Technetium has been identified as an element of interest for the safety assessment of a deep geological repository for used nuclear fuel. In this study, the sorption of Tc(IV) onto MX-80 bentonite, illite, and shale in ionic strength (I) 0.1–6 mol·kgw−1 (m) Na-Ca-Cl solutions at pHm = 4–9 and limestone at pHm = 5–9 was studied. Tc(IV) sorption on MX-80 increased with pHm from 4 to 6, reached the maximum at pHm = 6–7, and then gradually decreased with pHm from 7 to 9. Tc(IV) sorption on illite gradually increased with pHm from 4 to 7, and then decreased as pHm increased. The sorption properties of Tc(IV) on shale were quite similar to those on illite. Tc(IV) sorption on limestone slightly increased with pHm from 5 to 6 and then seemed to be constant at pHm = 6–9. Tc(IV) sorption on all four solids was independent of ionic strength (0.1–6 m). The 2 site protolysis non-electrostatic surface complexation and cation exchange model successfully simulated the sorption of Tc(IV) onto MX-80 and illite and the optimized values of surface complexation constants were estimated.
Technetium-99 is identified as an element of interest for the safety assessment of a deep geological repository for used nuclear fuel. The sorption behavior of Tc(IV) onto MX-80 and granite in Ca-Na-Cl solutions of varying ionic strength (0.05–1 mol·kgw−1 (m)) and across a pHm range of 4–9 was studied in this paper. Sorption of Tc(IV) was found to be independent of ionic strength in the range of 0.05 to 1 m for both MX-80 and granite. Sorption of Tc(IV) on MX-80 increased with pHm from 4 to 7 and then decreased with pHm from 8 to 9. Sorption of Tc(IV) on granite gradually increased with pHm from 4 to 8 and then became almost constant or slightly decreased with pHm from 8 to 9. A 2 site protolysis non-electrostatic surface complexation and cation exchange sorption model successfully simulated sorption of Tc(IV) on MX-80 and granite. Optimized values of surface complexation constants (log K0) are proposed.
Activated carbon (AC) is a versatile and extensively employed adsorbent in environmental remediation. It possesses distinct properties that can be enhanced to selectively target specific pollutants through modifications, including chemical impregnation or incorporation into composite materials. In this study, porous calcium alginate beads (PCAB) were synthesized by incorporating AC and natural alginate through ion gelation in a Ca(II) ion-containing solution, with the addition of sodium lauryl sulfate as a surfactant. The prepared PCAB was tested for Cu(II) removal. PCAB exhibited a spherical shape with higher porosity and surface area (160.19 m2. g−1) compared to calcium alginate beads (CAB) (0.04 m2. g−1). The adsorption kinetics followed the pseudo-first-order model for PCAB and the pseudo-second-order model for CAB. The Langmuir isotherm model provided the best fit for adsorption on PCAB, while the Freundlich model was suitable for CAB. Notably, PCAB demonstrated a maximum adsorption capacity of 75.54 mg.g−1, significantly higher than CAB's capacity of 9.16 mg. g−1. Desorption studies demonstrated that 0.1 M CaCl2 exhibited the highest efficiency (90%) in desorbing Cu(II) ions from PCAB, followed by 0.1 M HCl and 0.1 M NaCl. PCAB showed efficient reusability for up to four consecutive adsorption– desorption cycles. The fixed-bed column experiment confirmed the match with the Thomas model to the breakthrough curves with qTH of 120.12 mg.g−1 and 68.03 mg.g−1 at a flow rate of 1 mL.min−1 and 2 mL.min−1, respectively. This study indicated that PCAB could be an effective adsorbent for Cu(II) removal, offering insights for further application and design considerations.
이 연구의 목적은 기금조성용 옥외광고 산업의 현재를 분석하고, 산업 의 발전을 저해하는 요인으로 평가받는 불법 도로변 야립광고에 대한 해 법을 제시하고자 하는 것이다. 이를 위하여 전문가를 대상으로 하는 심 층 인터뷰를 실시하여 그 내용을 분석하였다. 이를 통해 본 연구는 기금 조성용 옥외광고가 옥외광고 산업의 발전에 중요할 역할을 했음을 확인 하였으나, 시스템과 비즈니스 차원에서 해결해야 할 여러 문제점이 있음 을 발견하였다. 또 불법 도로변 야립광고의 난립을 방지하기 위해 법적, 기술적, 경제적, 사회적 해법에 대한 전문가들의 다양한 의견을 수집함으 로써 관련 산업 정책에 대한 의미있는 기초자료를 제공한다는데 의의가 있다.
