Modeling of copper II and lead II adsorption on kaolinite based clay minerals individually and in the 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 Journal of Colloid and Interface Science (Q2)
Dergi ISSN 0021-9797 Dergi Bilgileri (2006)
Dergi Tarandığı Indeksler SCI
Makale Dili İngilizce Basım Tarihi 03-2006
Kabul Tarihi – Yayınlanma Tarihi 01-03-2006
Cilt / Sayı / Sayfa 295 / 1 / 1–13 DOI 10.1016/j.jcis.2005.08.005
Makale Linki https://linkinghub.elsevier.com/retrieve/pii/S0021979705008465
UAK Araştırma Alanları
Analitik Kimya
Özet
The aim of this study is to explain how clay minerals adsorb heavy metals individually and in the presence of humic acid, and to model heavy metal adsorption specifically based on surface-metal binary and surface-metal-ligand ternary complexation. The adsorption of Cu(II) and Pb(II) on kaolinite-based clay minerals has been modeled by the aid of the FITEQL3.2 computer program using single- and double-site binding models of the Langmuir approach. Potentiometric titrations and adsorption capacity experiments were carried out in solutions containing different concentrations of the inert electrolyte NaClO4; however, the modeling of binary and ternary surface complexation was deliberately done at high ionic strength (0.1 M electrolyte) for eliminating adsorption onto the permanent negatively charged sites of kaolinite. A "two-site, two pKa" model was adapted, and as for the two surface sites responsible for adsorption, it may be arbitrarily assigned that ≡S1OH sites represent silanol and organic functional groups such as carboxyl having pKa values close to that of silanol, and ≡S2OH sites represent aluminol and organic functional groups such as phenolics whose pKa values are close to that of aluminol, as all the studied clays contained organic carbon. Copper(II) showed a higher adsorption capacity and higher binding constants, while lead(II), being a softer cation (in respect to HSAB theory) preferred the softer basic sites with aluminol-phenol functional groups. Heavy metal cations are assumed to bind to the clay surface as the sole (unhydrolyzed) M(II) ion and form monodentate surface complexes. Cu(II) and Pb(II) adsorption in the presence of humic acid was modeled using a double-site binding model by the aid of FITEQL3.2, and then the whole system including binary surface-metal and surface-ligand and ternary surface-metal-ligand complexes was resolved with respect to species distributions and relevant stability constants. Electrostatic effects were accounted for using a diffuse layer model (DLM) requiring minimum number of adjustable parameters. Metal adsorption onto clay at low pH increased in the presence of humic acid, and the metal adsorption vs pH curves of metal-kaolinite-humic acid suspensions were much steeper (and distinctly S shaped) compared to the wider pH-gradient curves observed in binary clay-metal systems. The clay mineral in the presence of humic acid probably behaved more like a chelating ion-exchanger sorbent for heavy metals rather than being a simple inorganic ion exchanger. © 2005 Elsevier Inc. All rights reserved.
Anahtar Kelimeler
Adsorption | Clay minerals | Copper(II) | FITEQL | Humic acid | Kaolinite | Lead(II) | Modeling
Science Direct
BM Sürdürülebilir Kalkınma Amaçları
Atıf Sayıları
Web of Science 144
Scopus 153
Modeling of copper II and lead II adsorption on kaolinite based clay minerals individually and in the presence of humic acid
İletişim
  • Yalova Üniversitesi Rektörlüğü, Bahçelievler Mah. Çınarcık Yolu Caddesi No: 26 Merkez - YALOVA, 77200
  • unis@yalova.edu.tr 0226 815 50 00
Sosyal Media
Talentsoft Yazılım Talent Yazılım
Tasarım ve Programlama #2025