Spent ion exchange resins have been generated during the operation of nuclear facilities. These resins include radioactive nuclides. It is needed to fabricate them into a stable form for final disposal. Cement solidification process is a useful method for the fabrication of them into a waste form for final disposal. In this study, proper conditions for the fabrication of them into a stable waste form were determined using the cement solidification process. In-drum waste forms were then produced at the conditions, where the stability of representative samples was evaluated for final disposal. The samples were satisfied to the Waste Acceptance Criteria for low and intermediate level radioactive waste disposal sites. This result can be utilized to derive optimal conditions for the fabrication of spent ion exchange resins into a final disposal form.

Ion exchange resins are commonly employed in the treatment of liquid radioactive waste generated in nuclear power plants (NPP). The ion exchange resin used in NPP is a mixed-bed ion exchange resin known as IRN-150, which is of nuclear grade. This resin is a mixture of cation exchange resin and anion exchange resin. The cation exchange resin removes cationic radionuclides such as Cs and Co, while anion exchange resin handles anions (e.g., H14CO3 -), effectively purifying the liquid waste. Spent ion exchange resins (spent resin) containing C-14 are classified as low and intermediate level radioactive waste, and their radioactivity needs to be reduced as it exceeds the disposal limit regulated by law. Therefore, the microwave technology for the removal of C-14 from spent resin has been investigated. Previous studies have successfully developed a method for the effective removal of C-14 during the resin treatment process. However, it was observed that, in this process, functional groups in the resin were also removed, resulting in the generation of off-gases containing trimethylamine. These off-gases can dissolve in water from process, increasing its pH, which can subsequently hinder the recovery of C-14. In this study, we investigated the high-purity recovery of C-14 by adjusting the moisture content within the reactor following microwave treatment. Mock spent resins, consisting of 100 g of resin with HCO3 - ion-exchanged and 0, 25, or 50 g of deionized water, were subjected to microwave treatment for 40 or 60 minutes. Subsequently, the C-14 desorption efficiency of the mock spent resins was evaluated using an acid stripping process with H3PO4 solution. The functional group status of the mock spent resins was analyzed using 15N NMR spectroscopy. The results showed that the mock spent resins exhibited efficient C-14 recovery without significant functional group degradation. The highest C-14 desorption efficiency was achieved when 25 g of deionized water was used during microwave treatment.

Korea Atomic Energy Research Institute’s Post Irradiated Examination Facility safely stores spent nuclear fuel using a wet storage method to conduct research. Here, in order to remove the radioactivity released into the water, the stored water is passed through an ion exchange resin tower, and the radionuclides are exchanged with the bead-shaped ion exchange resin filled inside to lower the radioactivity concentration. At this time, because the stored water passes in one direction, clogging of the ion exchange resin occurs. If this phenomenon continues, the flow rate of the water treatment process decreases and operation efficiency decreases, so a backwashing process is necessary to re-mix the ion exchange resin and secure the flow rate again. In this study, the flow rate reduction trend according to the lifespan of the ion exchange resin and the flow rate recovery according to the backwash process operation amount were analyzed. The flow rate reduction trend of the ion exchange process was analyzed immediately after the backwashing process was started. In addition, the amount of flow recovery according to the backwash process operation amount was evaluated by the amount of waste generated during the backwash process and the number of days of operation until the backwash process was needed again. As a result, the flow rate of the ion exchange process decreased rapidly right after the backwash process until the position of the ion exchange resins was stabilized, and then stabilized. After that, it gradually decreased and reached the point where the backwash process was necessary. However, the decline trend was analyzed to be the same regardless of the lifespan of the ion exchange resin. In addition, the amount of waste generated during the operation of the backwash process was increased in the order of 400 L, 600 L, 1,100 L, 1,400 L, 3,500 L, and 4,200 L to increase the amount of operation of the backwash process. As a result, the number of days of ion exchange resin operation was 285 days, 338 days, and 342 days, was analyzed as 422 days, 322 days, and 720 days. Based on this study, it was confirmed that the flow rate reduction trend is the same regardless of the lifespan of the ion exchange resin, and as the backwash process operation increases, the number of days the ion exchange process can be operated increases, but there is a turning point where the waste treatment cost exceeds the number of days of operation.

An optical fluorescence quenching sensor based on functionally modified iron-doped carbon nanoparticles was designed for the selective and sensitive Cr(VI) ion detection. Multifunctional iron-doped carbon nanoparticles were enclosed in the scaffolds of a promising stable nanocarrier system called hyperbranched polyglycerol (HPG), which has been fluorescently modified with 1-pyrene butyric acid using the Steglich esterification procedure. The therapeutic and diagnostic capabilities were boosted when these nanoparticles were enclosed in the fluorescently modified dendritic structure, HPG. Iron-doped carbon nanoparticles coupled with fluorescently modified hyperbranched polyglycerol can be used as a sensor for metal ions and can then be used to successfully remove them from a sample. Moreover, the synthesised nanoparticles demonstrated promising antimicrobial efficacy against bacteria and fungi. These results are also discussed in detail.

