220 results on '"Mok, A."'
Search Results
2. Characteristics of Filter Cleaning and Dust Emission of Bag Filters Made of Filter Media Prepared by Different Surface Treatment Methods
- Author
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Dong-Soo Kim, Hee-Joo Cho, Joon-Mok Shim, Zainul Alim Ali Murtadlo, Churl-Hee Cho, and Hyun-Seol Park
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Environmental Engineering ,Environmental Chemistry ,Environmental Science (miscellaneous) ,Pollution - Published
- 2022
3. Inverse Vulcanization of Elemental Sulfur Catalyzed by Trialkyl Amines
- Author
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Jae Hyuk Hwang, Ji Mok Lee, Jong Hwi Seo, Guk Yun Noh, Wonmoo Byun, Seonggeon Kim, Woohwa Lee, Sungmin Park, Dong-Gyun Kim, and Yong Seok Kim
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Environmental Chemistry ,Pollution - Abstract
In this study, catalytic inverse vulcanization based on trialkyl amines (TAAs) is presented. With oleophilic alkyl chain moieties, low-cost organic TAAs promote time-efficient reactions as nucleophilic activators, even at a...
- Published
- 2023
4. Synthesis and characterization of ZnO–TiO2–chitosan–escin metallic nanocomposites: Evaluation of their antimicrobial and anticancer activities
- Author
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Abozer Y. Elderdery, Abdulaziz H. Alhamidi, Ahmed M. E. Elkhalifa, Maryam M. Althobiti, Entesar M. A. Tebien, Nawal Eltayeb Omer, Siddiqa M. A. Hamza, Fehaid Alanazi, Badr Alzahrani, Suresh Kumar Subbiah, and Pooi Ling Mok
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Fuel Technology ,Renewable Energy, Sustainability and the Environment ,Health, Toxicology and Mutagenesis ,General Chemical Engineering ,Environmental Chemistry ,Industrial and Manufacturing Engineering - Abstract
This work intended to formulate bio-nanocomposites of zinc oxide (ZnO), titanium oxide (TiO2), chitosan, and escin, characterize their physical properties, and evaluate their antimicrobial and anticancer properties. X-ray diffractometers (XRD) and scanning and transmission electron microscopes were applied to characterize the morphology and ultrastructure of chemically synthesized bio-nanocomposites. To investigate the functional groups of bio-nanocomposites, we used Perkin–Elmer spectrometers for Fourier transform infrared (FTIR) analysis and photoluminescence (PL) spectroscopy for PL spectrum analysis. Antimicrobial activities against bacterial and fungal strains were tested with agar well diffusion. Bio-nanocomposites were tested for anticancer effects on a MOLT4 blood cancer cell line using morphological analysis, methyl thiazole tetrazolium assay, apoptosis by acridine orange/ethidium bromide, and mitochondrial membrane potential (ΔΨm). In XRD, FTIR, and PL, the active compounds of ZnO–TiO2, chitosan, and escin peaks were observed. Our bio-nanocomposites demonstrated antimicrobial activity against bacterial and fungal pathogens. The bio-nanocomposite was cytotoxic to MOLT4 cells at an IC50 concentration of 33.4 µg·mL−1. Bio-nanocomposites caused cytotoxicity, changes in cell morphology, and mitochondrial membrane potential degradation, all of which resulted in apoptotic cell death. MOLT4 cells were found to be responsive to bio-nanocomposites based on ZnO–TiO2–chitosan–escin.
- Published
- 2022
5. Butyl acrylate/TiO2–copolymer hybrid one-dimensional photonic crystal–based colorimetric sensor for detection of C6–C16 n-alkanes of kerosene in adulterated diesel
- Author
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Tae Gyu Hwang, Minju Jeong, Jongnam Park, Yu Jin Jung, Do-Hoon Hwang, Hoyoul Kong, Dong Woo Cho, and Jong Mok Park
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
6. A comparative life-cycle assessment and cost analysis of biofilters amended with sludge-based activated carbon and commercial activated carbon for stormwater treatment
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Badr A. Mohamed, Carol Huang, Nico Mok, Omar Swei, Chris Johnston, and Loretta Y. Li
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Environmental Engineering ,Health, Toxicology and Mutagenesis ,Environmental Chemistry ,Pollution ,Waste Management and Disposal - Published
- 2023
7. Effects of reactive oxygen species generation induced by Wonju City particulate matter on mitochondrial dysfunction in human middle ear cell
- Author
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Seong Heon Kim, Carlos Noriega Polo, Dong Jun Park, Su Hoon Lee, Ha Sun Mok, Young Joon Seo, and Min Jae Jeong
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medicine.medical_specialty ,Health, Toxicology and Mutagenesis ,Cell ,Ear, Middle ,Motility ,Inflammation ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Internal medicine ,medicine ,Animals ,Humans ,Environmental Chemistry ,Cities ,Cytotoxicity ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Air Pollutants ,Reactive oxygen species ,General Medicine ,Pollution ,Mitochondria ,Oxidative Stress ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Apoptosis ,Toxicity ,Particulate Matter ,medicine.symptom ,Reactive Oxygen Species ,Oxidative stress - Abstract
Atmospheric particulate matter (PM) contains different components that can elicit varying adverse health effects in humans and animals. Studies on PM toxicity and its underlying mechanisms in the middle ear are limited, and they generally use a PM standard. However, as PM composition varies temporally and geographically, it is crucial to identify the toxic PM constituents according to season and region and investigate their associated health effects. Thus, we sought to determine whether PM induces cytotoxicity and inflammatory factor and reactive oxygen species (ROS) generation in human middle ear epithelial cells obtained from patients with otitis media. The cells were treated with both standard urban PM and PM directly captured from the atmosphere in Wonju City. The association between mitochondrial dysfunction and PM was investigated. PM exposure significantly increased COX-2 and TNF-α mRNA expression, increased ROS generation, induced inflammatory responses, and caused abnormalities in mitochondrial motility and function. Furthermore, PM induced cell apoptosis, which consequently reduced cell survival, particularly at the concentration of 100 μg/mL. Overall, our study provides new insights into the toxic effects of standard and atmospheric PM on middle ear cell line.
- Published
- 2021
8. High-Throughput NOx Removal by Two-Stage Plasma Honeycomb Monolith Catalyst
- Author
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Sang-Joon Kim, Iljeong Heo, Young Sun Mok, Nosir Matyakubov, Shirjana Saud, Young-Jin Kim, Duc Ba Nguyen, and Jin Hee Lee
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inorganic chemicals ,geography ,geography.geographical_feature_category ,Materials science ,Humidity ,General Chemistry ,Plasma ,respiratory system ,010501 environmental sciences ,01 natural sciences ,Catalysis ,Chemical engineering ,Electrode ,Honeycomb ,Environmental Chemistry ,Monolith ,NOx ,Water vapor ,0105 earth and related environmental sciences - Abstract
A two-stage plasma catalyst system for high-throughput NOx removal was investigated. Herein, the plasma stage involved the large-volume plasma discharge of humidified gas and was carried out in a sandwich-type honeycomb monolith reactor consisting of a commercial honeycomb catalyst (50 mm high; 93 mm in diameter) located between two parallel perforated disks that formed the electrodes. The results demonstrated that, in the plasma stage, the reduction of NOx did not occur at room temperature; instead, NO was only oxidized to NO2 and n-heptane to oxygenated hydrocarbons. The oxidation of NO and n-heptane in the honeycomb plasma discharge state was largely affected by the humidity of the feed gas. Furthermore, the oxidation of NO to NO2 occurs preferably to that of n-heptane with a tendency of the NO oxidation to decrease with increasing feed gas humidity. The reason is that the generation of O3 decreases as the amount of water vapor in the feed gas increases. Compared to the catalyst alone, the two-stage plasma catalyst system increased NOx removal by 29% at a temperature of 200 °C and an energy density of 25 J/L.
- Published
- 2021
9. Application of an electrochemical sensor using copper oxide nanoparticles/polyalizarin yellow R nanocomposite for hydrogen peroxide
- Author
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Bahaaldin Rashidzadeh, Nader Amini, Nasrin Amanollahi, Afshin Maleki, Seung-Mok Lee, and Jae-Kyu Yang
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Detection limit ,Nanocomposite ,Materials science ,Health, Toxicology and Mutagenesis ,Electrochemical Techniques ,Hydrogen Peroxide ,General Medicine ,010501 environmental sciences ,01 natural sciences ,Pollution ,Redox ,Nanocomposites ,Electrochemical gas sensor ,Dielectric spectroscopy ,Limit of Detection ,Electrode ,Nanoparticles ,Environmental Chemistry ,Graphite ,Differential pulse voltammetry ,Cyclic voltammetry ,Electrodes ,Copper ,0105 earth and related environmental sciences ,Nuclear chemistry - Abstract
In this study, copper oxide nanoparticles (CuONPs) were prepared by a simple chemical method and then characterized by scanning electron microscope (SEM). A novel electrochemical sensor for hydrogen peroxide (H2O2) analysis was prepared by immobilizing copper oxide nanoparticles and polyalizarin yellow R (PYAR) on bare glassy carbon electrode (PAYR/CuONPs/GCE). The electrocatalytical behavior of the proposed electrochemical sensor was also studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Based on the results, the PAYR/CuONP nanocomposite had significant electrocatalytic oxidation and reduction properties for the detection and determination of H2O2. Some parameters such as linear range, sensitivity, and detection limit for reduction peak were obtained as 0.1–140 μM, 1.4154 μA cm−2 μM−1, and 0.03 μM, respectively, by the DPV technique. Some advantages of this electrode were having widespread linear range, low detection limit, and, most importantly, ability in simultaneous oxidation and reduction of H2O2 at two applied potentials.
