• 한국세라믹학회지
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• 제46권6호
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• pp.561-567
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• 2009

The Fe-ACF/$TiO_2$ composites were prepared by a sol-gel method and were characterized by nitrogen adsorption, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Energy Dispersive X-ray (EDX). The Fe-ACF/$TiO_2$ composites were developed for the decomposition of organic dyes by using a UV lamp. The decomposition effect was investigated under various conditions, such as three selected non-biodegradable organic dyes like Methylene Blue (MB), Methyl Orange (MO), Rhodamine B (Rh.B), and in the presence of Fe and hydrogen peroxide ($H_2O_2$). The photocatalytic activity was derived from possible combination effects, such as (1) adsorption of ACF, (2) generation of electron/hole by $TiO_2$, (3) photo-Fenton reaction of Fe, and (4) oxidation of $Fe^{2+}\;to\;Fe^{3+}\;by\;H_2O_2$.

• 한국식품영양학회지
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• 제10권1호
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• pp.37-43
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• 1997

본 연구는 지질의 과산화에 대한 항산화 효과를 조사하기 위하여 엉겅퀴(Silybum marianum)로부터 silymarin 및 silybin을 정제하여 실험하였다. Silymarin 및 silybin은 xanthine oxidase system에서 superoxide anion의 생성을 억제하였다. 쥐의 간 mitochondria에서는 silymarin 및 silybin은 reduced nicotinamide adenine dinucleotide phosphate(NADPH)에 의해 효과적 또는 ascorbic acid 또는 Fenton's reagent에 의하여 비효소적으로 유도되는 지질의 과산화를 억제하였다. 또 mitochondria의 지질과산화도 silymarin 및 silybin에 의하여 억제되었고 NADPH 의존 cychrome P-450 reductase에 의한 Fe2+의 산화도 silymarin 및 silybin에 의하여 억제되었다. Silymarin 및 silybin은 microsome의 효소 시스템 및 linoleic acid hydroperoxide induced peroxidation system에서 지질의 과산화의 연쇄반응에서 유리기의 억제효과가 있었다.

• Molecules and Cells
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• 제22권1호
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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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• 제37권2호
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• pp.100-108
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• 2014

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu,Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

• BMB Reports
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• 제34권6호
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• pp.544-550
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• 2001

In pre-transplant total-body irradiation (TBI), the lung is a critical dose-limiting organ. Also, the possible role of oxidative stress was suggested in the development of TBI-induced lung damage. This study explores the association between TBI-induced oxidative stress and the induction of lung pathogenesis by investigating TBI-induced oxidative stress in the lungs of male C57BL/6 mice after a single dose of 10 Gy TBI. We showed significant increases of reactive oxygen species (ROS) formation and lipid peroxidation, and also a depletion and oxidation of glutathione after TBI. There is evidence that pretreatment with 1,10-phenanthroline (o-phen) significantly reduces oxidative stress in the lung. This indicates that the TBI-induced ROS generation involves a metal-catalyzed Fenton-type reaction. A pretreatment of buthionine sulfoximine (BSO) augmented the glutathione depletion and oxidation, but had no effect on the ROS formation and lipid peroxidation up to 6 h after TBI. Histopathological features that are consistent with pneumonitis were observed in the BSO pretreated-mice 1 week after irradiation. The results suggest that TBI-induced oxidative stress in the lung involves a generation of ROS through a Fenton-type reaction. Also, glutathione plays an important inhibitory role in the radiation-induced lung pathogenesis by participating in the self-amplifying cascade subsequent to the ROS generation by irradiation.

• 상하수도학회지
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• 제21권1호
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• pp.123-130
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• 2007

The effects of hydrogen peroxide treatment on the reduction of waterworks sludge were investigated in this study. Sludge treated by peroxidation $H_2O_2$ oxidation) was dewatered using a pressure filter at 3atm. It was observed that $H_2O_2$ treatment at the acidic condition significantly reduce both cake water content and specific resistance to filtration (SRF), indicating the enhancement of dewaterability and filterability. The filterability by hydrogen peroxide treatment at pH 3.5 was better than acidic treatment and became comparable with polymer conditioning. The sludge filterability evaluated by SRF was optimal at a dose 2ml $H_2O_2$/sludge($0.02g\;H_2O_2/gTS$) after adjusting of pH to 3.5. The $H_2O_2$ oxidation at pH 3.5 also produced even more dewatered cake when compared with polymer conditioning. The reduction rate of sludge mass at an optimal condition showed 34% compared with untreated sludge. The effects of peroxidation on sludge properties including zeta potential, bound water and particle size were also evaluated. Peroxidation at the acidic condition reduced both bound water and zeta potential. By $H_2O_2$ combined with sulfuric acid leached iron caused Fenton's reaction, which showed a potential to significantly reduce the amount of solids mass and to produce more compact cake with higher filterability.

