Modeling of cadmium(III) adsorption on kaolinite-based clays in the absence and presence of humic acid

HIZAL YÜCESOY, Fehime Jülide; Apak, Resat

doi:10.1016/j.clay.2006.02.002

Modeling of cadmium(III) adsorption on kaolinite-based clays in the absence and presence of humic acid

Yazarlar (2)

Prof. Dr. Fehime Jülide HIZAL YÜCESOY Istanbul Üniversitesi, Türkiye

Resat Apak
Istanbul Üniversitesi, Türkiye

Makale Türü	Özgün Makale (SSCI, AHCI, SCI, SCI-Exp dergilerinde yayınlanan tam makale)
Dergi Adı	Applied Clay Science (Q1)
Dergi ISSN	0169-1317 Dergi Bilgileri (2006)
Makale Dili	İngilizce	Basım Tarihi	05-2006
Cilt / Sayı / Sayfa	32 / 3 / 232–244	DOI	10.1016/j.clay.2006.02.002
UAK Araştırma Alanları

Özet

Cadmium adsorption on kaolinite-based clays in the absence and presence of humic acid was modeled with the aid of the FITEQL 3.2 computer program using a modified Langmuir approach for capacity calculations. Formation of surface-metal ion and surface-humate-metal ion complexes was assumed using the DLM approach. As Cd(II) adsorption was ionic strength-dependent, the adsorption experiments were carried out in solutions containing two different concentrations of an inert electrolyte (0.1 M and 0.005 M NaClO4). The surface sites responsible for the adsorption were assumed to be the permanent charges, ≡S1OH silanol groups and carboxyl groups having pKa values close to that of the silanol groups, and ≡S2OH aluminol groups and phenol groups with pKa values close to that of the aluminol groups, because the studied clays (partly composed of clay soil) contained organic carbon. Cd²⁺ ions were assumed to bind to the surface in the form of outer-sphere X2^2- Cd²⁺ and inner-sphere ≡SOCd⁺ monodentate complexes. When humic acid was added, Cd(II) adsorption was modeled using a multi-site binding model by the aid of FITEQL3.2. The fit between model and experimental values was excellent in each case. Since the stability of the ternary surface complexes in the presence of humic acid was higher than that of the corresponding binary surface-cadmium ion complexes, the adsorption vs. pH curves were much steeper (and distinctly S-shaped) compared to the tailed curves observed in binary clay-cadmium ion systems. The clay mineral in the presence of humic acid probably behaved more like a chelating ion-exchanger for heavy metal ions than as a simple inorganic ion exchanger. © 2006 Elsevier B.V. All rights reserved.

Anahtar Kelimeler

Science Direct

BM Sürdürülebilir Kalkınma Amaçları

Atıf Sayıları
Web of Science	103
Scopus	112

Modeling of cadmium(III) adsorption on kaolinite-based clays in the absence and presence of humic acid

Dergi Adı	APPLIED CLAY SCIENCE
Kısa Adı	APPL CLAY SCI
Yayıncı	ELSEVIER SCIENCE BV
Açık Erişim	Hayır
ISSN	0169-1317
E-ISSN	1872-9053
Wos Quartile	Q1
Scopus Quartile	Q1
Tarandığı Indeksler	SCIE , Scopus
WoS Kategoriler	MINERALOGY
Scopus Kategoriler	GEOLOGY \| GEOCHEMISTRY AND PETROLOGY