- Published
- 2021
10. Elucidation of microbial interactions, dynamics, and keystone microbes in high pressure anaerobic digestion
- Author
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Ajay, Thapa, Jeong-Hoon, Park, Seung Gu, Shin, Hong-Mok, Jo, Min-Sang, Kim, Yeongmi, Park, Uijeong, Han, and Si-Kyung, Cho
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Bioreactors ,Environmental Engineering ,Biofuels ,Microbial Interactions ,Environmental Chemistry ,Anaerobiosis ,Methane ,Pollution ,Waste Management and Disposal - Abstract
High-pressure anaerobic digestion (HPAD) is a promising technology for producing biogas enriched with high methane content in a single-step process. To enhance HPAD performance, a comprehensive understanding of microbial community dynamics and their interactions is essential. For this, mesophilic batch high-pressurized anaerobic reactors were operated under 3 bars (H3) and 6 bars (H6). The experimental results showed that the effect of high-pressure (up to 6 bar) on acidification was negligible while methanogenesis was significantly delayed. Microbial analysis showed the predominance of Defluviitoga affiliated with the phylum Thermotogae and the reduction of Thiopseudomonas under high-pressure conditions. In addition, the microbial cluster pattern in H3 and H6 was significantly different compared to the CR, indicating a clear shift in microbial community structure. Moreover, Methanobacterium, Methanomicrobiaceae, Alkaliphilus, and Petrimonas were strongly correlated in network analysis, and they could be identified as keystone microbes in the HPAD reactor.
- Published
- 2023
11. Synthesis and characterization of thermally cross-linkable poly(iminoarylene)-based hole injection layer for solution-processed organic light-emitting diodes
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Seon Lee Kwak, Hea Jung Park, Jae-Ho Jang, Jeong Yong Park, Jong Mok Park, Jihoon Lee, and Do-Hoon Hwang
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
12. NaCl-induced enhancement of thermodynamic and kinetic CO2 selectivity in CO2 + N2 hydrate formation and its significance for CO2 sequestration
- Author
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Junghoon Mok, Wonjung Choi, Sungwoo Kim, Jonghyuk Lee, and Yongwon Seo
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
13. The interplays among meteorology, source, and chemistry in high particulate matter pollution episodes in urban Shanghai, China
- Author
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Lulu, Zeng, Dan Dan, Huang, Shuhui, Zhu, Fangbing, Li, Min, Zhou, Liping, Qiao, Qian, Wang, Qiongqiong, Wang, Yingge, Ma, Shengrong, Lou, Huabin, Shi, Ka, In Hoi, Kai Meng, Mok, Xinlei, Ge, Hongli, Wang, Jian Zhen, Yu, Cheng, Huang, and Yong Jie, Li
- Subjects
Aerosols ,Air Pollutants ,China ,Meteorology ,Environmental Engineering ,Air Pollution ,Environmental Chemistry ,Particulate Matter ,Dust ,Environmental Pollutants ,Pollution ,Waste Management and Disposal ,Environmental Monitoring - Abstract
High particulate matter (PM) pollution episodes still occur occasionally in urban China, despite of improvements in recent years. Investigating the influencing factors of high-PM episodes is beneficial in the formulation of effective control measures. We herein present the effects of weather condition, emission source, and chemical conversion on the occurrence of high-PM episodes in urban Shanghai using multiple online measurements. Three high-PM episodes, i.e., locally-accumulated, regionally-transported, and dust-affected ones, as well as a clean period were selected. Stagnant air with temperature inversion was found in both locally-accumulated and regionally-transported high-PM episodes, but differences in PM evolution were observed. In the more complicated dust-affected episode, the weather condition interacted with the emission/transport sources and chemical conversion, resulting in consecutive stages with different PM characteristics. Specifically, there were (1) stronger local accumulation in the pre-dust period, (2) dust-laden air with aged organic aerosol (OA) upon dust arrival, (3) pollutants being swept into the ocean, and (4) back to the city with aged OA. Our results suggest that (a) local emissions could be rapidly oxidized in some episodes but not all, (b) aged OA from long-range transport (aged in space) had a similar degree of oxygenation compared to the prolonged local oxidation (aged in time), and (c) OA aged over land and over the ocean were similar in chemical characteristics. The findings help better understand the causes and evolution of high-PM episodes, which are manifested by the interplays among meteorology, source, and chemistry, providing a scientific basis for control measures.
- Published
- 2022
14. New insights in photocatalytic removal of Alizarin Yellow using reduced Ce3+/TiO2 catalyst
- Author
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Lalliansanga, Dong-Jin Kim, Seung-Mok Lee, and Diwakar Tiwari
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Aqueous solution ,Materials science ,Health, Toxicology and Mutagenesis ,General Medicine ,010501 environmental sciences ,Alizarin ,01 natural sciences ,Pollution ,Catalysis ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,X-ray photoelectron spectroscopy ,Transmission electron microscopy ,Photocatalysis ,Environmental Chemistry ,Degradation (geology) ,Thin film ,0105 earth and related environmental sciences - Abstract
The present communication aims to obtain a novel Ce3+/TiO2 thin film in a single step facile method using the in situ template process. The material was characterized by the XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), TEM (transmission electron microscope), and AFM (atomic force microscope) analyses. The thin film catalyst was intended to introduce in the degradation of one of potential dye Alizarin Yellow from aqueous solutions using the UV-A radiations. The mechanisms of degradation along with the physicochemical parametric studies were conducted extensively. The mineralization of pollutant and the replicate use of catalysts further enhance the applicability of present communication. Additionally, the real matrix treatment was conducted to simulate the treatment process.
- Published
- 2020
15. Quantification of PCBs using GC-ECD and Cost-effective Estimation of Dioxin-like PCBs in the Sediment of Urban Streams in Seoul, Korea
- Author
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Suk-Joo Cho, Hye-Gyeong Gil, Je-Seung Lee, and Mok-Young Lee
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Environmental chemistry ,Environmental science ,Sediment ,STREAMS - Published
- 2020
16. Improving Methane Mitigating Functionality of Blast Furnace Slag by Adding Electron Acceptor
- Author
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Snowie Jane C. Galgo, Ji Yeon Lim, Ronley C. Canatoy, Ji Su Ha, Keon Mok Sohn, and Pil Joo Kim
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Soil ,Environmental Engineering ,Iron ,Silicates ,Nitrous Oxide ,Environmental Chemistry ,Agriculture ,Electrons ,Oryza ,Fertilizers ,Pollution ,Waste Management and Disposal ,Methane - Abstract
Blast furnace slag (BFS), a byproduct of iron-producing process, has been applied as silicate fertilizer in rice paddy. Silicate fertilizer contains lime and silicate as main components and iron and manganese as electron acceptors. This amendment improves soil productivity and mitigates methane (CH
- Published
- 2022
17. A Comprehensive Study on Scaling Up Ethylene Abatement Via Intermittent Plasma-Catalytic Discharge Process in a Novel Reactor Configuration Comprising Multiple Honeycomb Monoliths
- Author
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Shirjana Saud, Roshan Mangal Bhattarai, Duc Ba Nguyen, Shankar Neupane, Nosir Matyakubov, Byungjin Lee, Young Jin Kim, Jin Hee Lee, Iljeong Heo, and Young Sun Mok
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2022
18. Mechanical Stimuli Enhance the Growth of Ulva fasciata (Chlorophyta) Spores
- Author
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Sungjune Jung, Sang Mok Jung, Hee Jung Jung, Dong Soo Hwang, Hwa-Rim Lee, Sinyang Kim, Jihyun Park, Seongju Kim, and Hyun Woung Shin
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Fouling ,biology ,Renewable Energy, Sustainability and the Environment ,Ecology ,General Chemical Engineering ,Climate change ,02 engineering and technology ,General Chemistry ,Chlorophyta ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,Spore ,Biofouling ,Ulva fasciata ,Environmental Chemistry ,Environmental science ,0210 nano-technology - Abstract
The macroalgal forest is being transformed to barren ground in coastal areas due to climate change. Current recovery technologies are ineffective, and an understanding of the fouling mechanism of m...
- Published
- 2020
19. Influence of Competitive Inclusion of CO2 and N2 on sII Hydrate–Flue Gas Replacement for Energy Recovery and CO2 Sequestration
- Author
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Yongwon Seo, Yohan Lee, Junghoon Mok, and Wonjung Choi
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Energy recovery ,Flue gas ,Chemistry ,macromolecular substances ,General Chemistry ,010501 environmental sciences ,Carbon sequestration ,01 natural sciences ,Structural transformation ,Chemical engineering ,Environmental Chemistry ,Gas chromatography ,Inclusion (mineral) ,Hydrate ,0105 earth and related environmental sciences - Abstract
This study investigated structural transformation, guest distributions, and the extent of replacement for CH4+C3H8 – flue gas replacement occurring in sII hydrates via gas chromatography, NMR spect...
- Published
- 2020
20. Fabrication of periodic nano-porous surface structure for highly sensitive gravimetric quartz crystal applications
- Author
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Woo-Sik Kim, Jong-Min Kim, Deuk-Yong Shim, and Sang-Mok Chang
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Fabrication ,Chemistry ,010401 analytical chemistry ,technology, industry, and agriculture ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,Crystal ,Electrode ,Environmental Chemistry ,Gravimetric analysis ,Composite material ,0210 nano-technology ,Porosity ,Quartz ,Layer (electronics) ,Spectroscopy - Abstract
A periodic nano-porous surface on quartz crystal electrodes was carefully fabricated for increasing the mass-sensitive areas. Detailed porous structures were prepared by analyzing Au electrochemical reduction process of PS layer coated quartz crystals. The sensitivity measurement of the porous quartz crystals was performed with several traditional methods, and an optimized reduction time for higher sensitivity was determined. The frequency shift of the nano-porous quartz crystals showed 10 times bigger change with the same concentration of target solutions in self-assembly procedures. In the procedures, the freshly increased surface portion did not produce additional molecular slip-effects on the measured resonant resistance values, thus, the periodic porous chips showed another side merit for the mass sensor applications. We propose a possible use of the current porous surface as a platform for developing other high-performance sensors and analyses.
