• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.37-41
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• 1977

Zeolite was applied of the tidal land and its effect on growth and yield of the two rice varieties, Yushin and Jinheung, was studied. The salinity of the zeolite treated soil was lower than that of the control. The effect of zeolite on growth of rice was appeared at the maximum tillering stage. The remarkable effect of zeolite on grain yield appeared in the variety Yushin, an indiea type. The amount of 600kg/10a was recognized to be an optimum amountd of the zeolite application in the tidal land.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.341-347
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• 2006

Adsorption characteristics of benzene by zeolite were investigated using irradiating microwave. Experimental apparatus was applied to a U-type fix-bed column equipped with microwave system. Zeolite, itself, seems to be inappropriated to remove benzene because of a hygroscopic property, Microwave irradiation to zeolite, however, brings about decreasing $H_{2}O$ adsorption and increasing benzene adsorption. This causes that the dipole material such as $H_{2}O$ was vibrated and heated by irradiation of microwave and desorbed from zeolite. And then, benzene starts to be absorbed by zeolite. In this study, the results showed that the selective adsorption of benzene was occurred by the microwave irradiation and the adsorption capacity of benzene was increased by increasing microwave energy. As a results, it was found that the zeolite could be used to adsorb benzene with microwave and this method make it feasible simultaneously to adsorb and desorb benzene.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.15-28
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• 2017

The adsorptive removal properties of synthetic A4 zeolite were investigated against a total of 16 offensive odors consisting of reduced sulfur compounds (RSCs), nitrogenous compounds (NCs), volatile fatty acids (VFAs), and phenols/indoles (PnI). Removal of these odors was measured using a laboratory-scale impinger-based adsorption setup containing 25 g of the zeolite bed (flow rate of $100mL\;min^{-1}$). The high est and lowest breakthrough (%) values were shown for PnIs and RSCs, respectively, and the maximum and minimum adsorption capacity (${\mu}g\;g^{-1}$) of the zeolite was observed for the RSCs (range of 0.77-3.4) and PnIs (0.06-0.104), respectively. As a result of sorptive removal by zeolite, a reduction in odor strength, measured as odor intensity (OI), was recorded from the minimum of approximately 0.7 OI units (indole [from 2.4 to 1.6]), skatole [2.2 to 1.4], and p-cresol [5.1 to 4.4]) to the maximum of approximately 4 OI units (methanethiol [11.4 to 7.5], n-valeric acid [10.4 to 6.5], i-butyric acid [7.9 to 4.4], and propionic acid [7.2 to 3.7]). Likewise, when removal was examined in terms of odor activity value (OAV), the extent of reduction was significant (i.e., 1000-fold) in the increasing order of amy acetate, i-butyric acid, phenol, propionic acid, and ammonia.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.687-694
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• 2012

Zeolite 4A was synthesized by fusion method from coal fly ash discharged at the thermal power plants. The synthesized zeolite(FAZ) was characterized through particle size analyzer, XRD, XRF and SEM. $N_2$ adsorption-desorption measurement was used to examine surface and pore structures. The adsorption experiments were carried out under dynamic conditions of trace $SO_2$ in $N_2$ to investigate $SO_2$ adsorption capacity of FAZ. The experiments were conducted to characterize the breakthrough characteristics of $SO_2$ in a fixed bed under different operating conditions including temperature(50-$125^{\circ}C$), concentration of $SO_2$(3000-10000 ppm) and FAZ with 4 kinds of commercial zeolite. The adsorption capacity of FAZ was 53.84 $mgSO_2/g$ adsorbent, larger than that of the same type commercial zeolite(WK4A).

• Geomechanics and Engineering
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• v.29 no.4
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• pp.421-434
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• 2022

In the present study, reference samples were prepared using ore preparation facility tailings taken from the copper mine (Kure, Kastamonu), Portland cement (PC) in certain proportions (3 wt%, 5 wt%, 7 wt%, 9wt% and 11 wt%), and water. Then natural zeolite taken from the Bigadic Region was mixed in certain proportions (10 wt%, 20 wt%, 30 wt% and 40 wt%) for each cement ratio, instead of the PC, to prepare zeolite-substituted CPB samples. Thus, the effect of using Zeolite instead of PC on CPB's strength was investigated. The obtained CPB samples were kept in the curing cabinet at a temperature of 25℃ and at least 80% humidity, and they were subjected to the Uniaxial Compressive Strength (UCS) test at the end of the curing periods of 3, 7, 14, 28, 56, and 90 days. Except for the 3 wt% cement ratio, zeolite substitution was observed to increase the compressive strength in all mixtures. Also, the liquefaction risk limit for paste backfill was achieved for all mixtures, and the desired strength limit value (0.7 MPa) was achieved for all mixtures with 28 days of curing time and 7 wt%, 9 wt%, 11 wt% cement ratios and 5% cement - 10% zeolite substituted mixture. Moreover, the limit value (4 MPa) required for use as roof support was obtained only for mixtures with 11% cement - 10% and 20% zeolite content. Generally, zeolite substitution seems to be more effective in early strength (up to 28th day). It has been determined that the long-term strength losses of zeolite-substituted paste backfill mixtures were caused by the reaction of sulfate and hydration products to form secondary gypsum, ettringite, and iron sulfate.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.281-288
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• 2020

