• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.174-177
• /
• 1998

The effects of surfactants affecting polycyclic Aromatic Hydrocarbon(PAHs) solubility and biodegradation in soil slurry were investigated. The critical micelle concentration(CMC) values of surfactants used in this study were 12.7mg/L(Brij 30), 13.4mg/L(Tween 80), 13.6mg/t(Triton X-100). The solubility of PAH increased as the Hydrophile-Lipophile Balance(HLB) value of surfactant decrease. At surfactant biodegradation and toxicity experiement using respirometer, Brij 30 did not show any toxic effect and substrate inhibition upon the level of 1.5g/L. Also, biodegradation of Brij 30 gave no reduction on the phenanthrene biodegradation rate. When the desorption rate of phenanthrene between sand and clay is compared, lower percentage of phenanthrene was desorbed at clay because of the larger surface aera and higher organic content of clay. At the biodegradation experiments of phenanthrene in soil slurry phase, more than 90% of initial phenanthrene adsorbed onto both sand and clay were biodegraded by phenanthrene- acclimated cultures.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.217-222
• /
• 2000

An understanding of the behaviour of soft clay soils is important in a large number of civil engineering applications, including dredging operations, land reclamation and slurry management such as disposal and storage. Although the details of the behaviour depend on parameters such as the soil mineralogy, the pore water chemistry, the organic content and the microbiology, there are general features that are typical in many cases. The purpose of this paper is to present and discuss some of evaporation and desiccation observed in laboratory experiments under controlled conditions. Desiccation of dredged material is basically removal of water by evaporation which is controlled by weather and material type, etc. This study shows that (1) solar radiation, (2) wind velocity, (3) material depth, (4) trench depth are important factors in desiccation of dredged ultra soft clay.

• Korean Journal of Microbiology
• /
• v.26 no.3
• /
• pp.237-246
• /
• 1988

The higher bacterial numbers on clay than on sand were caused by different environmental factors. Such factors affecting the adsorption of E. coli ATCC 11775 in the sediment as follows; optimal pH range for the adsorption of E. coli ATCC 11775 was pH 7.5-pH 9.5. E. coli ATCC 11775 were shown maxima in the salinity of 18.$75%_{o}$ on sand type sediment and $12.5%_{o}$ on clay type sediment. Bacteria attached better to clay typed sediment than to sand typed sediment when organic substance was eliminated. Beef extract of 0.5%-1% concentration was found to promote the attachment of E. coli ATCC 11775 effectively. Peptone of 0.5% was enganced the attachment on the clay, and peptone of 1.3%-5%, on the sand. E. coli ATCC 11775 was found to adsorb onto benthonite with the highest efficiency and on celite with the lowest efficiency. Efficiency of adsorption by inorganic ions was shown due to higher values of ion. Adsorption was achieved in the order of $Al^{3+}, Ca^{2+}, Na^{+}$.

• Journal of the Mineralogical Society of Korea
• /
• v.17 no.3
• /
• pp.189-199
• /
• 2004

Cretaceous sedimentary rocks bearing dinosaur tracks in the Goseong interchange area were studied for their conservation and public display in the aspect of applied mineralogy. Black clay layers alternate with silt layers in the sedimentary rocks. The verical and horizontal fissures are commonly filled with calcite veinlets, supergenetic iron and manganese oxides. The rocks are composed of quartz, albite, K-feldspar, calcite, chlorite, illite, muscovite, and biotite, with minor apatite and rutile. Silt layers are relatively rich in calcite and albite, whereas clay layers are abundant in quartz, illite, and chlorite. Al, Fe, Mg, K, Ti, and P are enriched in the clay layers, while Ca, Na, and Mn in silt. Most of trace elements including V, Cr, Co, Ni, Cs, Zr, REE, Th, and U are enriched in clay layers. Inorganic carbon are present in silt layers as calcite, while organic carbon in black clay layers. The black clay layers were partly altered to yellow clay layers along the fissures, simultaneously with the decrease of organic carbon. Selective exfoliation of clay-rich black and yellow clay layers, calcite matrix of silt layers and calcite infillings of fissures are estimated as the major weakness potentially promoting chemical and physical degradation of the track-bearing rock specimens.