- Published
- 2020
21. Perovskites fabricated on textured silicon surfaces for tandem solar cells
- Author
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Solhee Lee, Martin C. Schubert, Hae-Seok Lee, Jeewoong Yang, Seongtak Kim, Sung Bin Choi, Sang Won Lee, Won Mok Kim, Se Jin Park, Soohyun Bae, Sujeong Jeong, Dongjin Choi, Kyung-Jin Cho, Friedemann D. Heinz, Jae Keun Hwang, Yoonmook Kang, Dongkyun Kang, Stefan W. Glunz, Won-Kyu Lee, Donghwan Kim, Ji Yeon Hyun, and Publica
- Subjects
inorganic chemicals ,Materials science ,Farbstoff- und Perowskitsolarzellen ,Silicon ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,Surface finish ,010402 general chemistry ,01 natural sciences ,Biochemistry ,complex mixtures ,lcsh:Chemistry ,Sputtering ,Materials Chemistry ,Environmental Chemistry ,Texture (crystalline) ,Lead oxide ,Perovskite (structure) ,business.industry ,technology, industry, and agriculture ,General Chemistry ,021001 nanoscience & nanotechnology ,equipment and supplies ,Tandemsolarzellen auf kristallinem Silicium ,0104 chemical sciences ,Silicium-Photovoltaik ,stomatognathic diseases ,chemistry ,lcsh:QD1-999 ,Photovoltaik ,Optoelectronics ,Neuartige Photovoltaik-Technologien ,0210 nano-technology ,business ,Layer (electronics) ,Charakterisierung von Prozess- und Silicium-Materialien - Abstract
The silicon surface texture significantly affects the current density and efficiency of perovskite/silicon tandem solar cells. However, only a few studies have explored fabricating perovskite on textured silicon and the effect of texture on perovskite films because of the limitations of solution processes. Here we produce conformal perovskite on textured silicon with a dry two-step conversion process that incorporates lead oxide sputtering and direct contact with methyl ammonium iodide. To separately analyze the influence of each texture structure on perovskite films, patterned texture, high-resolution photoluminescence (μ-PL), and light beam-induced current (μ-LBIC), 3D mapping is used. This work elucidates conformal perovskite on textured surfaces and shows the effects of textured silicon on the perovskite layers with high-resolution 3D mapping. This approach can potentially be applied to any type of layer on any type of substrate. The efficiency of perovskite/silicon tandem solar cells is affected by silicon surface texture, however fabrication processes in solution limit surface studies. Here a perovskite layer on textured silicon is formed through a dry two-step conversion process with lead oxide sputtering and direct contact with methyl ammonium iodide.
- Published
- 2020
22. Study on the Detoxification of Asbestos-Containing Wastes (ACW) Using SiC Plate
- Author
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Jin-Ho Yoon, Myung Hwan Hong, Chan Gi Lee, Hyeok Mok Choi, and So Young Joo
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Detoxification ,Environmental chemistry ,medicine ,Environmental science ,medicine.disease_cause ,Asbestos - Published
- 2020
23. Association of urinary phthalate metabolites and phenolics with adipokines and insulin resistance related markers among women of reproductive age
- Author
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Hyo-Bang Moon, Sungkyoon Kim, Kyungho Choi, Inae Lee, Yunsun Jeong, Sunmi Kim, Sori Mok, Suhyeon Park, Su Young Kim, Jeongim Park, Sooran Choi, Hai Joong Kim, Aram Lee, Gyuyeon Choi, and Jangwoo Lee
- Subjects
Adult ,medicine.medical_specialty ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Urinary system ,medicine.medical_treatment ,Phthalic Acids ,Adipokine ,010501 environmental sciences ,01 natural sciences ,Young Adult ,chemistry.chemical_compound ,Insulin resistance ,Internal medicine ,Diabetes mellitus ,Republic of Korea ,medicine ,Humans ,Environmental Chemistry ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Adiponectin ,business.industry ,Reproduction ,Leptin ,Insulin ,Phthalate ,Environmental Exposure ,Middle Aged ,medicine.disease ,Pollution ,Endocrinology ,chemistry ,Environmental Pollutants ,Female ,Insulin Resistance ,business ,Biomarkers - Abstract
Chemicals such as phthalates and phenolics have been associated with metabolic markers in humans. However, most studies have only looked at a limited number of chemicals, and little is known about their potential effects on adipokines in humans. In the present study, the associations between dozens of urinary chemicals, including phthalate metabolites and phenolics, and markers related to insulin resistance as well as major adipokines, were assessed among the women of reproductive age (n = 459, between 20 and 48 years of age) recruited from major cities in Korea between 2015 and 2016. Adipokines such as adiponectin and leptin, and insulin resistance related markers such as glucose and insulin, were analyzed in serum. Associations between urinary chemicals and the adipokines or insulin resistance related markers were assessed in two steps. First, ordinary least squares (OLS) regression was used to assess the association of each urinary chemical with the adipokines or insulin resistance related markers (single-pollutant model). Second, several chemicals were selected using elastic net regression and were subsequently analyzed with OLS regression model (multi-pollutant model), considering simultaneous exposure to multiple chemicals. In both single- and multi-pollutant models, several urinary chemicals consistently showed significant associations with adipokines or the insulin resistance related markers. The sum of di-(2-ethylhexyl) phthalate metabolites (ΣDEHPm) and ethyl paraben (EtP) were associated with increased serum adiponectin levels. Urinary ΣDEHPm levels also showed positive associations with fasting glucose. Moreover, urinary mono-methyl phthalate (MMP), mono-isobutyl phthalate (MiBP), and bisphenol S (BPS) levels showed positive associations with the homeostasis model assessment for insulin resistance (HOMA-IR). Interestingly, urinary propyl paraben (PrP) levels showed a negative association with HOMA-IR, in both models. Our observations show that among many consumer chemicals, phthalates may affect serum adipokines, and thus glucose, and insulin resistance in adult females. Further confirmation is warranted in other populations.
- Published
- 2019
24. Corona discharge plasma-based degradation of simulated residual linear alkylbenzene sulphonate and dodecyl benzene sulfonate surfactants
- Author
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Pradeep Puligundla, T. Lee, C. Mok, and U. Park
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Environmental Engineering ,Dodecylbenzene ,Chemistry ,Linear alkylbenzene ,Sodium ,Kinetics ,Inorganic chemistry ,chemistry.chemical_element ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Sulfonate ,Wastewater ,Environmental Chemistry ,Degradation (geology) ,General Agricultural and Biological Sciences ,Corona discharge ,0105 earth and related environmental sciences - Abstract
Synthetic surfactants are used in a wide range of products ranging from household cleaning detergents to pesticide formulations. Due to their widespread use, residual surfactants are often released in large quantities into the environment, especially via wastewater and can act as potential toxicants. The present study explored the applicability of a non-thermal plasma, namely corona discharge plasma jet (CDPJ), for the degradation of residual surfactants so as to minimize their harmful effects to aquatic life. The plasma was generated using 20 kV DC power supply, with different input currents (1.00, 1.25 and 1.50 A) and at various electrode-to-sample distances (20, 25 and 30 mm). For degradation treatments, simulated residual surfactants (sodium dodecylbenzene sulfonate [DBS] and sodium linear alkylbenzene sulfonate [LAS]) and DBS-containing dishwashing detergents dispersed on slide glasses were exposed to CDPJ for predetermined periods of time (0–120 min). Results indicated that under optimal treatment conditions of 1.5 A current and 20 mm electrode-to-sample distance, the tested surfactants and surfactants in detergents were maximally degraded to about 57% following the plasma treatment for 120 min. Modeling of degradation kinetics indicated that Weibull distribution was the best-fit model, and decimal degradation times (δ) were calculated for different treatment conditions. The pure surfactants were degraded to a greater extent than surfactants in detergents.
- Published
- 2019
25. Enhanced Nitrite Production from the Aqueous Photolysis of Nitrate in the Presence of Vanillic Acid and Implications for the Roles of Light-Absorbing Organics
- Author
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Tianwei Hao, Beatrix Rosette Go Mabato, Qi Chen, Kai Meng Mok, Yalin Wang, Wanyi Huang, Ru-Jin Huang, Chak K. Chan, Yong Jie Li, Xue Li, Ka In Hoi, Ben Liu, Dandan Huang, Yunkai Tan, and Masao Gen
- Subjects
chemistry.chemical_classification ,Vanillic Acid ,Nitrous acid ,Aqueous solution ,Nitrates ,Photolysis ,Radical ,Nitrous Acid ,General Chemistry ,Photochemistry ,Organic compound ,chemistry.chemical_compound ,chemistry ,Nitrate ,Vanillic acid ,Environmental Chemistry ,Formate ,Nitrite ,Nitrites - Abstract
A prominent source of hydroxyl radicals (•OH), nitrous acid (HONO) plays a key role in tropospheric chemistry. Apart from direct emission, HONO (or its conjugate base nitrite, NO2-) can be formed secondarily in the atmosphere. Yet, how secondary HONO forms requires elucidation, especially for heterogeneous processes involving numerous organic compounds in atmospheric aerosols. We investigated nitrite production from aqueous photolysis of nitrate for a range of conditions (pH, organic compound, nitrate concentration, and cation). Upon adding small oxygenates such as ethanol, n-butanol, or formate as •OH scavengers, the average intrinsic quantum yield of nitrite [Φ(NO2-)] was 0.75 ± 0.15%. With near-UV-light-absorbing vanillic acid (VA), however, the effective Φ(NO2-) was strongly pH-dependent, reaching 8.0 ± 2.1% at a pH of 8 and 1.5 ± 0.39% at a more atmospherically relevant pH of 5. Our results suggest that brown carbon (BrC) may greatly enhance the nitrite production from the aqueous nitrate photolysis through photosensitizing reactions, where the triplet excited state of BrC may generate solvated electrons, which reduce nitrate to NO2 for further conversion to nitrite. This photosensitization process by BrC chromophores during nitrate photolysis under mildly acidic conditions may partly explain the missing HONO in urban environments.