BACKGROUND: Generally, ammonia occurs from agricultural waste disposal. Ammonia is known as a harmful substance to the human body and has a bad influence such as eutrophication on the ecosystem. It is possible to remove the ammonia by ammonia adsorption method using natural zeolite, without external influence. However, due to the natural zeolite shape, it is hard to reuse. METHODS AND RESULTS: Electrospinning method can produce fiber with constant diameter. Moreover, electrospinning method has no limitation for selecting the material to make the fiber, and thus, it is valuable to reform the surface of adsorbent. In this study, reusable membrane was made by electrospinning method. The highest removal efficiency was shown from the membrane with 20% of zeolite included, and it has been verified that it is possible to reuse the membrane through chemical treatment. The highest ammonia removal efficiency was about 92.4%. CONCLUSION: In this study, ammonia adsorption characteristics of zeolite fibers were studied. Electrospinning method can produce zeolite fiber with even distribution. Ammonia can be removed efficiently from ion exchange ability of the natural zeolite. The result of adsorption isotherm indicated that both Freundlich model and Langmuir model provided the best fit for equilibrium data. And study on desorption has demonstrated that the ion exchange from zeolite was reversible when 0.01 M NaCl and KCl solution were used.

• Macromolecular Research
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• v.15 no.7
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• pp.662-670
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• 2007

The crystallization behavior and fine structure of poly(ethylene terephthalate) (PET)/A-zeolite nanocomposites were assessed via differential scanning calorimetry (DSC) and time-resolved small-angle X-ray scattering (TR-SAXS). The Avrami exponent increased from 3.5 to approximately 4.5 with increasing A-zeolite contents, thereby indicating a change in crystal growth formation. The rate constant, k, evidenced an increasing trend with increases in A-zeolite contents. The SAXS data revealed morphological changes occurring during isothermal crystallization. As the zeolite content increased, the long period and amorphous region size also increased. It has been suggested that, since PET molecules passed through the zeolite pores, some of them are rejected into the amorphous region, thereby resulting in increased amorphous region size and increased long period, respectively. In addition, as PET chains piercing into A-zeolite pores cannot precipitate perfect crystal folding, imperfect crystals begin to melt at an earlier temperature, as was revealed by the SAXS profiles obtained during heating. However, the spherulite size was reduced with increasing nanofiller content, because impingement between adjacent spherulites in the nanocomposite occurs earlier than that of homo PET, due to the increase in nucleating sites.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2367-2374
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• 2013

Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis. The obtained organic-inorganic composite was effectively employed as a heterogeneous basic catalyst for synthesis of ${\alpha},{\beta}$-unsaturated carbonyl compounds. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present catalyst.

• Journal of the Korean Chemical Society
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• v.16 no.4
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• pp.249-256
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• 1972

Hadong-Kaolin was treated with aqueous sodium hydroxide solution. The crystalline structure was studied by X-ray powder diffraction method. The optimum conditions for various crystal formation were as follows: Crystal Concentration Temp. reating time Halloysite 1~4 N NaOH $60^{\circ}C$ 0.5${\sim}$4 hr Sodium A zeolite 0.5${\sim}$2 N NaOH 80${\sim}$$100^{\circ}C$ 6${\sim}$20 hr Hydoxysodalite > 4 N NaOH 80${\sim}$$100^{\circ}C$ > 4 hr The ratio of $Na_2O to SiO_2$ for crystallizing sodium A zeolite was 0.5-1.5. The $Ca^{++}$ ion exchange capacity of produced sodium A zeolite for 0.2 N $CaCl_2$ solution at $25^{\circ}C$ was amounted to 65% of theoretical value.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.155-157
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• 1987

Parameters of intraframework potential function suitable for aluminophosphate-5($AIPO_4-5$) are obtained by the constraint method. Using these parameters, we calculated the stabilization energies and their second derivatives of framework atoms and these values are compared with those of zeolite A. It is found that the oxygen atoms in $AIPO_4-5$ framework are more stable than those of zeolite A and that the aluminum atom is also more stable than that of zeolite A. On the other hand, the phosphorus atom in $AIPO_4-5$ framework, in which the silicon atoms of aluminosilicate are replaced by the phosphorus atom, is less stable than the silicon atom of aluminosilicate framework of dehydrated zeolite A.