Comparison of adsorption of acid orange II dye on chitosan and zirconium(IV)-chitosan

To increase the adsorption capacity of chitosan (Cht), which is an abundant biopolymer, zirconium (IV)-chitosan (Zr(IV)-Cht) composite was synthesized and adsorption capacity was compared with Cht using acid orange II (T-II). Batch studies were conducted to analyze the effect of Zr (IV) loading amount, solution pH, adsorbent dosage, contact time and temperature on T-II adsorption. The best responding isotherm model to the experimental data was found Langmuir adsorption isotherm model by analyzing Langmuir, Freundlich and Temkin isotherm models. The maximum adsorption capacities were found as 256.41 mg/g and 666.67 mg/g for Cht and Zr(IV)-Cht, respectively. Application of kinetic data to the pseudo-first order and pseudo-second order kinetic models, pseudo-second order model was the best-fitted model for the kinetic data. The adsorption process was found endothermic and spontaneously occurred for both Cht and Zr(IV)-Cht. According to adsorption/desorption experiments, after seventh cycle adsorption capacities were found 65% for Cht and 95% for Zr(IV)-Cht. The synthesized Zr(IV)-Cht composite was found as the high adsorption capacity, low-cost and non-toxic material for T-II adsorption and can be used for dye adsorption.

Asit turuncu II boyasýnýn kitosan ve zirkonyum(IV)-kitosan üzerine adsorpsiyonunun karþýlaþtýrýlmasý

Yaygýn olarak kullanýlan bir biyopolimer olan kitosanýn (Cht) adsorpsiyon kapasitesini arttýrmak amacýyla zirkonyum (IV)-kitosan (Zr(IV)-Cht) kompoziti sentezlenmiþ ve asit turuncu II (T-II) sentetik boyasý kullanýlarak Cht ile adsorpsiyon kapasiteleri karþýlaþtýrýlmýþtýr. Kesikli sistemde yapýlan denemelerde Zr(IV) miktarý, çözelti pH’ý, adsorban miktarý, temas süresi ve sýcaklýklýðýn T-II adsorpsiyonuna olan etkileri incelenmiþtir. Langmuir, Freundlich ve Temkin izoterm modelleri denenerek elde edilen deneysel verilere en uygun cevap veren izoterm modelinin Langmuir izoterm modeli olduðu bulunmuþtur. Maksimum adsorpsiyon kapasiteleri sýrasýyla Cht için 256.41 mg/g ve Zr(IV)/Cht için 666.67 mg/g olarak bulunmuþtur. Kinetik veriler yalancý-birinci dereceden ve yalancý-ikinci dereceden kinetik modellerine uygulandýðýnda yalancý-ikinci dereceden kinetik modelinin en uygun olduðu sonucuna varýlmýþtýr. Termodinamik veriler ýþýðýnda, T-II adsorpsiyonunun hem Cht, hem de Zr(IV)/Cht için endotermik olarak kendiliðinden gerçekleþen bir iþlem olduðu belirlenmiþtir. Adsorpsiyon/desorpsiyon denemelerinde yedinci döngü sonunda Cht’ýn adsorpsiyon kapasitesi %65, Zr(IV)-Cht’ýn adsorpsiyon kapasitesinin %95 olduðu bulunmuþtur. T-II adsorpsiyonu için sentezlenen Zr(IV)-Cht kompoziti yüksek adsorpsiyon kapasitesine sahip, ucuz ve toksik olmayan bir adsorban olarak boya gideriminde kullanýlabileceði sonucuna varýlmýþtýr.