많은 경우 연근해 어업에 종사하는 어선들은 출항, 조업지로의 항해, 조업, 조업지의 이동을 위한 항해, 조업, 귀항지로의 항해 로 이어지는 일정으로 운항하고 있다. 이로 인하여 대부분 1인 당직체계로 운영되는 어선의 선장은 휴식할 수 있는 시간이 거의 없어 졸 음운항으로 인한 사고가 빈번하게 발생하고 있다. 또한 피로에 지친 선장이 항해당직에 대한 기본적인 지식조차도 없는 무자격 부원에게 당직을 맡기고 침실에서 잠을 자다 발생하는 사고도 빈번하게 발생하고 있다. 이러한 문제점은 이미 오래전부터 논의되어 왔으나 현실적 으로 마땅한 대책이 없어 아직까지 해결되지 못하고 있다. 이러한 시고의 저감대책으로 이 글에서는 어선 당직부원 자격증 제도를 제안 하고자 한다.
This paper evaluates the adsorptive removal of sunset yellow (SY) from aqueous solutions using a new magnetic glycodendrimer (MGD). To synthesize the MGD, chitosan dendrons were cultivated on amine-functionalized magnetic graphene oxide. A number of analytical methods were employed to physicochemically characterize the synthesized MGD. Batch adsorption conditions were optimized using the Box–Behnken design. An optimized initial SY content of 633 mg/L, an optimized contact time of 33.37 min, and an optimized pH of 3.72 maximized the MGD adsorption capacity to 485 mg/g. The Langmuir isotherm was employed to describe adsorption equilibrium, while adsorption kinetics was studied via the Lagergren kinetics model. The SY adsorption onto the MGD was thermodynamically found to be spontaneous (ΔG° < 0) and exothermic (ΔH° = – 19.120 kJ/mol), leading to a decreased disorder (ΔS° = – 54.420 kJ/mol) in the solid–liquid interface. The MGD showed reusability and unique magnetic characteristics. It was concluded that the MGD could be a potential alternative for the adsorptive and magnetic removal of SY from an aqueous solution.
The rapid spread of Artificial Intelligence through various connected intelligent objects (wearables, robots) profoundly changes how service is delivered and experienced by the customers (Bolton et al., 2018; Larivière et al., 2017). Robotics, in combination with rapidly improving technologies, has brought prospects for a wide array of innovations that have the potential to transform service industries radically. Service robots provide businesses with new opportunities to reorganize their frontline and serve their customers in new and innovative ways. Advanced technological innovations that become better, smaller, and smarter are virtually renovating the servicescape (Wirtz & Zeithaml, 2018). Transformation in the Healthcare industry is happening the world over. The International Federation of Robots predicts an ever-increasing demand for healthcare robots, estimated at 9.1 billion USD market in coming year. RoboDocs (Robots helping Doctors) can help standardize the common surgical procedures and catalyze a paradigm shift in the healthcare sector. RoboDocs are the linchpin to greater efficiency, more value, and reducing surgical variability (Muaddi et al., 2021, Huang & Rust, 2018).
본 연구는 탄소 흐름 관점에서 기존 농촌경관 시스템 구조를 분석하고 이를 토대로 탄소중립 농촌경 관으로 전환하기 위한 자연기반해법을 제시하였다. 농촌경관 시스템은 생산경관, 자연경관, 생활경 관 하위 시스템으로 구성되어 있었으며, 각 하위 시스템을 인과지도 작성하고 이를 통합하였다. 통합 인과지도를 분석한 결과, 토지 이용 및 인간 활동 관리와 피드백 루프의 재구축을 위한 자연기반해법 전략이 필요하다는 것을 확인하였다. 이를 기반으로 본 연구는 ‘토양유기탄소 보존을 위한 탄소 농 업’, ‘탄소 흡수원 경관 관리’, ‘기후스마트 농업’, 그리고 ‘신재생에너지 기반 순환 농업’을 제안하였 다. 본 연구 결과는 기존 생산과정 중심의 농촌지역의 탄소중립 정책에서 벗어나 농촌경관 시스템의 전반적인 탄소 흐름을 확인하여 자연기반해법을 제시하였다는 데에 의의가 있다.
