• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.26-32
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• 2009

In this study, the degradation of BTEX (benzene, toluene, ethylbenzene, xylene) was tested in both (Fe$^{3+}$+chelating agent)/H$_2$O$_2$system [Fe(III) 1 mM, oxalate 6 mM, H$_2$O$_2$ 3%, and pH 6] and UV/(Fe3++ chelating agent)lHzOz system [UV dose 17.4 kWhlL, Fe(III) 1mM, oxalate 6 mM,H$_2$O$_2$ 1%, and pH 6]. The types of chelating agents used in experiments were catechol, NTA, gallic, acetyl acetone, succinic, acetate, EDTA, citrate, malonate, and oxalate and the optimum chelating agent for BTEX degradation was determined. The results showed that acetate was the optimum chelating agent for BTEX degradation in both (Fe$^{3+}$+chelating agent)/H$_2$O$_2$ and UV/(Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system, and UV radiation enhanced the degradation of BTEX with any types of chelating agents. Moreover, UV/(Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system, which chelating agent was acetate, removed effectively mixtures of BTEX and MTBE (methyl tert-butyl ether) when the concentration of both BTEX and MTBE was 200 mg/L, respectively. In this system, BTEX was degraded completely and 85% of MTBE was degraded at the reaction time of 180 min. Therefore, UV/((Fe$^{3+}$+chelating agent)/H$_2$O$_2$ system with acetate as a chelating agent removed not only BTEX but also BTEX and MTBE, effectively.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.1
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• pp.31-37
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• 2015

Chelating agents 1,4,7-triazacyclononanetriacetic acid (NOTA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and 30-amino-3,14,25-trihydroxy-3,9,14,20,25-penta-azatriacontane-2,10,13,21,24-pentaone (desferrioxamine, DFO) were labeled with $^{68}Ga$ and tested in vitro properties to check the feasibility of using DFO as a bifunctional chelating agent or renal imaging agent. The chelating agents of concentration $2{\mu}M$ were labeled with $^{68}Ga$ in 0.1 M HCl at pH 1.7-10.3 at room temperature and $80^{\circ}C$ and the optimal pH for labeling each chelating agent was found. And then, the chelating agents were labeled with $^{68}Ga$ in various concentration of chelating agents at optimal pH. The labeled chelating agents were subject to stability test in human serum and to binding studies to human red blood cell (RBC) and plasma protein. The optimal pH's of NOTA, DOTA and DFO for $^{68}Ga$-labeling were 4.4, 3.6 and 5.6, respectively. DFO ($10{\mu}M$) showed high labeling efficiency (>97%) at pH 5.6. All the labeled chelating agents showed high stability in human serum. $^{68}Ga$-DFO showed low RBC binding but significant amount was bound to plasma protein. The results demonstrated that $^{68}Ga$-DFO can be used as a bifunctional chelating agent but not as a renal imaging agent.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.30-36
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• 1989

Some chelating agents are evaluated as an antioxidant for the autoxidation of soybean oil. Soybean oil is autoxidized under a mild condition (the flow rate of 67ml $O_{2}/min$ and $50^{\circ}C$). The antioxidant effect is measured by active oxygen method, and the spectral change of autoxidized soybean oil examined. The antioxidant effect of chelating agents is increased in order of diphenic acid, naphthoquinone, pyromellitic acid, quinolinic acid and naphthalic acid, and particularly the effect is low in diphenic acid and naphthoquinone. It is found that the effect is more clearly demonstrated by NMR rather than IR and UV and that the effect is dependent on the functional group and geometric molecular structure of chelating agents.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.27-36
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• 2007

A recent study showed that MTBE can be degraded by Fenton's Reagent (FR). The treatment of MTBE with FR, however, has a definite limitation of extremely low pH requirement (optimum pH $3{\sim}4$) that makes the process impracticable under neutral pH condition on which the ferrous ion precipitate forming salt with hydroxyl anion, which result in the diminishment of the Fenton reaction and incompatible with biological treatment. Consequently, this process using only FR is not suitable for in-situ remediation of MTBE. In order to overcome this limitation, modified Fenton process using NTA, oxalate, and acetate as chelating reagents was introduced into this study. Modified Fenton reaction, available at near neutral pH, has been researched for the purpose of obtaining high performance of oxidation efficiency with stabilized ferrous or ferric ion by chelating agent. In the MTBE degradation experiment with modified Fenton reaction, it was observed that this reaction was influenced by some factors such as concentrations of ferric ion, hydrogen peroxide, and each chelating agent and pH. Six potential chelators including oxalate, succinate, acetate, citrate, NTA, and EDTA were tested to identify an appropriate chelator. Among them, oxalate, acetate, and NTA were selected based on their remediation efficiency and biodegradability of each chelator. Using NTA, the best result was obtained, showing more than 99.9% of MTBE degradation after 30 min at pH 7; the initial concentration of hydrogen peroxide, NTA, and ferric ion were 1470 mM, 6 mM, and 2 mM, respectively. Under the same experimental condition, the removal of MTBE using oxalate and acetate were 91.3% and 75.8%, respectively. Optimum concentration of iron ion were 3 mM using oxalate which showed the greatest removal efficiency. In case of acetate, $[MTBE]_0$ decreased gradually when concentration of iron ion increased above 5 mM. In this research, it was showed that modified Fenton reaction is proper for in-situ remediation of MTBE with great efficiency and the application of chelatimg agents, such as NTA, was able to make the ferric ion stable even at near neutral pH. In consequence, the outcomes of this study clearly showed that the modified Fenton process successfully coped with the limitation of the low pH requirement. Furthermore, the introduction of low molecular weight organic acids makes the process more available since these compounds have distinguishable biodegradability and it may be able to use natural iron mineral as catalyst for in situ remediation, so as to produce hydroxyl radical without the additional injection of ferric ion.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.130-131
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• 2016

