• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.37-43
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• 1997

This study was undertaken to evaluate as antioxidant activity against lipid peroxidation. Silymarin and silybin extracted from Silybum marianum were successively purified wit solvent fractionation by silica gel column chromatography. These isoflavonoid inhibited superoxide anion production in the xanthine oxidase system. In the rat liver microsomes, silymarin or silybin rapidly inhibited lipid peroxidation which was initiated enzymatically by reduced nicotinamide adenine dinucleotide phosphate(NADPH) or non-enzymatically by ascorbic acid or Fenton's reagent (H2O2+Fe2+). Mitochondrial lipid peroxidation was also inhibited by silymarin and silybin. silymarin and silybin inhibited on terminating radical chain reaction during lipid peroxidation in the enzymatic system of microsomes or in the linoleic acid hydroperoxide induced peroxidation system.

• Molecules and Cells
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• v.22 no.1
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• pp.21-29
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• 2006

The aim of this study was to determine if hydrogen peroxide ($H_2O_2$) generated by glucose oxidase (GO) induces apoptosis or necrosis of BJAB cells and which radical is the direct mediator of cell death. We found that GO produced $H_2O_2$ continuously in low concentrations, similar to in vivo conditions, and decreased proliferation and cell viability in a dose-dependent manner. The GO-mediated cytotoxicity resulted from apoptosis, and was confirmed by monitoring the cells after H33342/Annexin V/propidium iodide staining. Decreases of mitochondrial membrane potential and intracellular glutathione level were found to be critical events in the $H_2O_2$-mediated apoptosis. Additional experiments revealed that $H_2O_2$ exerted its apoptotic action through the formation of hydroxyl radicals via the Fenton rather than the Haber-Weiss reaction. Moreover, intracellular redox-active iron, but not copper, participated in the $H_2O_2$-mediated apoptosis.

• Molecules and Cells
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• v.22 no.2
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• pp.220-227
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• 2006

Oxidative alteration of mitochondrial cytochrome c has been linked to disease and is one of the causes of proapoptotic events. We have investigated the modification of cytochrome c by $H_2O_2$. When cytochrome c was incubated with $H_2O_2$, oligomerization of the protein increased and the formation of carbonyl derivatives and dityrosine was stimulated. Radical scavengers prevented these effects suggesting that free radicals are implicated in the $H_2O_2$-mediated oligomerization. Oligomerization was significantly inhibited by the iron chelator, deferoxamine. During incubation of deoxyribose with cytochrome c and $H_2O_2$, damage to the deoxyribose occurred in parallel with the release of iron from cytochrome c. When cytochrome c that had been exposed to $H_2O_2$ was analyzed by amino acid analysis, the tyrosine, histidine and methionine residues proved to be particularly sensitive. These results suggest that $H_2O_2$-mediated cytochrome c oligomerization is due to oxidative damage resulting from free radicals generated by a combination of the peroxidase activity of cytochrome c and the Fenton reaction of free iron released from the oxidatively-damaged protein.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1290-1296
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• 2012

Fenton reaction and iron autoxidation have been debated for the major process in ROS mediated DNA cleavage. We compared both processes on iron oxidation, DNA cleavage, and cyclic voltammetric experiment at different pHs. Both oxidation reactions were preferred at basic pH condition, unlike DNA cleavage. This indicates that iron oxidation and the following steps probably occur separately. The ROS generated from autoxidation seems to be superoxide radical since sod exerted the best inhibition on DNA cleavage when $H_2O_2$ was absent. In comparison of cyclic voltammograms of $Fe^{2+}$ in NaCl solution and phosphate buffer, DNA addition to phosphate buffer induced significant change in the redox cycle of iron, indicating that iron may bind DNA as a complex with phosphate. Different pulse voltammogram in the presence of ctDNA suggest that iron ions are recyclable at acidic pH, whereas they may form an electrically stable complex with DNA at high pH condition.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.51-59
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• 2005

