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Prof. Changhyun Roh
Korea Atomic Energy Research Institue

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Radiation
Nanomaterials
Nuclear Energy
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Catalysis
Nanotechnology
Chemosensors
Radioactive isotopes
decommissioning and decontamination science and technology

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Journal article
Published: 25 August 2021 in Chemosensors
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Plastic scintillators are widely used in various radiation measurement applications, and the use of plastic scintillators for nuclear applications including decommissioning, such as gamma-ray detection and measurement, is an important concern. With regard to efficient and effective gamma-ray detection, the optimization for thickness of plastic scintillator is strongly needed. Here, we elucidate optimization of the thickness of high-performance plastic scintillator using high atomic number material. Moreover, the EJ-200 of commercial plastic scintillators with the same thickness was compared. Two computational simulation codes (MCNP, GEANT4) were used for thickness optimization and were compared with experimental results to verify data obtained by computational simulation. From the obtained results, it was confirmed that the difference in total counts was less than 10% in the thickness of the scintillator of 50 mm or more, which means optimized thickness for high efficiency gamma-ray detection such as radioactive 137Cs and 60CO. Finally, simulated results, along with experimental data, were discussed in this study. The results of this study can be used as basic data for optimizing the thickness of plastic scintillators using high atomic number elements for radiation detection and monitoring.

ACS Style

Sujung Min; Youngsu Kim; Kwang-Hoon Ko; Bumkyung Seo; Jaehak Cheong; Changhyun Roh; Sangbum Hong. Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study. Chemosensors 2021, 9, 239 .

AMA Style

Sujung Min, Youngsu Kim, Kwang-Hoon Ko, Bumkyung Seo, Jaehak Cheong, Changhyun Roh, Sangbum Hong. Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study. Chemosensors. 2021; 9 (9):239.

Chicago/Turabian Style

Sujung Min; Youngsu Kim; Kwang-Hoon Ko; Bumkyung Seo; Jaehak Cheong; Changhyun Roh; Sangbum Hong. 2021. "Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study." Chemosensors 9, no. 9: 239.

Review
Published: 11 June 2021 in Sensors
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Herein, we review studies of the integration of Phoswich detectors with readout integrated circuits and the associated performance in a radiological sensing application. The basic concept and knowledge of interactions with scintillation materials and the mechanisms and characteristics of radiological detection are extensively discussed. Additionally, we summarize integrated multiple detection systems and Phoswich detectors in radiological measurements for their device performance. Moreover, we further exhibit recent progress and perspective in the future of Phoswich-based radiological detection and measurement. Finally, we provide perspectives to evaluate the detector performance for radiological detection and measurement. We expect this review can pave the way to understanding the recent status and future challenges for Phoswich detectors for radiological detection and measurement.

ACS Style

Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. Phoswich Detectors in Sensing Applications. Sensors 2021, 21, 4047 .

AMA Style

Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jaehak Cheong. Phoswich Detectors in Sensing Applications. Sensors. 2021; 21 (12):4047.

Chicago/Turabian Style

Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. 2021. "Phoswich Detectors in Sensing Applications." Sensors 21, no. 12: 4047.

Journal article
Published: 05 June 2021 in Journal of Hazardous Materials
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In this work, we prepared two-dimensional (2D) stack-structured aminopropylIsobutyl polyhedral oligomeric silsesquioxane (POSS-NH2) intercalated titanium carbide (Ti3C2Tx) MXene material (Ti3C2Tx/POSS-NH2) using a post-intercalation strategy as a potential adsorbent for the removal of cesium (Cs+) and strontium (Sr2+) ions from aqueous solutions. Ti3C2Tx/POSS-NH2 exhibited unprecedented adsorption capacities of 148 and 172 mg g-1 for Cs+ and Sr2+ ions, respectively. Batch adsorption experimental data well fitted the Freundlich isotherm model, which revealed multilayer adsorption of Cs+ and Sr2+ ions onto heterogeneous –OH, –F, –O, and –NH2 adsorption sites of Ti3C2Tx/POSS-NH2 with different energies. Ti3C2Tx/POSS-NH2 exhibited rapid Cs+/Sr2+ ions adsorption kinetics and attained equilibrium within 30 min. Also, Ti3C2Tx/POSS-NH2 exhibited recyclable capability over three cycles and remarkable selectivities of 89% and 93% for Cs+ and Sr2+ ions, respectively, in the presence of co-existing mono-and divalent cations. We suggest the high adsorption capacity of Ti3C2Tx/POSS-NH2 might be due to the synergistic effects of (i) increased inter-lamellar distance between Ti3C2Tx galleries due to POSS-NH2 intercalation, enabling diffusion and encapsulation of large numbers of Cs+/Sr2+ ions, (ii) strong complexation of amine (–NH2) groups of POSS-NH2 with Cs+/Sr2+ ions, and (iii) the presence of large numbers of heterogeneous surface functional groups (e.g., –OH, –F, and –O), which resulted in the adsorptions of Cs+/Sr2+ ions through electrostatic, ion exchange, and surface complexation mechanisms. Given the extraordinary adsorption capacities observed, intercalation appears to be a promising strategy for the effective removal of radioactive Cs+ and Sr2+ ions from aqueous media.

