GALLİK ASİDİN FOTOKATALİTİK GİDERİMİ: DÜŞÜK MOLEKÜLER AĞIRLIKLI BİLEŞENLER KULLANILARAK DOĞAL ORGANİK MADDE MODELLEMESİ

Öz

Özet: Hümik asitler gibi, doğal polimerlerin yapısal alt birimlerinden birini temsil eden gallik asitler, sucul sistemlerde doğal organik madde bozunmasının bir ürünü olarak kabul edilmektedir. Bu çalışmada, hümik maddelere yapısal olarak benzerlik gösteren küçük moleküler ağırlıklı gallik asit, model madde olarak değerlendirilmiştir. Gallik asidin fotokatalitik oksidasyonu, i) başlangıç madde konsantrasyonu, ii) fotokatalizör konsantrasyonu ve iii) fotokatalizör tipi gibi temel operasyon parametrelerinin etkisi araştırılarak incelenmiştir. Fotokatalizör olarak TiO₂ Degussa P-25, Hombikat UV-100, PC-10, PC-50 ve PC-105 kullanılmıştır. Gallik asidin zamana karşı fotokatalitik olarak giderimi, UV-vis ve floresans spektroskopik parametreler ve toplam organik karbon ölçümleri ile takip edilmiş ve birinci mertebeden kinetik model kullanılarak açıklanmıştır. Gallik asidin kinetik verilerinin, ana molekül olan hümik asidin fotokatalitik bozunma çalışmalarıyla ilişkilendirilebilmesi için karşılaştırmalı bir yaklaşım izlenmiştir. Gallik asidin farklı fotokatalizörler üzerindeki ön adsorpsiyon sonuçları, gallik asidin fotokatalitik giderim hızı ile doğru orantılı olarak ilişkilendirmiştir. Gallik asit giderim hız sabitlerinin UV₂₆₅ cinsinden karşılaştırılması; P-25> PC-10> UV-100> PC-105> PC-50 şekilinde sıralanırken, toplam organik karbon giderimi için hız sabitleri değişimi; PC-105> UV 100> PC-10> P-25> PC-50 olarak bulunmuştur. Test edilen çeşitli fotokatalizörler arasında PC-105' in, gallik asit giderimi için oldukça aktif olduğu bulunmuştur. PC-10 ve PC-50' nin küçük yüzey alanları göz önünde bulundurulduğunda, bu fotokatalizörlerin varlığında nispeten düşük giderim hızları elde edilmiştir.

Anahtar Kelimeler

• Tio2,gallik,fotokatalitik

Kaynakça

1. 1. Bekbölet, M. (1996) Destructive removal of humic acids in aqueous media by photocatalytic oxidation with illuminated titanium dioxide, Journal of Environmental Science and Health. Part A: Environmental Science and Engineering and Toxicology, 31,4, 845-858, doi:10.1080/10934529609376392
2. 2. Uyguner, C.S., Bekbölet, M. (2005a) A comparative study on the photocatalytic degradation of humic substances of various origins, Desalination,176, 1-3, 167-176, doi: 10.1016/j.desal.2004.11.006
3. 3. Uyguner, C.S. ve Bekbölet, M., (2005b) Evaluation of humic acid photocatalytic degradation by UV–vis and fluorescence spectroscopy, Catalysis Today, 101, 267-274, doi: 10.1016/j.cattod.2005.03.011
4. 4. Uyguner, C.S. ve Bekbölet, M., (2009) Application of photocatalysis for the removal of natural organic matter in simulated surface and ground waters, Journal of Advanced Oxidation Technologies, 12, 11, 87-92, doi: 10.1515/jaots-2009-0110
5. 5. Uyguner-Demirel, C.S., Birben, C., Bekbolet, M., (2013) Key role of common anions on the photocatalytic degradation profiles of the molecular size fractions of humic acids, Catalysis Today, 209, 122-126, doi: 10.1016/j.cattod.2012.11.020
6. 6. Bekbölet, M., Süphandağ, A.S., ve Uyguner, C.S., (2002) An investigation of the photocatalytic efficiencies of TiO2 powders on the decolourisation of humic acids, Journal of Photochemistry Photobiology A: Chemistry, 148, 121-128, doi:10.1016/S1010-6030(02)00081-3
7. 7. Uyguner-Demirel, C.S., Birben, N.C., Bekbölet, M., (2017) Elucidation of background organic matter matrix effect on photocatalytic treatment of contaminants using TiO2: A review, Catalysis Today, 284, 202–214, doi: 10.1016/j.cattod.2016.12.030
8. 8. Giannakopoulos, E., Stathi, P., Dimos, K., Gournis, D., Sanakis, Y. ve Deligiannakis, Y., (2006) Adsorption and radical stabilization of humic-Acid analogues and Pb2+ on restricted phyllomorphous clay, Langmuir, 22, 16, 6863-6874, doi: 10.1021/la053273m