A large amount of radioactive wastes are generated during the decommissioning of the nuclear power plant. The need for radioactive waste management is emerging as the permanent suspension of domestic nuclear power plants Gori Unit 1 and Wolseong Unit 1 has been decided. According to the analysis of the number of land transportation of Gori Unit 1, when the dismantling period is expected to be five years, the number of land transportation is 459. Accordingly, measures are needed to improve the acceptability of residents on land transportation routes. Currently, there is little preparation for the acceptance of residents by transporting radioactive waste in Korea. This study analyzed the literature related to radioactive waste and nuclear power generation to derive factors that affect the acceptance of residents on the transport route of radioactive waste. Factors Affecting Resident Acceptability • Mistrust of the measured dose levels themselves • fear of radiation • Lack of training in radiation, nuclear power • Insufficient information for easy identification of dose and concentration • economic compensation In order to improve the acceptability of residents when transporting radioactive waste on land, it is necessary to scientifically prove the safety of the low and intermediate level radioactive waste transport path, and policy improvement considering the acceptability of residents is needed. In subsequent studies, it is necessary to specifically derive solutions to the above factors. This study is significant in that it derived factors that could affect low and intermediate level radioactive waste transportation, considering that no countermeasures have been prepared to improve the acceptance of residents by transporting low and intermediate level radioactive waste in Korea.
90Sr is considered a hazardous radionuclide due to its long half-life of 28.8 years, radiotoxicity, and potential to bioaccumulate in various organisms. In the environment, strontium typically exists as divalent cation Sr2+ or in different complexes, depending on the environmental physical and chemical factors. Despite its mobility, Sr2+ transport remains affected by adsorption from solid phases, such as soil and sediments. This research aimed to investigate the efficiency of a magnetic flocculant (MNP/IF) in separating suspended soil and Sr2+ from a soil suspension. MNP/IF was prepared via the electrostatic interaction between magnetite particles and an inorganic flocculant (IF) composed of CaCO3 and Na2SO4. Analysis of the physical properties of MNP/IF confirmed that MNP/IF was successfully imparted with magnetism and had excellent adsorption capacity for Sr2+. The optimal MNP/IF dosage for the sedimentation of suspended soil was determined to be 0.3 g/g (mass ratio of flocculant to soil). The lower the pH, the more favorable the flocculation-sedimentation process of the suspended soil by MNP/IF, since Ca2+ and Mg2+, which are the most common strong flocculators, were further eluted from IF under acidic conditions. Besides, MNP/IF exhibited outstanding removal performance for Sr2+, with maximum adsorption capacities of 163.6 mg/g observed during the flocculation-sedimentation reaction of suspended soil. The adsorption of Sr2+ exhibited consistency with the Langmuir model and followed pseudo-second-order kinetics. These findings suggest that MNP/IF can be used for the simultaneous removal of suspended soil particles and Sr2+ from a radioactive soil suspension.
Bentonite is a potential buffer material of multi-barrier systems in high-level radioactive wastes repository. Montmorillonite, the main constituent of the bentonite, is 2:1 type aluminosilicate clay mineral with high swelling capacity and low permeability. Montmorillonite alteration under alkaline and saline conditions may affect the physico-chemical properties of the bentonite buffer. In this study, montmorillonite alteration by interaction with synthetic alkaline and saline solution and its retention capacity for cesium and iodide were investigated. The experiments were performed in three different batches (Milli-Q water, alkaline water, and saline water) doped with cesium and iodide for 7 days. Alteration characteristics and nuclide retention capacity of original- and reacted bentonite was analyzed by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), Nuclear Magnetic Resonance (NMR) and Cation Exchange Capacity (CEC) analysis. From the results, cesium retention occurred differently depending on the presence of competing ions such as K, Na, and Mg ions in synthetic solutions, while iodide was negligibly removed by bentonite. Montmorillonite alteration mainly occurred as cation exchange and zeolite minerals such as merlinoite and mordenite were new-formed during alkaline alteration of the montmorillonite. CEC value of reacted bentonite increased by formation of the zeolite minerals under alkaline conditions.