ACS Style

Muruganantham Rethinasabapathy; Seung Kyu Hwang; Sung-Min Kang; Changhyun Roh; Yun Suk Huh. Amino-functionalized POSS nanocage-intercalated titanium carbide (Ti3C2Tx) MXene stacks for efficient cesium and strontium radionuclide sequestration. Journal of Hazardous Materials 2021, 418, 126315 .

AMA Style

Muruganantham Rethinasabapathy, Seung Kyu Hwang, Sung-Min Kang, Changhyun Roh, Yun Suk Huh. Amino-functionalized POSS nanocage-intercalated titanium carbide (Ti3C2Tx) MXene stacks for efficient cesium and strontium radionuclide sequestration. Journal of Hazardous Materials. 2021; 418 ():126315.

Chicago/Turabian Style

Muruganantham Rethinasabapathy; Seung Kyu Hwang; Sung-Min Kang; Changhyun Roh; Yun Suk Huh. 2021. "Amino-functionalized POSS nanocage-intercalated titanium carbide (Ti3C2Tx) MXene stacks for efficient cesium and strontium radionuclide sequestration." Journal of Hazardous Materials 418, no. : 126315.

Journal article
Published: 04 June 2021 in Applied Sciences
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The highly reliable and direct detection of radioactive cesium has gained potential interest due to in-situ detection and monitoring in environments. In this study, we elucidated an integrated and portable probe based on functional plastic scintillator for detection of radioactive cesium. A functional plastic scintillator with improved detection efficiency was fabricated including CdTe (cadmium telluride) material. Monolith-typed functional plastic scintillator having a diameter of 50 mm and a thickness of 30 mm was manufactured by adding 2,5-diphenyloxazole (PPO, 0.4 wt%), 1,4 di[2-(5phenyloxazolyl)]benzene (POPOP, 0.01 wt%), and CdTe (0.2 wt%) materials in a styrene-based matrix. To evaluate the applicability of the plastic scintillator manufactured to in-situ radiological measurement, an integrated plastic detection system was created, and the measurement experiment was performed using the Cs-137 radiation source. Additionally, detection efficiency was compared with a commercial plastic scintillator. As results, the efficiency and light yield of a functional plastic scintillator including CdTe were higher than a commercial plastic scintillator. Furthermore, the remarkable performance of the functional plastic scintillator was confirmed through comparative analysis with Monte Carlo simulation.

ACS Style

Sujung Min; Hara Kang; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium. Applied Sciences 2021, 11, 5210 .

AMA Style

Sujung Min, Hara Kang, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jaehak Cheong. Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium. Applied Sciences. 2021; 11 (11):5210.

Chicago/Turabian Style

Sujung Min; Hara Kang; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. 2021. "Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium." Applied Sciences 11, no. 11: 5210.

Journal article
Published: 08 March 2021 in Chemosensors
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Functional plastic scintillators have attracted much attention for their usefulness in on-site monitoring and detection in environments. In this study, we elucidated a highly reliable and functional plastic scintillator for detection of radioactive strontium, which means a potent perovskite-loaded polymeric scintillation material based on epoxy and 2,5-diphenyloxazole (PPO). Moreover, Monte Carlo N-Particle (MCNP) simulation was performed to optimize the thickness of a plastic scintillator for efficient strontium detection. A thickness of 2 mm was found to be the optimum thickness for strontium beta-ray detection. A newly developed plastic scintillator with 430 nm emission from perovskite loading could trigger scintillation enhancement employing potential indication of perovskite energy transfer into a photomultiplier (PMT) detector. Furthermore, the response to beta-ray emitter of 90Sr was compared to commercial scintillator of BC-400 by exhibiting detection efficiency in the energy spectrum with a fabricated perovskite-loaded plastic scintillator. We believe that this suggested functional plastic scintillator could be employed as a radiation detector for strontium detection in a wide range of applications including decommissioning sites in nuclear facilities, nuclear security and monitoring, nonproliferation, and safeguards.

ACS Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection. Chemosensors 2021, 9, 53 .

AMA Style

Hara Kang, Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jae Cheong. Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection. Chemosensors. 2021; 9 (3):53.

Chicago/Turabian Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. 2021. "Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection." Chemosensors 9, no. 3: 53.

Review
Published: 28 October 2020 in Chemosensors
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The detection and monitoring systems of low energy beta particles are of important concern in nuclear facilities and decommissioning sites. Generally, low-energy beta-rays have been measured in systems such as liquid scintillation counters and gas proportional counters but time is required for pretreatment and sampling, and ultimately it is difficult to obtain a representation of the observables. The risk of external exposure for low energy beta-ray emitting radioisotopes has not been significantly considered due to the low transmittance of the isotopes, whereas radiation protection against internal exposure is necessary because it can cause radiation hazard to into the body through ingestion and inhalation. In this review, research to produce various types of detectors and to measure low-energy beta-rays by using or manufacturing plastic scintillators such as commercial plastic and optic fiber is discussed. Furthermore, the state-of-the-art beta particle detectors using plastic scintillators and other types of beta-ray counters were elucidated with regard to characteristics of low energy beta-ray emitting radioisotopes. Recent rapid advances in organic matter and nanotechnology have brought attention to scintillators combining plastics and nanomaterials for all types of radiation detection. Herein, we provide an in-depth review on low energy beta emitter measurement.

