• Title/Summary/Keyword: Ultrasound irradiation

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Ultrasound-Assisted Micellar Extraction for Paclitaxel Purification from Taxus chinensis (Taxus chinensis 유래 파클리탁셀 정제를 위한 초음파를 이용한 마이셀 추출)

  • Park, Ji-Min;Kim, Jin-Hyun
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.106-111
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    • 2021
  • In this study, an ultrasound-assisted micellar extraction process was developed to efficiently purify the anticancer substance paclitaxel from the plant cell Taxus chinensis. The problem of many extraction steps and long phase separation time in the traditional micellar process could be dramatically improved. The highest paclitaxel yield (~96%, extracted twice) was obtained at 180 W of ultrasonic power and 1.5 h of ultrasonic irradiation time, which was 24.7% higher than that of the traditional method. In addition, the partition coefficient (K) showed a maximum value (24.0) at 180 W of ultrasonic power and 1.5 h of irradiation time. There was no significant difference in the purity of paclitaxel, and the purity of initial paclitaxel (6.81%) increased to 22.0% after purification. Compared to the traditional method, the phase separation time of the back extraction decreased by 40.7-56.2% (ultrasonic power 80 W), 46.3-67.6% (ultrasonic power 180 W), and 51.9-67.6% (ultrasonic power 250 W), respectively. The phase separation time decreased as the ultrasonic power (80-250 W) and irradiation time (0.5-2.5 h) increased.

A Study on the Treatment of Nondegradable Pollutants by Ultrasonic Irradiation (초음파에 의한 난분해성물질 처리에 관한 연구)

  • 손종열;모세영;문경환
    • Journal of Environmental Health Sciences
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    • v.21 no.3
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    • pp.102-106
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    • 1995
  • This study was performed to examine factors affecting the decompostion of nondegradable polluants(trichloroethylene(TCE), phenol) using ultrasonic irradiation. The TCE and phenol, which are major hazard compounds causing environmental pollution, were not decomposable pollutants by conventional treatment. The results show that the oxidation and reduction reaction of ultrasound produced $H_2O_2$, $H^+$ and $OH^-$ radical, which decomposed pollutants of TCE and phenol in water. It was confirmed that the ultrasonic irradiation showed an excellent removal efficiency for the nondegradable pollutants than any other processes, utilized in the treatment of organic compounds in the industrial wastewater. Conclusively, these results suggest that ultrasonic irradiation may be highly useful for the treatment of wastewaters contaminated organic pollutants, which is difficult to treat economically by conventional process.

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Heavy Metals Extraction from Contaminated Soils using Aqua Regia Extraction (왕수를 이용한 중금속 오염토양에서의 추출방안 연구)

  • Lee, Dukyoung;Jung, Sunkook;Son, Younggyu
    • Journal of Soil and Groundwater Environment
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    • v.23 no.2
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    • pp.15-22
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    • 2018
  • Aqua regia extraction for the quantification of heavy metals and As in contaminated soils was investigated as one of preliminary steps for on-site monitoring using sensor technology. Soil samples were taken from closed railway depot, closed mines, and closed refinery and various extraction conditions including $30^{\circ}C/15min$, $30^{\circ}C/30min$, $30^{\circ}C/60min$, $30^{\circ}C/120min$, $80^{\circ}C/15min$, $80^{\circ}C/30min$, $80^{\circ}C/60min$, $80^{\circ}C/120min$ were tested. The optimal extraction condition was determined as $80^{\circ}C/60min$ because the extraction efficiencies of Zn were relatively low and did not reach the targeted level (80-100% of original concentrations) for $30^{\circ}C$ conditions. It was found that the fractionation of heavy metals and As using the sequential extraction method was useful to understand the degree of metal extraction. In order to enhance the extraction efficiency within short extraction time, ultrasound technology using a 20 kHz horn-type sonicator was additionally used for $30^{\circ}C/15min$. It was revealed that ultrasound could significantly enhance the extraction efficiency and pulsed irradiation showed higher efficiency than continuous irradiation due to the less formation of bubble clouds. However high temperature condition ($80^{\circ}C$) was required to achieve high extraction efficiency for Zn in spite of the use of ultrasound.

