석탄 비산재로부터 합성된 제올라이트의 암모니아의 흡착용량 및 파과특성

박종원,이창한,Park, Jong-Won,Lee, Chang-Han 한국환경과학회 2022 한국환경과학회지 Vol.31 No.10

A zeolite material with a Si/Al molar ratio of 1.2 was synthesized by changing the NaOH/CFA ratio of coal fly ash (CFA) via a fusion/hydrothermal reaction in the HD thermal power plant. The change in the crystal structure of the zeolite was confirmed using XRD and SEM, and the ammonia adsorption capacities of the synthesized zeolitic materials and a commercial zeolite (Na-A zeolite) were analyzed via an ammonia temperature-programmed desorption (NH₃-TPD) process. The SEM and XRD results revealed out the zeolitic materials from the coal fly ash maintained a hexagonal Linde-type crystal structure similar to that of Na-A zeolite, but the crystallinity of the synthesized zeolitic material was reduced due to impurities. The NH₃ adsorption capacity, determined from the NH₃-TPD analysis of was 1.122 mmol/g of the synthesized zeolitic material, which was lower than the NH₃ adsorption capacity of the Na-A zeolite.

산업폐기물로부터 합성된 제올라이트 물질의 망간 이온 흡착속도 및 등온흡착 특성

최정학,이창한,Choi, Jeong-Hak,Lee, Chang-Han 한국환경과학회 2020 한국환경과학회지 Vol.29 No.8

Zeolite material having XRD peaks of Na-A zeolite in the 2θ range of 7.18 to 34.18 can be synthesized from the waste catalyst using a fusion/hydrothermal method. The adsorption rate of Mn ions by a commercial Na-A zeolite and the synthesized zeolitic material increased as the adsorption temperature increased in the range of 10 ~ 40℃. The adsorption of Mn ion were very rapid in the first 30 min and then reached to the equilibrium state after approximately 60 min. The adsorption kinetics of Mn ions by the commercial Na-A zeolite and the zeolitic material were found to be well fitted to the pseudo-2^nd order kinetic model. Equilibrium data by the commercial Na-A zeolite and the zeolitic material fit the Langmuir, Koble-Corrigan, and Redlich-Peterson isotherm models well rather than Freundlich isotherm model. The removal capacity of the Mn ions by the commercial Na-A zeolite and the zeolitic material obtained from the Langmuir model was 135.2 mg/g and 128.9 mg/g at 30℃, respectively. The adsorption capacity of Mn ions by the synthesized zeolitic material was almost similar to that of commercial Na-A zeolite. The synthesized zeolitic material could be applied as an economically feasible commercial adsorbent.

제주 스코리아로부터 합성한 제올라이트 물질에 의한 암모니아성 질소의 흡착 특성

이창한,현성수,감상규,Lee, Chang-Han,Hyun, Sung-Su,Kam, Sang-Kyu 한국환경과학회 2020 한국환경과학회지 Vol.29 No.12

The characteristics of ammonia-nitrogen (NH4+-N) adsorption by a zeolitic material synthesized from Jeju scoria using the fusion and hydrothermal method was studied. The synthetic zeolitic material (Z-SA) was identified as a Na-A zeolite by X-ray diffraction, X-ray fluorescence analysis and scanning electron microscopy images. The adsorption of NH4+-N using Jeju scoria and different types of zeolite such as the Z-SA, natural zeolite, and commercial pure zeolite (Na-A zeolite, Z-CS) was compared. The equilibrium of NH4+-N adsorption was reached within 30 min for Z-SA and Z-CS, and after 60 min for Jeju scoria and natural zeolite. The adsorption capacity of NH4+-N increased with approaching to neutral when pH was in the range of 3-7, but decreased above 7. The removal efficiency of NH4+-N increased with increasing Z-SA dosage, however, its adsorption capacity decreased. For initial NH4+-N concentrations of 10-200 mg/L at pH 7, the adsorption rate of NH4+-N was well described by the pseudo second-order kinetic model than the pseudo first-order kinetic model. The adsorption isotherm was well fitted by the Langmuir model. The maximum uptake of NH4+-N obtained from the Langmuir model decreased in the order of Z-CS (46.8 mg/g) > Z-SA (31.3 mg/g) > natural zeolite (5.6 mg/g) > Jeju scoria (0.2 mg/g).

