• 한국환경과학회지
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• 제17권5호
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• pp.547-553
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• 2008

For the RhB removal from the wastewater, electrochemical method was adapted to this study. Three dimensionally stable anode (Pt, Ir and Ru) and graphite and Ru cathode were used. In order to identify decolorization, the effects of electrode, current density, electrolyte and air flow rate were investigated. The effects of electrode material, current, electrolyte concentration and air flow rate were investigated on the decolorization of RhB. Electro-Fenton's reaction was evaluated by added $Fe^{2+}$ and $H_2O_2$ generated by the graphite cathode. Performance for RhB decolorization of the four electrode systems lay in: Ru-graphite > Ru-Ru > Ir-graphite > Pt-graphite. A complete color removal was obtained for RhB (30 mg/L) at the end of 30 min of electrolysis under optimum operations of 2 g/L NaCl concentration and 2 A current. $Fe^{2+}$ addition increased initial reaction and decreased final RhB concentration. However the effect was not high.

• 한국환경보건학회지
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• 제28권1호
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• pp.51-65
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• 2002

This study was carried out to apply some basic physical and chemical treatment options including Fenton's oxidation, and to evaluate the performances and the characteristics of organic and nitrogen removal using lab-scale biological treatment system such as complete-mixing activated sludge and sequencing batch reactor(SBR) processes for the treatment of leachate from a municipal waste landfill in Gyeongnam province. The results were as follows: Chemical coagulation experiments using aluminium sulfate, ferrous sulfate and ferric chloride resulted in leachate CO $D_{Cr}$ removal of 32%, 23% and 21 % with optimum reaction dose ranges of 10,000～15,000 mg/$\ell$, 1,000 mg/$\ell$ and 500～2,000 mg/$\ell$, respectively. Fenton's oxidation required the optimum conditions including pH 3.5, 6 hours of reaction time, and hydrogen peroxide and ferrous sulfate concentrations of 2,000 ～ 3,000 mg/$\ell$ each with 1:1 weight ratio to remove more than 50% of COD in the leachate containing CO $D_{Cr}$ between 2,000 ～ 3,000 mg/$\ell$. Air-stripping achieved to remove more than 97% of N $H_3$-N in the leachate in spite of requiring high cost of chemicals and extensive stripping time, and, however, zeolite treatment removing 94% of N $H_3$-N showed high selectivity to N $H^{+}$ ion and much faster removal rate than air-stripping. The result from lab-scale experiment using a complete-mixing activated sludge process showed that biological treatability tended to increase more or less as HRT increased or F/M ratio decreased, and, however, COD removal efficiency was very poor by showing only 36% at HRT of 29 days. While COD removal was achieved more during Fenton's oxidation as compared to alum treatment for the landfill leachate, the ratio of BOD/COD after Fenton's oxidation considerably increased, and the consecutive activated sludge process significantly reduced organic strength to remove 50% of CO $D_{Cr}$ and 95% of BO $D_{5}$ . The SBR process was generally more capable of removing organics and nitrogen in the leachate than complete-mixing activated sludge process to achieve 74% removal of influent CO $D_{Cr}$ , 98% of BO $D_{5}$ and especially 99% of N $H_3$-N. However, organic removal rates of the SBR processes pre-treated with air-stripping and with zeolite were not much different with those without pre-treatment, and the SBR process treated with powdered activated carbon showed a little higher rate of CO $D_{Cr}$ removal than the process without any treatment. In conclusion, the biological treatment process using SBR proved to be the most applicable for the treatment of organic contents and nitrogen simultaneously and effectively in the landfill leachate.e.

• 한국지하수토양환경학회지:지하수토양환경
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• 제7권2호
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• pp.73-81
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• 2002