As a promising anode for sodium-ion batteries (SIBs), cobalt sulfide ( CoS2) has attracted extensive attention due to its high theoretical capacity, easy preparation, and superior electrochemical activity. However, its intrinsic low conductivity and large volume expansion result in poor cycling ability. Herein, nitrogen-doped carbon-coated CoS2 nanoparticles (N–C@ CoS2) were prepared by a C3N4 soft-template-assisted method. Carbon coating improves the conductivity and prevents the aggregation of CoS2 nanoparticles. In addition, the C3N4 template provides a porous graphene-like structure as a conductive framework, affording a fast and constant transport path for electrons and void space for buffering the volume change of CoS2 nanoparticles. Benefitting from the superiorities, the Na-storage properties of the N–C@CoS2 electrode are remarkably boosted. The advanced anode delivers a long-term capacity of 376.27 mAh g− 1 at 0.1 A g− 1 after 500 cycles. This method can also apply to preparing other metal sulfide materials for SIBs and provides the relevant experimental basis for the further development of energy storage materials.

Refined structured tin dioxide gets the amount of attraction because of its low cost and stability. The C@SnO2 nanospheres with mesoporous structures were produced using the hard template method in this work. The C@SnO2 is primarily gained attributed to the dehydration condensation of C6H12O6 and the hydrolysis of SnCl4 ·5H2O. The morphology of the C@SnO2 was analyzed by physical characterization and the diameter of the obtained C@SnO2 was around 138 nm. When C@SnO2 was applied to lithium-ion batteries as anode material, it performed outstanding electrochemical properties, with a capacity of 735 and 539 mA h g− 1 maintained at 1000 and 2000 mA g− 1, respectively. Furthermore, it exhibits favorable discharge/ charge cycle stability. This is probably because of the more chemically redox active sites provided by C@SnO2 nanocomposites and it also allows fast ion diffusion and electron migration.

Owing to the great demand for portable and wearable chemical sensors, the development of all-solid-state potentiometric ion sensors is highly desirable considering their simplicity and stability. However, most ion sensors are challenged by the penetration of water and gas molecules into ion-selective membranes, causing unstable and undesirable sensing performances. In this study, a hydrophobic ionic liquid-modified graphene (Gr) sheet was prepared using a fluid dynamics-induced exfoliation and functionalization process. The high hydrophobicity and electrical double-layer capacitance of Gr make it a potential solid-state ion-to-electron transducer for the development of potentiometric sodium-ion ( Na+) sensors. The as-prepared Na+ sensors effectively prevented the formation of the water layer and penetration of gas species, resulting in stable and high sensing performances. The Na+ sensors showed a Nernstian sensitivity of 58.11 mV/[Na+] with a low relative standard deviation (0.46), fast response time (5.1 s), good selectivity (K < 10− 4), and good durability. Furthermore, the Na+ sensor demonstrated its feasibility in practical applications by measuring accurate and reliable ion concentrations of artificial human sweat and tear samples, comparable to a commercial ion meter.

The flaw of low dispersibility in the metal matrix brought on by graphene's full crystal structure can be improved by the application of ion beam radiation to the surface of the material. Copper atoms are uniformly dispersed on the modified graphene oxide ( GOM) surface after being irradiated to a copper ion beam, and during the sputtering modification, the valence state of copper is changed, resulting in the formation of a new CuO phase on the graphene oxide (GO) surface. Therefore, after copper ion beam irradiation of graphene, the interfacial adhesion between GOM and copper matrix is enhanced, and the wear resistance is significantly improved. When the GOM content is low, it can withstand most of the load during the friction and wear test, which reduces the wear of the copper matrix and the occurrence of fatigue cracks at the interface of the composite material.

Transition metal chalcogenides are promising cathode materials for next-generation battery systems, particularly sodium-ion batteries. Ni3Co6S8-pitch-derived carbon composite microspheres with a yolk-shell structure (Ni3Co6S8@C-YS) were synthesized through a three-step process: spray pyrolysis, pitch coating, and post-heat treatment process. Ni3Co6S8@C-YS exhibited an impressive reversible capacity of 525.2 mA h g-1 at a current density of 0.5 A g-1 over 50 cycles when employed as an anode material for sodium-ion batteries. However, Ni3Co6S8 yolk shell nanopowder (Ni3Co6S8-YS) without pitch-derived carbon demonstrated a continuous decrease in capacity during charging and discharging. The superior sodium-ion storage properties of Ni3Co6S8@C-YS were attributed to the pitchderived carbon, which effectively adjusted the size and distribution of nanocrystals. The carbon-coated yolk-shell microspheres proposed here hold potential for various metal chalcogenide compounds and can be applied to various fields, including the energy storage field.

