An environmentally friendly and low-cost chitosan-containing polysaccharide (CP) composite ZIF-8/CP was designed and prepared based on the difficulty of separating the traditional adsorbent from the water phase. ZIF-8/CP was synthesized through in-situ growth approach. The physical, chemical and structure properties of ZIF-8/CP were determined through a series of characterization methods, including SEM, FT-IR and PXRD. The effects of touch time, pH, temperature, and coexisting ions on adsorption were assessed. In addition, kinetics, isotherms of adsorption and thermodynamics were examined. The data of isotherms for adsorption indicated that the adsorption of ZIF-8/CP on MG was similar to the Langmuir model, with a maximum adsorption capacity of 1428.57 mg/g. Moreover, the kinetic parameters were consistent with the pseudo- 2nd-order equation. Thermodynamic studies (ΔG < 0, ΔH > 0) demonstrated a heat-absorbing and spontaneous adsorption process. Our study reveals that ZIF-8/CP has good adsorption properties and environmental properties.

This study investigates the behavior of bentonite, used as a buffer material in deep geological disposal systems, in the context of pore morphology under the influence of field-collected groundwater conditions. The bentonite was processed into block form using cold isostatic press (CIP) and subsequently analyzed for its pore morphology in situ using synchrotron X-ray computed tomography (CT) within the field-collected groundwater environment. Bentonite buffers play a critical role in deep geological disposal systems by preventing contact between disposal containers and groundwater. Bentonite typically exhibits swelling upon contact with water, forming few layers of water molecules between its structural layers. However, the presence of ions such as K+ and Cl- can lead to a sharp reduction in swelling pressure. Loss of swelling pressure could negatively impact the integrity of future deep geological disposal systems, making its assessment crucial. This study involves processing various types of bentonite, including natural Na-type bentonite, into block forms and subjecting them to exposure in both deionized water and field-collected groundwater conditions. Internal pore morphology changes were measured using Xray CT technology.

본 연구는 사일리지 발효제 첨가가 볏짚 사일리지에서 곰팡이 독소 및 in situ 섬유소 소화율에 미치는 영향을 평가하고자 실시 하였다. 사일리지 발효제로 L. plantarum 단일제 및 L. plantarum 과 S. cerevisiae의 혼합제를 첨가하였을 때 사일리지의 발효 및 섬유소 분해에 영향을 주었을 뿐만 아니라 곰팡이독소 감소에도 영향을 주었다. 시험 시료에서 곰팡이독소 중 ochratoxin A 및 zearalenone만 발견되었다. Ochratoxin A 및 zearalenone는 대조구에서 각각 38.11±2.22 및 633.67±50.30 ug/kg 수준으로 발효제 첨가로 감소 경향이 나타났고, 혼합제에서만 각각 27.78±2.28 및 392.72± 25.04 ug/kg 수준으로 유의적 차이를 보였다(p<0.05). pH는 대조 구에 비하여 단일제 및 혼합제에서 낮았고(p<0.05), lactic acid는 대조구(8.18±0.93 mM)에 비하여 단일제(11.73±0.31 mM)가 높았고, 혼합제(16.01±0.88 mM)에서 가장 높은 수준을 나타내었다 (p<0.05). Acetic acid와 propionic acid는 발효제 첨가에 따라 유 의적으로 낮아짐을 발견하였다(p<0.05). 그리고 total VFA도 발 효제 첨가가 대조구에 비하여 낮았다(p<0.05). NDF 및 ADF의 반추위 in situ 분해율은 배양기간 동안 혼합제가 가장 높은 수준 의 분해율을 유지하였고, 다음으로 단일제가 높았으며, 대조구가 가장 낮은 수준을 유지하였다. 그리고 이들 NDF 및 ADF 분해율 은 각각 배양 12 및 24시간 이후 모든 시간대에서 실험구간 유의 차를 나타내었다(p<0.05). 이상의 연구 결과는 볏짚 사일리지 제조에서 사일리지 발효제 사용은 발효 및 섬유소 분해에 영향을 주었을 뿐만 아니라 곰팡 이독소 감소에도 영향을 주었다. 그리고 곰팡이독소 감소는 L. plantarum 단일제보다 L. plantarum과 S. cerevisiae 혼합제의 효능이 더 크게 나타났다. 따라서 사일리지 조제를 위한 발효제로 L. plantarum과 L. plantarum 첨가제의 사용은 사일리지의 품질 과 안정성을 더 증진할 것으로 사료 된다.

The pitch-based activated carbon fibers (ACFs) were prepared from ethylene tar-derived pitches containing nickelocene (CNi) or nickel nitrate (NiN). The effects of different anions and contents of metal salts on the microstructure and surface chemical properties of fibers were investigated. The results revealed that Ni2+ from CNi mainly remained its pristine molecule in the organometal salt-derived pitch (OP-xCNi), while Ni2+ from NiN occurred complexation reaction with polycyclic aromatic hydrocarbons (PAHs) in the inorganic metal salt-derived pitch (IP-xNiN) due to the weaker binding ability between anions and Ni2+ of CNi than CNi. The XRD and SEM results confirmed that IP-3NiN-ACF contained Ni, NiO, Ni2O3 nanoparticles with different size distributions, while OP-3CNi-ACF only contained more uniformly distributed Ni nanoparticles with small size. Furthermore, OP-3.0CNi-ACF presented higher specific surface area of 1862 m2/ g and a pore volume of 1.69 cm3/ g than those of IP-3.0NiN-ACF due to the formation of pore structure during the in-situ catalytic activation of different metal nanoparticles. Therefore, this work further pointed out that the desired pore structure and surface chemistry of pitch-based ACFs could be obtained through regulating and controlling the interaction of anion species, metal cations and PAHs during the synthesis of pitch precursors.

