Utilization of Semiconductor Ceramic Plates as a Photocatalytic Material in the Removal of Organics from Waste Waters

Öz

Semiconductor ZnO (“wurtzite”) and TiO2 (“anatase”) powders were mixed and produced by tape casting method by varying ratios of mole% (100/0, 90/10, 80/20, 70/30, 50/50). Green tapes were laminated under 40 MPa pressure followed by sintering at 700°C with 1 hour dwelling time. Final samples were characterized by BET, XRD and SEM-EDX analyses. The activities of the photocatalyst plates were tested by decomposition of a common waste azo dye, RR180. For this purpose, three plates were immersed inside of a 50 mg/L concentrated RR180 solution for 90 minute photocatalytic run under UVA irradiaton. The increasing TiO ratios decreased the decolorization ability of the plates. The reason is the Zn2TiO4 ve Zn2Ti3O8 phases leading the decrease on the amount of active semiconductors (ZnO or TiO2) which are produced after sintering. The highest efficiency was found for the 10% TiO2 containing plates and the photocatalytic activity decreased for the increasing amount of TiO2 inside the plates. © Afyon Kocatepe Üniversitesi

Anahtar Kelimeler

• Photocatalysis

Yarıiletken Seramik Plakalarının Atık Sulardaki Organiklerin Gideriminde Fotokatalizör Malzeme Olarak Kullanımı

Öz

Yarıiletken ZnO (“wurtzite”) ve TiO2 (“anatase”) tozları değişik ZnO/TiO2 oranlarında (100/0, 90/10, 80/20, 70/30, 50/50) karıştırılarak şerit döküm yöntemiyle şekillendirilmişlerdir. Elde edilen yaş haldeki şeritler 40 MPa basınç altında lamine edilerek hepsi 700°C 'de 1 saat süreyle sinterlenmiştir. Elde edilen plakalar BET, XRD ve SEM-EDX yöntemleriyle karakterize edilmiştir. Fotokatalizör malzeme olarak kullanılan plakaların etkinliği, tekstil atık sularında sıkça rastlanan azo boyar madde RR180 'in giderimiyle test edilmiştir. Bu amaçla, derişimi 50 mg/L olan RR180 sulu çözeltisine her bir grup plaka daldırılarak 90 dakika süreyle UVA ışınımı altında fotokatalitik süreçler gerçekleştirilmiştir. Artan TiO2oranları, plakaların renk giderim verimini düşürmüştür. Bunun nedeni, sinterleme neticesinde oluşan Zn2TiO4 ve Zn2Ti3O8 fazlarının yapıdaki aktif yarıiletken (ZnO veya TiO2) miktarını azaltmasıdır. En yüksek verim %10 TiO2 katkılı plakalardan elde edilmiş ve artan TiO2 katkısına bağlı olarak fotokatalitik verimin düştüğü görülmüştür

Anahtar Kelimeler

• Fotokataliz, Kompozit Plaka, ZnO, TiO2, RR180

Kaynakça

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