Fe compounds in scoria as distributed in the south-western area of Jeju Island were investigatedusing X-ray fluorescence spectroscopy, X-ray diffractometry, and 57Fe Mössbauer spectroscopy. The sampleswere prepared from four parasite volcanoes. It was found that these samples are typical basalt comprised ofSiO2, Al2O3, Fe, and silicate minerals. The Mössbauer spectra showed doublets for olivine, pyroxene, andilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge statewith a slight 2+ charge state. It is expected that these results will add to the body of information related tothe formation mechanisms of Jeju Island.

제주도 여러 도로현장에서 송이(화산쇄설물)는 빈번하게 접하는 토목재료이다. 송이는 일반적으로 파쇄성이 크고, 입자가 큰 재료로 알려져 있을 뿐, 이 화산쇄설물에 대한 연구가 미미하여 이 송이에 대한 처리방법에 많은 어려운 점이 따르고 있다. 본 연구에서는 제주도 각 지역에서 채취한 송이의 기본적인 강도특성에 관하여 연구하였다. 연구결과로 구한 송이의 강도특성 값은 추후 도로, 옹벽, 사면 등의 각종 설계 시 기본적인 자료로써 적용되어 질 수 있을 것이다.

제주도 여러 도로현장에서 송이(화산쇄설물)는 빈번하게 접하는 토목재료이다. 송이는 일반적으로 파쇄성이 크고, 입자가 큰 재료로 알려져 있을 뿐, 이 화산쇄설물에 대한 연구가 미미하여 이 송이에 대한 처리방법에 많은 어려운 점이 따르고 있다. 본 연구에서는 제주도 각 지역에서 채취한 송이의 기본적인 강도특성에 관하여 연구하였다. 연구결과로 구한 송이의 강도특성 값은 추후 도로, 옹벽, 사면 등의 각종 설계 시 기본적인 자료로써 적용되어 질 수 있을 것이다.

The characteristics of ammonia-nitrogen (NH4 +-N) adsorption by a zeolitic material synthesized from Jeju scoria using the fusion and hydrothermal method was studied. The synthetic zeolitic material (Z-SA) was identified as a Na-A zeolite by X-ray diffraction, X-ray fluorescence analysis and scanning electron microscopy images. The adsorption of NH4 +-N using Jeju scoria and different types of zeolite such as the Z-SA, natural zeolite, and commercial pure zeolite (Na-A zeolite, Z-CS) was compared. The equilibrium of NH4 +-N adsorption was reached within 30 min for Z-SA and Z-CS, and after 60 min for Jeju scoria and natural zeolite. The adsorption capacity of NH4 +-N increased with approaching to neutral when pH was in the range of 3-7, but decreased above 7. The removal efficiency of NH4 +-N increased with increasing Z-SA dosage, however, its adsorption capacity decreased. For initial NH4 +-N concentrations of 10-200 mg/L at pH 7, the adsorption rate of NH4 +-N was well described by the pseudo second-order kinetic model than the pseudo first-order kinetic model. The adsorption isotherm was well fitted by the Langmuir model. The maximum uptake of NH4 +-N obtained from the Langmuir model decreased in the order of Z-CS (46.8 mg/g) > Z-SA (31.3 mg/g) > natural zeolite (5.6 mg/g) > Jeju scoria (0.2 mg/g).

The characteristics of heavy metal ion (Ni2+, Zn2+, and Cr3+) adsorption by zeolite synthesized from Jeju scoria using the fusion and hydrothermal method, were studied. The synthetic zeolite was identified as a Na-A zeolite by X-ray diffraction analysis and scanning electron microscopy images. The equilibrium of heavy metal ion adsorption by synthetic zeolite was reached within 60 min for Ni2+ and Zn2+, and 90 min for Cr3+. The uptake of heavy metal ions increased with increasing pH in the range of pH 3-6 and the uptake decreased in the order of Cr3+ > Zn2+ > Ni2+. For initial heavy metal concentrations of 20-250 mg/L at nonadjusted pH, the adsoption of heavy metal ions was well described by the pseudo second-order kinetic model and was well fitted by the Langmuir isotherm model. The maximum uptake of heavy metal ions obtained from the Langmuir model, decreased in the order of Zn2+ > Ni2+ > Cr3+, differing from the effect of pH on the uptake, which was mainly based on the different pH of the solutions.

The adsorption properties of Cs+ and Cu2+ ions were evaluated by using a polysulfone scoria zeolite (PSf-SZ) composite with synthetic zeolite synthesized from Jeju volcanic rocks (scoria). In order to investigate the adsorption properties, various parameters, such as pH, contact time, reaction rate, concentration, and temperature in aqueous solutions, were evaluated by tests carried out in batch experiments. The adsorption capacities of Cs+ and Cu2+ ions increased between pH 2 but achieved equilibrium at pH 4 and above. The adsorption rate increased rapidly up to the initial 24 h, after which it plateaued ; the adsorption rate then sustained at equilibrium from 48 h. The adsorption kinetics of Cs+ and Cu2+ ions were described better by the pseudo-second-order kinetic model than the pseudo-first-order kinetic model. The Langmuir model fitted the adsorption isotherm data better than the Freundlich model. The maximum adsorption capacities of Cs+ and Cu2+ ions obtained from the Langmuir model were 53.8 mg/g and 84.7 mg/g, respectively. The calculated thermodynamic parameters showed that the adsorption of Cs+ and Cu2+ ions on PSf-SZ was feasible, spontaneous and endothermic reaction.

The adsorption performance of lead ion was studied using five zeolites (Na-P1, sodalite (SOD), analcime (ANA), nepheline hydrate (JBW), cancrinite (CAN)) synthesized from Jeju scoria. The adsorption performances of lead ion decreased in the order of Na-P1 > SOD > ANA > JBW > CAN. These results showed that the synthetic zeolite with a higher cationic exchange capacity showed a higher adsorption performance. The uptake of lead ion by synthetic zeolites were described by Freundlich model better than Langmuir model. The adsorption kinetics of lead ion by synthetic zeolites fitted the pseudo 2nd order kinetics better than pseudo 1st order kinetics. The effective diffusion coefficients of lead ion by synthetic zeolites were ten times higher than the zeolite A synthesized from coal fly ash.

The removal performances of divalent heavy metal ions (Pb2+, Cu2+, Cd2+, Sr2+ and Mn2+) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of Pb2+>Cu2+>Cd2+>Sr2+>Mn2+ based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for Mn2+ decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90% of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.

This study aimed at improving the TiO2 photocatalytic degradation of HA. ·In this study, the Degradation of Humic Acid using Jeju Scoria Coated with WO3/TiO2 in the presence of UV irradiation was investigated as a function of different experimental condition : photocatalyst dosage, Ca2+ and HCO3- addition and pH of the solution. Photodegradation efficiency increased with increasing photocatalyst dosage, the optimum catalyst dosage is 2.5 g/L and Photodegradation efficiency is maximized to WO3/TiO2=3/7. This indicates that WO3 retains a much higher Lewis surface acidity than TiO2, and WO3 has a higher affinity for chemical species having unpaired electrons. The addtion of cation(Ca2+) in water increased the photodegradaion efficiency. But the addtion of HCO3- ion in water decreased a photodegradation efficiency. Photodegradation efficiency increased with decreasing pH. At pH < pzc, the electrostatic repulsion between the HA and the surface of TiO2 decreased.