• Title/Summary/Keyword: P adsorption

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Establishment of Analytical Method for Methylmercury in Fish by Using HPLC-ICP/MS (고성능액체크로마토그래피-유도결합플라즈마 질량분석기를 이용한 어류 중 메틸수은 분석법 확립)

  • Yoo, Kyung-Yoal;Bahn, Kyeong-Nyeo;Kim, Eun-Jung;Kim, Yang-Sun;Myung, Jyong-Eun;Yoon, Hae-Seong;Kim, Mee-Hye
    • Korean Journal of Environmental Agriculture
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    • v.30 no.3
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    • pp.288-294
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    • 2011
  • BACKGROUND: Methylmercury is analyzed by HPLC-ICP/MS because of the simplicity for sample preparation and interference. However, most of the pre-treatment methods for methylmercury need a further pH adjustment of the extracted solution and removal of organic matter for HPLC. The purpose of this study was to establish a rapid and accurate analytical method for determination of methylmercury in fish by using HPLC-ICP/MS. METHOD AND RESULTS: We conducted an experiment for pre-treatment and instrument conditions and analytical method verification. Pre-treatment condition was established with aqueous 1% L-cysteine HCl and heated at $60^{\circ}C$ in microwave for 20 min. Methylmercury in $50{\mu}L$ of filtered extract was separated by a C18 column and aqueous 0.1% L-cysteine HCl + 0.1% L-cysteine mobile phase at $25^{\circ}C$. The presence of cysteine in mobile phase and sample solution was essential to eliminate adsorption, peak tailing and memory effect problems. Correlation coefficient($r^2$) for the linearity was 0.9998. The limits of detection and quantitation for this method were 0.15 and $0.45{\mu}g/kg$ respectively. CONCLUSION: Result for analytical method verification, accuracy and repeatability of the analytes were in good agreement with the certified reference materials values of methylmercury at a 95% confidence level. The advantage of the established method is that the extracted solution can be directly injected into the HPLC column without additional processes and the memory effect of mercury in the ICP-MS can be eliminated.

Applied-Mineralogical Characterization and Assessment of Some Domestic Bentonites (II): Mineralogical Characteristics, Surface Area, Rheological Properties, and Their Relationships (국내산 벤토나이트에 대한 응용광물학적 특성 평가 (II): 광물학적 특징, 체표면적 및 유변학적 특성과 그 연계성)

  • 노진환;유재영;최우진
    • Journal of the Mineralogical Society of Korea
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    • v.16 no.1
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    • pp.33-47
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    • 2003
  • Various applied-mineralogical characterization including measurements of surface area, size distribution, swelling index, and viscosity were done for some domestic bentonites in order to decipher the rheological properties and their controlling factors. The bentonites, which are Ca-type and relatively low-grade (rnontmorillonite contents: 30 ∼ 75 wt%), occur mostly as subhedral lamellas with the size range of 2 ∼ 4 $\mu\textrm{m}$. The size distribution of mineral fractions in bentonite suspension is dominant in the range of 10 ∼ 100 $\mu\textrm{m}$, and though rather complicated, exhibits roughly bimodal patterns. The feature is more conspicuous in the case of zeolitic bentonite. The bentonites have surface areas ranging 269 ∼ 735 $\m^2$/g, which are measured by EGME adsorption method. The EGME surface areas are nearly proportional to the rnontmorillonite contents, moisture contents, or total CEC. In the surface area measurements, zeolitic bentonites have slightly higher values than those zeolite- free types. The measured swelling index and viscosity of domestic bentonites are comparatively low in values. The swelling values of bentonites were measured to be 250∼500% at maximum by progressively mixing amounts of 2 ∼ 5 wt% Na$_2$CO$_3$, which varies depending on the contents of rnontmorillonite and other impurities, especially zeolite. Much amount of sodium carbonate is required for optimum swelling property of zeolitic bentonited which has usually strong Na- exchanged capacity. The bentonites, which are comparatively feldspar-rich and low in size and crystallinity, tend to be higher in viscosity values. Tn addition, the viscosity is largely higher in case of the bentonites with higher pH in suspension. However, the rheological properties of bentonites such as swelling index and viscosity do not show any obvious relationships with rnontmorillonite contents and mean particle size in suspension. In contrast, roughly speaking, the swelling index of bentonites is reversely proportional to the values of surface area which can be regarded as a collective physico-chemical parameter encompassing all the effects caused by mineral composition, surface charge, particle size, morphological farm, and etc. in bentonites. Thus, the rheological properties in bentonite suspension appear to be rather complicated characteristics which mainly depend on the flocculation of clay particles and the mode of particle association, i.e. quasicrystals, controlled by surface charge, morphology, size, and texture of rnon-tmorillonite, and which partly affected by the finer impurities such as zeolite.