• Korean Chemical Engineering Research
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• 제60권1호
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• pp.7-11
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• 2022

고분자전해질 연료전지의(PEMFC)의 제막 과정에서 성능 및 내구성을 위해 건조와 어닐링의 열처리 과정이 필요하다. 본 연구에서는 고분자막 내구성 향상을 위한 최적의 어닐링 온도에 대해 연구하였다. 125~175 ℃ 온도 범위에서 어닐링하였고, 각 어닐링 온도에서 내구성의 기초 자료로 열 안정성 및 수소투과도를 측정하였다. 펜톤 반응과 OCV holding에 의해 전기화학적 내구성을 분석했다. 165 ℃ 어닐링 온도가 열 안정성과 수소투과도 면에서 최적의 온도였다. 펜톤 반응에서 165 ℃에서 어닐링한 막의 불소유출속도가 제일 낮고, OCV holding 실험에서도 165 ℃에서 어닐링한 막의 수명이 제일 길어, 165 ℃가 고분자막의 내구성을 위한 최적의 온도임을 확인했다.

• Journal of Microbiology and Biotechnology
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• 제33권8호
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• pp.992-997
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• 2023

Ferroptosis is a new kind of programmed cell death of which occurrence in microorganisms is not clearly verified. The elevated level of reactive oxygen species (ROS) influences cellular metabolisms through highly reactive hydroxyl radical formation under the iron-dependent Fenton reaction. Iron contributes to ROS production and acts as a cofactor for lipoxygenase to catalyze poly unsaturated fatty acid (PUFA) oxidation, exerting oxidative damage in cells. While ferroptosis is known to take place only in mammalian cells, recent studies discovered the possible ferroptosis-like death in few specific microorganisms. Capacity of integrating PUFA into intracellular membrane phospholipid has been considered as a key factor in bacterial or fungal ferroptosis-like death. Vibrio species in bacteria and Saccharomyces cerevisiae in fungi exhibited certain characteristics. Therefore, this review focus on introducing the occurrence of ferroptosis-like death in microorganisms and investigating the mode of action underlying the cells based on contribution of lipid peroxidation and iron-dependent reaction.

• 자원리싸이클링
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• 제9권1호
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• pp.36-43
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• 2000

본 연구는 B 염색조합 공동폐수처리장의염색폐수 처리공정중 Fenton 공정에서 발생되는 무기슬러지의 처리 및 재활용에 관한 연구로서, Pilot plant에 의하여 재용해철($Fe^{3+}$)과 FECL의 혼합용액을 사용한 연속식 산화실험 결과, 처리수의 $COD_{cl}$ 는 대략 100 mg/l이하였으며 이때 $COD_{cl}$제거율은 78.9%로 $H_2O_2/Fe^{total}$가 대략 1.5범위에서 최적치를 나타내었다. 슬러지의 용해공정 후에 배출되는 2차 슬러지에 대하여 3성분을 측정하여 1차 슬러지와 비교해 볼 때 회분은 약 85%가 감소되었으며, 건조기준 총 슬러지는 약 65%의 감량율을 나타내었고, 슬러지의 속의 철염의 재용해율은 대략 90~95%정도였다 슬러지 재활용공정의 예상투자비용은 시설용량 30,000 $m^3$/d/d 기준으로 약 3.5억원이 소요되며, 예상운영비는 하루에 약 130만원(연간 4.2억원)의 절감을 예상할 수 있으며, 투자비에 대한 이자비용을 감안하면 설비투자비용에 대한 투자자본금 회수기간(PP)은 약 10.5개월이 필요하고, 회계적이익율(ARR)은 179%, 순현재가치(NPV)는 7.92억원, 내부수익률(IRR)은 약 110%로 충분한 투자가치가 있는 것으로 판명되었다.

• 대한환경공학회지
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• 제32권7호
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• pp.706-713
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• 2010

최근 초음파를 이용한 유기오염물질의 분해 연구가 진행 중이며, 보다 향상된 초음파 조건을 찾는 연구가 주목을 받고 있다. 본 연구에서는 초음파에 의한 분해 대상물질로 나프탈렌 및 페놀을 선정하여 다양한 주파수(28 kHz, 580 kHz, 1,000 kHz) 및 보조제($TiO_2$, $H_2O_2$, $FeSO_4$, Zeolite, Cu) 첨가 효과를 비교 분석하여 초음파 처리 시스템의 최적 분해효율 조건을 확인하였다. 주파수 변화에 따른 초음파 분해효율은 나프탈렌과 페놀 모두에서 580 kHz가 가장 우수한 효율을 보였으며, OH 라디칼 역시 동일 주파수에서 가장 많이 발생한 점을 미루어 볼 때, 580 kHz 근처의 초음파 영역에서 최적의 열분해 및 산화분해를 일으킬 수 있는 공동현상 조건이 형성된다는 것을 확인하였다. 100 mg/L의 다양한 보조제를 첨가하여 초음파 분해효율을 비교한 결과 $FeSO_4$의 분해효율 및 $k_1$값이 무첨가 초음파 반응에 비해 약 1.8배씩 우수하게 조사되었으며, 이것은 초음파와 펜톤 반응이 연계되어 OH 라디칼 생성을 촉진시켜 대상물질의 산화분해를 향상시킨 것으로 판단된다. 그러나 초음파와 펜톤 연계시스템은 배치식 조건에서만 제한적으로 적용 가능할 것이며, 연속식 초음파 시스템에서는 철의 손실, 반응조의 부식 및 새로운 오염물질을 발생시키는 문제를 야기할 수 있다. 이에 반해 $TiO_2$를 첨가한 초음파 분해속도가 무첨가 반응보다 약 20% 이상 향상된 점을 감안할 때, 초음파와 연계된 연속식 처리 공정에서는 $TiO_2$가 효과적인 보조제로 사용될 수 있을 것이다.