아미노글리코사이드계 항생제(Aminoglycosides, AGs) 는 그람음성균과 양성균에 광범위하게 작용하는 동물용 의약품으로, 최근 배양육에 사용된다고 알려져 있어, 안 전성 관리를 위한 분석법 마련이 반드시 필요하다. AGs 는 고극성 화합물로 성분 간의 분리를 위해 이온쌍 시 약(ion-pairing reagent, IPR)을 사용하고 있으나 IPR을 이동상에 첨가하는 기존 분석방법의 경우 용매가 흐르 는 동안 질량분석기로 주입되는 IPR로 인해 기기적인 문 제가 발생할 가능성이 높아, IPR를 바이알에 직접 첨가 하는 분석방법을 검토하였다. 본 연구에서 10종 AGs 성 분에 대한 분석방법을 확인하고 유효성을 검증하였다. 검출한계와 정량한계는 각각 0.0001-0.0038 mg/kg 와 0.004-0.011 mg/kg의 범위로 나타났으며, 0.01-0.5 mg/ kg 범위 내의 직선성(R2)은 0.99 이상이었다. AGs의 시 료 회수율을 확인하고자 소고기와 세포배양배지(cell culture medium) 매질에서 회수율과 상대표준편차로 나 타낸 정밀도를 확인한 결과 각각 70.7-120.6% 및 0.2 to 24.7%로 나타났다. 기존의 이동상에 IP 첨가 방법과 비 교하였을 때 유사한 수준으로 양호하였다. 검증된 AGs 분석법은 국내 유통되는 닭고기, 소고기, 돼지고기 15품 목과 배양육 배지 첨가제 6품목에 적용해보았다. 그 결 과 국내 유통되는 육류 15품목 모두 AGs 성분이 검출 되지 않았으나, 세포배양배지에서 streptomycin은 695.85- 1152.71 mg/kg, dehydrostreptomyci은 6.35-11.11 mg/kg 로 검출되었다. 따라서 IRR을 바이알에 직접 첨가하는 LC-MS/MS 방식은 육류, 세포배양배지, 배지첨가제 중 AGs 분석 및 안전성 평가를 위한 기초자료로 활용될 것 으로 기대된다.

막 축전식 탈염 공정(membrane capacitive deionization, MCDI)은 이온교환막을 다공성 전극과 함께 사용하여 탈 염 효율을 향상시킬 수 있는 CDI 공정의 변형이다. 이온교환막은 MCDI의 성능에 큰 영향을 미치는 핵심 구성요소이다. 본 연구에서는 MCDI의 탈염 효율을 크게 향상시킬 수 있는 이온교환막의 최적 제조 인자를 도출하고자 하였다. 이를 위해 PE 다공성 필름의 세공에 단량체를 충진하고 in-situ 광중합을 진행하여 세공충진 이온교환막(pore-filled ion-exchange membranes, PFIEMs)을 제조하였다. 실험 결과, 제조된 PFIEMs은 다양한 탈염 및 에너지 변환 공정에 적용할 수 있는 수준의 우 수한 전기화학적 특성을 나타내었다. 또한, MCDI 성능과 막 특성 인자와의 상관성 분석을 통해 막의 가교도를 제어하여 막 의 전기적 저항이 충분히 낮은 범위에서 이온 선택 투과성을 최대화하는 것이 MCDI의 성능 향상을 위해 가장 바람직한 막 제조 조건이라는 결론을 얻었다.

최근 우리는 Hg2+에 대한 높은 선택성을 가지며 Hg2+와 결합하여 밝은 녹색 형광을 보이는 tetraphenylethylene-bis(thiophen-2-ylmethyl)amine (TPE-BTA)의 착화합물(TPE-BTA-2Hg2+)의 구조를 밝혀내기 위해 시 간 의존적(time-dependent, TD) 밀도 함수 이론(DFT)을 이용하였다. 그러나 우리는 이 과정 속에서 Hg2+ 이온에 대한 모든 전자(all electron, AE) basis set인 x2c-TZVPPall만이 실험 스펙트럼에 가까운 흡수 및 형광 스펙트럼을 성공적으 로 재현한다는 것을 발견했다. 많이 알려져 있는 effective core potential (ECP) 기반인 LANL2DZ는 형광스펙트럼 계산 과 관련된 들뜬 상태의 구조 최적화 계산을 모두 실패했으며 또한, LANL2DZ는 첫 번째 들뜬 상태의 최적화 과정에서 너무 작은 형광 에너지를 제공했다. 이때 LANL2DZ는 리간드와 Hg2+ 사이의 거리가 증가함에 따라 빠르게 감소하는 HOMO-LUMO gap을 제공하는 반면, x2c-TZVPPall은 점진적으로 감소하는 안정적인 HOMO-LUMO gap을 보여줬다. 우리는 적어도 Hg2+ 이온을 포함하는 착화합물 시스템에서 ECP에서 발생하는 기하학적 문제들을 피하기 위해서는 모 든 전자 기본 세트를 사용하거나 새로운 ECP를 만들어야 된다고 조심스럽게 제안한다.

