• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.849-860
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• 1996

Natural zeolites which were known to occur in sedimentary clinoptilolite, were treated by thermal and chemical methods, and their adsorption characteristics of Cu(II) were studied. Analyses by FT-IR, S. E. M, TGA/DSC, and XRD showed that the adsorption capacity of Cu(II) on the zeolite decreased gradually at the temperatures of above $400^{\circ}C$. The zeolites, which treated with NaOH and NaCl, show higher absorbility in acid solution. The adsorption rate of Cu(II) in the presence of surfactants(LAS, POE AE) on the thermally or chemically treated zeolites varied depending on pH, anion or nonion surfactants.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.2
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• pp.105-111
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• 1999

This study was performed about composting in a batch reactor of laboratory scale using garbage waste and swine waste. Sawdust and coconut peat were materials to control optimum moisture, C/N ratio and specific gravity in the study. Comparing compost using only sawdust with compost using sawdust and coconut peat, the latter was higher at reduction rate and decomposition rate. Coconut peat was accelerated aerobic fermentation, because it had moisture holding ability, initial moisture was low, ventilation was good and control of optimum specific gravity was possible. Compost by only garbage waste was under standard of manure. but mixtures in same proportion of garbage waste and swine waste producted high quality compost. CEC value was average 63.8me/100g. The initial C/N ratio of compost was regulated effectively because of high C/N ratio of sawdust. As the C/N ratio(>40) was higher, reduction rate was higher. During the composting C/N ratio was improved more and more.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.33-41
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• 2021

Feldspar, along with Quartz, are the most frequently produced minerals in Korea; however, the potential value is estimated to be significantly low because of the scarce research on the development and application of material properties, except for their limited use in manufacturing minerals, glass, and paints. In this study, we analyzed the eco-friendly material and reactivity improvement characteristics of weathered feldspar through activation technique. The joint structural features observed on the surface of the weathered feldspar show that the joint arrangements are irregularly distributed, and the cavities are interconnected. Due to the irregularly connected cavities on the surface of weathered feldspar, the reaction area of the weathered feldspar is increased; hence the weathered feldspar is considered as a highly reactive pozzolan material when combined with cement. As a result of applying the thermal, mechanical, and chemical activation techniques to improve the functionality of the weathered feldspar, the cation exchange capacity, density, and uniaxial compression strength characteristics were improved. It is considered that weathered feldspar by these porous characteristics can be used as an eco-friendly construction material with excellent physical and chemical properties.

• Polymer(Korea)
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• v.34 no.2
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• pp.137-143
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• 2010

A series of partially fluorinated, sulfonated poly(biphenylene-co-sulfone)ether containing perfluorocyclobutane(PFCB) groups were prepared for fuel cell applications through three synthetic steps: synthesis of trifluorovinylether-terminated monomers, thermal cycloaddition and post-sulfonation. Two kinds of trifluorovinylether-terminated monomers were synthesized and statistically copolymerized via thermal cycloaddition to obtain a series of polymers containing 20-60 mol% of biphenyl units(PBS-X). The post-sulfonation of PBS-X was carried out using chlorosulfonic acid(CSA) to obtain copolymers with various sulfonation levels(SPBS-X). All the synthesized compounds, monomers and polymers were characterized by $^1H$-NMR, $^{19}F$-NMR and FT-IR. It was confirmed that the ion exchange capacity(IEC), water uptake and ion conductivity of SPBS-X increased with the increment of sulfonated biphenyl units. Particularly, SPBS-60 showed higher ion conductivity compared to Nafion$^{(R)}$-115 at 25~80 $^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.55-62
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• 1996

The purpose of this study is the evaluation of adsorption capacity of casts for heavy metals comparing with the activated carbon. The casts was obtained from vermicomposting of the mixed organic sludges which were generated from the treatment facilities for leather wastewater and cattle wastewater. The physico-chemical characteristics of cast was investigated. Also, the batch adsorption experiments of cast and activated carbon for heavy metals were carried out, and the results were analyzed by Freundlich isotherm. The buffering capacity to the acidic wastewater was founded in the cast, and the cation exchange capacity of cast impling adsorption capacity for soluble substances was evaluated as about 55me/100g. Those were implied that the cast have a large potential as a good adsorbent for soluble pollutants in wastewater. From the results of batch experiments, the removal efficiencies of tested various heavy metals including Pb, Cu, Cd, and Cr were very high value as 89-98% for the activated car-bon, and 80~95% for the casts except for Zn. The adsorption equilibriums for the two materials were achieved within 90 minutes. The order of preferable metals in the adsorption was found to be Pb>Cu>Cd>Cr>Zn on the cast and to be Pb>Cd>Cu>Cr>Zn on the activated carbon, respectively. From the above results, it might be con-cluded that cast is effectively available as a good adsorbent to treating the heavy metal bearing wastewater.

