://doi.org/10.1021/acs.iecr.5b03147 CrossRefGoogle Scholar
- Luxbacher T, Coday B, Cath T (2014) Does the surface zeta potential approach zero at high salinity? The 2014 Word Congress on Advances in Civil, Environmental, and Materials Research (ACEM14), Busan, Korea, 2014.08.24–28Google Scholar
- Mahani H, Keya AL, Berg S, Bartels WB, Nasralla R, Rossen W (2015) Driving mechanism of low salinity flooding in carbonate rocks (SPE 174300). doi: https://doi.org/10.2118/174300-MS
- Mogyorósi K, Balázs N, Srankó FD, Tombácz E, Dékány I, Oszkó A, Sipos P, Dombi A (2010) The effect of particle shape on the activity of nanocrystalline TiO2 photocatalysts in phenol decomposition. Part 3: the importance of surface quality. Appl Catal B-Environ 96(3-4):577–585. https://doi.org/10.1016/j.apcatb.2010.03.007 CrossRefGoogle Scholar
- Ruckenstein E, Kalthod DG (1981) Role of hydrodynamics and physical interactions in the adsorption and desorption of hydrosols or globular proteins. In Hallstrom B, Lund DB, Ch. Tragardh, (ed) Fundamentals and applications of surface phenomena associated with fouling and cleaning in food processing, Tylosand, Sweden, pp. 115–167Google Scholar
- Veréb G, Ambrus Z, Pap Z, Kmetykó Á, Dombi A, Danciu V, Cheesman A, Mogyorósi K (2012) Comparative study on UV and visible light sensitive bare and doped titanium dioxide photocatalysts for the decomposition of environmental pollutants in water. Appl Catal A-Gen 417–418:26–36. https://doi.org/10.1016/j.apcata.2011.12.018 CrossRefGoogle Scholar