ACS Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. Low Energy Beta Emitter Measurement: A Review. Chemosensors 2020, 8, 106 .

AMA Style

Hara Kang, Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jae Cheong. Low Energy Beta Emitter Measurement: A Review. Chemosensors. 2020; 8 (4):106.

Chicago/Turabian Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. 2020. "Low Energy Beta Emitter Measurement: A Review." Chemosensors 8, no. 4: 106.

Review article
Published: 12 May 2020 in Chemical Engineering Journal
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MXenes have very recently emerged as an intriguing family of graphene-like two-dimensional (2D) layer-structured transition metal carbides and/or nitrides with a high specific surface area, a large interlayer spacing, hydrophilicity, and abundant highly active surface sites, and they have found a niche in environmental remediation, as materials capable of efficiently removing and sequestering heavy metals, dyes, and radioactive nuclides. With exceptional surface tunable chemical compatibility and compositional flexibility, MXenes are resistant to radiation-induced damage and show high chemical compatibility and excellent thermal stability. They are thought to have the potential to serve as ideal adsorbents for a plethora of radionuclides such as uranium (238U), thorium (232Th), cesium (137Cs), and strontium (90Sr) with respect to technology and the economy. In this article, we comprehensively review state-of-the-art research progress on and the promising potential of MXenes as an adsorbent for the removal of radioactive nuclides from the environment. First, we discuss the structure, synthesis, intercalation/delamination and properties of MXenes. Subsequently, we emphasize their radionuclide removal applications. Finally, we present an outlook on the current challenges in the use of MXene materials for the adsorptive remediation of radionuclides and outline future opportunities for these materials. This article presents a timely and systematic review of MXenes as efficient and cost-effective radionuclide adsorbents. Furthermore, it highlights the main challenges in their use for environmental remediation and provides possible research directions.

ACS Style

Seung Kyu Hwang; Sung-Min Kang; Muruganantham Rethinasabapathy; Changhyun Roh; Yun Suk Huh. MXene: An emerging two-dimensional layered material for removal of radioactive pollutants. Chemical Engineering Journal 2020, 397, 125428 .

AMA Style

Seung Kyu Hwang, Sung-Min Kang, Muruganantham Rethinasabapathy, Changhyun Roh, Yun Suk Huh. MXene: An emerging two-dimensional layered material for removal of radioactive pollutants. Chemical Engineering Journal. 2020; 397 ():125428.

Chicago/Turabian Style

Seung Kyu Hwang; Sung-Min Kang; Muruganantham Rethinasabapathy; Changhyun Roh; Yun Suk Huh. 2020. "MXene: An emerging two-dimensional layered material for removal of radioactive pollutants." Chemical Engineering Journal 397, no. : 125428.

Journal article
Published: 18 October 2019 in Energies
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The aim of nuclear facility decommissioning is to make local settlements safe, sustainable and professedly acceptable. The challenges are the clean-up of the nuclear site and waste management. This means a definite promise in terms of safety and security, taking into account social and environmental accountability. There is an essential need to develop safe and efficient methods for nuclear decommissioning. Thus, chemical decontamination technology is of great significance to the decommissioning of nuclear energy facilities. In particular, chemical decontamination technology is applicable to the pipelines and internal loop. The iron-rich oxides, such as Fe3O4 or NiOFe2O3, of a nuclear power plant should have sound decontamination follow-through and should put through a very small amount of secondary waste. It is important to be able to detect and quantify hydrazine in decontamination situations with high sensitivity and selectivity. A colorimetric assay is a technique used to determine the concentration of colored compounds in a solution. However, detecting targeted species rapidly and easily, and with high sensitivity and specificity, is still challenging. Here, the catalytic reaction of oxidants in the p-dimethylaminobenzaldehyde and hydrazine reaction is elucidated. Oxidants can catalyze the reaction of hydrazine and p-dimethylaminobenzaldehyde to form an azine complex such as p-dimethylaminobenzaldazine, with high selectivity and sensitivity within 30 min at ambient temperatures. In the absence of an oxidant such as iron or hydrogen peroxide no detectable colorimetric change was observed by the reaction of p-dimethylaminobenzaldehyde and hydrazine unless an external oxidant was present in the system. In this study, we demonstrated a colorimetric method for the sensitive detection of hydrazine decomposition in the chemical decontamination process. Furthermore, the colorimetric response was easy to monitor with the unaided eye, without any sophisticated instrumentation. This method is thus suitable for on-site detection of contamination in a nuclear facility. In addition, this colorimetric method is convenient, non-invasive, free of complex equipment, and low-cost, making it possible to analyze hydrazine in industrial nuclear facilities. The proposed method was successfully applied to the determination of hydrazine decomposition in the nuclear decontamination process.

ACS Style

Jungsoon Park; Hee-Chul Eun; Seonbyeong Kim; Changhyun Roh; So-Jin Park. Colorimetric Method for Detection of Hydrazine Decomposition in Chemical Decontamination Process. Energies 2019, 12, 3967 .

AMA Style

Jungsoon Park, Hee-Chul Eun, Seonbyeong Kim, Changhyun Roh, So-Jin Park. Colorimetric Method for Detection of Hydrazine Decomposition in Chemical Decontamination Process. Energies. 2019; 12 (20):3967.