- Published
- 2021
26. Phosphorus Dynamics Associated With Organic Carbon Mineralization by Reduction of Sulfate and Iron in Sediment Exposed to Fish Farming
- Author
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Bomina Kim, Hyungchul Kim, Jonguk Kim, Jin-Sook Mok, Jung-Ho Hyun, Ayeon Choi, Cheolho Yoon, Sung-Uk An, and Won-Chan Lee
- Subjects
Science ,benthic nutrient flux ,chemistry.chemical_element ,Ocean Engineering ,Aquatic Science ,QH1-199.5 ,Oceanography ,Mineralization (biology) ,Commercial fish feed ,Water column ,sulfate reduction ,Organic matter ,biogenic apatite P ,Water Science and Technology ,chemistry.chemical_classification ,Global and Planetary Change ,Phosphorus ,Sediment ,phosphorus speciation ,General. Including nature conservation, geographical distribution ,chemistry ,aquaculture ,Benthic zone ,P regeneration ,Environmental chemistry ,Eutrophication - Abstract
The expansion of the aquaculture industry has resulted in accumulation of phosphorus (P)-rich organic matter via uneaten fish feed. To elucidate the impact of fish farming on P dynamics, P speciation, and benthic P release along with partitioning of organic carbon (Corg) mineralization coupled to sulfate reduction (SR) and iron reduction (FeR) were investigated in the sediments from Jinju Bay, off the southern coast of South Korea, in July 2013. SR in the farm sediment was 6.9-fold higher than the control sediment, and depth-integrated (0–10 cm) concentrations of NH4+, PO43–, and H2S in pore water of the farm sediment were 2.2-, 3.3-, and 7.4-fold higher than that in control sediment, respectively. High biogenic-P that comprised 28% of total P directly reflected the impact of P-rich fish feed, which ultimately enhanced the bioavailability (58% of total P) of P in the surface sediment of the farm site. In the farm sediment where SR dominated Corg mineralization, H2S oxidation coupled to the reduction of FeOOH stimulated release of P bound to iron oxide, which resulted in high regeneration efficiency (85%) of P in farm sediments. Enhanced P desorption from FeOOH was responsible for the increase in authigenic-P and benthic P flux. Authigenic-P comprised 33% of total P, and benthic P flux to the overlying water column accounted for approximately 800% of the P required for primary production. Consequently, excessive benthic P release resulting directly from oversupply of P-rich fish feed was a significant internal source of P for the water column, and may induce undesirable eutrophication and harmful algal blooms in shallow coastal ecosystems.
- Published
- 2021
27. Activated carbon derived from cherry flower biowaste with a self-doped heteroatom and large specific surface area for supercapacitor and sodium-ion battery applications
- Author
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Roshan Mangal Bhattarai, Kisan Chhetri, Subramanian Natarajan, Shirjana Saud, Sang Jae Kim, and Young Sun Mok
- Subjects
Ions ,Environmental Engineering ,Nitrogen ,Charcoal ,Health, Toxicology and Mutagenesis ,Sodium ,Public Health, Environmental and Occupational Health ,Environmental Chemistry ,Flowers ,General Medicine ,General Chemistry ,Porosity ,Pollution - Abstract
Herein, cherry flower waste-derived activated carbon (CFAC) with self-doped nitrogen is synthesized as a viable energy storage material for green and sustainable energy solutions. The activated carbon derived in this way is examined as an electric double-layer capacitance (EDLC)-type electrode material and sodium-ion battery (NIB) electrode material, and commendable performance is demonstrated for both of these energy storage applications. The specific surface area (SSA) and nitrogen content are observed to play a very delicate role in determining the charge storage ability of the CFAC, and the performance is optimized only by carefully balancing both of these properties. The optimized CFAC electrode supplied an excellent performance with a specific capacitance of 333.8 F g
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- 2022
28. Plasma-catalytic ethylene removal by a ZSM-5 washcoat honeycomb monolith impregnated with palladium
- Author
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Hyungwon Jeon, Shirjana Saud, Seung-min Ryu, Young Sun Mok, Duc Ba Nguyen, Van Toan Nguyen, Roshan Mangal Bhattarai, Nosir Matyakubov, and Seong Bong Kim
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geography ,Environmental Engineering ,Materials science ,Ethylene ,geography.geographical_feature_category ,Health, Toxicology and Mutagenesis ,chemistry.chemical_element ,Ethylenes ,Pollution ,Catalysis ,chemistry.chemical_compound ,Adsorption ,chemistry ,Chemical engineering ,Honeycomb ,Environmental Chemistry ,ZSM-5 ,Monolith ,Waste Management and Disposal ,Oxidation-Reduction ,NOx ,Palladium - Abstract
The effective removal of dilute ethylene in a novel honeycomb plasma reactor was investigated using a honeycomb catalyst (Pd/ZSM-5/monolith) sandwiched between two-perforated electrodes operating at ambient temperature. Herein, the dependence of catalyst performance on the binder fraction, catalyst preparation method, and catalyst loading was examined. Ethylene removal was carried out by a process comprising cycles of 30-min adsorption conjugated with 15-min plasma-catalytic oxidation. Interestingly, the performance of the cyclic process was superior to continuous plasma-catalytic oxidation and thermally activated catalyst in terms of energy conservation, i.e., ~36 compared to ~105 and ~300 J/L, respectively. Hence, the novel cyclic process can be considered advanced-oxidation technology that features room-temperature oxidation, offers low energy consumption, negligible hazardous by-products emissions such as NOx and O3. Moreover, the process operated under described conditions: low-pressure drop, ambient atmosphere, a mechanically stable system, and a simple reactor configuration, suggesting the practical applicability of this plasma process.
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- 2021
29. Chemical Removal of Cu and Zn from Swine Feces before Soil Application
- Author
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Moo-Joon Shim and Seung-Mok Lee
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chemistry.chemical_classification ,swine feces ,removal ,Agriculture (General) ,metals ,04 agricultural and veterinary sciences ,Plant Science ,010501 environmental sciences ,engineering.material ,fertilizer ,01 natural sciences ,S1-972 ,sludge ,chemistry ,Environmental chemistry ,040103 agronomy & agriculture ,engineering ,Total nitrogen ,0401 agriculture, forestry, and fisheries ,Organic matter ,Fertilizer ,Agronomy and Crop Science ,Feces ,0105 earth and related environmental sciences ,Food Science - Abstract
Cu and Zn are known to be abundant in swine feces, hence, concentrations of these metals need to be lowered before swine feces are applied to land in order to prevent potential environmental problems. The main objective of this study was to develop an appropriate chemical process to remove Cu and Zn from swine feces using acid extractions. The removal efficiencies of Cu and Zn decreased in the order of H2SO4 >, HNO3 >, organic acids (citric and oxalic acids). Owing to the highest removal efficiencies of Cu and Zn by using H2SO4, it was selected for further elimination of Cu and Zn from swine feces. By using H2SO4, the optimal concentration, solid-to-liquid ratio, and reaction time were 2%, 1:50, and 8 h, respectively. At the optimum conditions, Cu concentration was decreased from 198 mg/kg to 40.1 mg/kg and Zn concentration from 474 mg/kg to 80.0 mg/kg, with removal rates of 79.7% and 83.1%, respectively. The low Cu removal efficiency, resulting from the strong complexation between Cu and organic matter of swine feces, was improved by the increase in the reaction time and H2SO4 solution concentrations. However, about half of the total nitrogen (TN) was also removed by using H2SO4, indicating that the swine feces treated with H2SO4 may have poor value as fertilizer. Additional studies are required to find an optimal method to maintain TN concentrations while simultaneously removing Cu and Zn.
- Published
- 2021
30. Realization of Superhydrophobic Surface for the Detection of Residual Detergent Concentration
- Author
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Gitae Namgung, Chulkyoon Mok, Eunbin Cho, and Jin-Seo Noh
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Contact angle ,chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Renewable Energy, Sustainability and the Environment ,Capillary action ,General Chemical Engineering ,Environmental Chemistry ,Substrate (chemistry) ,Nanorod ,General Chemistry ,Stearic acid - Abstract
A superhydrophobic surface was realized on a glass substrate and on the inner wall of a capillary tube, employing a combination of ZnO nanorod arrays and stearic acid. The vertical ZnO nanorod arra...
- Published
- 2019
31. Kinetic CO2 selectivity in clathrate-based CO2 capture for upgrading CO2-rich natural gas and biogas
- Author
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Yongwon Seo, Wonjung Choi, Jiyeon Lim, and Junghoon Mok
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business.industry ,General Chemical Engineering ,Clathrate hydrate ,Inorganic chemistry ,Kinetics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Chloride ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Biogas ,Natural gas ,Phase (matter) ,medicine ,Environmental Chemistry ,0210 nano-technology ,business ,Selectivity ,Tetrahydrofuran ,medicine.drug - Abstract
Upgrading CO2-rich natural gas or biogas through CO2 capture is essential to reduce greenhouse gas emissions and to increase its energy density. In this study, clathrate-based CO2 capture from CO2-rich natural gas or biogas was investigated with a primary focus on kinetic CO2 selectivity. The time-dependent CO2 selectivity during clathrate formation for pure water, tetrahydrofuran (THF, 5.6 mol%) solution, and tetra-n-butylammonium chloride (TBAC, 3.3 mol%) solution was examined through direct composition analysis and in situ Raman spectroscopy. In pure water, the CO2 composition in the clathrate phase was much higher at the early stage of clathrate formation than that at equilibrium, indicating that CO2 is kinetically and thermodynamically selective. For both the THF (5.6 mol%) and TBAC (3.3 mol%) solutions, the CO2 composition in the clathrate phase was almost constant during clathrate formation. However, the TBAC (3.3 mol%) solution showed significantly higher CO2 composition (∼74%) throughout the reaction, whereas the THF (5.6 mol%) solution exhibited enrichment of CH4 in the clathrate phase. The experimental results clearly demonstrate that CO2 selectivity is dependent on both kinetics and equilibrium of clathrate hydrates and that the addition of thermodynamic promoters, such as THF and TBAC, can affect kinetic CO2 selectivity as well as equilibrium CO2 selectivity in the clathrate phase.
