PES membranes with different pore sizes (0.05 and 0.2 micrometer) were coated with commercial TiO2 P25 and synthetized TiO2 nanoparticles. In order to test the photocatalytic activity of Acid red 1 dye solutios were filtered through the modified membranes. Coated membranes had lower fluxes compared to the neat membranes, contact angle measurements showed the changes of wettability of the membranes

Beszédes, Sándor

Hodúr, Cecilia

Kertész, Szabolcs

Kovács, Ildikó

Kukovecz, Ákos

László, Zsuzsanna

Papp, Ibolya Zita

Kovács Ildikó

Kertész Szabolcs

Beszédes Sándor

Hodúr Cecilia

Papp Ibolya Zita

Kukovecz Ákos

László Zsuzsanna

SZTE Publicatio Repozitórium - SZTE - Repository of Publications

The International Ozone Association is pleased to present the22nd World Congress 8t Exhibition28 June — 3 July 2015, Barcelona, SpainOzone and Advanced Oxidation Leading-edge science and technologiesPROCEEDINGSNo. ISBN: 979-10-92607-02-4 Water TreatmentScience and TechnologyResearch Development Events MembersKnowledge AdvancesFundamentals , S*®ndards Awards Field application iDClUStrV NewsFood Processing En9ineerin9 Ozone Therapy WorldwideAgriculture Publica,'onsIPA World Congress, Barcelona, Spain -  28 June-3 July, 2015Removal o f Acid Red 1 by TÍO2 nanoparticles coated po lyethersulfone membraneunder UV irradiationIldikó Kovács1. Szabolcs Kertész1, Sándor Beszédes1, Cecilia Hodúr1, Ibolya Zita Papp2,Ákos Kukovecz23, Zsuzsanna László11. University of Szeged, Department of Process Engineering, Moszkvai str.9, H-6725 Szeged, Hungary2. Department of Applied and Environmental Chemistry, University of Szeged, H-6720 Szeged, Rerrich Béla tér 1., Hungary3. MTA-SZTE "Lendület" Porous Nanocomposites Research Group, H-6720 Szeged, Rerrich Béla tér 1., HungaryAbstractPolyethersulfone (PES) membranes are used in a wide range for water and wastewater treatment doe to their physical and chemical properties, but despite their improved properties membrane fouling remains a problem. In order to overcome this problem a great deal of interest has been focused on modifying membranes with Ti02 as a photocatalyst to reduce fouling and to make the organic component removal more efficient.In this study polyethersulfone membranes with different pore sizes (0.05 and 0.2 pm) were coated with commercial T i02 P25 and synthesized Ti02 nanoparticles (NP) by filtering the Ti02 solution thruogh the membrane. In order to test the photocatalytic activity of Acid Red 1 dye solutions were filtered with commercial PES membranes with and without Ti02 coating. Coated membranes had significantly lower fluxes compared to the neat membranes. Contact angle measurements showed that Ti02 P25 formed a very hydrophilic coat on the membranes on the contrary T i02 NP increased the hydrophobicity of the surface. UV irradiation had an effect on both the neat and coated membranes flux values. Relative dye fluxes were calculated against the equivalent water fluxes and were compared. UV irradiation increased the dye elimination efficiency of the coated membranes, which proves the Ti02 coatings photocatalytic activity.Key-words: Membrane filtration, Polyethersulfone (PES) membrane, Ti02 nanopaticles, Acid red 1IntroductionColored effluents from textile industries represent one of the major problems concerning textile wastewaters. Dyes are intensely colored and represent a special problem by their discharge into waste streams without treatment by the textile industry worldwide. Most of the dyes are difficult to decolorize due to their complex structure and synthetic origin [1]. Acid Red 1 (AR1, Azophloxine) dye was used as a model pollutant to determine the photocatalytic activity of the membranes Ti02 coating. AR1 is a reactive azo dye belonging to the largest class of dyes commonly employed in textile industry [2].Advanced oxidation processes (AOPs) are extensively investigated and used in water, air and wastewater treatment. AOPs are very effective and useful for the degradation of substances that are resistant to conventional treatment technologies [3]. AOPs generate hydroxyl radicals (’OH) that are very effective in degrading organic pollutants due to their non-selectivity and strong oxidant power (E° = 2.80 V) [1], Semiconductor photocatalysis with a primary focus on Ti02 as a durable photocatalyst has been applied to a variety of