일본 정부는 2021년 4월 13일 일방적으로 후쿠시마 원전 오염수를 해양에 방 류하기로 결정했다. 일본의 원전 오염수 해양 방류는 후쿠시마 주변 해역 및 연안의 해양환경에 미치는 방사능 오염뿐만 아니라 우리나라 연안과 태평양 전 역으로 방사능이 유입되어 피해가 발생할 수 있으며, 해양 생태계 변화 등의 심각한 문제도 발생할 것이다. 일본의 원전 오염수 방류 결정에 대한 다양한 대응 방안이 검토되고 있으며, 유엔해양법협약을 중심으로 국제해양법재판소 제소 및 심각한 피해의 가능성과 상황의 긴급성이 있는 경우 잠정조치 신청도 할 수 있다. 이 논문에서는 일본의 원전 오염수 방류 결정에 대한 문제점을 살펴보고, 해 양환경 오염으로 인한 국제환경분쟁의 의의와 주요 특성에 관한 내용을 검토하 고, 소송에 대비하여 유엔해양법협약 관련 규정 및 판례들을 검토하여 시사점 을 도출하였다. 일본의 후쿠시마 원전 오염수 방류가 임박한 시점에서 문제 해 결을 위하여 최우선으로 유엔해양법협약을 근거하여 ITLOS 제소 및 잠정조치 신청을 하는 사법적 해결방안을 모색하고 동시에 한일 양국 간 또는 국제사회 의 공동 협력체계를 통한 외교적(비사법적) 해결방안 등 실효적인 해결방안을 제시하고자 한다.
본 연구는 관상가치가 있는 자생 참두메부추와 갯부추를 절화소재로 이용하고자 수행되었다. 실험은 절화가 수확된 직후, gibberellic acid(GA3) 50, 75, 100mg·L-1, silver thiosulfate(STS) 0.1, 0.3, 0.5mM, 8-hydroxyquinoline sulfate(8-HQS) 25, 50, 100mg·L-1, 그리고 시중에 판매되 고 있는 Chrysal 8mL·L-1, Floralife 10mL·L-1의 보존용액 에 처리되었다. 참두메부추의 절화수명 연장에는 Chrysal 보 존용액 처리가 가장 효과적이었으며 다음으로 75mg·L-1 GA3 처리가 효과적이었다. 한편 8-HQS와 STS는 참두메부추의 절화수명을 단축하고 줄기가 갈변하는 등의 부정적인 영향을 끼쳤다. Chrysal과 더불어 Floralife 보존용액 처리는 절화 참두메부추의 상대 생체중변화율을 높이는데 효과가 있었다. 반면 갯부추는 100mg·L-1 GA3 처리에서 절화수명이 유일하 게 7일까지 연장되었다. GA3 보존용액 처리를 제외한 다른 처리에서 갯부추의 절화수명은 증류수인 대조구보다 비슷하 거나 약간 높은 수준이었다. 절화 갯부추의 수분흡수율은 실 험 초반 100mg·L-1 8-HQS 처리에서, 상대 생체중변화율은 Chrysal 보존용액 처리에서 가장 높게 조사되었으나 두 처 리 모두 절화수명이 유의하게 연장되지 않았다. 갯부추는 100mg·L-1 GA3 처리에서 절화수명을 비롯한 절화품질이 가 장 우수하였다.
Neptunium (Np) is one of the daughter elements included in the decay chain of Pu. The quantitative analysis of Np isotopes is required for radioactive waste characterization, research on actinide chemistry, etc. Np-237 has a long half-life (2.144 million years), but its daughter Pa-233 has a relatively short half-life (26.975 days). For this reason, after a sufficient time elapses following the chemical preparation process of the analyte, the two nuclides are in radiation equilibrium in the sample. Np-237 emits alpha-rays while Pa-233 emits beta-rays. Both nuclides also emit gamma- and X-rays. In this study, alpha-rays were measured using liquid scintillation counting (LSC) method and alpha spectrometry. Gamma-spectrometry with a HPGe detector was used for the analysis of gammaand X-rays. In addition, we compared the radiometric results with quantitative analysis of Np using UV-Vis absorption spectrometry. The LSC method and the HPGe gamma-spectroscopy do not require extensive sample preparation procedures. Alpha spectroscopy requires a standard material spiking, separation by coprecipitation, and disk-type sample preparation procedure to obtain measurement efficiency and recovery factor. A reference material sample with a concentration of 5.8 mM was analyzed by the four analysis methods, and all of the measured results agreed well within a difference level of 4%.