- Published
- 2019
32. Hierarchically Porous Nanostructured Nickel Phosphide with Carbon Particles Embedded by Dielectric Barrier Discharge Plasma Deposition as a Binder-Free Electrode for Hybrid Supercapacitors
- Author
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Md. Mokter Hossain, Young Sun Mok, Sang-Jae Kim, Parthiban Pazhamalai, Gnanaselvan Gnanasekaran, Surjit Sahoo, Roshan Mangal Bhattarai, and Sudhakaran M.S.P
- Subjects
Supercapacitor ,Fabrication ,Materials science ,Renewable Energy, Sustainability and the Environment ,Phosphide ,General Chemical Engineering ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Dielectric barrier discharge ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Nickel ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Electrode ,medicine ,Environmental Chemistry ,0210 nano-technology ,Porosity ,Activated carbon ,medicine.drug - Abstract
Three-dimensional (3D) metal phosphides are promising superior electrode components for supercapacitors. In this study, 3D porous nickel phosphide nanoarrays are successfully enrooted on the surface of nickel foam (Ni2P/NF) by low-temperature hydrothermal treatment. Subsequently, a nanocarbon was embedded over Ni2P@NF by efficient utilization of the environmental pollutant ethylene gas via a dielectric barrier discharge plasma reactor. This nanocarbon was deposited on porous Ni2P/NF nanoarrays (Ni2P-C/NF) as a positive electrode sandwiched with peanut shell-derived porous activated carbon (PNS-AC) as a negative electrode for the fabrication of a hybrid supercapacitor device. The hybrid supercapacitor device (Ni2P-C/NF//PNS-AC) delivers an enormous amount of areal and gravimetric capacities values at a 1 A g–1 current density of 318.8 μAh cm–2 and 106.2 mAh g–1, respectively. Moreover, the hybrid supercapacitor device achieved outstanding energy and power density with excellent cyclic durability (90.1%) ev...
- Published
- 2019
33. Evaluation of the effect of electrospun nanofibrous membrane on removal of diazinon from aqueous solutions
- Author
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Afshin Maleki, Saeed Dehestani Athar, Reza Ghanbari, Lalhmunsiama, Behzad Shahmoradi, Reza Rezaee, Amir hossein Ziaee, Mehrdad Khamforoush, Mohammad Amin Pordel, Hiua Daraei, Mehdi Safari, and Seung-Mok Lee
- Subjects
Aqueous solution ,Diazinon ,Polymers and Plastics ,General Chemical Engineering ,Nanoparticle ,02 engineering and technology ,General Chemistry ,010501 environmental sciences ,Contamination ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Membrane ,chemistry ,Chemical engineering ,Materials Chemistry ,Environmental Chemistry ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Porosity ,Iron oxide nanoparticles ,0105 earth and related environmental sciences - Abstract
Widespread application of pesticides in agriculture results in contamination of water sources with such compounds. Diazinon is a major environmental challenge in Iran since it is one of the most commonly used pesticides with adverse effects on human health. Therefore, the current study aimed at fabricating and modifying electrospun nanofibrous membrane (ENM) using iron oxide nanoparticles, and investigating its efficiency in removing diazinon from aqueous environments. The current study investigated the effect of different parameters such as nanoparticle concentration in the membrane (0.01, 0.1, and 1%), and soluble parameters such as diazinon concentration (10, 20, 30, and 40 mg/l), pH (5, 7, and 9), and flux in the removal of diazinon from aqueous solutions. The characteristics of ENM were determined by FTIR, SEM, and XRD analysis, and results showed that, the pure nanofibrous membrane was uniform with mean diameter of 180 nm and porosity of 79%. The results also showed that the highest removal efficiency under optimal conditions (pH 7, diazinon concentration of 10 mg/l, and 0.1% nanoparticles) was 83.7%. The modified ENM with proper mechanical properties and porosity, and high flux can be applied as an effective and environment-friendly material to remove diazinon from aqueous solutions.
- Published
- 2019
34. Synthesis and characterization of Ag0(NPs)/TiO2 nanocomposite: insight studies of triclosan removal from aqueous solutions
- Author
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Alka Tiwari, Seung-Mok Lee, Lalliansanga, Alok Shukla, and Diwakar Tiwari
- Subjects
Materials science ,Aqueous solution ,Nanocomposite ,0208 environmental biotechnology ,Kinetics ,02 engineering and technology ,General Medicine ,010501 environmental sciences ,01 natural sciences ,020801 environmental engineering ,Triclosan ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Photocatalysis ,Environmental Chemistry ,Thin film ,Mesoporous material ,Hybrid material ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Nanocomposite mesoporous Ag0(NPs)/TiO2 thin film materials were synthesized and assessed for its efficient application in the elimination of potentially important drug triclosan from aqueous solutions. A template synthesis using the polyethylene glycol was enabled to obtain the Ag0(NPs)/TiO2 nanocomposite materials where zerovalent Ag was in situ doped to the titania network. The nanocomposite materials were characterized by the scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX) elemental mapping, X-ray diffraction (XRD) analyses and Brunauer-Emmett-Teller (BET) methods. Further, the diffuse reflectance spectroscopy (DRS) was introduced to estimate the band gap of these solids. The thin film materials were subjected for the remediation of water contaminated with triclosan using the UV-A light. The oxidative elimination of triclosan was demonstrated as a function of pH, concentration of triclosan and presence of several co-existing ions. Increase in pH (4.0–10.0) and triclosan concentrations (0.5–15.0 mg/L) had decreased significantly the percentage degradation of triclosan. The pseudo-first order kinetics was shown in degradation of triclosan and rate constant was significantly decreased with the increase in pollutant concentration (0.5–15.0 mg/L) and pH (4.0–10.0). The 1000 times presence of scavengers showed that •OH were, predominantly, caused the oxidation of triclosan. Moreover, multiple application of nanocomposite Ag0(NPs)/TiO2(B) revealed that the thin film was fairly intact since the photocatalytic efficiency of triclosan removal was almost unaffected.
- Published
- 2019
35. A large artificial dyke greatly alters partitioning of sulfate and iron reduction and resultant phosphorus dynamics in sediments of the Yeongsan River estuary, Yellow Sea
- Author
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Jin-Sook Mok, Sung-Han Kim, Jae-Hoon Choi, Jung-Ho Hyun, and Sung-Uk An
- Subjects
Total organic carbon ,geography ,Environmental Engineering ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Phosphorus ,chemistry.chemical_element ,Sediment ,Estuary ,010501 environmental sciences ,01 natural sciences ,Pollution ,chemistry.chemical_compound ,Water column ,chemistry ,Benthic zone ,Environmental chemistry ,River mouth ,Environmental Chemistry ,Sulfate ,Waste Management and Disposal ,0105 earth and related environmental sciences - Abstract
We investigated sediment geochemistry, partitioning of organic carbon (Corg) oxidation by iron reduction (FeR) and sulfate reduction (SR), and benthic phosphorus (P) release, together with the P speciation in the sediments to elucidate the P dynamics in two contrasting sediments (i.e., estuarine vs. limnetic) separated by a large dyke in the Yeongsan River estuary of the Yellow Sea. In the sediments of the Yeongsan River estuary (St. YE), SR dominated the Corg oxidation pathway, accounting for 81.7% of total anaerobic Corg oxidation. Under the SR-dominated condition, H2S derived from SR reacts quickly with iron oxides to form iron sulfides, which ultimately release the P bound to Fe(III) into the pore water. The enhanced benthic P flux (0.24 mmol m−2 d−1) at the YE site accounted for 80% of the P required for primary production in the water column. In contrast, in the limnetic sediments of the Yeongsan Lake (St. YL), where high levels of CH4 accumulated, most P was bound to Fe and Al, which resulted in a low benthic P flux (0.03 mmol m−2 d−1). The results suggest that the frequent discharge of relatively P-depleted freshwater into the estuary via the artificial dyke may result in relatively P-limiting conditions in estuarine ecosystems. As a result, benthic P release from the SR-dominated estuarine sediment is a significant internal source of P in the coastal ecosystem. Our results indicate that the construction of a large dyke at a river mouth greatly alters Corg oxidation pathways and P dynamics in coastal ecosystems.
- Published
- 2019
36. Desorption and solubilization of anthracene by a rhamnolipid biosurfactant fromRhodococcus fascians
- Author
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Dong Wan Lee, Chul Hwan Kim, Young Mok Heo, Gyu Hyeok Kim, Hanbyul Lee, Jae Jin Kim, and Yeonjae Yoo
- Subjects
Environmental remediation ,Polycyclic aromatic hydrocarbon ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Surface-Active Agents ,chemistry.chemical_compound ,Bioremediation ,Rhodococcus fascians ,020401 chemical engineering ,Desorption ,Rhodococcus ,Environmental Chemistry ,0204 chemical engineering ,Solubility ,Waste Management and Disposal ,Environmental Restoration and Remediation ,0105 earth and related environmental sciences ,Water Science and Technology ,Anthracenes ,chemistry.chemical_classification ,Anthracene ,Chromatography ,biology ,Ecological Modeling ,Rhamnolipid ,biology.organism_classification ,Pollution ,chemistry ,Environmental Pollutants ,Glycolipids - Abstract
The rhamnolipid biosurfactant-producing bacterium, strain SDRB-G7, was isolated from the sediment of Sindu-ri beach and identified as Rhodococcus fascians based on a phylogenetic analysis. Optimal activity, with the highest yield (2.441 g/L) and surface tension-reducing activity (24.38 mN/m), was observed when the cells were grown on olive oil as their sole source of carbon at pH 8.0. The rhamnolipid biosurfactant showed environmental stability at a variety of NaCl concentrations (2-20%) and pH values (2-12) even under acidic conditions. Of the initial anthracene, 66% was solubilized by 100% crude biosurfactant. Furthermore, 100% crude biosurfactant desorbed 81% of the anthracene in sediment into the aqueous phase. These results suggest that the rhamnolipid biosurfactant produced from R. fascians SDRB-G7 is a promising candidate for polycyclic aromatic hydrocarbon (PAH) removal from the sediment and can be an effective agent for processes that bioremediate PAHs such as surfactant-enhanced remediation. PRACTITIONER POINTS: Biosurfactants can accelerate desorption of PAHs and improve their solubility. BS-producing R. fascians SDRB-G7 was selected by screening of biochemical tests. Solubility of anthracene was enhanced by rhamnolipid produced by strain SDRB-G7. Microbial surfactant is a promising alternative for bioremediation of PAH-polluted sites.
