ALEV SPREY PİROLİZİ İLE İÇİ BOŞ Al2O3 KÜRECİKLERİN SENTEZLENMESİNDE BAŞLANGIÇ KİMYASALI OLARAK KULLANILAN EMÜLSİYONLARIN MORFOLOJİ ÜZERİNE ETKİLERİ

Yıl 2023, Cilt: 31 Sayı: 3, 787 - 794, 16.12.2023

Ertuğrul İşlek Hüseyin Boğaç Poyraz İsmail Özgür Özer

https://doi.org/10.31796/ogummf.1272408

Öz

Bu çalışmada, Alev Sprey Pirolizi (ASP) metodunun içi boş Al2O3 küreciklerin sentezinde kullanılabilirliği incelenmiştir. Nihai partikül sentezini sağlayacak başlangıç kimyasalı reaktöre emülsiyon formunda beslenmiştir. Emülsiyonlar, alüminyum nitrat sulu çözeltilerinin, hacimce %9,4 ile %18,8 arasında değişen konsantrasyonlarda yüzey etken madde (PEG-30 dipolihidroksistearat) içeren ksilen sisteminde dağıtılması ile elde edilmiştir. Nitrat çözeltisi/ksilen oranı 1:2 – 1:4 aralığında değiştirilmiş ve çalışılan her oranda artan PEG-30 miktarının dağılan faz boyutunu azalttığı ve emülsiyon kararlığını arttırdığı gözlenmiştir. Hazırlanan emülsiyonlar sabit yanma koşullarında reaktöre beslenmiştir. Partiküllerin fiziksel ve kimyasal analizleri taramalı elektron mikroskobu ile yapılmıştır. Analizlerde, kullanılan her bir sistem için, dolu partiküller ile birlikte içi boş küreciklerin bir arada bulunduğu heterojen bir yapı gözlenmiştir. Emülsiyonlardaki normal dağılıma göre daha geniş ve bimodal dağılıma sahip partiküller, emülsiyon üniform yapısının reaktörde korunamadığını ve/veya oluşan farklı yanma koşullarının damlacıktan-partiküle ve gazdan-partiküle olmak üzere iki farklı mekanizmaya sebep olduğunu göstermiştir. Bütünlüğünü koruyan içi boş partiküllerin belirli boyutun altında oluşabildiği, iri boş partiküllerin ise deforme oldukları gözlenmiştir.

Anahtar Kelimeler

Alev Sprey Pirolizi, Emülsiyon, İçi Boş Kürecik

Teşekkür

Bu çalışma, Türkiye Bilimsel Teknik Araştırma Kurumu (TÜBİTAK) tarafından desteklenen 315M528 numaralı proje kapsamında tasarlanıp imal edilmiş Alev Sprey Pirolizi reaktörüyle ve yapılan çalışmalardan elde edilen birikimle gerçekleşmiştir. Yazarlar, deneysel çalışmalara katkıda bulunun Elif KÜÇÜKKARDEŞ’e, Sarp Yalın VURAL’a, Sema ALTUN’a ve Ahmet Furkan VAYNİ’ye teşekkürlerini sunar.

EFFECTS OF EMULSION PRECURSORS ON THE MORPHOLOGY OF HOLLOW Al2O3 PARTICLES SYNTHESIZED BY FLAME SPRAY PYROLYSIS

Öz

In this study, Flame Spray Pyrolysis (ASP) method was used to synthesize hollow Al2O3 particles. The precursors were fed to the reactor in emulsion form. Emulsions were obtained by dispersing aluminum nitrate aqueous solutions in a xylene system containing surfactant (PEG-30 dipolyhydroxystearate) at concentrations ranging from 9.4 vol. % to 18.8 vol. %. The nitrate solution/xylene ratio was changed in the range of 1:2 – 1:4. It was observed that increasing amount of PEG-30 in all emulsion concentrations decreased the dispersed phase size and increased the emulsion stability. Prepared emulsions were fed to the reactor under constant combustion conditions. Physical and chemical analyzes of the particles were made by scanning electron microscopy. In the analyses, a heterogeneous structure consisting of solid and hollow particles was observed. Particles with a larger and bimodal distribution than the normal distribution in emulsions showed that the uniform structure of the emulsion could not be maintained in the reactor. These results may also indicate a large temperature gradient in the reactor causing two different mechanisms: droplet-to-particle and gas-to-particle. It has been observed that hollow particles that maintain their integrity can form below a certain size, while large hollow particles are deformed.

Anahtar Kelimeler

Flame Spray Pyrolysis, Emulsion, Hollow Particles

Kaynakça

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