Although many metals contaminated sediment from coastal area contain both anionic and cationic heavy metals, the current remediation technologies are not effective for stabilize heavy metals of both anionic and cationic elements from contaminated coastal region. the present work investigated the efficiency and mechanism of immobilization of Fe, Zn, Cr, Cu, Pb and Cd metal solutions in modified zeolite based biostimulant ball. Biostimulant ball containing acetate, nitrate and sulphate which are enhance the activity of marine microorganisms and it can act as electron donors and electron acceptors. Modified zeolite and chelating agent is greatly enhance the metal stabilization due to increased immobility of the analysed metals. The XRD, FT-IR and SEM of modified zeolite which cheating agents containing heavy metals were investigated. The results indicated that heavy metals could be effectively immobilized in modified zeolite and chelating agents in BSB added sediment. The immobilization of heavy metals in modified zeolite and chelating agents along with BSB could be due to stabilize of heavy metal cations. Immobilization of heavy metals using BSB with modified zeolite and chelating agent has lower cost effect and enhance the sediment quality.

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.42-44
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• 2002

• Journal of Powder Materials
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• v.28 no.1
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• pp.25-30
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• 2021

The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.

• The Journal of the Korean dental association
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• v.53 no.9
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• pp.618-627
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• 2015

Purpose : The purpose of this clinical study was to evaluate the effect of chelating and deproteinizing agent containing dental conditioning gel on alleviation of peri-implant mucosa inflammation. Methods: 36 patients with functionally loaded implants for at least 1 year and have clinical signs of peri-implant mucositis were recruited. At baseline, all implants received subgingival prophylaxis with ultrasonic scaler. In the test group, patients were provided a chelating and deproteinizing agent dental conditioning gel (Clinplant$^{(R)}$) and were given instructions to applicate it around the implants using an interdental brush for 2 weeks. Chlorhexidine and saline were provided to the positive control group and negative control group, respectively. The modified sulcus bleeding index (mSBI), modified plaque index (mPI), and probing pocket depth (PPD) were evaluated at baseline, 1 week, and 2 weeks. Results: In the Clinplant$^{(R)}$ and chlorhexidine group, mSBI (-0.81, -0.85 respectively; p<0.01), mPI (-0.46, -0.5 respectively; p<0.01), and PPD (-0.58, -0.48 respectively; p<0.01) at 2 weeks were significantly reduced from baseline. In the saline group, all the clinical parameters were reduced but there was no statistical significance. The saline may be attributed to the influence of prophylaxis at baseline. Conclusions: The present study demonstrated the beneficial clinical effects of chelating and deproteinizing agent containing dental conditioning gel to decrease peri-implant mucosa inflammation equivalent to chlorhexidine. This dental conditioning gel might be useful for alleviation of peri-implant mucosa inflammation.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.348-351
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• 2011

In this research, we developed a sensor system which can easily detect several chelating agents using polydiacetylene(PDA) vesicles. In comparison to other sensors, PDA based sensor has several advantages. First, detection method is much simpler and faster because it does not require any labeling step in the experiment procedure. Second, significant color-transition from blue to red based upon external stimulus allows us the detection by naked eyes. Finally, it is also possible to perform quantitative analysis of the concentration of the chelating agent by measuring the colorimetric response. In this paper, five types of chelating agents were used, including EDTA, EGTA, NTA, DCTA and DTPA. Among them, EDTA and DCTA triggered especially strong color-transition. In conclusion, this study has led to a successful development of a color transition-based PDA sensor system for easy and rapid detection of chelating agents.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.97-101
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• 1992

A mathematical model has been developed for an analytical calculation of distribution coefficient (K$_1$) in the presence of a chelating agent, The newley formulated K$\_$D/ is given as a function of the mole fraction of a free metal ion in the solution, ${\beta}$, and will serve as an alternative for the tedious individual measurements of K$\_$D/. This formulation will be used to analyze the effects of the presence of chelating agents on the adsorption capacity of geologic media such as clay minerals and soils. The present method may be a significant progess for the evaluation of the transport phenomena and separation processes of metal ions (or radionuclides) in the presence of chelating agents.