A Study of the Utilization of Feldspathic Sand as a Fortified Functional Filtering Material for Water Purification (고 기능성 수질 정화 여과재로서의 장석질 모래 활용연구)

  • 고상모;송민섭;홍석정
    • Journal of the Mineralogical Society of Korea
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    • v.16 no.4
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    • pp.283-293
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    • 2003
  • Domestic water treatment plants operate the rapid and slow filtering system using the filtering sands. Most of them are composed of beach sands, which have less sorption capacity of heavy metals as well as organic contaminants. Therefore, the development of fortified functional filtering materials with high removal capacity of organic and inorganic contaminants is needed to prevent the unexpected load of contaminated source water. This study aims to test the hydrochemical change and the removing capacity of heavy metals such as Cd, Cu, and Pb on the Jumunjin sand, feldspathic sand(weathering product of Jecheon granite), feldspathic mixing sand I(feldspathic sand mixed with 10 wt% zeolite), and feldspathic mixing sand II (feldspathic sand mixed with 20 wt% zeolite). Feldspathic mixing sand I and II showed the eruption of higher amounts of cations and anions compared with the Jumunjin sand and feldspathic sand. They also showed higher eruption of Si, Ca, $SO_4$ ions than that of Al, $NO_3$, Fe, K, Mg, and P. Feldspathic mixing sand II caused higher eruption of some cations of Na, Ca, Al than feldspathic mixing sud I, which is the result controlled by the dissolution of zeolite. Jumunjin sand and feldspathic sand showed very weak sorption of Cd, Cu and Pb. In contrast to this, feldspathic mixing sand I and II showed the high sorption and removal capacity of the increasing order of Cd, Cu and Pb. Feldspathic mixing sand II including 20% zeolite showed a fortified removal capacity of some heavy metals. Therefore, feldspathic mixing sand mixed with some contents of zeolite could be used as the fortified filtering materials for the water filtering and purification in the domestic water treatment plants.

Identification of Antagonistic Bacteria, Pseudomonas aurantiaca YC4963 to Colletotri­chum orbiculare Causing Anthracnose of Cucumber and Production of the Antibiotic Phenazine-l-carboxylic acid (Colletotrichum orbiculare에 대한 길항세균 Pseudomonas aurantiaca YC4963의 분리 동정 및 항균물질 Phenazine-1-carboxylic acid의 생산)

  • Chae Hee-Jung;Kim Rumi;Moon Surk-Sik;Ahn Jong-Woong;Chung Young-Ryun
    • Korean Journal of Microbiology
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    • v.40 no.4
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    • pp.342-347
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    • 2004
  • A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens Makino in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bac­terial strain was identified as Pseudomonas aurantiaca. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antifungal activity was found from the culture filtrate of this isolate and the active compound was quantitatively bound to XAD adsorption resin. The antibiotic compound was purified and identified as phenazine-l-carboxylic acid on the basis of combined spectral and chemical analyses data. This is the first report on the production of phenazine-l-carboxylic acid by Pseudomonas aurantiaca.

Photocatalytic Oxidation of Arsenite Using Goethite and UVC-Lamp (침철석과 UVC-Lamp를 이용한 아비산염의 광촉매 산화)

