Econ. Environ. Geol. 2013; 46(6): 521-533

Published online December 31, 2013

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Removal of Aqueous Arsenic Via Adsorption onto Si Slag

Seong Hee Kim, Jeong Woo Seol, Woo Chun Lee and Soon-Oh Kim*

Department of Earth and Environmental Sciences and Research Institute of Natural Science(RINS), Gyeongsang National University, Jinju, 660-701, Republic of Korea

Correspondence to : sokim@gnu.ac.kr

Received: October 27, 2013; Revised: November 21, 2013; Accepted: December 19, 2013

Abstract

This study was initiated to evaluate the applicability of Si slag as an adsorbent via investigation of the main properties of Si slag as an adsorbent aw well as characterization of adsorption features between aqueous arsenic and Si slag. The specific surface area of Si slag was measured to be 6.71 m2/g which seems to be slightly higher than those of other slags, but relatively lower than those of iron (oxyhydr)oxides extensively used for arsenic controlling processes. The point of zero salt effect (PZSE) of Si slag determined by potentiometric titration appeared to be comparatively high (7.3), indicating the Si slag may be favorably used for adsorption of arsenic which predominantly exists as an oxy-anions. The results of adsorption isotherm indicate that regardless of arsenic species, Langmuir- type isotherm is the most suitable to simulate the adsorption of arsenic onto Si slag. With regard to pHdependence of arsenic adsorption, the adsorption maxima of arsenite was centered at pH 7, and the adsorption was remarkably decreased in the other pH conditions. In the case of arsenate, on the other hand, the adsorption was highest at the lowest pH (4.0) and then gradually decreased with the increase of pH. Based on the results of kinetic experiments, it is likely that the adsorption of arsenite approached equilibrium within 2 hr, but it took about 8 hr for arsenate adsorption to be equilibrated. In addition, the Pseudo second order was evaluated to be most consistent with the empirical data of arsenic adsorption onto Si slag in this study. Under identical conditions, the affinity of arsenate onto Si slag was estimated to be nearly 6 times higher than that of arsenite.

Keywords steel making slag, Si slag, arsenite, arsenate, adsorption

Article

Econ. Environ. Geol. 2013; 46(6): 521-533

Published online December 31, 2013

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Removal of Aqueous Arsenic Via Adsorption onto Si Slag

Seong Hee Kim, Jeong Woo Seol, Woo Chun Lee and Soon-Oh Kim*

Department of Earth and Environmental Sciences and Research Institute of Natural Science(RINS), Gyeongsang National University, Jinju, 660-701, Republic of Korea

Correspondence to:sokim@gnu.ac.kr

Received: October 27, 2013; Revised: November 21, 2013; Accepted: December 19, 2013

Abstract

This study was initiated to evaluate the applicability of Si slag as an adsorbent via investigation of the main properties of Si slag as an adsorbent aw well as characterization of adsorption features between aqueous arsenic and Si slag. The specific surface area of Si slag was measured to be 6.71 m2/g which seems to be slightly higher than those of other slags, but relatively lower than those of iron (oxyhydr)oxides extensively used for arsenic controlling processes. The point of zero salt effect (PZSE) of Si slag determined by potentiometric titration appeared to be comparatively high (7.3), indicating the Si slag may be favorably used for adsorption of arsenic which predominantly exists as an oxy-anions. The results of adsorption isotherm indicate that regardless of arsenic species, Langmuir- type isotherm is the most suitable to simulate the adsorption of arsenic onto Si slag. With regard to pHdependence of arsenic adsorption, the adsorption maxima of arsenite was centered at pH 7, and the adsorption was remarkably decreased in the other pH conditions. In the case of arsenate, on the other hand, the adsorption was highest at the lowest pH (4.0) and then gradually decreased with the increase of pH. Based on the results of kinetic experiments, it is likely that the adsorption of arsenite approached equilibrium within 2 hr, but it took about 8 hr for arsenate adsorption to be equilibrated. In addition, the Pseudo second order was evaluated to be most consistent with the empirical data of arsenic adsorption onto Si slag in this study. Under identical conditions, the affinity of arsenate onto Si slag was estimated to be nearly 6 times higher than that of arsenite.

Keywords steel making slag, Si slag, arsenite, arsenate, adsorption

    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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