problems of environmental interest in addition to water and air purification. It has been shown to be useful amongst many others for the destruction of microorganisms such as bacteria and viruses, for odor control and for the cleanup of oil spills [3].In membrane preparation nanoparticles have been used to produce membranes with a desirable structure or to control the membrane fouling [4], PES membranes are used in a wide range for water and wastewater treatment do to their physical and chemical properties. Despite10.2-1their great properties like high temperature and good chemical resistance, wide pH tolerances, broader range of pore sizes, membrane fouling remains a problem [5].Chemical membrane modifications, by assembling additional compounds in membrane composition, have been proposed to realize high membrane permeability over a prolonged period of time [6]. Over the last decades, a great deal of interest has been focused on modifying membranes with Ti02 as a photocatalyst, among others to reduce fouling and to make the organic component removal more efficient. T i02 is favored over other semiconductors due to its good physical and chemical properties, availability, photocatalytic activity, desirable hydrophilic and potential antifouling properties [4] and [7],The mechanisam of the heterogenius photocatalysis is as follows(Fig. 1): when a semi­conductor is irradiated by a ray equal or greater than the band gap energy in ordinary conditions, an electron is transferred from valence band to conduction band of the semi-conductor. Therefore a pairs of holes and electrons are created on the surface of the semi-conductor. Since Ti02 is a semi-conductor, the UV ray leads to the appearance of the electrons and holes. The photo­generated electrons can reduce the dissolved oxigen and produce super-oxide (0*~) radical anions. The photo-generated holes have a very high oxidation potential and can react with water which is adsorbed on the catalyst surface and generate (’OH) radicals. These two types of created groups are among strong oxidant reagents that lead to the decomposition and removal of the impurities especially organic compounds [8] and [3].orReductiono2•OHOxidationh2oFigure 1. Mechanism of photocatalysisNanocomposite Ti02 PES membranes have been manufactured by two ways: coating the nanoparticles on the surface of the porous membranes or blending them with polymeric casting solution [4] and [7], Most of the proposed processes apply the phase inversion technique to produce hybrid polymeric membrane adding a known amount of T i02 in the main solution. This mixture is then precipitated in a solvent solution. An alternative procedure is to dip the neat polymeric membrane into a Ti02 solution [6]. Rahimpour et al. showed that coating Ti02 onto membrane surface is a superior method compared to entrapping Ti02 particles in the membrane matrix. The former option enables higher permeate fluxes and smaller membrane resistances[6].In this study the membrane performance and azo dye (Aid red1) removal of PES membrane coated with commercial Ti02 P25 and synthesized Ti02 NP under UV irradiation was investigated. Contact angle measurements were carried out to determine the coatings effect on the membrane surfaces wettability.10.2-2Material and methodsMaterialsTi02 (anatase) (BA01-01), T i02 P25 (80% anatase, 20% rutile) and Acid red1 were supplied by UNIVAR, EVONIC Industries and Synthesia respectively. The concentration of AR1 solution used in membrane filtration measurements was 15 mg L'1.Preparation of TiO? nanoparticlesIn 1L 10M NaOH solution 250g Ti02 (anatase) was suspended, then for 24 hours the suspension was stirred in a rotating autoclave at 3 rpm and 155°C. Than the resulting product was washed and protonated with 0.1 M HCI, after maintaining a pH value between 3 and 4 for 30 minutes the product was washed with 0.01 M HCI for 3 days than with distilled water to remove the remaining chloride ions. The resulting Ti02 nanotubes were dried at 80°C for a day. The Ti02 nanotubes (NT) were than heat treated at 600°C for 6 hours. As a resulting product Ti02 nanoparticles (Ti02 NP) arose (Fig. 2).Figure 2. TEM images of a) Ti02 NT and b) Ti02 NPMembrane modificationPolyethersulfone membranes (PES-MF and MP005 (NEW LOGIC Research INC, USA) with a0.2 pm and 0.05 pm pore size respectively were coated