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- 2019
37. Thermodynamic and kinetic influences of NaCl on HFC-125a hydrates and their significance in gas hydrate-based desalination
- Author
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Ju Dong Lee, Yongwon Seo, Seungmin Lee, Yohan Lee, Junghoon Mok, and Wonjung Choi
- Subjects
Chemistry ,Rietveld refinement ,General Chemical Engineering ,Sodium ,Clathrate hydrate ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Kinetic energy ,01 natural sciences ,Desalination ,6. Clean water ,Industrial and Manufacturing Engineering ,Dissociation (chemistry) ,0104 chemical sciences ,Environmental Chemistry ,0210 nano-technology ,Hydrate ,Powder diffraction - Abstract
Highlights • Thermodynamic and kinetic influences of NaCl on HFC-125a hydrate were investigated. • NaCl enrichment in the unconverted solution resulted in a lower conversion. • The presence of NaCl had little effect on the ΔH of HFC-125a hydrate. • The hydrate dissociation was retarded due to the formation of NaCl⋅2H2O. In this study, HFC-125a was selected as a hydrate-forming guest for gas hydrate-based desalination. The thermodynamic and kinetic effects of NaCl on HFC-125a hydrates were investigated with a primary focus on phase equilibria, gas uptake, dissociation enthalpy, and dissociation behavior. The equilibrium curve of HFC-125a hydrate shifted to higher pressure regions at any given temperature depending on the concentration of NaCl. The presence of NaCl also reduced the gas uptake and conversion to hydrates, because of the enrichment of NaCl in the solution during gas-hydrate formation. Even though NaCl did not affect the dissociation enthalpy of the HFC-125a hydrate, the thermograms obtained using a high-pressure micro-differential scanning calorimeter (HP μ-DSC) demonstrated that HFC-125a + NaCl hydrates started to dissociate at lower temperatures due to NaCl in unconverted solutions. Rietveld refinement of powder X-ray diffraction (PXRD) patterns indicated that the HFC-125a hydrate (sII) was transformed into Ih as it dissociated. The dissociation of HFC-125a + NaCl hydrates was retarded and completely ended at higher temperatures compared to the pure HFC-125a hydrate by the sodium chloride dihydrate (NaCl⋅2H2O). Overall, these results could facilitate a better understanding of HFC-125a hydrates in the presence of NaCl; further, they might also be useful in the design and operation of hydrate-based desalination plants using HFC-125a.
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- 2019
38. Biochar and clinoptilolite zeolite on selected chemical properties of soil cultivated with maize (Zea mays L.)
- Author
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Normah Awang Besar, Baba Musta, Osumanu Haruna Ahmed, Mohamadu Boyie Jalloh, Azwan Awang, Lum Mok Sam, Siti Wardah Zaidun, and Latifah Omar
- Subjects
agriculture waste ,Science ,Soil Science ,Plant Science ,010501 environmental sciences ,Environmental Science (miscellaneous) ,01 natural sciences ,clinoptilolite zeolite ,Soil pH ,Biochar ,Cation-exchange capacity ,lcsh:Agriculture (General) ,0105 earth and related environmental sciences ,Clinoptilolite ,Fen ,Chemistry ,Soil classification ,04 agricultural and veterinary sciences ,Ultisol ,tropical acid soil ,lcsh:S1-972 ,Soil conditioner ,Environmental chemistry ,040103 agronomy & agriculture ,Biochar,clinoptilolite zeolite,EFB-POME,tropical acid soil,agriculture waste ,0401 agriculture, forestry, and fisheries ,EFB-POME ,Soil fertility ,Agronomy and Crop Science - Abstract
Increase in cost of chemical fertilizers encourages the use of soil amendments such as biochar and zeolites to improve soil fertility. In this study, biochar produced from empty fruit bunch-palm oil mill effluent (EFB-POME) and clinoptilolite zeolite were used as soil amendments to improve soil fertility. The field experiment was carried out for two planting cycles to determine the effects of different rates of EFB POME biochar (0, 10, and 20 t ha -1 ), clinoptilolite zeolite (0, 1.25, and 2.5 t ha -1 ), and urea (60 and 120 kg ha -1 ) on selected soil chemical properties of Tanjung Lipat ( Typic Paleudults ). Biochar produced from EFB-POME increase soil total N, P, K, Ca, and Mg. The higher soil total N, P, K, Ca, and Mg could be related to the increase in soil pH, cation exchange capacity, and total organic carbon in soil with EFB-POME biochar but not with clinoptilolite zeolite. Thus, EFB-POME biochar was more suitable to be used in a tropical soil ( Typic Paleudults ) compared to clinoptilolite zeolite for improving the selected soil pH, CEC, TOC and available P, K, Ca and Mg.
- Published
- 2019
39. Occurrence and Sources of Synthetic Musk Fragrances in the Sewage Treatment Plants and the Han River, Korea
- Author
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Jin-Hyo Lee, Ju-Hee Hong, Seok-Ryul Oh, Hyunju Ha, Jun-Yeon Lee, Mok-Young Lee, Kyung-Duk Zoh, and Young-Min Lee
- Subjects
lcsh:Hydraulic engineering ,Geography, Planning and Development ,sewage treatment plant ,0211 other engineering and technologies ,Sewage ,02 engineering and technology ,010501 environmental sciences ,Aquatic Science ,Hair care ,01 natural sciences ,Biochemistry ,synthetic musk fragrance ,lcsh:Water supply for domestic and industrial purposes ,lcsh:TC1-978 ,Tributary ,AHTN ,HHCB ,Effluent ,0105 earth and related environmental sciences ,Water Science and Technology ,021110 strategic, defence & security studies ,geography ,Musk ketone ,lcsh:TD201-500 ,geography.geographical_feature_category ,business.industry ,musk ketone ,personal care product ,Synthetic musk ,Environmental chemistry ,Environmental science ,Sewage treatment ,business - Abstract
Levels of synthetic musk fragrances (SMFs) and various personal care products (PCPs) were measured in the Han River and its tributaries in Seoul, Korea. The most abundant SMF in all river and PCP samples was 4,6,6,7,8,8-hexamethyl-1,3,4,7-tetrahydrocyclopenta(g)sochromene (HHCB), followed by 1-(3,5,5,6,8,8-hexamethyl-6,7-dihydronaphthalen-2-yl)ethanone (AHTN), musk ketone (MK), and 1,1,2,3,3-pentamethyl-2,5,6,7-tetrahydroinden-4-one (DPMI). The most abundant SMF in both PCPs and the Han River samples was HHCB, followed by AHTN. Moving from upstream to downstream in the Han River, the median SMF concentration was 6.756, 2.945, 0.304, and 0.141 μg/L in the sewage treatment plant (STP) influents, effluents, tributaries, and mainstream, respectively, implying that effective SMF removal was achieved during the sewage treatment process, followed by dilution in the receiving water. Four STPs using advanced biological treatment processes had removal efficiencies of 58.5%, 56.8%, and 38.1% for HHCB, AHTN, and MK, respectively. The highest SMF concentrations in the tributaries were observed at locations close to the STPs. Our study confirmed that the main source of SMFs in the receiving water were sewage effluents containing untreated SMFs, which largely originate from household PCPs, especially hair care products (e.g., shampoo) and perfumes.
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- 2021
40. Removal of ethyl acetate in air by using different types of corona discharges generated in a honeycomb monolith structure coated with Pd/γ-alumina
- Author
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Young Sun Mok, Duy Khoe Dinh, Hyeongwon Jeon, Kyeong Hwan Yoon, Duc Ba Nguyen, Seong Bong Kim, Seungmin Ryu, Van Toan Nguyen, Md. Mokter Hossain, and Shirjana Saud
- Subjects
geography ,Environmental Engineering ,geography.geographical_feature_category ,Materials science ,Atmospheric pressure ,Health, Toxicology and Mutagenesis ,Direct current ,High voltage ,Pollution ,Honeycomb structure ,Chemical engineering ,Honeycomb ,Environmental Chemistry ,Monolith ,Waste Management and Disposal ,Corona discharge ,Space velocity - Abstract
A method based on the corona discharge produced by high voltage alternating current (AC) and direct current (DC) over a Pd/γ-Al2O3 catalyst supported on a honeycomb structure monolith was developed to eliminate ethyl acetate (EA) from the air at atmospheric pressure. The characteristics of the AC and DC corona discharge generated inside the honeycomb structure monolith were investigated by varying the humidity, gas hourly space velocity (GHSV), and temperature. The results showed that the DC corona discharge is more stable and easily operated at different operating conditions such as humidity, GHSV, and gas temperature compared to the AC discharge. At a given applied voltage, the EA conversion in the DC honeycomb catalyst discharge is, therefore, higher compared with that in the AC honeycomb catalyst discharge (e.g., 96% of EA conversion compared with approximately 68%, respectively, at 11.2 kV). These new results can open opportunities for wide applications of DC corona discharge combined with honeycomb catalysts to VOC treatment.