Chicago/Turabian Style

Jungsoon Park; Hee-Chul Eun; Seonbyeong Kim; Changhyun Roh; So-Jin Park. 2019. "Colorimetric Method for Detection of Hydrazine Decomposition in Chemical Decontamination Process." Energies 12, no. 20: 3967.

Journal article
Published: 09 October 2019 in Mechanics of Materials
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Using personal protective equipment, such as safety helmets, at industrial sites, is the last method to prevent disasters, and such equipment are widely recognized as consumables. Among them, industrial safety helmets use ABS (acrylonitrile butadiene styrene) or PE (polyethylene) resins as the main material of the shell to absorb shocks, and they also possess a relatively good heat resistance. However, efforts to develop new materials by a simple fabrication method are not actively performed. In this study, to improve the safety performance of industrial helmets, an epoxy resin was used as a matrix to produce a p-aramid/carbon fiber composite as a simple cross-ply, and compared to p-aramid fiber-reinforced composites, carbon fiber-reinforced composites, and ABS plastic. The specimens were prepared by the compression molding method, and their mechanical properties including the impact strength, tensile strength, flexural strength, and inter-laminar shear strength along with heat resistance properties were observed via thermogravimetric analysis.

ACS Style

Sanghyun Kim; Jaewoong Lee; Changhyun Roh; Jonghyun Eun; Chankyu Kang. Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads. Mechanics of Materials 2019, 139, 103203 .

AMA Style

Sanghyun Kim, Jaewoong Lee, Changhyun Roh, Jonghyun Eun, Chankyu Kang. Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads. Mechanics of Materials. 2019; 139 ():103203.

Chicago/Turabian Style

Sanghyun Kim; Jaewoong Lee; Changhyun Roh; Jonghyun Eun; Chankyu Kang. 2019. "Evaluation of carbon fiber and p-aramid composite for industrial helmet using simple cross-ply for protecting human heads." Mechanics of Materials 139, no. : 103203.

Journal article
Published: 06 September 2019 in Sustainability
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Despite recent extensive research and technical development to prevent and mitigate dust explosions, processes that produce and handle combustible materials in the form of powders and dusts, either as a main product or as an undesired by-product, have become a constant dust explosion threat as they become more sophisticated and complicated. This study analyzed the characteristics of 53 dust explosions that occurred in South Korea over the last 30 years, and investigated the differences of dust explosions that happened in various countries, such as Japan, the United States, the United Kingdom, and France. In addition, case studies showed the severity of dust explosions occurring in South Korea. Through the special focus on the three most recent years of dust explosions, the causes and processes of the accidents were identified. Analyses of dust explosions in South Korea show that they were mainly caused by organic matter and metal, and, unfortunately, dust explosions occurred repeatedly during grinding, mixing, and injection of powder materials into facilities. No reported accidents occurred during the production processes of wood or paper during the last three years. Taking these characteristics into account, effective ways to prevent or mitigate dust explosions at workplaces where many dust explosions occurred were suggested.

ACS Style

Seonggyu Pak; Seongho Jung; Changhyun Roh; Chankyu Kang. Case Studies for Dangerous Dust Explosions in South Korea during Recent Years. Sustainability 2019, 11, 4888 .

AMA Style

Seonggyu Pak, Seongho Jung, Changhyun Roh, Chankyu Kang. Case Studies for Dangerous Dust Explosions in South Korea during Recent Years. Sustainability. 2019; 11 (18):4888.

Chicago/Turabian Style

Seonggyu Pak; Seongho Jung; Changhyun Roh; Chankyu Kang. 2019. "Case Studies for Dangerous Dust Explosions in South Korea during Recent Years." Sustainability 11, no. 18: 4888.

Journal article
Published: 01 May 2019 in Royal Society Open Science
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Recently, the impact of radioactive caesium (Cs) and strontium (Sr) on human health and the ecosystem has been a major concern due to the use of nuclear energy. However, this study observed changes in green-fluorescent (GFP)-tagged Pseudomonas aeruginosa PAO1 biofilms by injecting non-radioactive caesium chloride (CsCl) and strontium chloride (SrCl 2 ) into microstructures embedded in polydimethylsiloxane microfluidic devices, which were used due to their strong toxicity limitations. Four types of microstructures with two different diameters were used in the study. The change of biofilm thickness from fluid velocity and wall shear stress was estimated using computational fluid dynamics and observed throughout the experiment. The effect of pore space became a significant physical factor when the fluid was flowing through the microfluidic devices. As the pore space increased, the biofilm growth increased; therefore, triangular microstructures with the largest pore space showed the best growth of biofilm. Caesium chloride (CsCl) and strontium chloride (SrCl 2 ), less toxic than radioactive caesium (Cs) and strontium (Sr), completely eradicated the P. aeruginosa PAO1 biofilm with low concentrations. The combined effect of toxicity, fluid velocity, wall shear stress and microstructures increased the efficiency of biofilm eradication. These findings on microfluidic chips can help to indirectly predict the impact on human public health and ecosystems without using radioactive chemicals.

ACS Style

Changhyun Roh; Thi Toan Nguyen; Jae-Jin Shim; Chankyu Kang. Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform. Royal Society Open Science 2019, 6, 182069 .

AMA Style

Changhyun Roh, Thi Toan Nguyen, Jae-Jin Shim, Chankyu Kang. Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform. Royal Society Open Science. 2019; 6 (5):182069.