9. 9. Kus, M., Gernjak, W, Ibanez, P.F., Rodriguez, S.M., Galvez, J.B., ve Icli, S., (2006) A comparative study of supported TiO2 as photocatalyst in water decontamination at solar pilot plant scale, Journal of Solar Energy Engineering-Transactions of the ASME, 128, 331–333, doi:10.1115/1.2210494
10. 10. Gumy, D., Rincon, A.G., Hajdu, R., Pulgarin, C., (2006) Solar photocatalysis for detoxification and disinfection of water: Different types of suspended and fixed TiO2 catalysts study, Solar Energy, 80, 10, 1376-1381, doi: 10.1016/j.solener.2005.04.026
11. 11. Beltran, F.J., Gimeno, O., Rivas, F.J. ve Carbajo, M., (2006) Photocatalytic ozonation of gallic acid in water, Journal of Chemical Technology and Biotechnology, 81, 1787-1796.
12. 12. Luna, A.L., Valenzuela, M.A., Colbeau-Justin, C., Vázquez, P.,Rodriguez, J.L., Juan, R. Avendano, J.R., Alfaro, S., Tirado, S., Garduno, A. ve De la Rosa, J.M., (2016) Photocatalytic degradation of gallic acid over CuO–TiO2 composites under UV/Vis LEDs irradiation, Applied Catalysis A: General, 52, 140–148, doi: 10.1016/j.apcata.2015.10.044
13. 13. Quici N. ve Litter, M. I., (2009) Heterogeneous photocatalytic degradation of gallic acid under different experimental conditions, Photochemistry and Photobiological Sciences, 8, 975-984, doi: 10.1039/B901904A
14. 14. Gernjak, W., Krutzler, T., Glaser, A., Malato, S., Caceres, J., Bauer, R. ve Fernandez-Alba, A.R., (2003) Photo-Fenton treatment of water containing natural phenolic pollutants, Chemosphere, 50, 71-78, doi: 10.1016/S0045-6535(02)00403-4
15. 15. Carbajo, M., Beltran, F.J., Medina, F., Gimeno, O. ve Rivas, F.J. (2006) Catalytic ozonation of phenolic compounds. The case of gallic acid, Applied Catalysis B: Environmental, 67, 177–186, doi: 10.1016/j.apcatb.2006.04.019
16. 16. Silva, M. T., Nouli, E., Carmo-Apolinario, A.C., Xekoukoulotakis, N.P. ve Mantzavinos, D., (2007) Sonophotocatalytic/H2O2 degradation of phenolic compounds in agro-industrial effluents, Catalysis Today, 124, 232–239, doi: 10.1016/j.cattod.2007.03.057
17. 17. Herrmann, J. M., Guillard, C., Disdier, J., Lehaut, C., Malato, S. ve Blanco, J., (2002) New industrial titania photocatalysts for the solar detoxification of water containing various pollutants, Applied Catalysis B: Environmental, 35, 281-294, doi: 10.1016/S0926-3373(01)00265-X
18. 18. Zertal, A., Molnár-Gábor, D., Malouki, M.A., Sehili, T., Boule, P., (2004) Photocatalytic transformation of 4-chloro2-methylphenoxyacetic acid (MCPA) on several kinds of TiO2, Applied Catalysis B: Environmental, 49, 83–89, doi: 10.1016/j.apcatb.2003.11.015
19. 19. Hatchard, C.G. ve Parker, C.A., (1956) A new sensitive chemical actinometer. II. Potassium ferrioxalate as a standard chemical, Proceedings of Royal Society London Series A, Mathematical and Physical Sciences, 235, 518-536, doi: 10.1098/rspa.1956.0102
