• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.126.2-126
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• 2003

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.113-117
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• 1993

The purpose of this study is to raise the strength of concrete with admixture. The natural zeolites and mud stone, abundant in this country, were used as admixture for high-strengthening of concrete. Proper workability was gained by using the superplasticizer. The optimum replacement ratio of zeolite mud stone was 10% on unit -cement amount. At these optimum replacement ratio, the strength development over the plain concrete was 34% for zeolite and 16% for mud stone. Through this study, we concluded the natural zeolite and mud stone were adequate admixture for the high-strengthening of concrete.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 2005.10a
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• pp.27-27
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• 2005

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2773-2776
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• 2009

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.263-266
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• 2001

Isopropylation of phenol with 2-propanol has been carried out over Na-exchanged ZSM-5 zeolites to determine the effect of catalyst acidity on phenol conversion and product selectivity. The acid type and strength of the catalyst such as Lewis, weak and strong Bronsted acid sites are measured by pyridine adsorbed XPS and the catalytic properties are interpreted in terms of the acid properties. The active site and mechanism for the reaction are suggested based on evidence of study from the reactant adsorbed FT-IR.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.240-247
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• 2015

Zeolite A was prepared from coal fly ash upon NaOH fusion treatment, followed by hydrothermal treatment. The effects of treatment conditions such as NaOH/ash ratio, fusion temperature, the amount of sodium aluminate added, hydrothermal treatment temperature and time on the type and the crystallinity of zeolites were investigated. The optimal NaOH/ash weight ratio and fusion temperature to produce high crystalline zeolite A were 1.2 and $550^{\circ}C$, respectively. The dissolution of $Si^{4+}$ and $Al^{3+}$ from the fused fly ash was not affected by stirring time. The type of synthetic zeolites was found to be dependent on the amount of sodium aluminate added. The low amount of sodium aluminate favored zeolite X, while a single phase zeolite A was produced by increasing the amount sodium aluminate. Zeolite A was transformed into hydroxysodalite with increasing hydrothermal treatment time and temperature. A high crystalline zeolite A could be obtained by decreasing the temperature increasing time up to the reaction temperature.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.407-414
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• 2016

Ex-situ catalytic pyrolysis of a Korean native oak tree over microporous zeolites (HZSM-5, HBeta, and HY) was performed by using a fixed bed reactor. The effect of sample to catalyst ratio and reaction temperature was also investigated to optimize production conditions of high quality bio-oil. Among three catalysts, HZSM-5 showed the highest aromatic formation due to its proper pore size and strong acidity. Although HY and HBeta also showed the catalytic activity, they produced larger amounts of coke due to their larger pore size. The smaller ratio of the sample to the catalyst and higher reaction temperature were also required to maximize the yields of aromatic hydrocarbons via the catalytic pyrolysis of oak tree over HZSM-5.

• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.254-258
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• 2006

Zeolites with excellent adsorption capacity of volatile organic compounds were attached onto inorganic fibers which were the raw materials of honeycomb-type adsorbers. The amounts of zeolite particles attached onto the fibers considerably increased by treating them with hydrochloric acid, sulfuric acid, or hydrofluoric acid. Various functional groups such as chloropropyl, aminopropyl and epoxy groups of silane compounds, and amine groups of polyethylenimine were employed as covalent linkage materials between the fibers and zeolite particles. The state of the fibers coated with zeolite particles was examined by scanning electron microscopy, and the amounts of zeolite particles bound to the fibers were estimated from their BET surface areas. The largest amount was obtained when polyethylenimine was employed as a linkage material. Polyethylenimine was the most effective for attaching zeolite particles onto the inorganic fibers among various linkers employed.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.534-539
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• 2010

The adsorptive removal of organic sulfur compounds including tert-butylmercaptane(TBM), tetrahydrothiophene(THT) and dimethylsulfide(DMS) in methane was investigated over NaY and copper-exchanged NaY(CuNaY) zeolites at 303 K and atmospheric pressure. In the ternary adsorption system, the preferential adsorption of THT over other sulfur compounds on NaY and the concurrent adsorption of all sulfur compounds on CuNaY were achieved, which could be explained by the breakthrough curve, the temperature-programmed desorption, and the apparent activation energy for desorption. The sulfur uptake capacity of CuNaY(2.90~3.20 mmol/g) was much higher than that of NaY(0.70~0.90 mmol/g). A comparative study indicated that the $Cu^{1+}$ sites and acidity of CuNaY were probably responsible for the strong interaction with sulfur atom and high sulfur uptake abilities.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.588-594
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• 2005

We have investigated Y zeolite and activated carbon for an adsorptive desulfurization of diesel. In batch experiments, cation ($Cu^{2+}$, $Ni^{2+}$) exchanged Y zeolites showed high equilibrium adsorption capacity for sulfur compounds in model diesel, which contained BT, DBT and 4,6-DMDBT of each 50 ppmw in n-octane. But the cation exchanged Y zeolites lost its capacity in commercial diesel (186 ppmw). On the other hand, activated carbon showed reasonable adsorption capacity for sulfur compounds in both model and commercial diesel. The adsorption capacity of sulfur on Ni-Y zeolite was decreased with the increase of benzene concentration in model diesel but the sorption capacity on activated carbon was insensitive to aromatic concentration. In breakthrough test, activated carbon of 1 g could treat 15 ml of commercial diesel with 186 ppmw sulfur. Toluene showed good solvent for regenerating activated carbon among several solvents.