ASİT AKTİFLEŞTİRİLMİŞ BENTONİT (ÜNYE) NUMELERİNDEKİ ASİDİK MERKEZLERİNİN TEŞHİSİ

Öz

Tutunmuş piridin türlerine ait 1540 cm-1’deki ve 1450 ve 1610-1605 cm-1’deki piklerin şiddetleri esas alınarak asitle aktifleştirilmiş bentonit numunelerinin Brønsted asitlikleri 6A-8A->4A->2A->10A-bentonit biçiminde verilmiştir. Saf bentonitin yüzey alanı asitle aktifleştirme ile artmış ve 4A-bentonitte en yüksek değere ulaşmıştır. Tüm bentonit numunelerine piridin tutunmasının akabinde yüzey alanlarının azalması mikro- ve mezogözenek girişlerinin tutunan piridin molekülleri tarafından kapatılmasıyla ilişkilidir. Saf bentonitin DTA eğrisinde tutunan suyun ve tabakalar arası katyona bağlı suyun uzaklaşmasından doğan 99 ve 166 ºC merkezli iki endotermik pik tespit edilmiştir. Buna ilaveten numunelerde H-bağlı piridin moleküllerinin uzaklaşmasından kaynaklanan endotermik DTA pikleri yaklaşık 200 ºC’de ve Brønsted merkezlerine bağlı piridin moleküllerine ait endotermik pikleri ise yaklaşık 300 ºC’de gözlenmiştir.

Anahtar Kelimeler

• Bentonit, Brİnsted ve Lewis asitliği, piridin, ATR

Kaynakça

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