Chicago/Turabian Style

Changhyun Roh; Thi Toan Nguyen; Jae-Jin Shim; Chankyu Kang. 2019. "Physico-chemical characterization of caesium and strontium using fluorescent intensity of bacteria in a microfluidic platform." Royal Society Open Science 6, no. 5: 182069.

Short communication
Published: 19 January 2019 in Materials Letters
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In this work, a Prussian blue (PB)/graphene oxide (GO)/chitosan (CS) organic-inorganic composite was successfully synthesized and utilized as an adsorbent for the selective removal of cesium (Cs+) ions. Taking the advantage of synergistic effect GO, CS and PB nanoparticles, the PB/GO/CS composite exhibited maximum adsorption capacity of 48.35 mg g−1 for Cs+ ions. In the presence of competitive monovalent cations (K+ and Na+), PB/GO/CS showed excellent selectivity (86%) for Cs+ ions and had a 6-fold higher distribution coefficient (Kd) than GO/CS. This enhanced adsorption capacity with high selectivity of PB/GO/CS for Cs+ ions may have been attributed to (i) the presence of carboxylic, hydroxyl and amino functional groups on GO/CS matrix which strongly bind Cs+ ions through electrostatic attraction and chelation, and (ii) the trapping of Cs+ ions by the voids of the FCC-structured PB lattice whose size is equivalent to the hydration radius of Cs+ ions. Due to its low-cost, facile preparation, high adsorption capacity, and superior Cs+ ions selectivity, PB/GO/CS is a promising material for the selective removal of the Cs+ ions from the environment and for protecting ecosystems from the radiation hazards.

ACS Style

Muruganantham Rethinasabapathy; Sung-Min Kang; Ilsong Lee; Go-Woon Lee; Sunmook Lee; Changhyun Roh; Yun Suk Huh. Highly stable Prussian blue nanoparticles containing graphene oxide–chitosan matrix for selective radioactive cesium removal. Materials Letters 2019, 241, 194 -197.

AMA Style

Muruganantham Rethinasabapathy, Sung-Min Kang, Ilsong Lee, Go-Woon Lee, Sunmook Lee, Changhyun Roh, Yun Suk Huh. Highly stable Prussian blue nanoparticles containing graphene oxide–chitosan matrix for selective radioactive cesium removal. Materials Letters. 2019; 241 ():194-197.

Chicago/Turabian Style

Muruganantham Rethinasabapathy; Sung-Min Kang; Ilsong Lee; Go-Woon Lee; Sunmook Lee; Changhyun Roh; Yun Suk Huh. 2019. "Highly stable Prussian blue nanoparticles containing graphene oxide–chitosan matrix for selective radioactive cesium removal." Materials Letters 241, no. : 194-197.

Journals
Published: 18 December 2018 in Journal of Materials Chemistry A
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Gamma-ray mediated synthesis of ultra-low dense porous 3D-network structured [email protected]/rGO aerogel with high mechanical stability for the removal of Cs+ ions, methylene blue and n-hexadecane.

ACS Style

Ilsong Lee; Sung-Min Kang; Sung-Chan Jang; Go-Woon Lee; Ha Eun Shim; Muruganantham Rethinasabapathy; Changhyun Roh; Yun Suk Huh. One-pot gamma ray-induced green synthesis of a Prussian blue-laden polyvinylpyrrolidone/reduced graphene oxide aerogel for the removal of hazardous pollutants. Journal of Materials Chemistry A 2018, 7, 1737 -1748.

AMA Style

Ilsong Lee, Sung-Min Kang, Sung-Chan Jang, Go-Woon Lee, Ha Eun Shim, Muruganantham Rethinasabapathy, Changhyun Roh, Yun Suk Huh. One-pot gamma ray-induced green synthesis of a Prussian blue-laden polyvinylpyrrolidone/reduced graphene oxide aerogel for the removal of hazardous pollutants. Journal of Materials Chemistry A. 2018; 7 (4):1737-1748.

Chicago/Turabian Style

Ilsong Lee; Sung-Min Kang; Sung-Chan Jang; Go-Woon Lee; Ha Eun Shim; Muruganantham Rethinasabapathy; Changhyun Roh; Yun Suk Huh. 2018. "One-pot gamma ray-induced green synthesis of a Prussian blue-laden polyvinylpyrrolidone/reduced graphene oxide aerogel for the removal of hazardous pollutants." Journal of Materials Chemistry A 7, no. 4: 1737-1748.

Review
Published: 24 October 2018 in Chemical Engineering Journal
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Over the past two decades, the radiosynthesis of metallic nanoclusters (MNCs) using γ-irradiation (γ-radiosynthesis) has presented a wealth of opportunities for the application of nanomaterials in areas such as medicine, energy, catalysis, and sensors. Unlike conventional methods, this technique provides fully reduced and highly stable MNCs that are free from by-products or impurities. γ-Radiosynthesis has thus proven to be a clean and green approach for bulk fabrication of MNCs with tunable particle sizes and morphologies. More recently, the in-situ decoration of MNCs on support materials using γ-irradiation has attracted much attention due to the synergistic effect between MNCs and the underlying support. In this review, we discuss the current state of research into the mechanisms underlying the γ-radiosynthesis of supported and unsupported mono- and bi-metallic nanoclusters and summarize the use of MNCs in catalytic, sensing, biomedical, and energy applications.