  • Jeon, Ji-Hun;Kim, Seong-Hee;Cho, Hyen-Goo;Kim, Soon-Oh
    • Economic and Environmental Geology
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    • v.50 no.3
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    • pp.215-224
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    • 2017
  • Arsenic (As) is known to be the most toxic element and frequently detected in groundwater environment. Inorganic As exists as arsenite [As(III)] and arsenate [As(V)] in reduced and oxidized environments, respectively. It has been reported that the toxicity of arsenite is much higher than that of arsenate and furthermore arsenite shows relatively higher mobility in aqueous environments. For this reason, there have been numerous researches on the process for oxidation of arsenite to arsenate to reduce the toxicity of arsenic. In particular, photooxidation has been considered to be simple, economical, and efficient to attain such goal. This study was conducted to evaluate the applicability of naturally-occurring goethite as a photocatalyst to substitute for $TiO_2$ which has been mostly used in the photooxidation processes so far. In addition, the effects of several factors on the overall performance of arsenite photocatalytic oxidation process were evaluated. The results show that the efficiency of the process was affected by total concentration of dissolved cations rather than by the kind of those cations and also the relatively higher pH conditions seemed to be more favorable to the process. In the case of coexistence of arsenite and arsenate, the removal tendency by adsorption onto goethite appeared to be different between arsenite and arsenate due to their different affinities with goethite, but any effect on the photocatalytic oxidation of arsenite was not observed. In terms of effect of humic acid on the process, it is likely that the higher concentration of humic acid reduced the overall performance of the arsenite photocatalytic oxidation as a result of competing interaction of activated oxygen species, such as hydroxyl and superoxide radicals, with arsenite and humic acid. In addition, it is revealed that the injection of oxygen gas improved the process because oxygen contributes to arsenite oxidation as an electron acceptor. Based on the results of the study, consequently, the photocatalytic oxidation of aqueous arsenite using goethite seems to be greatly feasible with the optimization of process.

Synthesis of Artificial Zeolite from Fly Ash for Preparing Nursery Bed Soils and the Effects on the Growth of Chinese Cabbage (석탄회(石炭灰)를 이용한 육묘(育苗) 상토용(床土用) 인공(人工) 제올라이트의 제조와 배추 생육에 미치는 효과(效果))

  • Kim, Yong-Woong;Lee, Hyun-Hee;Yoon, Chung-Han;Shin, Bang-Sup;Kim, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.31 no.2
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    • pp.95-106
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    • 1998
  • To reduce the environmental contamination and to utilize fly ash massively produced from the coal power plant every year, we synthesized the artificial zeolite using fly ash treated with alkaline, and then analyzed the mineralogical and morphological properties by X-ray, IR, and SEM. The amount of $NH_4{^+}$, $K^+$, and $H_2PO_4{^-}$ adsorbed by the fly ash and the artificial zeolite were determined with reaction time, amount of adsorbate used, ion concentrations. The results obtained from the pot experiments packed with the top soil, amended with granulated artificial zeolite which was made by treatment of 4% polyvinylalcohol, showed that CEC of the artificial zeolite was $257.7cmol^+kg^{-1}$, that was almost 36 times greater than that of fly ash. The ratio of $SiO_2/Al_2O_3$ decreased but the amount of Na increased. The physico-chemical properties analyzed by X-ray, IT, and SEM represented that the artificial zeolite synthesized had a similar morphological structure to that of the natural zeolite. The structures of the artificial zeolite had a significantly enlarged surface having a lot of pores, while the fly ash looked like spherical smooth shape with having not pores on the surface. Thus, the artificial zeolite was successfully synthesized. The results of adsorption isotherms of fly ash and artificial zeolite showed that the amount of $NH_4{^+}$, $K^+$, and $H_2PO_4{^-}$ adsorbed increased as the equilibrium concentration increased, while $NH_4{^+}$ was strongly adsorbed on the surface of fly ash and artificial zeolite than that of $K^+$. The most distinctive growth of Chinese cabbage was found from the top soil(NPK + soils + 20% of granulated artificial zeolite + 5% of compost). Therefore, we concluded that one of the most effective methods to effectively recycle a fly ash was to make the artificial zeolite as we did in this experiment.