• Journal of the Mineralogical Society of Korea
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• v.21 no.1
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• pp.37-44
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• 2008

This study was performed to synthesize Na-A type zeolite with melting slag from the Mapo incineration site and recycle the zeolite as an environmental remediation agent. The melting slag used had a favorable composition containing 26.6% $SiO_2$, 10.9% $Al_2O_3$ and 2.7% $Na_2O$ for zeolite synthesis although there were high contents of iron oxides, including 19.6% $Fe_2O_3$ and 18.9% FeO, which had been used as a flux for the melting. It was confirmed that the Na-A type zeolite could be successfully synthesized at $80^{\circ}C$ and $SiO_2/Al_2O_3\;=\;0.80{\sim}1.96$. The cation exchange capacities (CEC) of the zeolites was determined to be about 220 cmol/kg leveled off at the synthetic time more than 10hrs. The adsorption capacities of zeolite to heavy metals (Cd, Cu, Mn and Pb) were high except for As arid Cr. It was also confirmed through the Eh and pH analysis that As and Cr existed in the forms of $HAsO_4^{2-}$ and $CrO_4^{2-}$. The low absorption rates of zeolite for As and Cr are attributed to the fact that the pore size ($4\;{\AA}$) of Na-A type is smaller than those of $HAsO_4^{2-}$ and $CrO_4^{2-}$ ions ($4\;{\AA}$ ionic radii and $8\;{\AA}$ diameter).

• Journal of the Korean Chemical Society
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• v.38 no.10
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• pp.753-762
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• 1994

Dephosphorylation of diphenyl- or isopropylphenyl-4-nitrophenylphosphinate (DPNPIN or IPNPIN) mediated by $OH^-$ or o-iodosobenzoate ion ($IB^-$) are relatively slow in aqueous solution. The reactions in CTAX micellar solutions are, however, very accelerated, because CTAX micelles can accommodate both reactants in their Stern layer in which they can easily react, while hydrophilic $OH^-$(or $IB^-$) and hydrophobic phosphinates are not mixed in water. Even though the concentrations (> $10^{-3}$ M) of $OH^-$(or $IB^-$) in CTAX solutions are much larger amounts than those ($6{\times}10^{-6}$ M) of phosphinates, the rate constants of the dephosphorylations are largely influenced by change of the concentration of the ions, which means that the reactions are not followed by the pseudo first order kinetics. In comparison to effect of the counter ions of CTAX in the reactions, CTACl is more effective on the dephosphorylation of DPNPIN (or IPNPIN) than CTABr due to easier expelling of $Cl^-$ ion by $OH^-$(or $IB^-$) ion from the micelle, because of easier solvation $Cl^-$ ion by water molecules. The reactivity of IPNPIN with $OH^-$(or $IB^-$) is lower than that of DPNPIN. The reason seems that the 'bulky' isopropyl group of IPNPIN hinders the attack of the nucleophiles. The mechanism of reaction of IPNPIN with IB- ion concluded as 'nucleophilic' instead of 'general basic' by a trapping experiment and a measured kinetic isotope effect.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.2
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• pp.105-112
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• 1994

To investigate the migration behavior of contaminants in rocks. adsorption and diffusion experiments for Sr as a sorbing contaminant and for Cr-EDTA as a non-sorbing contaminant were carried out on granitic rocks. The Sr adsorption on separated minerals and crushed rocks tends to slightly increase with increasing pH. It also greatly decreases with the increase of ionic strength in NaCl solution. Among separated minerals, biotite and sericite have adsorbed much more amount of Sr than other rock-forming minerals, such as quartz, plagioclase, and potassic feldspar, because the specific surfaces and cation exchange capacities of phyllosilicates are generally much greater than those of the other rock-forming minerals. The intrinsic diffusion coefficients of Cr-EBTA for granitic rocks differ little from those of Sr. This indicates that they are independent of water-rock interactions. Experimental data show that the intrinsic diffusion coefficients are positively correlated with the porosities of the rocks. They are close to the theoretically predicted values, especially in pre-steady state diffusion region, with the increase of rock sample thickness.

• Korean Journal of Environmental Agriculture
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• v.10 no.1
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• pp.11-19
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• 1991

This study was carried out to develop the low-priced adsorbent by synthesizing the zeolite of high CEC with the natural zeolite and examining the ability of this zeolite to adsorb heavy metals. The dominant clay minerals were clinoptilolite and mordenite in natural zeolite, while phillipsite in the synthesized zeolite. Adsorption reaction of Cu and Zn on clays were reached to equilibrium after 1 hr. The amount of adsorption was increased as the concentrations of heavy metals or the initial pH of suspension was increased. The synthesized zeolite adsorbed heavy metals about twice as much as the natural zeolite. The adsorption of heavy metals on the synthesized zeolite was less affected by the initial pH of suspension than that on natural zeolite. At cumulative adsorption, the synthesized zeolite adsorbed much more heavy metals at early three treatments than the natural zeolite did. The amount of desorption by chloride salts was increased as the concentration of chloride salts was increased. The ability of salt to desorb was in the order of NaCl>$CaC1_2$>$AlC1_3$. It is estimated that the ability of the synthesized zeolite to remove heavy metals was better than that of the natural zeolite.