Small-film-type ion sensors are garnering considerable interest in the fields of wearable healthcare and home-based monitoring systems. The performance of these sensors primarily relies on electrode capacitance, often employing nanocomposite materials composed of nano- and sub-micrometer particles. Traditional techniques for enhancing capacitance involve the creation of nanoparticles on film electrodes, which require cost-intensive and complex chemical synthesis processes, followed by additional coating optimization. In this study, we introduce a simple one-step electrochemical method for fabricating gold nanoparticles on a carbon nanotube (Au NP–CNT) electrode surface through cyclic voltammetry deposition. Furthermore, we assess the improvement in capacitance by distinguishing between the electrical double-layer capacitance and diffusion-controlled capacitance, thereby clarifying the principles underpinning the material design. The Au NP–CNT electrode maintains its stability and sensitivity for up to 50 d, signifying its potential for advanced ion sensing. Additionally, integration with a mobile wireless data system highlights the versatility of the sensor for health applications.

In this study, we investigate the opportunity of using waste tire char as a cathode material for lithium-ion primary batteries (LPBs). The char obtained by carbonizing waste tires was washed with acid and thermally fluorinated to produce CFX. The structural and chemical properties of the char and CFX were analyzed to evaluate the effect of thermal fluorination. The carbon structure of the char was increasingly converted to CFX structure as the fluorination temperature increased. In addition, the manufactured CFX- based LPBs were evaluated through electrochemical analysis. The discharge capacity of the CFX reached a maximum of 800 mAh/g, which is comparable to that of CFX- based LPBs manufactured from other carbon sources. On the basis of these results, the use of waste tire char-based CFX as a cathode material for LPBs is presented as a new opportunity in the field of waste tire recycling.

본 연구에서는 현탁중합을 통해 이온교환입자를 합성하였다. 또한 음이온 교환막을 제조하기 위해 brominated poly(phenylene oxide) (Br-PPO)로 교환막 합성을 진행하였으며, 합성한 이온교환입자를 Br-PPO에 첨가하여 음이온 교환막 에 성능을 향상시키고자 하였고, 이를 적용하여 음이온 교환막 연료전지 시스템의 성능 평가를 진행했다. 이온교환입자는 FT-IR, TGA 및 UTM을 통해 구조 분석, 열적 기계적 특성을 평가하였다. Br-PPO는 NMR을 통해 화학적 구조 분석 및 합성 여부를 확인하였고, 음이온 교환막 연료 전지 셀 테스트를 진행하기 전 이온전도도와 이온교환용량, 팽윤도 및 수분함수율을 측정해 연구되고 있는 다른 음이온 교환막들과 비교를 통해 성능을 평가했다. 최종적으로 가장 성능이 우수했던 이온교환입 자를 0.7 wt%를 첨가한 Br-PPO-TMA- SDV 음이온 교환막을 연료전지 시스템에 도입하여 상용 막인 FAA-3-50과 성능을 비 교했다.

전고체 전지는 전기 자동차의 안정성을 향상시키기 위해 기존의 리튬 이온 전지를 대체할 주요 후보로 간주되고 있 습니다. 그러나 전고체 전지에 사용되는 황화물계 고체 전해질은 산화 환원 안정성이 부족하며 양극복합전극과 표면 에서 부반응을 이르켜 문제를 야기시킵니다. 때문에 양극 표면 코팅법이 제안되었고 이는 충방전 사이클 안정성 및 속도 특성의 개선에 유용한 효과를 나타낼 수 있습니다. 본 논문에서는 결정학적 분석을 통하여 신규 Li-Zr-O 조성 탐색을 하였고, 다양한 양극 소재 코팅소재 후보군 중 리튬 이온 전도체인 Li6Zr2O7 구조가 매우 유망하다는 연구 결 과를 확인했습니다. 본 논문은 기존에 사용되는 LiNbO3, Li4Ti5O12가 아닌 새로운 다양한 구조 및 조성의 양극 코팅 소 재개발에 대한 필요성 및 가능성을 시사합니다.