전통적인 펜톤반응에서 Superoxide radical (${O_2}^-$.)에 의한 사염화탄소의 환원반응을 조사하였으며 과산화수소의 농도구배와 pH의 변화에 따른 ${O_2}^-$.의 생성률을 측정하였다. 펜톤반응에서 1-헥산올의 분해율은 pH가 증가함에 따라 90% (pH3) 에서 5% (pH5) 급격하게 감소한 반면 사염화탄소의 분해율은 pH가 증가함에 따라서 증가하였다. 이러한 결과는 펜톤반응이 Hydroxyl radical (${O_2}^-$.)의 산화반응과 ${O_2}^-$.의 환원반응이 공존하는 반응임을 보이는 결과이다. ${O_2}^-$.의 생성률은 pH 11에서 $H_2$O$_2$의 농도가 29.4mM에서 294mM로 증가함에 따라 (45.3$\pm$7.8) X $10^{-6}$ M/s에서 (151.0$\pm$26.2) X $10^{v}$ / M/s로 증가하였으며 294mM의 H$_2$$O_2$에서 pH가 7에서 11로 증가함에 따라 (22.1$\pm$3.8) x $10^{-6}$ / M/s에서 (151.0$\pm$26.2) x $10^{-6}$ M/s 증가하였다. 이러한 결과는 ${O_2}^-$.의 환원력을 적용한 펜톤반응이 넓은 pH영역에서 적용될 수 있음을 나타내는 결과이다. 특별히 토양내 흡착력이 약하고 지하수내에 쉽게 용해될 수 있으며 독성 및 발암성물질로 알려진 사염화탄소와 같은 염소계 유기화합물의 제거에 효과적으로 적용될 수 있을 것으로 사료된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권2호
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• pp.33-40
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• 2017

In typical remediation practices, separate washing systems have to be applied to clean up the soils contaminated with both oil and heavy metals. In this study, we evaluated the efficiency of successive two-stage soil washing in removal of mixed-contaminants from soil matrix. Two-stage soil washing experiments were conducted using different combinations of chemical agent: 1) persulfate oxidation, followed by organic acid washing, and 2) Fenton oxidation, followed by inorganic acid washing. Persulfate oxidation-organic acid washing efficiently removed both organic and inorganic contaminants to meet the regulatory soil quality standard. The average removal rates of total petroleum hydrocarbons (TPH), Cu, Pb, and Zn were 88.9%, 82.2%, 77.5%, and 66.3% respectively, (S/L 1:10, reaction time 1 h, persulfate 0.5 M, persulfate:activator 3:1, citric acid 2 M). Fenton oxidation-inorganic acid washing also gave satisfactory performances to give 89%, 80.9%, 87.1%, and 67.7% removal of TPH, Cu, Pb, and Zn, respectively (S/L 1:10, reaction time 1 hr, hydrogen peroxide 0.3 M, hydrogen peroxide:activator 5:1, inorganic acid 1 M).

• Nutrition Research and Practice
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• 제2권3호
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• pp.143-151
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• 2008

Many herbs have been used as therapeutics in Korean traditional medicine. In view of their clinical indications, anti-oxidant activity may contribute to their pharmacological effects. However, anti-oxidant information on these plants has not been available. In this study, seventy herbs which have been used in Korean traditional medicine were selected and screened for anti-oxidant activity using their water extracts. The anti-oxidant activity was assessed by their ability to inhibit three oxidation reactions; luminol/Fenton reagent, 2, 7-dichlorodihydrofluorescein(DCHF)/Fenton reagent and DCHF/peroxynitrite. In each assay, 70 herbs were divided into two groups; anti-oxidant group which inhibited the respective oxidation reaction and was majority(about 60 herbs), and pro-oxidant group which enhanced the oxidation reaction but was minority(more or less 10 herbs). When the herbs were listed in the order of their anti-oxidant strength, the orders obtained from each assay were found to be quite similar. The upper top rankers(more or less 10 herbs) in each assay showed strong activity compared to the others. The uppermost rankers in each assay were Rubus coreanus Miquel/Rubus schizostylus(覆盆子), Schisandra chinensis Baillon/Schizandra chinensis(五味子) and Terminalia chebula Retziusl Terminalia chebula(訶子). Of the pro-oxidant herbs, about 4-5 herbs were strongly pro-oxidant, which enhanced the control oxidation reactions to 150-300%. But the meaning of this observation is not known since few of them in one assay were also anti-oxidant in other assays. The results obtained in the present study may serve as information for understanding pharmacological effects of these herbs and developing new drugs from them.

• 대한환경공학회지
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• 제30권5호
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• pp.517-523
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• 2008