용융/수열합성법으로부터 Na₂CO₃ 첨가량에 따른 석탄비산재의 제올라이트화 특성

이창한 ( Chang-han Lee ) 한국환경과학회 2019 한국환경과학회지 Vol.28 No.6

In this study, zeolitic materials at Na₂CO₃/CFA ratio of 0.6 1.8 were synthesized from coal fly ash from a thermal power plant using a fusion/hydrothermal method. The zeolitic materials were found to have cubic crystals structure and X-ray diffraction (XRD) peaks of Na-A zeolite by XRD and SEM analysis. When the zeolitic materials were synthesized from the coal fly ash, the XRD peaks of the zeolitic materials at Na₂CO₃/CFA ratios of 0.9-1.8 had the same location as the XRD peaks of commercial Na-A zeolite. The XRD peaks of the Na-A zeolite (Na₁₂Al₁₂Si₁₂O₄₈27.4H₂O) were confirmed in the 2θ in the range of 7.18-34.18. However, it was also confirmed that peaks of CaCO₃, an impurity inhibiting synthesis of Na-A zeolite from CaO and Na₂CO₃ in the coal fly ash, occurred in the XRD peaks of the zeolitic materials at Na₂CO₃/CFA ratio of 1.5-1.8. The crystallinities of the zeolitic materials tended to increase gradually within the Na₂CO₃/CFA ratio range of 0.6-1.8.

Evaluation of Sr and Cs ions adsorption capacities with zeolitic materials synthesized from various mass ratios of NaOH to coal fly ash

Jeong-Hak Choi,Chang-Han Lee 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.2

The adsorptive aqueous removal of Sr<SUP>2+</SUP> and Cs<SUP>+</SUP> was performed using zeolitic materials prepared with fused coal fly ash (CFA) using a hydrothermal method. The influence of the mass ratio of NaOH to CFA of 0.3-1.2 in the synthesis of zeolitic material was evaluated its crystallization properties by X-ray diffraction (XRD) analysis. The zeolitic materials synthesized at the mass ratio of NaOH to CFA of 0.6-1.2 could be identified to have the same location as the XRD peaks of Na-A zeolite at 2θ = 7.18 - 34.18. They appeared to be zeolitic materials which were crystalline particles with a cubic structure by scanning electron microscopy (SEM). The experimental adsorption data for Sr<SUP>2+</SUP> and Cs<SUP>+</SUP> using the zeolitic materials were estimated satisfactory using pseudo-2<SUP>nd</SUP>-order kinetics and Langmuir isotherm models. The highest maximum adsorption capacities (qm) of 147.6 mg/g for Sr<SUP>2+</SUP> and 160.2 mg/g for Cs<SUP>+</SUP> were estimated by using the zeolitic material. This material demostrated superior crystallinity and was synthesized at a mass ratio of NaOH to CFA of 0.6. Consequently, the zeolitic material prepared from the fused CFA through the hydrothermal method could be used effectively for the adsorption of Sr<SUP>2+</SUP> and Cs<SUP>+</SUP> in aqueous solutions.

수소 저장용 다공성 제올라이트 탐색을 위한 고속 대량 스크리닝 계산

여병철 대한금속·재료학회 2022 대한금속·재료학회지 Vol.60 No.7

Hydrogen is considered an attractive energy resource because it is eco-friendly in contrast with fossil fuels. Hydrogen storage remains as essential technology for increasing the use of the hydrogen in applications such as hydrogen vehicles and fuel cells. Hydrogen storage requires retaining a high density of hydrogen molecules at ambient temperature in a suitable tank. Zeolites are one of the promising hydrogen storage materials, but experimentally investigating them for hydrogen storage is difficult since the number of the zeolites in the large-scale material database has been increasing. In the present study I developed an efficient method of exploring potential zeolites in the database that had high volumetric hydrogen storage capacity. To do this I employed a high-throughput screening approach to automatically construct a zeolite database for hydrogen storage in the Inorganic Crystal Structural Database (ICSD). Also, I performed grand canonical Monte Carlo (GCMC) simulations to estimate hydrogen adsorption isotherms at operating ambient temperatures, to determine the volumetric hydrogen storage capacity of the zeolites. Finally, I found 10 top ranked materials in the zeolite database for H2 storage, and I calculated Pearson’s correlation coefficient to revealed the linear correlations between the hydrogen storage capacities and 3 structural characteristics (i.e., surface area, largest cavity diameter, pore limiting diameter). Furthermore, I investigated atom species in the 10 materials to show the relation between the hydrogen storage capacities and chemical elements. In future works, I expect the method can be easily applied to accelerate the discovery and design of porous materials for storing CO2 or toxic gases.