- Published
- 2021
41. Efficient and selective use of functionalized material in the decontamination of water: removal of emerging micro-pollutants from aqueous wastes
- Author
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Ralte Malsawmdawngzela, Dong-Jin Kim, Lalhmunsiama Siama, Seung-Mok Lee, and Diwakar Tiwari
- Subjects
Langmuir ,Aqueous solution ,General Medicine ,Human decontamination ,Grafting ,Silane ,chemistry.chemical_compound ,Adsorption ,chemistry ,Bentonite ,Environmental Chemistry ,Water treatment ,Waste Management and Disposal ,Water Science and Technology ,Nuclear chemistry - Abstract
The contamination of the aquatic environment with emerging micro-pollutants is a serious global concern. The aim of this investigation was to synthesize novel functionalized material (BNAPTES) precursor to natural bentonite in a single pot facile synthetic route. The material was utilized for efficient and selective removal of tetracycline (TC) and triclosan (TCS) in aqueous wastes. The grafting of silane was confirmed with the FT-IR (Fourier Transform Infra-Red) analysis and the EDX (Energy Dispersive X-ray) analysis showed the incorporation of amino group with the bentonite. The structural changes of clay due to silane grafting were studied with the help of XRD (X-ray Diffraction) and BET (Brunner-Emmett-Teller) surface area analyses. Batch adsorption studies showed that functionalized clay significantly increased the selectivity and adsorption capacity of bentonite for TC and TCS. The Langmuir monolayer adsorption capacity was found to be 15.36 and 17.15 mg/g for TC and TCS, respectively. The rapid uptake of TC and TCS by functionalized material followed pseudo-second-rate kinetics. Further, a total of 78% of TC and 73% of TCS were removed within 5 min of contact and the adsorption equilibrium was achieved within 120 min. The influence of background electrolytes and co-existing ions indicated that TC and TCS were selective towards BNAPTES. The loading capacities of the column packed with BNAPTES were found to be 56.00 and 44.42 mg/g for TC and TCS, respectively. Further, BNAPTES was found efficient even in real water treatment since the attenuation of TC and TCS was not affected significantly in the real water matrix.
- Published
- 2021
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42. Practical-scale honeycomb catalytic reactor coupled with non-thermal plasma for high-throughput removal of isopropanol
- Author
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Van Toan Nguyen, Md. Mokter Hossain, Kyeong Hwan Yoon, Young Sun Mok, Jin Hee Lee, Young-Jin Kim, Iljeong Heo, Duc Ba Nguyen, Shirjana Saud, Sang-Joon Kim, and Duy Khoe Dinh
- Subjects
geography ,Reaction mechanism ,geography.geographical_feature_category ,Materials science ,General Chemical Engineering ,chemistry.chemical_element ,General Chemistry ,Nonthermal plasma ,Industrial and Manufacturing Engineering ,Catalysis ,chemistry.chemical_compound ,Honeycomb structure ,chemistry ,Chemical engineering ,Honeycomb ,Acetone ,Environmental Chemistry ,Monolith ,Palladium - Abstract
A practical-scale sandwich-type honeycomb catalyst reactor incorporating non-thermal plasma was developed for the high-throughput removal of isopropanol (IPA) from air. The Pd/γ-Al2O3/honeycomb catalyst was fabricated by coating a cordierite monolith with γ-alumina powder on which to support the palladium (Pd). The supported catalyst showed good activity and the combination of the honeycomb structure with plasma produced a uniform plasma inside the catalyst chamber. The influence of different parameters, including the energy density (SIE), humidity, initial concentration, and flow rate, on the plasma characteristics and IPA removal efficiency was investigated. The results showed that the SIE has the strongest effect on the IPA removal efficiency. The efficiency of IPA removal was 94.5% and the CO2 selectivity was 85% for an SIE of 180 J/L. Using optical emission spectroscopy, we found that the increased formation of atomic oxygen and reactive species plays an essential role in the oxidation of IPA by plasma catalysis. The main byproducts were identified by GC-MS, which indicated that acetone is the major liquid product. A plausible reaction mechanism for the plasma-catalytic oxidation of IPA is proposed based on the intermediates and byproducts.
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- 2022
43. Creating new value of blast furnace slag as soil amendment to mitigate methane emission and improve rice cropping environments
- Author
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Snowie Jane C. Galgo, Ji Yeon Lim, Yeong Gyeong Kang, Pil Joo Kim, and Keon Mok Sohn
- Subjects
Environmental Engineering ,Nitrous Oxide ,Amendment ,engineering.material ,Soil ,chemistry.chemical_compound ,Human fertilization ,Japanese rice ,Environmental Chemistry ,Fertilizers ,Waste Management and Disposal ,biology ,food and beverages ,Agriculture ,Oryza ,biology.organism_classification ,Pollution ,Soil quality ,Silicate ,Agronomy ,chemistry ,Ground granulated blast-furnace slag ,engineering ,Environmental science ,Paddy field ,Fertilizer ,Methane - Abstract
Blast furnace slag (BFS), a by-product of iron making, has been utilized as silicate fertilizer in Korean and Japanese rice paddy. Silicate fertilizer, which has high contents of active iron and manganese as electron acceptor, was newly known to suppress methane (CH4) emission in flooded rice paddies, but the effect of its long-term application on rice cropping environment is still debatable. To evaluate the effect of silicate fertilization on suppressing CH4 emissions, the changes of CH4 index, indicating the ratio (%) of seasonal CH4 flux at the silicate fertilization treatment to that at the control, were generalized using the global investigation data (42 observations from 8 fields in Bangladesh, China, and Korea). Seasonal CH4 fluxes significantly decreased with increasing silicate fertilization levels. In CH4 index changes, 1.5 Mg ha−1 of silicate fertilizer application (the recommended level of rice cultivation in Korea) decreased by 15% of seasonal CH4 fluxes. Rice grain yield highly increased with increasing silicate fertilization rates and maximized at approximately 4 Mg ha−1 with 18% higher than no-silicate fertilization due to overall improvement of soil properties. To evaluate the long-term silicate fertilization effect on rice cropping environments, silicate (1.5 Mg ha−1 year−1) and non-silicate fertilization treatments were installed in a typical temperate-monsoon climate paddy field in South Korea in 1990. Periodic silicate fertilization significantly increased rice grain productivity by an average of 14% over the control for the last 28 years. This fertilization evidently improved rice quality without changes in chemical quality. Consecutive silicate fertilization effectively improved soil physical and chemical properties but did not increase any acid extractable heavy metal concentration in soil. In conclusion, BFS as silicate fertilizer could be a beneficial amendment to mitigate CH4 emission in the rice paddy and improve soil properties and rice productivity and quality without hazardous material accumulation.
- Published
- 2022
44. Efficient removal of anionic, cationic textile dyes and salt mixture using a novel CS/MIL-100 (Fe) based nanofiltration membrane
- Author
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Young Sun Mok, Gnanaselvan Gnanasekaran, Eunjin Jwa, Jeongho Han, M. S. P. Sudhakaran, Gangasalam Arthanareeswaran, and Dilafruz Kulmatova
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Environmental Engineering ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,02 engineering and technology ,Sodium Chloride ,010501 environmental sciences ,01 natural sciences ,Water Purification ,Chitosan ,chemistry.chemical_compound ,Spectroscopy, Fourier Transform Infrared ,Zeta potential ,Methyl orange ,Environmental Chemistry ,Coloring Agents ,0105 earth and related environmental sciences ,Fouling ,Textiles ,Public Health, Environmental and Occupational Health ,Cationic polymerization ,Membranes, Artificial ,General Medicine ,General Chemistry ,Pollution ,020801 environmental engineering ,Lysergic Acid Diethylamide ,Membrane ,chemistry ,Wastewater ,Nanofiltration ,Nuclear chemistry - Abstract
The purification of hazardous textile dyeing wastewater has exhibited many challenges because it consists of a complex mixture, including dyestuff, additives, and salts. It is necessary to fabricate membranes with enhanced permeability, fouling resistance, stability, and superior dyes and salts removal from wastewater. Incorporating a highly water stable metal-organic framework (MOFs) into membranes would meet the requirements for the efficient purification of textile wastewater. In this study, nanofiltration (NF) membranes are fabricated by incorporating MIL-100 (Fe) into the chitosan (CS) through film casting technique. The effect of MIL-100 (Fe) loadings on chitosan characterized by FT-IR, XRD, contact angle measurement, FESEM-EDS, XPS, zeta potential, and surface roughness analysis. The membrane characterization confirmed the enhanced surface roughness, pore size, surface charge, and hydrophilicity. The CS/MIL-100 (Fe) membrane exhibited an improved pure water flux from 5 to 52 L/m2h as well as 99% rejection efficiency for cationic methylene blue (MB) and anionic methyl orange (MO). We obtained the rejection efficiency trend for the MB mixed salts in the order of MgSO4 (Mg2+ - 51.6%, SO42− - 52.5%) > Na2SO4 (Na+ - 26.3%, SO42− - 29.3%) > CaCl2 (Ca2+ - 21.4%, Cl− - 23.8%) > NaCl (Na+ - 16.8%, Cl− - 19.2%). In addition, the CS/MIL-100 (Fe) composite membrane showed excellent rejection efficiency and antifouling performances with high recycling stability. These stunning results evidenced that the CS/MIL-100 (Fe) nanofiltration membrane is a promising candidate for removing toxic pollutants in the textile dyeing wastewater.
- Published
- 2021
45. Pandanus tectorius fruit extract promotes Hsp70 accumulation, immune-related genes expression and Vibrio parahaemolyticus tolerance in the white-leg shrimp Penaeus vannamei
- Author
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Mat Taib Mimi Iryani, Muhd Danish-Daniel, Anupa Anirudhan, Yeong Yik Sung, Patrick Sorgeloos, Tengku Sifzizul Tengku-Muhammad, Li Lian Wong, Yosie Andriani, Victor Tosin Okomoda, Mohd Effendy Abd Wahid, Min Pau Tan, and Wen Jye Mok
- Subjects
0301 basic medicine ,Pandanus tectorius ,Aquatic Science ,Median lethal dose ,Microbiology ,03 medical and health sciences ,Penaeidae ,Environmental Chemistry ,Animals ,HSP70 Heat-Shock Proteins ,Penaeus ,Pandanaceae ,biology ,Macrobrachium rosenbergii ,Plant Extracts ,Vibrio parahaemolyticus ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,Animal Feed ,Vibrio ,Immunity, Innate ,Shrimp ,Diet ,030104 developmental biology ,Fruit ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,Hepatopancreas - Abstract
Plants and herbal extracts are indispensable for controlling the spread of disease-causing bacteria, including those that infect aquatic organisms used in aquaculture. The use of plant or herbal extract is expected to be safe for aquatic animals and less harmful to the environment, as opposed to conventional therapeutic alternatives such as antibiotics that promote the occurrence of potential antibiotic-resistant bacteria when used improperly. The efficacy of Pandanus tectorius fruit extract in the regulation of Hsp70 expression, pro-phenoloxidase (ProPO), peroxinectin, penaeidin, crustin and transglutaminase, all immune peptides essential for Vibrio tolerance in white leg shrimp, Penaeus vannamei, was investigated in this study, which included the determination of the safety levels of the extract. Tolerance of shrimp against Vibrio parahaemolyticus, a pathogenic bacteria that causes Acute Hepatopancreas Necrosis Disease (AHPND), was assessed on the basis of median lethal dose challenge survival (LD50 = 106 cells/ml). Mortality was not observed 24 h after exposure of 0.5–6 g/L of the fruit extract, indicating that P. tectorius was not toxic to shrimp at these concentrations. A 24-h incubation of 2–6 g/L of the fruit extract increased shrimp tolerance to V. parahaemolyticus, with survival doubled when the maximum dose tested in this study was used. Concomitant with a rise in survival was the increase in immune-related proteins, with Hsp70, ProPO, peroxinectin, penaeidin, crustin and transglutaminase increased 10, 11, 11, 0.4, 8 and 13-fold respectively. Histological examination of the hepatopancreas and muscle tissues of Vibrio-infected shrimp primed with P. tectorius extract revealed reduced signs of histopathological degeneration, possibly due to the accumulation of Hsp70, a molecular chaperone crucial to cellular protein folding, tissue repair and immune response of living organisms, including Penaeid shrimp.