with commertional Ti02 P25 and Ti02 NP. Membranes were prepared by filtering 50 mL, 0.4 g/L Ti02 suspension through the membranes using a dead end cell. The applied transmembrane pressure (TMP) of 0.1 MPa was constant and achieved by inert nitrogen gas. Neat membranes were pretreated in distilled water for 24 hours before use.Membrane filtrationWater flux was measured using a dead end cell (Millipore, N°96) coupled with a low pressure mercury UV lamp (Lightech, Hungary). The flux measurements of distilled water and the azo dye were done at 1 bar and room temperature with the effective membrane area of 0.00342 m2. UV irradiation of certain samples was done in the dead end cells before the filtration as a pretreatment for 60 minutes.Analytical methodsTransmission electron microscopy (TEM; Philis CM 10) images were recorded to determine the morphology and size of the Ti02 NT and Ti02 NP.10.2-3The concentration of the dye was measured by spectrophotometer (Nanocolor® UV/Vis, Macherey-Nagel GmbH, Germany) at A=532 nm.Membrane hydrophobicity was quantified by measuring the contact angle that was formed between the (neat and coated) membrane surface and distilled water. 10pl_ water was carefully dropped on the top of the membrane surface. Contact angles were measured using the sessile drop method (Datapysics Contact Angle System OCA15Pro, Germany).Results and discussionThe effect of modification with TiO? P25 and TiO? NP on the membrane performanceWater fluxes for unmodified and modified PES-MF and MP005 membranes with Ti02 P25 and Ti02 NP were measured. The coated membranes showed a lower flux compared to the neat membranes, which suggests that Ti02 nanoparticles narrow and plug the membrane pores (Fig. 3). The primary particle size of commercial Ti02 nanoparticles such as P25 is about 20 nm, its particle size as powder or in dispersions is in a range of hundreds of nanometers due to agglomeration [7], A similar behavior was observed on the TEM pictures of the Ti02 NP with a singular nanoparticle sizes about 60nm. Ti02 NP coated membranes had a higher flux compared to the Ti02 P25 coated ones and that this growth was more expressed in case of the MP005 membrane which has the smaller 0.05 pm pore size. This could suggest that the Ti02 P25 particles cause a more pronounced membrane fouling.P F S - M F n e a t  P F S -M F  P ?5 i P F S -M F  N P  M  P o m  n e a t  M P f lO S  P 7 r> M P O O F i N PFigure 3. Influence of different coatings on the average water fluxesContact angle measurements showed that the wettability of Ti02 NP coated membranes decreased compared to the neat membranes (Fig. 4). In case of Ti02 P25 coated membranes contact angle was unmeasurably low due to the catalysts extent hydrophilic character. It has been recognized that the reactivity of Ti02 surface, and in particular its affinity toward water is dependent on Ti02 crystal phase. The hydrophilicity of the mixture of the two polymorphs (anatase and rutile) is close to that of the main component, i.e. anatase [9],Figure 4. Neat, Ti02 NP and P25 coated PES membranes wettability10.2-4Microfiltration of AR 1 solutionMicrofiltration of AR 1 was carried out with coated membranes and with the coated membranes coupled with UV irradiation. In case of UV irradiation the water fluxes without an exception were about 50% higher than without the irradiation (Fig. 5). This can be explained by that the irradiation of PES membranes by UV light causes crosslinking and chain scission, two parallel competitive processes, shaping the transport properties of the modified membrane [11]. Similar behavior was observed in the case of dye solution fluxes; the UV irradiation resulted in higher fluxes in both membranes.Figure 5. Ti02 NP and P25 coated PES membranes relative dye fluxPhotocatalvtic and elimination efficiency of TiO? P25 and TiO? NP coated membranes during MF of AR 1Elimination and photocatalytic efficiencies of T i02 P25 and Ti02 NP coated membranes in the presence of UV irradiation during MF of AR 1 were compared (Figure 6). The membranes with smaller pore size (0.05 pm) showed higher dye retention. The dye retention of the irradiated membrane decreased due to the degradation of dye molecules, but the overall dye elimination increased by combining heterogeneous photocatalysis and microfiltration. In case of 0.2 pm pore size PES