SURFACE COMPLEXATION MODELS FOR COPPER(II) ADSORPTION ON KAOLINITE

Yim, Soo Bin

doi:2003.8.2.91

Environmental Engineering Research 2003;8(2): 91-97. DOI: https://doi.org/10.4491/eer.2003.8.2.091

SURFACE COMPLEXATION MODELS FOR COPPER(II) ADSORPTION ON KAOLINITE

Soo Bin Yim^†

School of Urban and Civil Engineering Hongik University, Seoul 121-791, Korea

Corresponding Author: Soo Bin Yim ,Tel: +82-2325-8815, Fax: +82-2325-8815, Email: ysb9643@hotmail.com

Received: November 15, 2002; Accepted: March 11, 2003.

ABSTRACT

Adsorption experiments of Cu(ll) to kaolinite were conducted to investigate the adsorption behavior of Cu(ll) at a variety of aqueous conditions. Three electrostatic surface complexation models (i.e., Constant Capacitance Model (CCM), Diffuse Layer Model (DLM), and Triple Layer Model (TLM)) were used to simulate and predict the adsorption behavior of Cu(II) to kaolinite using MINTEQA2 program. The experimental data for adsorption edges of Cu(II) to kaolinite were compared to the modeling results predicted by surface complex models. The TLM among three surface complexation models showed excellent fitting results for Cu(ll) adsorption data. These results suggest that TLM surface complexation model can successfully describe the adsorption behavior of Cu(II) to kaolinite. The speciation of copper ion at different pH conditions was calculated to investigate the dominant Cu ion species that lead to Cu(ll) adsorption to kaolinite. The dominant species that caused the Cu(II) adsorption to kaolinite were AKK'u . =AIOHCu" and (AlOi.-Cu for CCM and DLM, and AlOCuOH. AKK'u . and AlOIICif for TLM. The aluminol sites (sAIOH) of kaolinite may have much stronger affinity of Cu(Il) adsorption than silanol sites ( ^SiOH). The hydrolytic complexes of Cu(II) on the kaolinite surfaces can be of much importance in Cu(Il) adsorption to kaolinite.