The presence of dyes in water is the most popular problem recently, so the current study was directed towards the synthesis of an effective material consisting of NiO and MWCNTs. The NiO/F-MWCNTs nanocomposite was synthesized using a simple hydrothermal method after functionalization of MWCNTs using sulfuric acid and nitric acid and utilized as an efficient surface to adsorption of malachite green dye from polluted water. The nanocomposite sample was characterized using several techniques are X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FESEM), High- resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) surface area analysis, Barrett-Joyner-Halenda (BJH) analysis and Energy dispersive X-ray (EDX). The analytical results showed that the prepared nanocomposite is of good crystalline nature with a particle size of 25.43 nm. A significant specific surface area was 412.08 m2/ g which indicates the effective impact of the nanocomposite in the adsorption of malachite green (MG) dye. On the other hand, the effect of adsorbent dose, temperature, acidic function and contact time on the adsorption efficiency of dye was studied. The kinetics of dye adsorption were also investigated employing two kinetic models, pseudo-first-order model and pseudo-second-order model. Finally, the thermodynamic functions were determined to identify the type of the reaction and the spontaneity of the process.

Abstract In the present study, the effect of nickel nitrate addition as a catalytic precursor for the in situ formation of Ni nanoparticles during the heating process has been investigated on the modification of microstructure and graphitization of amorphous carbon resulting from pyrolysis of phenolic resin. For this purpose, the prepared resin samples were cured in carbon substrate with and without additives at temperatures of 800, 1000, and 1250 °C. XRD, FESEM, and TEM studies were performed to investigate the phase and microstructural changes in the samples during the heating process. In addition to phase and microstructural studies, thermodynamic calculations of the reactions performed for the in situ formation of nickel nanoparticles and their effective factors during the curing process were performed. The results indicated that nickel nitrate is transformed to nickel nanoparticles of different sizes during the reduction process in a reduced atmosphere. The in situ formation of nickel nanoparticles and its catalytic effect led to the graphitization of carbon resulting from the pyrolysis of phenolic resin at a temperature of 800 °C and above. By increasing temperature, the morphology of the formed graphite changed and hollow carbon nanotubes, carbon cells, and onion skin carbon were formed in the microstructure. It was also observed that by increasing the temperature and the amount of additive, carbon nanotubes and their size are increased. A noteworthy point from thermodynamic calculations during the formation of nickel nanoparticles was that the nickel nanoparticles themselves acted as accelerators of nickel oxide reduction reactions and the formation of nickel nanoparticles. This increases the amount of amorphous carbon graphitization resulting from the pyrolysis of phenolic resin which leads to the formation of more carbon nanotubes at higher temperatures.

An application of the final decommissioning plan for unit 1 of Kori NPP was submitted to NSSC on 14 May 2021. We have been implementing the project related to the radiological characterization for the plan since 2019. However, the project was not running smoothly due to the regulatory environment. The destructive sampling from the objects was not allowed, so only smear (swipe) samples are available. In this study, the sampling way and the analytical results of radionuclides are presented. In addition, we propose in-situ measurement using gamma camera and in-situ gamma spectroscopy to obtain more comprehensive radiological information on the object.

For the peaceful use of nuclear energy, the international community has devoted itself to fulfilling its obligations under the Safeguards Agreement with IAEA. In this regard, uranium in a radioactive waste drum should be analyzed and reported in terms of mass and 235U enrichment. In order to characterize radioactive wastes, gamma spectroscopy techniques can be effectively applied. In the case of high-resolution gamma spectroscopy, because an HPGe detector can provide excellent energy resolution, it can be applied to analyze a mixture having a complicated isotopic composition. However, other substances such as wood, concrete, and ash are mixed in radioactive waste with various form factors; hence, the efficiency calibration is difficult. On the other hand, In Situ Object Counting System (ISOCS) has a capability of efficiency calibration without standard materials, making it possible to analyze complex radioactive wastes. In this study, the analysis procedure with the ISOCS was optimized for quantification of radioactive waste. To this end, a standard radioactive waste drum at KEPCO NF and low-level radioactive waste drums at Korea Radioactive Waste Agency (KORAD) were measured. The performance of the ISOCS was then evaluated by Monte Carlo simulations, Multi-Group Analysis for Uranium (MGAU) code, and destructive analysis. As a result, the ISOCS showed good performance in the quantification of uranium for a drum with the homogenized simple geometry and long measurement time. It is confirmed that the ISOCS gamma spectroscopy technique could be used for control and accountancy of nuclear materials contained in a radioactive waste drum.

Jeotgal is a salty and fermented traditional Korean fish sauce. Unlike most other previous studies that investigated samples purchased from retail markets, this study focused on samples of jeotgal with traceable history to Yeonggwang, a timehonored fishing village in Korea. Three jeotgal samples, which were made from small yellow croakers, largehead hairtail, and miscellaneous fish, were selected based on information obtained from interviews with local craftsmen and literature reviews. Bacterial community profiles of the three jeotgal samples were investigated to identify indicator (and potentially core) bacteria for jeotgal ripening. The 16S rRNA gene-based metagenomic analysis revealed that the dominant phyla and classes, (Gammaproteobacteria, Betaproteobacteria, Bacilli, and Clostridia) of the three different jeotgal were identical, albeit with different composition ratios. Diversification was evident beginning at the order level. Interestingly, each dominant order was mainly comprised of single members even at the genus level. The dominant genera included Halomonas, Tetragenococcus, Halanaerobium, Pseudomonas, Massilia, and Lentibacillus. This observed genus-level heterogeneity suggests that there are diverse bacterial signatures in jeotgal and that these can be used as indicators for jeotgal ripening and/or as starters to increase its sensory quality and functionality.