A Study on Adsorption of Pb, Cu, Zn and Cd Onto Natural Clay Young Do, N.1* and Park, H. I.2

Document Type: Original Research Paper

Authors

1 Senior Researcher, Research and Development Institute, LOTTE EandC, 104 Wonhyo1ga Yongsan-gu, Seoul, Korea

2 General Manager, Institute of Technology, Samsung C and T, 23th Fl., Samsung Corp. Bldg. 1321-20, Seocho2-Dong, Seocho-Gu, Seoul, 137-956, Korea

Abstract

The effect of temperature on the adsorption of heavy metals on not only natural bulk clay, but
also for the individual phases that composed the bulk clay sample, was investigated. Combined Adsorption-
Sequential extraction Analysis (CASA) for Pb, Cu, Zn and Cd were conducted under various temperatures that
ranged from 150C to 550C. As a result, it was found that heavy metals adsorption for bulk clay increased about
12% when the temperature increased from 150C to 550C. The effect of temperature on the individual phases
was mainly observed in oxide, including Fe-and Mn-oxide, and the organic phases of all of the metals. As for
the Phase Concentration Factors (PCFs) of the metals, the largest increase of the values was observed in the
oxide phase. Based on the thermodynamic parameters of the individual phases, the adsorption of metals on
natural clay was an endothermic reaction with the exception of exchangeable phase adsorption. This shows
that adsorption affinity and capacity tend to increase when the temperature increase for all adsorption phases
of soil, except for adsorption in the exchangeable phase. In the case of Pb, Zn, and Cu adsorption, the
considerable enthalpy changes were observed in carbonates, Fe-oxides, and organic phases, which means the
adsorption affinity for those phases were largely affected by temperature change. On the other hand, relatively
small enthalpy changes in the Cd adsorption were observed in bulk and all individual phases when it was
compared with the other metals enthalpy changes for the same phases. This means that Cd adsorption mainly
occurred in the exchangeable phase, which was affected a little by temperature change.

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