• Economic and Environmental Geology
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• v.38 no.1
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• pp.23-31
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• 2005

This study was performed to investigate the effect of humic acid on the adsorption of arsenic onto hematite and its binding mechanism through the chemical speciation modeling in the binary system and the adsorption modeling in the ternary system. The complexation modeling of arsenic and humic acid was suitable for the binding model with the basis of the electrostatic repulsion and the effect of bridging metal. In comparison with the experimental adsorption data in the ternary system, the competitive adsorption model from the binary intrinsic equilibrium constants was consistent with the amount of arsenic adsorption. However, the additive rule showed the deviation of model in the opposite way of cationic heavy metals, because the reduced organic complexation of arsenic and the enhanced oxyanionic competition diminished the adsorption of arsenic. In terms of the reaction mechanism, the organic complex of arsenic, neutral As(III) and oxyanionic As(V) species were transported and adsorbed competitively to the hematite surface forming the inner-sphere complex in the presence of humic acid.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.571-577
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• 2005

Permeable reactive barrier using iron oxide coated sand is one of effective technologies for As(V) contaminated groundwater. However, this method is restricted to As(III), because As(III) species tends to be more weakly bound to adsorbent. In order to overcome the limitation of iron oxide coated sand application to As(III) contaminated groundwater, manganese oxide materials as promoter of As(III) removal were combined to the conventional technology in this study. For combined use of iron oxide coated sand and manganese oxide coated sand, two kinds of removal methods, sequential removal method and simultaneous removal method, were introduced. Both methods showed similar removal efficiency over $85\%$ for 6 hrs. However, the sequential method converted the As contaminated water to acid state (pH 4.5), on the contrary, the simultaneous method maintained neutral state (pH 6.0). Therefore, simultaneous As removal method was ascertained as a suitable treatment technology of As contaminated water. Moreover, for more effective As(III) remediation technique, polypropylene textile which has the characteristics of high surface area, low specific gravity and flexibility was applied as alternative material of sand. The combined use of coated polypropylenes by simultaneous method showed much more prominent and rapid remediation efficiency over $99\%$ after 6 hrs; besides, it has practical advantages in replacement or disposal of adsorbent for simple conventional removal device.

• The Journal of the Petrological Society of Korea
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• v.15 no.3 s.45
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• pp.139-153
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• 2006

For the characteristics of rock material and standardization, flagstones of the trifurcated path in Jongmyo Royal Shrine, registered as World Cultural Heritage, were studied on the basis of petrographic, petrochemical and magnetic properties. The flagstones are composed mainly of pale gray fine to medium grained hornblende biotite granite, pale gray fine to medium grained biotite granite, pale pink medium to coarse grained biotite granite, pink medium to coarse grained biotite granite and minor pegmatite and schist. Flagstone represents the average size of $65cm{\times}4cm$ (standard deviation $12cm{\times}7cm$) and suitable (34.7%), common (41.4%) and unsuitable (23%) in roughness. It is interpreted that pale pink and pink granite, pegmatite, schist and other flagstones with unsuitable state are not original rock materials and were exchanged during restoration, in the past. The number of these non-original rock materials is about 560 flagstones. We suggests that the standard flagstone of the trifurcated path is pale gray fine to medium grained biotite granite (${\pm}$hornblende in trace), 70wt.% in $SiO_2$, content, and ${\pm}0.1{\times}10^{-3}\;SI$ in magnetic susceptibility.