To manufacture hightech easycare wool, there are several methods which use strong oxidising agent or the resin treatment, however, neither are environmentally friendly methods. Moreover it may deteriorate the handle. The aim of this study is to manufacture the hightech easycare wool using the modified Fenton method which can be formed by hydrogen peroxide and ferric sulfate and enzyme treatment. The method was pretreated by ferric sulfate on the wool surface and then the surface of wool scale was selectively removed by ferric ion catalyst. Subsequently the Enchiron which is one of the proteolytic enzymes was treated on the wool surface. The treated wool had the result of having optimum weight loss and excellent whiteness and good handle. Therefore implications of these results suggest that this method using the modified Fenton method and enzyme treatment may be one way of manufacturing the hightech easycare wool.

• Advances in environmental research
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• v.5 no.1
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• pp.61-77
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• 2016

$NanoTiO_2$ was synthesized by ultrasonication assisted sol-gel process and subjected to iron doping and carbon-iron codoping. The synthesized catalysts were characterized by XRD, HR-SEM, EDX, UV-Vis absorption spectroscopy and BET specific surface area analysis. The average crystallite size of pure $TiO_2$ was in the range of 30 - 33 nm, and that of Fe-$TiO_2$ and C-Fe $TiO_2$ was in the range of 7 - 13 nm respectively. The specific surface area of the iron doped and carbon-iron codoped nanoparticles was around $105m^2/g$ and $91m^2/g$ respectively. The coupled semiconductor photo-Fenton's activity of the synthesized catalysts was evaluated by the degradation of a cationic dye (C.I. Basic blue 9) and an anionic dye (C.I. Acid orange 52) with concurrent investigation on the operating variables such as pH, catalyst dosage, oxidant concentration and initial pollutant concentration. The most efficient C-Fe codoped catalyst was found to effectively destruct synthetic dyes and potentially treat real textile effluent achieving 93.4% of COD removal under minimal solar intensity (35-40 kiloLUX). This reveals the practical applicability of the process for the treatment of real wastewater in both high and low insolation regimes.

• Advances in nano research
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• v.12 no.4
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• pp.415-426
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• 2022

Nickel substituted cobalt-zinc ferrite nanoparticles with composition Co_0.5Zn_0.5Ni_xFe_2-xO₄ (x = 0.25, 0.5, 0.75, 1.0) were synthesized using a wet chemical method named citrate precursor method. Various characterizations of the prepared nanoferrites were done using X-ray powder diffractometry (XRD), Scanning electron microscopy (SEM), UV visible spectroscopy and Fourier transform spectroscopy technique (FT-IR). XRD confirmed the formation of cubic spinel structure of the samples with single phase having one characteristic peak at (311). The value of optical band gap (E_g) was found to decrease with Ni substitution and have values in the range 2.30eV to 1.69eV. A Fenton-type system was created by photocatalytic activity using source of visible light for removal of methylene blue dye. Observations revealed increase in the degradation of methylene blue dye with increasing nickel content in the samples. The degradation percentage was increased from 77.32% for x = 0.25 to 90.16% for x = 1.0 in one hour under the irradiation of visible light. Also, the degradation process was found to have pseudo first order kinetics model. Hence, it can be observed that synthesized nickel doped cobalt-zinc ferrites have good capability for water purification and its degradation efficiency enhanced with increase in nickel concentration.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.105-114
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• 2007