- Published
- 2020
46. Nonthermal plasma in practical-scale honeycomb catalysts for the removal of toluene
- Author
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Young Sun Mok, Young-Jin Kim, Sang-Joon Kim, Iljeong Heo, Duc Ba Nguyen, Md. Mokter Hossain, and Jin Hee Lee
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Environmental Engineering ,Materials science ,Health, Toxicology and Mutagenesis ,Drop (liquid) ,Humidity ,Plasma ,Nonthermal plasma ,Pollution ,Toluene ,Volumetric flow rate ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Environmental Chemistry ,Specific energy ,Waste Management and Disposal - Abstract
Nonthermal plasma combined with a practical-scale honeycomb catalyst of 5.0 cm in height and 9.3 cm in diameter was investigated for the removal of toluene. The creation of plasma in the honeycomb catalyst greatly depended on the humidity of the feed gas and the presence of metals on the honeycomb surface. Compared to the bare ceramic honeycomb, the metal-loaded one gave higher toluene removal efficiency because the decomposition of toluene by the plasma-generated reactive species occurred not only homogeneously in the gas phase but also heterogeneously on the catalyst surface. The present plasma-catalytic reactor was able to successfully remove about 80% of dilute toluene (15 ppm in air) at a large flow rate of 60 L/min with a specific energy input of 58 J/L. The honeycomb-based plasma-catalytic reactor system is promising for practical applications since it can overcome such problems as high-pressure drop and difficulty in scale-up encountered in packed-bed reactors.
- Published
- 2020
47. Exposure to phthalates and bisphenol analogues among childbearing-aged women in Korea: Influencing factors and potential health risks
- Author
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Sungkyoon Kim, Yunsun Jeong, Sori Mok, Sunmi Kim, Inae Lee, Kyungho Choi, Minkyu Park, Hyo-Bang Moon, and Jeongim Park
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Adult ,endocrine system ,Environmental Engineering ,Bisphenol ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,Phthalic Acids ,02 engineering and technology ,Urine ,Cosmetics ,010501 environmental sciences ,Diethyl phthalate ,urologic and male genital diseases ,01 natural sciences ,chemistry.chemical_compound ,Young Adult ,Phenols ,Environmental health ,Republic of Korea ,Environmental Chemistry ,Medicine ,Humans ,Benzhydryl Compounds ,0105 earth and related environmental sciences ,Exposure assessment ,business.industry ,Public Health, Environmental and Occupational Health ,Phthalate ,General Medicine ,General Chemistry ,Baseline data ,Environmental Exposure ,Pollution ,020801 environmental engineering ,Cumulative risk ,Chemistry ,chemistry ,Bisphenol S ,Female ,business ,hormones, hormone substitutes, and hormone antagonists - Abstract
Phthalates and bisphenol A (BPA), widely applied in industrial and consumer products, can affect hormones associated with the human reproductive system. Because the incidence of reproductive diseases is increasing, a comprehensive exposure assessment of phthalates and bisphenol analogues (BPs) is required for childbearing-aged women. Phthalate metabolites and BPs were measured in urine samples collected from 509 childbearing-aged women (20–48 years) in Korea to investigate their current exposure status, profiles, influencing factors, and potential health risks. DEHP metabolites and BPA were the dominant compounds found, indicating that they are highly consumed in daily life. Bisphenol S (BPS), as an alternative to BPA, was detected in most urine samples. Total concentrations of phthalate metabolites and BPs ranged from 3.42 to 3570 (GM: 45.6) ng/mL and from
- Published
- 2020
48. Near-field dynamics and plume dispersion after an on-road truck: Implication to remote sensing
- Author
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Chun-Ho Liu, Ziwei Mo, Wai-chuen Mok, Yuhan Huang, and Jingwei Xie
- Subjects
Jet (fluid) ,Environmental Engineering ,010504 meteorology & atmospheric sciences ,Turbulence ,Sampling (statistics) ,Aerodynamics ,010501 environmental sciences ,Wake ,01 natural sciences ,Pollution ,Plume ,Environmental Chemistry ,Environmental science ,Dispersion (water waves) ,Entrainment (chronobiology) ,Waste Management and Disposal ,Environmental Sciences ,0105 earth and related environmental sciences ,Remote sensing - Abstract
Apart from the aerodynamic performance (efficiency and safety), the wake after an on-road vehicle substantially influences the tailpipe pollutant dispersion (environment). Remote sensing is the most practicable measures for large-scale emission control. Its reliability, however, is largely dictated by how well the complicated vehicular flows and instrumentation constraint are tackled. Specifically, the broad range of motion scales and the short sampling duration (less than 1 s) are the most prominent ones. Their impact on remote sensing has not been studied. Large-eddy simulation (LES) is thus employed in this paper to look into the dynamics and the plume dispersion after an on-road heavy-duty truck at speed U∞ so as to elucidate the transport mechanism, examine the sampling uncertainty and develop the remedial measures. A major recirculation of size comparable to the truck height h is induced collectively by the roof-level prevailing flows, side entrainment and underbody wall jet. The tailpipe is enclosed by dividing streamlines so the plume is carried back to the truck right after emission. The recirculation augments the pollutant mixing, resulting in a more homogeneous pollutant distribution together with a rather high fluctuating concentration (over 20% of the time-averaged concentrations). The plume ascends mildly before being purged out of the major recirculation to the far field by turbulence, leading to a huge reduction in pollutant concentration (an order of magnitude) outside the near wake. In the far-field, the plume is higher than the tailpipe and disperses in a conventional Gaussian distribution manner. Under this circumstance, a sampling duration for remote sensing longer than h/U∞ would be prone to underestimating the tailpipe emission.
- Published
- 2020
49. Influence of iron mining activity on heavy metal contamination in the sediments of the Aqyazi River, Iran
- Author
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Moo Joon Shim, Behzad Shahmoradi, Afshin Maleki, Seung-Mok Lee, Kitirote Wantalla, Sahar Hajimirzaei, and Jamil Amanollahi
- Subjects
Pollution ,Geologic Sediments ,Metal contamination ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Iron ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Iran ,01 natural sciences ,Risk Assessment ,Mining ,Metals, Heavy ,Ecotoxicology ,0105 earth and related environmental sciences ,General Environmental Science ,media_common ,Sediment ,General Medicine ,Contamination ,Iron mining ,Wastewater ,Environmental chemistry ,Soil water ,Environmental science ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
In order to investigate the degree of contamination of heavy metals (As, Cd, Cr, Cu, Fe, Pb, and Ni) in the Aqyazi River in Iran, sediment samples were collected from the river receiving wastewater from an iron-manufacturing plant. For this study, contamination indices, geoaccumulation index (Igeo), contamination factor (CF), and pollution load index (PLI), were used to assess contamination by the heavy metals. The results of the Igeo indicated that the sediments were moderately contaminated by Cu and strongly to extremely contaminated by Cd. Based on spatial distribution of concentrations and the Igeo, mining activity was the source of Cu and Cd in the Aqyazi River. Furthermore, the elevated Igeo of Cd at upmost northern station was not influenced by the mining activity, suggesting that there may be another upstream anthropogenic source of Cd. The CF values indicated the same trend as the Igeo. The PLI was calculated using all the metals analyzed in this study, and displayed that the sediments were not polluted. However, the PLI was re-calculated using only Cu and Cd and indicated that the sediments were polluted. Our results suggest further studies to trace another source of Cd upstream of the Aqyazi River and to investigate influence of the river waters on accumulation of heavy metals in soils and vegetables downstream.
- Published
- 2020
50. Publisher Correction: Perovskites fabricated on textured silicon surfaces for tandem solar cells
- Author
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Jeewoong Yang, Stefan W. Glunz, Yoonmook Kang, Donghwan Kim, Seongtak Kim, Ji Yeon Hyun, Solhee Lee, Hae-Seok Lee, Dongjin Choi, Won-Kyu Lee, Kyung-Jin Cho, Won Mok Kim, Friedemann D. Heinz, Jae Keun Hwang, Sung Bin Choi, Soohyun Bae, Martin C. Schubert, Se Jin Park, Sang Won Lee, Dongkyun Kang, Sujeong Jeong, and Publica
- Subjects
Materials science ,Silicon ,Tandem ,business.industry ,chemistry.chemical_element ,General Chemistry ,Biochemistry ,lcsh:Chemistry ,lcsh:QD1-999 ,chemistry ,Materials Chemistry ,Environmental Chemistry ,Optoelectronics ,business - Abstract
Correction to: Communications Chemistry https://doi.org/10.1038/s42004-020-0283-4, published online 25 March 2020. The original version of this Article incorrectly designated Yoonmook Kang as a corresponding author and listed their e-mail address in error. This has now been corrected in the PDF and HTML versions of the Article.
- Published
- 2020
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