membranes Ti02 P25 coated membrane showed lower elimination and photocatalytic efficiency compared to the Ti02 NP coated PES-MF membrane. It was found that the highest dye elimination and photocatalytic efficiency was achieved by Ti02NP coated MP005 membranes. Membrane pares which only differ in the aspect of irradiation show that the decrease of relative flux is in correlation with the elimination efficiency. Higher elimination efficiency caused lower relative fluxes due to the concentration polarization on the surface of the membrane.Figure 6. Elimination and photocatalytic efficiencies10.2 - 5ConclusionsRemoval of AR 1 by MF using MP005 and PES-MF membranes coated with T i02 P25 and Ti02 NP was an indicator weather these membranes gain any positive qualities as a result of coating. It was found that coated membranes had significantly lower fluxes compared to the neat membranes due to the fouling of the pores by nanoparticles. Contact angle measurements showed that T i02 P25 formed a very hydrophilic coat on the membranes on the contrary Ti02 NP increased the hydrophobicity of the surface. UV irradiation had an effect on both the neat and coated membranes flux values; UV light may causes crosslinking and chain scission shaping the transport properties of the modified membrane. The retention and photocatalytic qualities of the coated membranes were significant which makes them candidates for further investigations to determine whether they can be used in water and wastewater treatment.References1. Daud K., Hameed B., Decolorization of Acid Red 1 by Fenton-like process using rice husk ash-based catalyst, Journal of Hazardous Materials, 176 (1-3), 938-944 (2010).2. Foldvary Cs., Wojnarovits L., The effect of high-energy radiation on aqueous solution of Acid Red 1 textile dye, Radiation Physics and Chemistry, 76, 1485-1488 (2007).3. Hoffmann M., Martin S., Choi W., Bahnemann D., Environmental Applications of Semiconductor Photocatalysis, Chemical Reviews, 95, 69-96 (1995).4. Vatanpour V., Maadaeni S. S., Khataee R. A.,Salehi E., Zinadini S., Monfared A. H., Ti02 embedded mixed matrix PES nanocomposite membranes: Influence of different sizes and types of nanoparticles on antifouling and performance, Desalination, 292, 19-29 (2012).5. Li J. F., Xu Z. L, Yang H., Yu L. Y., Liu M., Effect of Ti02 nanoparticles on the surface morphology and performance of microporous PES membrane, Applied Surface Science, 255 (9), 4725-4732 (2009).6. Bergamasco R., Silva F. V., Arakawa F. S., Yamaguchi N. U., Reis M. H. M., Tavares C. J., Amorim M. T. P. S., Tavares C. R. G., Drinking water treatment in a gravimetric flow system with Ti02coated membranes, 174 (1), 102-109 (2011).7. Razmjoua A., Mansouri J., Chen V., The effects of mechanical and chemical modification of Ti02 nanoparticles on the surface chemistry, structure and fouling performance of PES ultrafiltration membranes, Journal of Membrane Science, 378 (1-2), 73-84 (2011).8. Rahimpour A., Madaeni S. S., Taheri A. H., Mansourpanah Y., Coupling Ti02 nanoparticles with UV irradiation for modification of polyethersulfone ultrafiltration membranes, Journal of Membrane Science, 313(2008) 158-169.9. Bolis V., Buscoa C., Ciarletta M., Distasi C., Erriquez J., Fenoglio I., Livraghi S., Morel S., Hydrophilic/hydrophobic features of Ti02 nanoparticles as a function of crystal phase, surface area and coating, in relation to their potential toxicity in peripheral nervous system, Journal of Colloid and Interface Science, 369 (1), 28-39 (2012).10. Diebold U., Ruzycki N., Herman G.S., Selloni A., One step towards bridging the materials gap: surface studies of Ti02 anatase, Catalysis Today, 85, 93-100 (2003).11. Kaeselev B., Kingshottb P., Jonsson G., Influence of the surface structure on the filtration performance of UV-modified PES membranes, Desalination, 146 (1-3), 265-271 (2002).10.2 - 6

Removal of Acid red 1 by TiO2 nanoparticles coated polyethersulfone membrane under UV irradiation

Papp, Zita Ibolya

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Removal od acid red 1 by TiO2 nanoparticles coated polyethersulfone membrane under UV irradiation

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Removal of Acid red 1 by TiO2 nanoparticles coated polyethersulfone membrane under UV irradiation

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