• 한국환경과학회지
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• 제2권4호
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• pp.347-356
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• 1993

The three natural zeolites collected in Yungil-gun, Kyungsangbuk-do, Korea, were analyzed by means of chemical wet methods and X-ray diffraction. The results indicated that the primary species of those zeolites were clinoptilolite mixed with heulandite, feldspar, montmorillonite, and quartz. These zeolites were chemically treated with NaOH, $\textrm{Ca(OH)}_2$, and HCl solution and their differences were also studied with X-ray diffraction method. The capabilities of removing $Cs^+$ and Sr^{2+}$ ions with chemically untreated zeolites, chemically treated zeolites, and also with synthetic zeolites were compared. The effect of other cations in removing Sr^{2+}$ ions was also studied. The experimental results showed that$Cs^+$ and Sr^{2+}$ ions could be removed up to 98% and 95% respectively out of 5 ppm with chemically untrearted natural zeolites. The treatment of 0.02N-$\textrm{Ca(OH)}_2$ and that of 2N-NaOH were most effective In removing $Cs^+$ and Sr^{2+}$ ions, respectively. It was found that the mountaintop of Sangjung 1-dong natural zeolite treated with 2N-NaOH was most efficient in removing Sr^{2+}$ ions mixed with other cations, compared with any other chemically treated and untreated natural zeolites in this work.

• 한국환경과학회지
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• 제8권3호
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• pp.399-409
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• 1999

The three domestic natural zeolites(Yong dong-ri (Y), Daesin-ri (D), Seogdong-ri (S)) harvested in Kyeongju-shi and Pohang-shi, Kyungsangbug-Do, were pretreatd with each of the NaOH, $Ca(OH)_2$ and NaOH following HCl solutions, and the removal performances of divalent haevy metals(Cu, Mn, Pb, and Sr) for natural and pretreated zeolites were investigated and compared in the single and mixed solutions. The natural zeolite-heavy metal system attained the final equilibrium plateau within 20 min, irrespective of initial heavy metal concentration. The heavy metal uptakes increased with increasing initial heavy metal concentration and pH. The heavy metal uptakes for natural zeolites decreased in the following sequences : D>Y>S among the natural zeolites; Pb>Cu>Sr>Mn among the heavy metals. The pretreated zeolites showed higher heavy metal removal performances than natural zeolites and decreased in the order of NaOH, NaOH following HCl, $Ca(OH)_2$ treatment among the pretreatment methods. The heavy metal ion exchange capacity by natural and pretreated zeolites was described either by Freundlich equation or Langmuir equation, but it followed the former better than the latter. The heavy metal uptakes for natural zeolites decreased in the mixed solution, in comparing with those in the single solution and especially, the manganese uptake decreased greatly in the mixed solution. The pretreated zeolites showed the improved removal performances of heavy metals in the mixed solution than in the single solution and the heavy metal uptakes by those in the mixed solution showed the same trends in the single solution among the chemical treatment methods and heavy metals.

• 한국농공학회지
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• 제44권2호
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• pp.161-173
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• 2002

Recently, absorbent biofilters, which are inexpensive and easy to manacle, have been supplied to the rural areas, but have limitations in removing the nutrients effectively. Accordingly, as an alternative plan. natural zeolites were arranged in front or at the rear of the absorbent biofilters, and their removal efficiency for nitrogen and, ultimately, their applicability to the on-site wastewater treatment system were studied. Furthermore, the same experiments were carried out on artificial zeolites, made from coal ashes at National Honam Agricultural Experiment Station, to compare natural zeolites with artificial ones. Treated wastewater through the Absorbent Biofilter showed 22.6% nitrogen removal efficiency, while 64.6% was attained when natural Zeolites were placed in front of the absorbent biofilters (Zeolite-Aerobic process). As an addition, phosphorus was also efficiently removed. On the other hand, Aerobic-Zeolite process, which arranged natural zeolites at the rear of the biofilters, did not have significantly higher nitrogen removal as compared to the treatment using only the absorbent biofilters. Furthermore, upon regeneration of the natural zeolite, the ion exchange rate was fecund to increase over 10% as compared to before regeneration. Our results show that natural zeolites, applied to the on-site wastewater treatment system through the Zeolite-Aerobic process, not only increase the removal efficiency of nutrients, but, by choosing the appropriate regeneration time, can also be cast-effective. Artificial zeolites, on the other hand, though more efficient in removing nutrients, cannot be regenerated and, therefore, are not cost-effective.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.811-813
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• 2008

To see the effect of magnesium on adhesion to natural zeolites, a series of batch tests were performed in this research. Mixed bacteria were sampled from the digestion tank at a local sewage treatment plant in Seoul. Magnesium-zeolites were synthesized by mixing natural zeolites with 0.096 M, 0.24 M, and 0.48 M of MgCl2 solution. For comparison, manganese and trivalent ferric zeolites were also prepared. Two grams of 0.2 mm $\sim$ 0.3 mm sized zeolites(non-treated, Mg, Mn and Fe(III) treated zeolites) and 20 mL of water were mixed in a Corex 25 mL tube. Five milliliters of culture solution including bacteria was added to the tube. The tubes were equilibrated in a shaking incubator at mesophilic temperature $(30{\pm}2^{\circ}C)$. The bacterial concentrations were measured with a Microluminometer (New Horizons 3550i) and total organic carbon (TOC) spectrophotometer (Multi NC-3100).

