KİTOSAN KAPLI KAOLİN BONCUKLARIN SULU ÇÖZELTİLERDEN KROM(VI) UZAKLAŞTIRILMASINDA ADSORBAN OLARAK KULLANIMI

Öz

Filtrasyon, iyon değişimi, kimyasal çöktürme ve membran sistemleri gibi fizikokimyasal prosesler ağır metaller içeren atık suların saflaştırılmasında kullanılmaktadır. Adsorpsiyon metodu daha ekonomiktir ve diğer proseslere göre bazı üstünlüklere sahiptir. Son yıllarda araştırmacılar düşük maliyetli ve kolayca elde edilebilen adsorbanların elde edilmesi yönünde çalışmalar yapmaktadırlar. Bu çalışmada, sulu çözeltilerden Cr(VI) iyonlarının giderilmesinde düşük maliyetli adsorban olarak hazırlanılan kitosan kaplı kaolin kompozit boncukların kullanımı araştırılmıştır. Kitosan kaplı kaolin kürecikleri kullanarak sulu çözeltiden Cr(VI) adsorpsiyonu üzerine pH, sorbent dozu, başlangıç metal konsantrasyonu ve temas süresinin etkileri sistematik olarak incelendi. Çözeltinin pH'sı 2-6 aralığında değiştirilmiş ve kitosan kaplı kaolin boncukları ile Cr(VI) adsorpsiyonunun pH’ya bağlı olduğu tespit edilmiştir. Denge verilerini tanımlamak için Langmuir ve Freundlich adsorpsiyon izoterm modelleri uygulanmıştır. Verilerin Langmuir modele uygun olduğu görülmüş ve 120 dk. temas süresince kitosan kaplı kaolin boncukların Cr(VI) için maksimum adsorpsiyon kapasitesi 31,98 mg/g olarak bulunmuştur.

Anahtar Kelimeler

• Adsorpsiyon,Kaolin,Kitosan,Krom,İzoterm

Removal of Chromium (VI) From Aqueous Solutions Using Chitosan Coated Kaoline Beads As Adsorbent

Abstract

Various physicochemical process such as filtration, ion exchange, chemical precipitation, and membran systems are used in treatment of waste waters including heavy metals. Among these processes, adsorption technique is more economical process and has some advantages over the other techniques. Recently, researchers have many studies on the low cost and easily obtainable adsorbents. In this study, the usege of chitosan coated kaoline composite beads as low-cost adsorbent to removal of Cr(VI) ions from the aqueous solutions has been investigated. The effects of pH, sorbent dosage, initial metal concentration and contact time on the adsorption of Cr(VI) from aqueous soluiton using the chitosan coated kaoline beads were studied systemically. The pH of the solution was varied over a range of 2-6 and the adsorption of Cr(VI) ions on chitosan coated kaoline beads was determined to be pH-dependent. The Freundlich and Langmuir adsorption isotherm models were applied to describe equilibrium data. The data fitted well with Langmuir model and maximum adsorption capacity of chitosan-coated kaoline beads was determined to be 31,98 mg/g for Cr(VI) at 120 sec. of contact time.

Keywords

• Adsorption,Kaoline,Chitosan,Chromium,Isotherm

Kaynakça

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