금속 이온이 교환된 석탄 비산재 유래 합성 제올라이트 물질의 암모니아 흡착성능 평가

박종원,곽주영,이창한,Jong-Won Park,Joo-Young Kwak,Chang-Han Lee 한국환경과학회 2023 한국환경과학회지 Vol.32 No.5

A zeolite material (ZCH) was synthesized from coal fly ash in an HD thermal power plant using a fusion/hydrothermal method. ZCH with high crystallinity could be synthesized at the NaOH/CFA ratio of 0.9. Ion-exchanged ZCH adsorbents for ammonia removal were prepared by ion-exchanging various cation (Cu²⁺, Co²⁺, Fe³⁺, and Mn²⁺) on the ZCH. They were used to evaluate the ammonia adsorption breakthrough curves and adsorption capacities. The ammonia adsorption capacities of the ZCH and ion-exchanged ZCHs were high in the order of Mn-ZCH > Cu-ZCH ≅ Co-ZCH > Fe-ZCH > ZCH according to NH₃-TPD measurements. Mn-ZCH ion-exchanged with Mn has more Brønsted acid sites than other adsorbents. The ion-exchanged Cu²⁺, Co²⁺, Fe³⁺, or Mn²⁺ ions uniformly distributed on the surface or in the pores of the ZCH, and the number of acidic sites increased on the alumina sites to form the crystal structure of zeolite material. Therefore, when the ion-exchanged ZCH was used, the adsorption capacity for ammonia gas increased.

Template Synthesis and Characterization of Host (Nanocavity of Zeolite Y)-Guest ([Cu([18]aneN₄S₂)]²⁺, [Cu([20]aneN₄S₂)]²⁺, [Cu(Bzo₂[18]aneN₄S₂)]<sup>2+</su

Salavati-Niasari, Masoud,Mirsattari, Seyed Nezamodin,Saberyan, Kamal Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.2

Copper(II) complexes with tetraoxo dithia tetraaza macrocyclic ligands; [18]ane$N_4S_2$: 1,4,10,13-tetraaza-5,9,14,18-tetraoxo-7,16-dithia-cyclooctadecane, [20]ane$N_4S_2$: 1,5,11,15-tetraaza-6,10,16,20-tetraoxo-8,18-dithia-cyclocosane,Bzo2[18]ane$N_4S_2$: dibenzo-1,4,10,13-tetraaza-5,9,14,18-tetraoxo-7,16-dithia-cyclooctadecane, Bzo2[20]ane$N_4S_2$: dibenzo-1,5,11,15-tetraaza-6,10,16,20-tetraoxo-8,18-dithia-cyclocosane; were entrapped in the nanopores of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)copper(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); $[Cu(N-N)_2]^{2+}$-NaY; in the nanopores of the zeolite, and (ii) in situ template condensation of the copper(II) precursor complex with thiodiglycolic acid. The obtained complexes and new host-guest nanocomposite materials; $[Cu([18]aneN_4S_2)]^{2+}-NaY,\;[Cu([20]aneN_4S_2)]^{2+}-NaY,\;[Cu(Bzo_2[18]aneN_4S_2)]^{2+}-NaY,\;[Cu(Bzo_2[20]aneN_4S_2)]^{2+}$-NaY; have been characterized by elemental analysis FT-IR, DRS and UV-Vis spectroscopic techniques, molar conductance and magnetic moment data, XRD and, as well as nitrogen adsorption. Analysis of data indicates all of the complexes have been encapsulated within nanopore of zeolite Y without affecting the zeolite framework structure.

의치상 이장재 표면의 캔디다 균주에 대한 항균제의 억제 효과

장경수,Jang, Kyung-Soo 대한치과보철학회 1999 대한치과보철학회지 Vol.37 No.3

The purpose of this study was to evaluate the in vitro antifungal effect of several kinds of denture lining materials containing nystatin and silver-zeolite on Candida albicans. Three commercially available tissue conditioners (Soft-Liner, Coe-Comfort, Coe-Soft) and two direct denture relining materials (Tokuso Rebase, Durabase) were selected. In terms of the zone of inhibition and some basic physical properties, I could find the following results ; 1. Nystatin or silver-zeolite included in those relining materials had definite antifungal activities against the Candida albicans. 2. As times went on, both of the antifungal agents's activities decreased gradually. 3. Antifungal agents did not affect the relining materials' basic physical properties. 4 Direct chairside relining materials showed unfavorable dark discoloration with response to silver-zeolite.

Co‐Co3O4 Embedded in Carbon Nanotube Derived from a Zeolitic‐Imidazolate Framework as Anode Material for Lithium‐Ion Batteries

Hao Nguyen Thi My,Ahmed Sheraz,An Jung‐Chul,Sun Ho‐Jung,Park Gyungse,Shim Joongpyo 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.9

Co and carbon nanotube (CNT) were prepared as anode materials to be used in lithium rechargeable batteries from the zeolitic-imidazolate framework-67 (ZIF-67) using the solvothermal method. By annealing ZIF-67 at different temperatures between 400 and 700 C, the carbon framework was changed to CNTs, and Co or Co3O4 nanoparticles were embedded in the CNTs (Co or Co3O4/CNT). The Co/CNT was converted to Co-Co3O4/CNT by further treatment at 160 C in air. The Co3O4/CNT showed high initial capacities (1582 mAh/g) but poor capacity retention during cycling. However, the air treatment of the Co/CNT at 160 C enhanced its discharge capacity (935 mAh/g) and capacity retention during cycling.