• Journal of the Korean Ceramic Society
• /
• v.49 no.3
• /
• pp.231-235
• /
• 2012

Plasticity is the ability of clay to respond to pressure with a continuous and permanent change of shape in any direction without breaking apart, and hold that shape when released. In this work, the effect of water content and aging period on the plasticity of porcelain clay was evaluated using the capillary rheometer to measure the flow rate and the shear stress. The shear stress of porcelain clay was slightly increased with increasing the aging period, indicating that the plasticity of porcelain clay was influenced by an organic content. It was also observed that the water content in the porcelain clay had a great influence on the plasticity of porcelain clay. The shear stress with water content of 21 wt% was sharply increased with increasing shear rate, but the shear stresses with water contents of 24 and 27 wt% is gently incremented.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.6 no.1
• /
• pp.55-63
• /
• 2008

A swelling clay should remain physically and chemically stable for a long time to perform its functions as a buffer material of a high-level waste (HLW) repository. The longevity issues in the swelling clay were reviewed to evaluate their importance in the performance of a repository. The review results suggest that an elevated temperature due to decay heat, groundwater chemistry, high pH environment by concrete, organic matter and microbes, radiation, and mechanical disturbance might significantly affect the long-term performance of a swelling clay as a buffer material. This paper will be used as basic informations to design the swelling clay buffer for a HLW repository.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.6
• /
• pp.813-818
• /
• 2016

Distribution of clay minerals separated from clay fraction of corn fields in Korea has been investigated along with their characterization. Crystalline phases of the clay minerals were identified by powder X-ray diffraction (XRD) pattern, and their relative chemical compositions were analyzed by X-ray fluorescence spectrometry (XRF). The soils were found to have pH 6.4, organic matter $37.2g\;kg^{-1}$, available $P_2O_5$ $599mg\;kg^{-1}$, respectively, and exchangeable K, Ca and Mg were 1.2, 7.3 and $1.8cmol_c\;kg^{-1}$, respectively. Major primary minerals consisted mainly of quartz and mica, and kaolinite and chlorite were identified as major secondary clay minerals. For most of soils, mica phase was identified to be muscovite rather than biotite. The average contents of $SiO_2$, $Al_2O_3$ and $Fe_2O_3$ were 43.7, 23.6 and 8.8%, respectively, although they were different with the locations.

• Economic and Environmental Geology
• /
• v.30 no.6
• /
• pp.567-586
• /
• 1997

Concentrations of several heavy metals in soils derived from black shale and slate have been reported to be higher than the average concentrations in non-polluted soils. This study describes and characterizes soil minerals, and investigates the distribution of heavy metals in soils, and then examines their relationship. Soils in the study area are mainly consist of guartz and feldspars with minor amount of kaolin, illite, vermiculite, chlorite and illite-vermiculite interstratified minerals. Mineral compositions are similar in mountain-, farmland-, and paddy-soils. The residual soils derived from sandy phyllites contain less illites than those from black shale and black slate. Heavy metals appear to be more concentrated in soils than in rocks. The concentrate ratios in soils to rocks ranges 1.1 times for Cr, 2 for Cu, 1.4 for Ni. The contour maps of Cd, Zn, Pb, Cu contents using 0.43N $HNO_3$-extraction imply that these elements are highly concentrated in the soils near the past uranium exploration region, coal seams, black slate beds and tailings than other parts of the study area. The proportions of the day in most soils are less than 10%. In spite of small proportions of the clay, the concentrations of heavy metals from clay fractions to the total concentrations are high: 1~2.4 times for Co, 1.4~2.5 for Cu, 1.2~2.6 for Ni, 1~5 for Pb, 1~2.7 for Zn and 1.6~1.8 for Cr and V. The contents of organic carbons in clay fractions are also 1.5~3.9 times higher than in silt and sand fractions. Cu, Pb and organic carbons show positive relationship in all size fractions. In the size-fractionated soil profile samples, the contents of heavy metals and organic carbons show analogous trends with depth. For the clay fractions of soil profile samples, the contents of heavy metals with depth have analogous trends to abundances of vermiculites, which have the high CEC in main clay minerals.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.295-304
• /
• 2010

Performance of a landfill liner is evaluated based on leakage rate and mass flux. In this study, the recently utilized double composite liner system, which consists of a geomembrane (GM), a geosynthetic clay liner (GCL), a GM, and a compacted clay layer (61 or 91.5 cm) is compared with other popular composite liners including the single GCL system, the Subtitle D liner system, and the Wisconsin NR500 liner system. The leakage rate through circular and long defects in the GM of the landfill liners is analyzed using numerical models. For the mass flux criterion, the analyses of inorganic contaminant transport through defects in the GM component of liner systems and diffusion of organic compounds through intact landfill liners are conducted using three- and one-dimensional numerical models, respectively. Cadmium and toluene are used in the analyses as a typical inorganic and organic substance, respectively, which will be chemical species encountered during landfill operation. The comparison shows that the double composite liner systems are superior to the other liner systems according to the performance-based evaluation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.4
• /
• pp.197-200
• /
• 1974

PCP adsorption experiment was carried out with six soils various in clay mineral and organic matter content and soil pH. The results were as follows; 1. The major factor governing the PCP adsorption is pH 2. The adsorption was increased with organic matter content at a certain pH 3. The adsorption was less related to crystalline clay mineral species.