ACS Style

Seyed Majid Ghoreishian; Sung-Min Kang; G. Seeta Rama Raju; Mohammad Norouzi; Sung-Chan Jang; Hyung Joong Yun; Sung Taek Lim; Young-Kyu Han; Changhyun Roh; Yun Suk Huh. γ-Radiolysis as a highly efficient green approach to the synthesis of metal nanoclusters: A review of mechanisms and applications. Chemical Engineering Journal 2018, 360, 1390 -1406.

AMA Style

Seyed Majid Ghoreishian, Sung-Min Kang, G. Seeta Rama Raju, Mohammad Norouzi, Sung-Chan Jang, Hyung Joong Yun, Sung Taek Lim, Young-Kyu Han, Changhyun Roh, Yun Suk Huh. γ-Radiolysis as a highly efficient green approach to the synthesis of metal nanoclusters: A review of mechanisms and applications. Chemical Engineering Journal. 2018; 360 ():1390-1406.

Chicago/Turabian Style

Seyed Majid Ghoreishian; Sung-Min Kang; G. Seeta Rama Raju; Mohammad Norouzi; Sung-Chan Jang; Hyung Joong Yun; Sung Taek Lim; Young-Kyu Han; Changhyun Roh; Yun Suk Huh. 2018. "γ-Radiolysis as a highly efficient green approach to the synthesis of metal nanoclusters: A review of mechanisms and applications." Chemical Engineering Journal 360, no. : 1390-1406.

Research article
Published: 25 September 2018 in Industrial & Engineering Chemistry Research
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In this work, multifunctional Fe-aminoclay (FeAC)/carboxymethyl cellulose (CMC)/ polyhedral oligomeric silsesquioxane (POSS) composite (FeAC/CMC/POSS) with layered structure was successfully synthesized and utilized as adsorbent for the removal of cesium ions (Cs+) and cationic dyes methylene blue (MB) and chrysoidine G (CG) from aqueous solutions. The FeAC/CMC/POSS exhibit excellent adsorption capacities for Cs+ ions, MB and CG of 152, 438 and 791 mg g-1, respectively. The adsorption capacities for Cs+ ions, MB and CG are substantially greater than those of many previously reported adsorbents due to (i) the layered morphology of the composite and abundance of amino (–NH2) groups on clay surface; (ii) existence of carboxylate (–COO-) and hydroxyl (–OH-) groups on the CMC backbone, which contribute to the adsorption of large number of Cs+ ions and dye molecules through electrostatic attraction and ion exchange process. More importantly, the incorporation of POSS increases the interlayer spacing of Fe-aminoclay by intercalation providing room for the encapsulation of Cs+ ions and dye molecules. Owing to its unprecedented adsorption capacity, the devised FeAC/CMC/POSS composite could be a promising organic-inorganic material used to cost-effectively remove the multitude of environmental pollutants.

ACS Style

Muruganantham Rethinasabapathy; Sung-Min Kang; Ilsong Lee; Go-Woon Lee; Seung Kyu Hwang; Changhyun Roh; Yun Suk Huh. Layer-Structured POSS-Modified Fe-Aminoclay/Carboxymethyl Cellulose Composite as a Superior Adsorbent for the Removal of Radioactive Cesium and Cationic Dyes. Industrial & Engineering Chemistry Research 2018, 57, 13731 -13741.

AMA Style

Muruganantham Rethinasabapathy, Sung-Min Kang, Ilsong Lee, Go-Woon Lee, Seung Kyu Hwang, Changhyun Roh, Yun Suk Huh. Layer-Structured POSS-Modified Fe-Aminoclay/Carboxymethyl Cellulose Composite as a Superior Adsorbent for the Removal of Radioactive Cesium and Cationic Dyes. Industrial & Engineering Chemistry Research. 2018; 57 (41):13731-13741.

Chicago/Turabian Style

Muruganantham Rethinasabapathy; Sung-Min Kang; Ilsong Lee; Go-Woon Lee; Seung Kyu Hwang; Changhyun Roh; Yun Suk Huh. 2018. "Layer-Structured POSS-Modified Fe-Aminoclay/Carboxymethyl Cellulose Composite as a Superior Adsorbent for the Removal of Radioactive Cesium and Cationic Dyes." Industrial & Engineering Chemistry Research 57, no. 41: 13731-13741.

Journal article
Published: 10 September 2018 in Journal of Cleaner Production
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Several industries using gamma sterilization techniques for food safety, and long shelf-life purposes. Nuclear energy production has increased the amount of spent nuclear fuel produced, which poses risks of severe diseases in human. Cesium is one of the most hazardous material can cause human exposure to air, water, and food. The efficient removal of cesium ions (Cs+) has been emphasized using biological control strategies. In this study, we isolated a new Cs+-tolerant (100, 500, and 750 ppm) and gamma radiation resistant (1, 3, and 5 kGy) soil bacterium (CR1) from the soil around a nuclear power plant in Korea, which was identified as Exiguobacterium acetylicum CR1 by 16S rRNA sequencing. E. acetylicum CR1 was found to be resistant to high doses of gamma radiation without any loss in Cs+ tolerance or survival. Furthermore, E. acetylicum CR1 was found to act as a microbiological control agent with respect to the removal of cesium from contaminated water. Interestingly, after gamma radiation exposure, E. acetylicum CR1 developed significantly (p < 0.05) greater Cs+ bio-sorption capacity than non-irradiated control cells (24.63 ± 0.02% vs. 12.54 ± 0.06%), which confirmed that gamma radiation had no negative impact on its ability to remove Cs+ or on its growth/survival. The ability of E. acetylicum CR1 to adsorb Cs+ from contaminated water samples or radioactive environmental waste suggests it has broad spectrum potential as an environmentally friendly remedial tool in the contexts of soil ecology, agriculture, crop management, food, and medicine.