Clinical Result of Combined Radiotherapy and Hyperthermia Induced by 915 MHz Microwave and Ultrasound in Locally Advanced Malignant Tumors of Head and Neck (915 MHz 극초단파 및 초음파를 이용한 온열치료와 방사선치료 병합치료에 의한 두경부암의 치료성적)

  • Koh Kyoung-Hwan;Park Young-Hwan;Cho Chul-Koo;Yoo Seong-Yul
    • Korean Journal of Head & Neck Oncology
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    • v.6 no.1
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    • pp.40-45
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    • 1990
  • Thirty five lesions of 35 patients with locally advanced malignant tumors of head and neck were received thermoradiotherapy with ultrasound and/or 915 MHz microwave. Most of all patients were failed with previous conventional therapeutic trial. Hyperthermia had been done immediately after radiotherapy, twice a week, $43^{\circ}C$ for one hour and radiotherapy had been done 5 fractions per week with a fraction size of 2 Gy up to total 30 to 60 Gy. Conclusions are as follows; 1) Total response rate (CR+PR) of thermoradiotherapy with microwave and ultrasound was 80%. 2) Tumor depth, minimum temperature of tumor center, number of heat fraction and irradiation dose were statistically significant factors affecting response. 3) Hyperthermia with microwave and ultrasound can be used efficiently to control locally advanced malignant tumors in head and neck whether previously received near tolerance dose of radiotherapy or not.

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Embryonic Effects of Ultrasound Irradiation on Preimplantation Stage of ICR Mouse Embryos - About embryonic death and malformation of ultrasound mechanisms - (초음파(超音波)에 대한 ICR Mouse 착상전기(着床前期)의 개체(個體) Level 영향(影響)(기형(奇形).배사망.(胚死亡))으로부터 초음파(超音波)의 물리학적(物理學的) 특성(特性)에 대한 연구(硏究))

  • Song, Jae-Kwan;Kim, Ye-Hyun
    • Journal of radiological science and technology
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    • v.18 no.2
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    • pp.75-86
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    • 1995
  • Embryos and fetuses are more sensitive to various environmental agents than adults of children biological effects following the exposure, such as intrauterin, malformation, have intimate conception with the prenatal exposure. There have been many studies on radiation and other agent. However, imformation about the ultrasound effects is limited. It is very important to study the effect of ultrasound with these kinds of fatera in consideration of ultrasound protection and safty. In this study, embryonic and fefal effects of ICR mouse embryos irradiated on 24, 48, 12 and 192 hpc of preimplantation and organogenesis period at the intensity of $0.5{\sim}3\;W/cm^2$ were investigated. Many type of external malformation observed in mouse irradiated on 72 hpc and 192 hpc. However, the embryos irradiated on 24 hpc and 48 hpc, at witch embryos had less then 6 cells and were pre-compaction stage, had no sensitivity for external malformation. The threshold doses of external malformation in mouse irradiated on 72 hpc and 192 hpc, at which embryos were consisted of $16{\sim}32$ cells and neural formation stage, were $1\;W/cm^2$ and $0.5\;W/cm^2$.

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Characteristics of TCE, Benzene & 2,4 Dichlorophenol Degradation in Aqueous solution by Ulrasonic Irraditation (초음파 조사에 의한 수중의 TCE, Benzene & 2,4 Dichlorophenol의 분해 특성)

  • 손종렬;모세영
    • Journal of environmental and Sanitary engineering
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    • v.11 no.2
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    • pp.33-41
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    • 1996
  • This study was performed to examine the factors influencing on the degradation of TCE, Benzene and 2,4 DCP in aqueous solution using ultrasonic irradiation. The TCE,Benzene and 2,4 DCP, which are hazard compounds causing environmental pollution, were not decomposable pollutants by convientional treatment. The results shows that the generation of H$_{2}$O$_{2}$, H$^{+}$ and OH$^{-}$ radical was formed by the oxidation and reduction reaction of ultrasound, and then theses decomposed the refractory pollutants of TCE, Benzene & 2,4 DCP in aqueous solution. we conformed that the ultrasonic irradiation was excellent in removal efficiency of the refractory pollutants any other than Advanced Oxidation Processes(AOP), utilized the treatment of organic compounds in the industrial wastewater. Consequently, these results suggest that ultrasonic irradiation may be extremely useful for the treatment of wastewaters contaminated organic pollutants, which is difficult to treat economically by conventional process.

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Improvement of Fouling in Membrane Separation Process for Leachate Treatment using Ultrasound(II) : Analysis of Membrane Materials, Solutes and Multi-ultrasonic Effect (초음파를 이용한 침출수 처리를 위한 막분리 공정의 막힘현상 개선(II) : 막의 재질, 용질과 복합초음파의 효과 분석)

