Adsorption Properties of Cr VI onto Microspheres Carrying Imidazole Functional Groups: Kinetic and Isotherm Studies

Abstract

Poly ethylene glycol dimethacrylate-n-vinyl imidazole [poly EGDMA-VIM ] microspheres average diameter=150-200 μm were prepared by copolymerizing of ethylene glycol dimethacrylate EGDMA with n-vinyl imidazole VIM . Poly EGDMA-VIM microspheres were characterized by swelling studies and scanning electron microscope SEM . The adsorption of Cr VI onto the poly EGDMA-VIM microspheres was examined in aqueous solutions. The adsorption of Cr VI from aqueous solutions was carried at different contact times, Cr VI concentrations, and pH. The amount of Cr VI adsorbed increased with increasing concentration and decreasing pH. The intraparticle diffusion rate constant was calculated. Adsorption isotherms poly EGDMA-VIM have been determined with common isotherm equations such as Langmuir and Freundlich isotherm models. The pseudo first-order kinetic model was used to describe the kinetic data. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. Values of the dimensionless separation factor RL and the distrubition coefficient KD were evaluated.

Keywords

• Adsorption kinetic,Adsorption isotherm,Adsorption thermodynamic,Cr VI

İmidazol Fonksiyonel Grupları Taşıyan Mikrokürelerin Cr VI Adsorpsiyonunun Özellikleri: Kinetik ve İzoterm Çalışmaları

Abstract

Poli etilen glikol dimetakrilat-n-vinil imidazol [poli EGDMA-VIM ] mikroküreleri ortalama çap=150-200 μm etilen glikol dimetakrilat EGDMA ile n-vinil imidazol VIM ün kopolimerizasyonu ile elde edildiler. Poli EGDMA-VIM mikroküreleri, şişme çalışmaları ve taramalı elektron mikroskobu SEM ile karakterize edildiler. Poli EGDMA-VIM mikrokürelerinin Cr VI adsorpsiyonu sulu çözeltilerde çalışıldı. Sulu çözeltilerden Cr VI adsorpsiyonu farklı kontakt zamanlarında, Cr VI konsantrasyonlarında ve pH yapıldı. Adsorbe olan Cr VI iyonu miktarı başlangıç konsantrasyonunun artması ve pH azalmasıyla arttı. Partikül içi hız sabiti hesaplandı. Adsorpsiyon izotermleri Langmuir ve Freundlich gibi yaygın izoterm eşitlikleriyle belirlendi. Langmuir adsorpsiyon izoterminin Freundlich adsorpsiyon izoterminden daha uygun olduğu görüldü. Yalancıbirinci derece kinetik model kinetik verileri açıklamak için kullanıldı. Boyutsuz ayırma faktörü ve dağılım katsayısı değerleri incelendi.

Keywords

• Adsorpsiyon kinetik, Adsorpsiyon izoterm, Adsorpsiyon termodinamik, Cr VI

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