The most advanced oxidation processes (AOPs) are based on reactivity of strong and non-selective oxidants such as hydroxyl radical (${\cdot}OH$). Decomposition of typical DNAPL chlorinated compounds (TCE, PCE) using various advanced oxidation processes ($UV/Fe^{3+}$-chelating agent/$H_2O_2$ process, $UV/H_2O_2$ process) was approached to develop appropriate methods treating chlorinated compound (TCE, PCE) for further field application. $UV/H_2O_2$ oxidation system was most efficient for degrading TCE and PCE at neutral pH and the system could remove 99.92% of TCE after 150 min reaction time at pH 6($[H_2O_2]$ = 147 mM, UVdose = 17.4 kwh/L) and degrade 99.99% of PCE within 120 min ($[H_2O_2]$ = 29.4 mM, UVdose = 52.2 kwh/L). Whereas, $UV/Fe^{3+}$-chelating agent/$H_2O_2$ system removed TCE and PCE ca. > 90% (UVdose = 34.8 kwh/L, $[Fe^{3+}]$ = 0.1 mM, [Oxalate] = 0.6 mM, $[H_2O_2]$ = 147 mM) and 98% after 6hrs (UVdose = 17.4 kwh/L, $[Fe^{3+}]$ = 0.1 mM, [Oxalate] = 0.6 mM, $[H_2O_2]$ = 29.4 mM), respectively. We improved the reproduction system with addition of UV light to modified Fenton reaction by increasing reduction rate of $Fe^{3+}$ to $Fe^{2+}$. We expect that the system save the treatment time and improve the removal efficiencies. Moreover, we expect the activity of low molecular organic compounds such as acetate or oxalate be effective for maintaining pH condition as neutral. This oxidation system could be an economical, environmental friendly, and practical treatment process since the organic compounds and iron minerals exist in nature soil conditions.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.257-264
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• 2006

This study investigated the effects of hybrid process(chemical coagulation, Fenton oxidation and ceramic UF(ultrafiltration)) on COD and color removals of commercial reactive dyestuffs. In the case of chemical coagulation, the optimal concentrations of $Fe^{3+}$ coagulant for COD and color removals of RB49(reactive blue 49) and RY84(reactive yellow 84) were determined according to the different coagulant dose at the optimal pH. They were 2.78 mM(pH 7) in RB49 and 1.85 mM(pH 6) in RY84, respectively. In the case of Fenton oxidation, the optimal concentrations of $Fe^{3+}\;and\;H_2O_2$ were obtained. Optimal $[Fe^{2+}]:[H_2O_2]$ molar ratio of COD and color removals of RB49 and RY84 were 4.41:5.73 mM and 1.15:0.81 mM, respectively. In the case of ceramic UF, the flux and rejection of supernatant after Fenton oxidation were investigated. After ceramic UF for 9 hr, the average flux of RB49 and RY84 solutions were $53.4L/m^2hr\;and\;67.4L/m^2hr$ at 1 bar, respectively. In addition, the permeate flux increased and the average flux recovery were 98.5-99.9%(RB49) and 91.0-97.3%(RY84) according to adopting off-line cleaning(5% $H_2SO_4$). Finally, COD and color removals were 91.6-95.7% and 99.8% by hybrid process, respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.85-90
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• 2007

Fenton's Reagent is applied to directly dissolve the cation-exchange resin, IRN-77. The characteristics of the experimental procedure is to dry the resin first and $FeSO_4$ solution is completely absorbed into the resin, and then $H_2O_2$ is introduced later for an effective reaction between the reagents within the resin. An a characteristic of the dissolution, the lag time is needed for about 1 hour until the main reaction is occurred, which was more affected with the less concentration of $FeSO_4$ and the less initial dose of $H_2O_2$. The dose of $H_2O_2$ was equally divided into the early stage and the later stage after the initial reaction to provide an effective and safe reaction condition. The optimum conditions is appeared that the concentration of $FeSO_4$ is 0.9M and the dose of 15% $H_2O_2$ solution is 6-7 volume for the dissolution of unit weight of IRN-77. The effect of the heating on the lag time was checked and the time could be reduced within 5 minutes at $50^{\circ}C$, which is a relatively low temperature. The large amount of the resin, 5g and 10g, was also completely decomposed by increasing the dose of $H_2O_2$ to 9-10 volume ratio.