  • Kim, Seok-Wan;Lim, Jae-Lim;Lee, Jun-Geol
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.2
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    • pp.207-215
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    • 2006
  • This study evaluated the effect of ultrasonic irradiation on reducing membrane fouling for the treatment of chemically treated leachate and biologically treated leachate. The experiments on improvement of membrane flux according to the membrane types(MF and UF) and membrane materials were performed with changing frequency(40 kHz and 120 kHz) and intensity(200 W and 400 W) of ultrasound in ultrasonic membrane separation apparatus which ultrasound can be periodically irradiated. Additionally, the effect of dual frequency ultrasound which 40 kHz md 120 kHz are irradiated simultaneously was evaluated. The improvement of membrane flux by periodical ultrasound irradiation was higher in microfiltration(MF) membrane than in ultrafiltration(UF) membrane. It was sustained more in the MF membrane of polyvinylidene fluoride(PVDF) than in that of polysulfon(PS). Ultrasonic improvement of membrane flux was different depending on the characteristics of target wastewater. It was sustainably maintained without reclogging using dual frequency ultrasound although the improvement of membrane flux was lower.

Rheological properties of branched polycarbonate prepared by an ultrasound-assisted intensive mixer

  • Kim, Hyung-Su;Lee, Hoo-Seok;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.19 no.1
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    • pp.1-5
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    • 2007
  • By combining ultrasonic energy which is essential for the chain scission of polymer molecules and a multifunctional agent (MFA) having double bonds at its ends, we were able to modify the molecular structure of polycarbonate (PC) from linear to a branched structure during melt processing. The three double bonds in chain ends of MFA were expected to act as sites for trapping macroradicals of PC during the course of ultrasound-assisted mixing process. The transformation of molecular structure of PC was confirmed by the measurements of rheological properties of the modified PC. After the ultrasonic irradiation of PC together with MFA, increase in complex viscosities and shear-thinning behavior were observed. The Cole-Cole plot and measurement of extensional viscosities revealed the characteristic features of branched structure with well-defined extensional behavior which is comparable to that of a commercial branched PC.

Removal Characteristics of Organic Contaminants by Ultrasonic Soil Washing (토양 세척 시 초음파 적용에 따른 유기 오염물 제거 특성 평가)

  • Lim, Chan-Soo;Kim, Seog-Ku;Kim, Weon-Jae;Ko, Seok-Oh
    • Journal of Soil and Groundwater Environment
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    • v.19 no.6
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    • pp.72-79
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    • 2014
  • Cavitation generated by ultrasonic irradiation can enhance the diffusional transport of organic contaminants from soil surfaces or pores. Therefore, ultrasound soil washing can be an alternative of traditional soil washing process. In this study, soil was artificially contaminated with n-tetradecane, n-hexadecane and phenanthrene. A plate type ultrasonic reactor at 25 kHz frequency and 1000W power was used for laboratory soil washing experiments. Ultrasonic soil washing efficiency was compared with those of traditional soil washing using mechanical mixing. Various operational parameter such as soil/liquid ratio, irradiation time, particle size, and soil organic matter content was tested to find out the optimum condition. It was found that ultrasonic soil washing demonstrates better performance than mechanical soil washing. Optimum soil:liquid ratio for ultrasonic soil washing was 1 : 5. Desorption of organic contaminants from soils by ultrasonic irradiation was relatively fast and reached equilibrium within 10 minute. However, decrease in the soil particle sizes by ultrasonic irradiation results in re-adsorption of contaminants to soil phase. It was also observed that soil particle size distribution and soil organic matter content have significant effects on the efficiency of ultrasonic soil washing.

Characteristics of the sonolytic reaction of refractory aromatic compounds in aqueous solution by ultrasound (초음파에 의한 수중의 난분해성 방향족화합물의 반응특성)

  • Sohn, Jong-Ryueul;Mo, Se-Young
    • Journal of Korean Society on Water Environment
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    • v.18 no.4
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    • pp.411-419
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    • 2002
  • In this study, the series of ultrasonic irradiation for removal of refractory aromatic compounds has been selected as a model reaction in the batch reactor system in order to obtain the reaction kinetics. The products obtained from the ultrasonic irradiation were analysed by GC and GC/MSD. The decomposition of benzene produced toluene, phenol, and C1-C4 compounds, while the intermediates during the ultrasonic irradiation of 2,4-Dichlorophenol(DCP) were phenol, HCl, catechol, hydroquinone, and benzoquinone. It was found that more than 80% of benzene, and 2,4-DCP solutions were removed within 2 hours in all reaction conditions. The reaction order in the degradation of these three compounds was verified as pseudo-zero or first order. From the fore-mentioned results, it can be concluded that the refractory organic compounds could be removed by the ultrasonic irradiation with radicals, such as $H{\cdot}$ and $OH{\cdot}$ radical causing the high increase of pressure and temperature. Finally, it appeared that the technology using ultrasonic irradiation can be applied to the treatment of refractory compounds which are difficult to be decomposed by the conventional methods.