ACS Style

Seo Yeong Oh; Nam Su Heo; Shruti Shukla; Sung-Min Kang; Ilsong Lee; Hoomin Lee; Vivek K. Bajpai; Sung-Chan Jang; Young-Kyu Han; Changhyun Roh; Yun Suk Huh. Multi-stress radioactive-tolerant Exiguobacterium acetylicum CR1 and its applicability to environmental cesium uptake bioremediation. Journal of Cleaner Production 2018, 205, 281 -290.

AMA Style

Seo Yeong Oh, Nam Su Heo, Shruti Shukla, Sung-Min Kang, Ilsong Lee, Hoomin Lee, Vivek K. Bajpai, Sung-Chan Jang, Young-Kyu Han, Changhyun Roh, Yun Suk Huh. Multi-stress radioactive-tolerant Exiguobacterium acetylicum CR1 and its applicability to environmental cesium uptake bioremediation. Journal of Cleaner Production. 2018; 205 ():281-290.

Chicago/Turabian Style

Seo Yeong Oh; Nam Su Heo; Shruti Shukla; Sung-Min Kang; Ilsong Lee; Hoomin Lee; Vivek K. Bajpai; Sung-Chan Jang; Young-Kyu Han; Changhyun Roh; Yun Suk Huh. 2018. "Multi-stress radioactive-tolerant Exiguobacterium acetylicum CR1 and its applicability to environmental cesium uptake bioremediation." Journal of Cleaner Production 205, no. : 281-290.

Journal article
Published: 12 June 2018 in Materials
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In this work, we elucidate polymer-layered hollow Prussian blue-coated magnetic nanocomposites as an adsorbent to remove radioactive cesium from environmentally contaminated water. To do this, Fe3O4 nanoparticles prepared using a coprecipitation method were thickly covered with a layer of cationic polymer to attach hollow Prussian blue through a self-assembly process. The as-synthesized adsorbent was confirmed through various analytical techniques. The adsorbent showed a high surface area (166.16 m2/g) with an excellent cesium adsorbent capacity and removal efficiency of 32.8 mg/g and 99.69%, respectively. Moreover, the superparamagnetism allows effective recovery of the adsorbent using an external magnetic field after the adsorption process. Therefore, the magnetic adsorbent with a high adsorption efficiency and convenient recovery is expected to be effectively used for rapid remediation of radioactive contamination.

ACS Style

Sung-Chan Jang; Sung-Min Kang; Gi Yong Kim; Muruganantham Rethinasabapathy; Yuvaraj Haldorai; Ilsong Lee; Young-Kyu Han; Joanna C. Renshaw; Changhyun Roh; Yun Suk Huh. Versatile Poly(Diallyl Dimethyl Ammonium Chloride)-Layered Nanocomposites for Removal of Cesium in Water Purification. Materials 2018, 11, 998 .

AMA Style

Sung-Chan Jang, Sung-Min Kang, Gi Yong Kim, Muruganantham Rethinasabapathy, Yuvaraj Haldorai, Ilsong Lee, Young-Kyu Han, Joanna C. Renshaw, Changhyun Roh, Yun Suk Huh. Versatile Poly(Diallyl Dimethyl Ammonium Chloride)-Layered Nanocomposites for Removal of Cesium in Water Purification. Materials. 2018; 11 (6):998.

Chicago/Turabian Style

Sung-Chan Jang; Sung-Min Kang; Gi Yong Kim; Muruganantham Rethinasabapathy; Yuvaraj Haldorai; Ilsong Lee; Young-Kyu Han; Joanna C. Renshaw; Changhyun Roh; Yun Suk Huh. 2018. "Versatile Poly(Diallyl Dimethyl Ammonium Chloride)-Layered Nanocomposites for Removal of Cesium in Water Purification." Materials 11, no. 6: 998.

Communication
Published: 04 June 2018 in Biomolecules
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Polydimethyl-siloxane (PDMS) is often applied to fabricate cell chips. In this study, we fabricated an adipocyte microcell pattern chips using PDMS to analyze the inhibition activity of lipid droplets in mouse embryo fibroblast cells (3T3-L1) with anti-obesity agents. To form the PDMS based micropattern, we applied the micro-contact printing technique using PDMS micro-stamps that had been fabricated by conventional soft lithography. This PDMS micro-pattern enabled the selective growth of 3T3-L1 cells onto the specific region by preventing cell adhesion on the PDMS region. It then allowed growth of the 3T3-L1 cells in the chip for 10 days and confirmed that lipid droplets were formed in the 3T3-L1 cells. After treatment of orlistat and quercetin were treated in an adipocyte micro-cell pattern chip with 3T3-L1 cells for six days, we found that orlistat and quercetin exhibited fat inhibition capacities of 19.3% and 24.4% from 0.2 μM of lipid droplets in 3T3-L1 cells. In addition, we conducted a direct quantitative analysis of 3T3-L1 cell differentiation using Oil Red O staining. In conclusion, PDMS-based adipocyte micro-cell pattern chips may contribute to the development of novel bioactive compounds.