• Smart Structures and Systems
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• 제24권3호
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• pp.415-425
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• 2019

This study was carried out to evaluate the natural zeolite in producing green concrete as an effort to prevent global warming and environmental impact problems of cement industries. To achieve this target, two types of natural zeolites applied to study physical, chemical and compressive strength of concrete containing different percentages of zeolites. The results in comparison with control samples indicate that compressive strength of zeolites mixes increases with the 15% replacement of zeolite instead of cement in all types of samples. In the water-cement ratio of 0.6, results showed an increase in the compressive strength of all percentages of replacement. This results indicate that using natural zeolites could be produced a green concrete by a huge reduction and saving in the consumption of cement.

• 한국환경과학회지
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• 제12권10호
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• pp.1061-1069
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• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• 한국환경과학회지
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• 제31권12호
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• pp.1103-1115
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• 2022

The adsorption characteristics of four pesticides (phosphamidon, fenitrothion, triadimefon, and diniconazole) on natural clinoptilolite (CLI_N) and three synthetic zeolites were investigated. The synthetic zeolites included faujasite (FAU_F) synthesized from coal fly ash; the mixture of FAU and Na-P1 (FAU + Na-P1)_SF synthesized using Jeju scoria and coal fly ash at the ratio of 1.5 by weight; and waste fluid catalytic cracking catalyst (FCC_W). The distribution coefficient, K_D and the Freundlich constant, K_F decreased in the following sequence: FCC_W > FAU_F > (FAU + Na-P1)_SF > CLI_N among the zeolites and diniconazole>fenitrothion> triadimefon> phosphamidon among the pesticides. The pesticide adsorptivity increased with increasing temperature for FAU_F, (FAU+Na-P1)_SF and FCC_W, however, it decreased for CLI_N, regardless of the type of pesticide. The adsorptivity of pesticides was independent of pH for phosphamidon, fenitrothion and triadimefon, whereas it decreased with increasing pH for diniconazole, regardless of zeolite type.

• 자원환경지질
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• 제9권3호
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• pp.165-168
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• 1976

Zeolites are aluminosilicates with a three dimensional framework structure enclosing pores occupied by cation and water molecules, both of which have considerable freedom of movement within certain limits. The ability of zeolites to exchange cation is one of the mere useful of their characteristics. The ion exchange condition of zeolites strongly affects absorption as well as other properties. The application, techniques of identification and evaluation of clinoptilolite, chabazite, mordenite and phillipsite are reviewed.

• 공업화학
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• 제4권3호
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• pp.488-496
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• 1993

천연 제올라이트는 공업적으로 그 용도가 매우 다양하여 최근에 연구의 초점이 되어왔다. 여러 종류의 국내산 천연 제올라이트 중에서 clinoptilolite는 가장 각광을 받는 천연 제올라이트 중의 하나이다. 그러나 clinoptilolite와 구조가 유사한 heulandite가 clinoptilolite와 공존할 가능성이 항상 내포되어 있다. 그러나 heulandite는 열적으로 매우 불안정하기 때문에 공업적으로 이용되는데 많은 제한을 받아왔다. 본 논문에서는 이온교환 및 열처리가 국내산 천연 제올라이트인 huelandite의 열적 안정성에 미치는 영향에 관하여 논하고자 한다. 2종류의 이온교환을 실시한 후 여러 온도에서 열처리를 수행하였다. X-ray, IR 및 AA 흡광 분석을 실시한 결과 $Na^+$이온으로 이온교환할 때 heulandite의 열적 안정성의 향상을 가져오는 것을 알 수 있었다.

• 대한화학회지
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• 제28권3호
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• pp.194-202
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• 1984

陽이온 交換한 天然제올라이트에 依한 有機黃化合物의 液相吸着特性을 考察하였다. 平衡吸着量은 天然제올라이트의 交換한 陽이온과 吸着質인 有機黃化合物의 構造에 影響을 받고 있음을 알 수 있었다. 또한 平衡吸着量은 메르캅탄(mercaptane), 설파이드(sulfide), 디설파이드(disulfide), 치오펜(thiopen) 順으로 減小하였으며, 치오펜 誘導體의 경우는 ${\pi}$ 電子가 많아짐에 따라 吸着能은 교환 이온의 polarizing power에 比例하였다. 吸着速度로부터 有機黃化合物의 吸着은 pore 내의 擴散이 律速段階임을 알수 있었고, 水分과 같은 작은 吸着質은 micro pore에 吸着이 일어나는 反面, 有機黃化合物은 transitional-pore에 吸着이 일어났다.