• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.177-184
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• 2003

Although clay can sorb significant amounts of inorganic contaminants from soils and wastewater, the hydration of exchangeable cations in clay minerals makes it hydrophilic at the clay mineral surfaces and interlayers. Thus, natural clays are often ineffective in complexing and stabilizing toxic organic contaminants in soils and groundwater environment. But, substituting these hydrated cations with cationic surfactant such as QAC(Quaternary ammonium Compound) can change the natural clay from hydrophilic to hydropobic. Furthermore functionalized organoclay can act as a powerful dual function sorbent for both toxic metals and organic compounds. It also can be used as landfill clay liners, slurry walls, nano-composite materials, petroleum tank farms, waste treatment, and filter systems. To use this modified clay minerals effectively, it is required to understand the fundamental chemistry of organoclay, synthetic procedures, its engineering application, bioavailability of sorbed ion-clay complex, and potential risk of organoclay. In this review, we investigate the use, application and historical background of the organoclay in remediation technology. The state-of-the-art of organoclay research is also discussed. Finally, we suggest some future implications of organoclay in environmental research.

• Advances in materials Research
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• v.13 no.3
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• pp.173-181
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• 2024

Fly ash, plastic waste, and clay are mineral materials and residues commonly found in Malaysia. In this study, these materials were fully utilized as raw materials for synthesizing carbon nanotubes (CNTs). Recycled polypropylene, previously used as a food container, served as a carbon source. Fly ash and clay were explored as potential substrates for CNTs growth. The recycled polypropylene was thermally decomposed at 900 ℃ in an inert environment for 90 minutes. Carbon atoms released during this process were deposited on fly ash and clay substrates, which had been immersed in a ferrocene solution to provide a metal catalyst for CNTs growth. The deposited products were characterized using a Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). Morphological analysis revealed that both fly ash and clay were coated with fiber-like structures, confirmed to be CNTs based on a diffraction peak around 26° from the XRD pattern. In conclusion, clay and fly ash demonstrate the potential to be utilized as substrates for CNTs formation.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.465-470
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• 2006

Siloxanes are widely used in industrial processes and consumer products. When landfill gas is used as fuel for gas engines, volatile siloxane in landfill gas causes serious damage to gas engines and pretreatment facilities. In this study, the applicability of various clay minerals was evaluated as the alternative adsorbents of activated carbon. SEM and BET analyses of illite, vermiculite, and activated carbon were performed for comparing those physical properties. Siloxane adsorption capacities of illite and vermiculite were estimated very high to 1.7 g/g illite, 3.8 g/g vermiculite respectively through the adsorption experiments of D5 siloxane.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.381-388
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• 1995

The petrographic, geochemical, and physical properties of the Jangseong and Chinese coals were investigated. The most common mineral matters of Jangseong coal are kaolinite, muscovite, sericite, illite, quartz and pyrophyllite. Mineral matters in Chinese coal are mainly composed of quartz, calcite, dolomite and kaolinite. Jangseong coal ash has higher content of $Al_2O_3$, $K_2O$, $TiO_2$, As, Rb and V, and lower content of CaO, MgO, $Na_2O$, $Fe_2O_3$ and $P_2O_5$ than those of Chinese coal ash. The liquid limit and the plasticity index of Jangseong coal were compared with those of Chinese coal. The result shows that the briquetting ability of Jangseong coal is a little bit better than that of Chinese coal. The briquetting ability is found to be principally dependent on the type and the content of mineral matter in coal, especially clay mineral.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.153-163
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• 2020

Mineral and geochemical analysis were conducted on two sections (~3.5 m) of red-brown claysilt sediments covering the gneiss and granite weathering zones in Suwon-si for establishing Quaternary paleoenvironmental changes in Korea. The sections were divided into four sedimentary layers (Unit 1-4) by vertical changes in mineral composition and chemical composition. The lowermost unit 1 was a sandy sediment with a high K-feldspar content with a significant contribution of weathered bedrock. Unit 2 was a transition layer showing intermediate characteristics. Unit 3 was a reddish brown clay-silt sediment, with a total clay content of 58% on average, and the main clay minerals were illite-smectite mixed layer minerals and hydroxy-interlayered vermiculite/smectite. Unit 3 contained almost no plagioclase, while the content of kaolin minerals derived by the plagioclase weathering was higher than in the other layers. Unit 4 had similar mineral composition and chemical properties to Unit 3, but had a higher content of plagioclase and chlorite and lower content of kaolin minerals. The chemical compositions of the sections were compared with those in other regions of Korea, suggesting the eolian origin of Units 3 and 4. The paleoenvironmental change in the sedimentary section of this region was interpreted as follows. Weathered products of gneiss and granite, which are bedrocks of this region, were eroded and deposited as sandy sediments in the periphery to form the lower layers (Unit 1, 2), followed by the deposition of the claysilty rich eolian sediments (Unit 3) during the glacial. Unit 3 was chemically weathered during the warm humid climate during the last interglacial, developing a reddish brown color. After that, a eolian sediment layer (Unit 4) was deposited during the last glacial.

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

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.229-230
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• 2003

In these days, it is actively investigated to use loess in textile industry. The loess have been reported for emissivity of far-infrared and negative ion, and antibacterial efficacy. The loess consist of quartz, feldspar, clay mineral, iron oxide mineral, gibbsite [Al(OH)$_3$], etc. The main component of loess is clay minerals which have great adsorption about ion exchange and far-infrared emission properties. Recently, various inner-wears, sheets, and interior goods are manufactured using the loess due to its improved blood circulation, metabolism, antibacterial and deodorizing properties. (omitted)

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.326-331
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• 2010

Montmorillonite is one of representative inorganic clay particles. As the characteristics of clay particulate matter in aqueous environment determine the efficiencies of wastewater treatment and some industrial operations, it is essential to understand its aquatic behavior in relation with turbidity. The change of electrokinetic potential of montmorillonite suspension shows that it tends to negatively increase as the pH of suspension increases. In addition, it is observed that its potential is around 0mV when the solution pH is ca. 5. The turbidity of suspension is shown to be very low when pH is lower than its isoelectric point. However, the turbidity gradually enhances according to beyond isoelectric point. These results reveal that the correlation between electrokinetic potential and turbidity for clay mineral suspension is peculiar which should be fundamentally considered for systematic treatment of wastewater.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.261-268
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• 2014

Four clays (both natural and commercial types) mainly used in Korea were tested for removal efficiency of Microcystis spp. and ecotoxicity on Daphnia magna and Vibrio fischeri. Four clays (clay A~D) were composed of 91.9~100% of sand (0.02~0.2 mm in particle size). Clay D consisted of lager particles than other clays. Major elements of the four clays were $SiO_2$ (45.3~62.8%), $Al_2O_3$ (18.5~29.7%) and $Fe_2O_3$ (5.4~7.9%). They contained kaolinite (clay mineral), quartz, muscovite, and so on. Clay C and D contained montmorillonite, one of the clay minerals improving clay-cell aggregation. For clay A, B and C, removal efficiency of Microcystis spp. was over 60% at 2 g/L. It reached about 100% at over 5 g/L. For clay D, it was over 60% and 95~100% at 5 g/L and 20 g/L respectively. After adding clays, pH decreased. The greatest drop of pH appeared at clay C. Except for addition of 100 g/L clay C, ecotoxicity on D. magna and V. fischeri didn't appeared at all dose of clays.

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