ACS Style

Gi Yong Kim; Su-Jin Yeom; Sung-Chan Jang; Chang-Soo Lee; Changhyun Roh; Heon-Ho Jeong. Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip. Biomolecules 2018, 8, 37 .

AMA Style

Gi Yong Kim, Su-Jin Yeom, Sung-Chan Jang, Chang-Soo Lee, Changhyun Roh, Heon-Ho Jeong. Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip. Biomolecules. 2018; 8 (2):37.

Chicago/Turabian Style

Gi Yong Kim; Su-Jin Yeom; Sung-Chan Jang; Chang-Soo Lee; Changhyun Roh; Heon-Ho Jeong. 2018. "Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip." Biomolecules 8, no. 2: 37.

Review
Published: 29 May 2018 in Biomolecules
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In this study, we elucidate that polyamine metabolite is a powerful biomarker to study post-radiation changes. Metabolomics in radiation biodosimetry, the application of a metabolomics analysis to the field of radiobiology, promises to increase the understanding of biological responses by ionizing radiation (IR). Radiation exposure triggers a complex network of molecular and cellular responses that impacts metabolic processes and alters the levels of metabolites. Such metabolites have potential as biomarkers for radiation dosimetry. Among metabolites, polyamine is one of many potential biomarkers to estimate radiation response. In addition, this review provides an opportunity for the understanding of a radiation metabolomics in biodosimetry and a polyamine case study.

ACS Style

Changhyun Roh. Metabolomics in Radiation-Induced Biological Dosimetry: A Mini-Review and a Polyamine Study. Biomolecules 2018, 8, 34 .

AMA Style

Changhyun Roh. Metabolomics in Radiation-Induced Biological Dosimetry: A Mini-Review and a Polyamine Study. Biomolecules. 2018; 8 (2):34.

Chicago/Turabian Style

Changhyun Roh. 2018. "Metabolomics in Radiation-Induced Biological Dosimetry: A Mini-Review and a Polyamine Study." Biomolecules 8, no. 2: 34.

Journal article
Published: 01 May 2018 in Separation and Purification Technology
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We describe a facile, economic, and environment friendly green method for simultaneous detection of palladium ions (Pd2+) and recovery Pd nanoparticles (Pd NPs) from wastewater through a non-toxic gamma-irradiation based reduction reaction. Basic orange 2 (BO), an azo dye, is used as a sensing probe in Pd2+ detection and acts as a stabilizing agent in the recovery of monodispersed small Pd NPs. The presence of Pd2+ in waste water was easily observed by naked eye through the color change from yellow to red upon adding the Basic orange 2. More importantly, Pd forms a square-planar structured complex with Pd2+ which aids the development of smaller and monodispersed Pd NPs during radiolytic reduction. The size control mechanism during the recovery of Pd NPs was ascertained by varying the intensity of gamma-ray (from 10 to 50 kGy) and initial concentrations of Pd2+ (from 20 to 100 ppm). We are able to control the size of Pd NPs from 5 to 400 nm by irradiating gamma-ray doses from 1 and 50 kGy, as evident from UV-vis absorption spectra (UV-vis) and transmission electron microscopy (TEM) images. About 15 nm colloidal Pd NPs were formed at 10 kGy gamma-irradiation, and various sizes of aggregates, which may be attributed to Ostwald ripening crystal growth, were observed in the irradiation condition of 20 kGy to 50 kGy. Further, the size of the recovered Pd NPs increases as the Pd2+ concentration increased, due to the increase in the ion association rate. Our proposed green method is a promising strategy that can easily detect Pd2+ from waste water and recover Pd NPs in desired size and morphology.

ACS Style

Sung-Min Kang; Cheol Hwan Kwak; Muruganantham Rethinasabapathy; Sung-Chan Jang; Sang-Rak Choe; Changhyun Roh; Young-Kyu Han; Yun Suk Huh. Gamma radiation mediated green technology for Pd nanoparticles recovery from wastewater. Separation and Purification Technology 2018, 197, 220 -227.

AMA Style

Sung-Min Kang, Cheol Hwan Kwak, Muruganantham Rethinasabapathy, Sung-Chan Jang, Sang-Rak Choe, Changhyun Roh, Young-Kyu Han, Yun Suk Huh. Gamma radiation mediated green technology for Pd nanoparticles recovery from wastewater. Separation and Purification Technology. 2018; 197 ():220-227.

Chicago/Turabian Style

Sung-Min Kang; Cheol Hwan Kwak; Muruganantham Rethinasabapathy; Sung-Chan Jang; Sang-Rak Choe; Changhyun Roh; Young-Kyu Han; Yun Suk Huh. 2018. "Gamma radiation mediated green technology for Pd nanoparticles recovery from wastewater." Separation and Purification Technology 197, no. : 220-227.