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Mineralogical Study on the Clay Formation and Heavy Metal Speciation in the Acidified Soil Profile of the Onsan Industrial Area (온산공업지역 산성 토양 프로화일 내에서의 점토광물의 생성과 중금속 이온의 거동에 관한 광물학적 연구)

  • 이상수;김수진
    • Journal of the Mineralogical Society of Korea
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    • v.15 no.1
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    • pp.1-10
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    • 2002
  • The present study is focused on the granite weathering and soil formation, and the heavy metal contamination in soils in the Onsan industrial area. For profile study, soil sampling was conducted on each depth and experimental analyses have been conducted on those samples. X-ray diffraction analyses show that clay minerals consist mainly of kaolin minerals, vermiculite, and minor illite. Most of kaolin minerals in the lower kiwi of the profile consist of halloysite as confirmed by formamide intercalation, but the content of halloysite decreases gradually toward the surface since it has been transformed to kaolinite in the upper part of the profile. Thermal treatment by heating at $110^{\circ}C,\;300^{\circ}C,\;and\;550^{\circ}C$ shows a diffuse and broad peak the between 10 and $14\;{\AA}$ region in X-ray diffractograms. This suggests the possible existence of the hydroxy-Al interlayerecl vermiculite. Na-citrate extraction method reaconfirms this result showing transition of $14\;{\AA}$ peak to $10\;{\AA}$ In by removing the interlayer materials and restoring the vermiculite to its original state. The occurrence of hydroxy-Al interlayered vermiculite is also supported by soil pH distribution room 3.9 In the lower part to 3.6 in the upper part of the profile. Sequential extraction experiment was conducted to investigate the states of heavy metals in soils. The experiment shows that relatively high amounts of heavy metals are concentrated in the upper part of the profile and that most of them are bound to Fe/Mn oxides and organic matters while less concentration in clay minerals. The result indicates that most of heavy metal pollutants are concentrated in the surface soil and that the low concentrations of heavy metals in clays are mainly due to the low adsorption capacities of clay minerals such as kaolin minerals and hydroxy-Al interlayered vermiculite in acidified soil condition.

Exploration of Virulence Markers and Genes of Listeria monocytogenes Isolated from Animal Products (축산물유래 Listeria monocytogenes의 virulence marker 및 gene 조사)

  • Yi, Chul-Hyeon;Song, Hyeon-Ho;Kim, Mi-Ryung;Kang, Ho-Jo;Son, Won-Geun
    • Journal of Food Hygiene and Safety
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    • v.23 no.3
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    • pp.248-256
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    • 2008
  • To investigate the epidemiological characteristics of 68 Listeria monocytogenes isolates, including 11 reference strains and 57 isolates from imported US beef, domestic meats(beef, pork, chicken meat), raw milk, and milk plants. L. monocytogenes was to evaluate the production of virulence proteins, such as hemolysin(LLO) and lecithinase(LCP), the adsorption of Congo red(CRA), and to detect virulence genes using the polymerase chain reaction(PCR). In the study of virulence protein production, 68(100%), 62(91.2%), and 54(79.4%) of the 68 L. monocytogenes strains were positive for LLO production, the LCP test, and the CRA test, respectively, while strains of other species, such as L. innocua, L. gray, L. murrayi, and L. welshimeri, were not. There were no significant differences between L. monocytogenes serotypes and the ability to produce LLO or LCP. L. monocytogenesstrains had very high hemolytic titers(2 to 16 fold), while the other Listeria species, other than L. ivanovii and L. seeligeri, did not. The hemolysin activities of L. monocytogenes, L. ivanovii, and L. seeligeri usually exceeded 1.0 HU/mg, while those of other Listeria spp. were less than 0.04 HU/mg. In the PCR assay, all of the L. monocytogenes strains contained the hlyA, plcA, plcB, inlA, and inlB virulence genes and produced a product of the expected size. In the PCR of the actA gene, the expected 385-bp product was seen in 39(57.4%) L. monocytogenesstrains, while an unexpected 268-bp product was seen in 29(42.6%) strains. Most L. monocytogenes strains isolated from Hanwoo beef produced the 385-bp actA gene product, while strains of imported US beef usually produced the 268-bp actA gene product. By contrast, no virulence gene products were amplified in the other Listeria spp.

Screening and Identification of a Cesium-tolerant Strain of Bacteria for Cesium Biosorption (환경유래의 세슘 저항성 균주 선별 및 세슘 흡착제거 연구)

  • Kim, Gi Yong;Jang, Sung-Chan;Song, Young Ho;Lee, Chang-Soo;Huh, Yun Suk;Roh, Changhyun
    • Korean Journal of Environmental Biology
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    • v.34 no.4
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    • pp.304-313
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    • 2016
  • One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.