20. 20. Singleton, V.L. ve Rossi, J.A. (1965) Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents, American Journal of Enology and Viticulture, 16, 144-158.
21. 21. Blekas, G., Psomiadou, E., Tsimidou, M., Boskou, D., (2002) On the importance of total polar phenols to monitor the stability of Greek virgin olive oil, European Journal of Lipid Science and Technology, 104, 340-346, doi: 10.1002/1438-9312(200206)104:6<340::AID-EJLT340>3.0.CO;2-L
22. 22. Gimeno, O., Carbajo, M., Lopez, M. J., Melero, J. A., Beltran, F., Rivas, F. J. (2007) Photocatalytic promoted oxidation of phenolic mixtures: An insight into the operating andmechanistic aspects, Water Research, 41 (20), 4672–4684, doi: 10.1016/j.watres.2007.06.042
23. 23. Benitez, F. J., Real, F. J., Acero, J. L., Leal, A.I., ve Garcia, C. (2005) Gallic acid degradation in aqueous solutions by UV/H2O2 treatment, Fenton’s reagent and the photo-Fenton system, Journal of Hazardous Materials, B126, 31–39, doi: 10.1016/j.jhazmat.2005.04.040
24. 24. Polewski, K., Kniat, S. ve Slawinska, D. (2002) Gallic acid, a natural antioxidant, inaqueous and micellar environment: spectroscopic studies, Current Topics in Biophysics, 26, 217-227.
25. 25. Arana, J., Lopez, V.M.R., Melian, E.P., Reyes, M.I.S., Rodriguez, J.M.D., Diaz, O.G. (2007) Comparative study of phenolic compounds mixtures, Catalysis Today, 129, 177-184.
26. 26. Schlafani, A. ve Herrmann, J.M. (1996) Comparison of the photoelectronic and photocatalytic activities of various anatase and rutile forms of titania in pure liquid organic phases and in aqueous solutions, Journal of Physical Chemistry, 100, 32, 13655-13661, doi: 10.1021/jp9533584.
27. 27. Rincon, A.G., ve Pulgarin, C., (2003) Photocatalytical inactivation of E. coli: effect of (continuous–intermittent) light intensity and of (suspended–fixed) TiO2 concentration, Applied Catalysis B: Environmental, 44, 263-284, doi:10.1016/S0926-3373(03)00076-6
28. 28. Guillard, C., Disdier, J., Herrmann, J.M., Lehaut, C., Chopin, T., Malato, S., Blanco, J. (1999) Comparison of various titania samples of industrial origin in the solar photocatalytic detoxification of water containing 4-chlorophenol, Catalysis Today, 54, 217–228, doi: 10.1016/S0920-5861(99)00184-4
29. 29. Saadoun L., Ayllon, J.A., Becerril, J.J., Peral, J., Domenech, X. ve Clemente, R.R. (1999) 1,2-diolates of titanium as suitable precursors for the preparation of photoactive high surface titania, Applied Catalysis B: Environmental, 21, 269-277, doi: 10.1016/S0926-3373(99)00031-4
30. 30. Uyguner-Demirel, C.S., Birben, NC. ve Bekbölet, M. (2017) Elucidation of background organic matter matrix effect on photocatalytic treatment of contaminants using TiO2: A review, Catalysis Today, 284, 202–214, doi: 10.1016/j.cattod.2016.12.030