본 연구에서는 펜톤반응, 광반응, 그리고 Fe$^{2+}$와 UV의 조합반응을 이용하여 항균제이면서 신종오염물질 중의 하나인 Triclosan (TCS)에 대한 분해 메커니즘을 해석하였다. 결과에 의하면 Fe$^{2+}$의 산화율은 $H_2O_2$와 UV-C에서 각각 30%와 28%로 차이를 보이지 않은 반면 UV-A의 경우 15%로 차이를 보였다. TCS의 초기 분해속도는 광반응(UV-C > UV-A)이 Fe$^{2+}$와 UV 조합반응과 펜톤 반응보다 높았으나 반응시간의 경과와 함께 Fe$^{2+}$가 포함된 조합반응에서의 분해속도 증가가 관찰되었다. 또한 반응중 메탄올의 첨가에 의해 모든 반응에서 영향을 받았고 펜톤반응의 경우 20분 동안 분해효율 90%에서 5%로 급감되었다. 이온성 부산물인 Cl$^-$의 생성율은 Fe$^{2+}$와 UV-C 조합반응에서 가장 높았으며(77% / 150 min) 메탄올이 첨가된 반응 초기에서는(15 min) 12%의 Cl$^-$ 생성을 보인반면 다른 반응들은 무시할 수준($\leq$2%)이었다. TOC의 제거 역시 Fe$^{2+}$와 UV-C의 조합반응에서 가장 높았으며 펜톤반응, Fe$^{2+}$와 UV-A 조합반응, UV-C 광반응, 그리고 UV-A의 광반응 순으로 낮았다. 그러나 펜톤반응의 경우 90분 후 부터는 반응이 거의 중지되는 것이 관찰되었는데 이는 $H_2O_2$에 의한 Fe$^{2+}$의 산화반응이 중지되었기 때문이다. 이에 반해 Fe$^{2+}$와 UV의 조합공정에서 반응은 지속되었다. 또한 초기 Cl$^-$ 생성은 Fe$^{2+}$와 UV-C의 조합반응에서 환원반응에 의한 TCS의 분해메커니즘을 가지고 있다고 할 수 있다. 환원에 의한 분해는 할로겐화유기화합물의 무기화에 매우 유리하므로 TCS의 대안적 처리방법으로 UV-C와 Fe$^{2+}$의 조합반응은 적용가능하다.

• 방사성폐기물학회지
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• 제5권1호
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• pp.85-90
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• 2007

양이온교환수지인 IRN-77을 직접 분해 처리하기 위하여 Fonton시약을 적용하였으며, 분해반응의 특징으로써 반응의 효율 및 안전을 위해 수지를 먼저 건조시키고 $FeSO_4$ 용액을 수지에 완전히 흡수시킨 후 $H_2O_2$를 첨가하는 방법을 적용하였다. 수지 분해반응의 특성은 반응이 개시되기까지 반응유도시간이 필요하였으며, 반응유도시간은 $FeSO_4$의 농도가 낮을수록 또한 $H_2O_2$의 초기 첨가량이 적을수록 길었다. 단위량의 수지를 분해하는데 적절한 반응조건으로서 $FeSO_4$의 농도는 0.9 M 및 15% $H_2O_2$의 용액의 첨가량은 수지량에 대해 6-7배 비율로 나타났으며, 반응유도시간을 포함하여 1.5시간 이내에 완전 분해가 가능하였다. $H_2O_2$의 첨가방법은 반응 초기 및 반응개시 후로 나누어 첨가하므로서 $H_2O_2$의 분해효율 및 첨가량을 최소화하였다. 가열효과로서 분해반응 개시 전에 비교적 낮은 온도인 $50^{\circ}C$ 정도로 가열하면 반응유도시간이 5분 이내로 단축되었으며, 수지의 양을 5g 및 10g 으로 증가시킨 결과, $H_2O_2$의 첨가비율을 9-10배 정도로 증가시키면 완전분해가 가능하였다.

• 한국토양환경학회지
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• 제3권3호
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• pp.87-92
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• 1998

The effect of chemically oxidized intermediates of Polynuclear Aromatic Hydrocarbon (PAH) compounds on the degradation of the parent PAHs was characterized and evaluated for the context of cooxidation. Anthracene and pyrene exhibited extensive degradation (mean percent removal of 57.5%) after 28 days of incubation by introducing the Fenton oxidation intermediate of the PAH compounds, while unoxidized anthracene and pyrene exhibited 12.5% removal The chemical oxidation products can serve as a structually similar analogue substrates for a consortia of soil microorganisms and as a metabolic intermediates in the biodegradation sequence of the parent PAH compounds. These results may be interpreted in the context of cooxidation mechanism whereby high recalcitrant PAH compounds are biodegraded in the soil and suggest a potential tool for bioremediation of PAHs contaminated soils and protection of groundwater.

• 한국환경과학회지
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• 제16권4호
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• pp.393-397
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• 2007

The sonolytic decomposition of NHCs(Nitrogen Heterocyclic Compounds), such as atrazine[6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], simazine(6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N'-triethyl-1,3, 5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range $1.06{\sim}2.07({\times}10^{-2}min^{-1})$ under air and $1.30{\sim}2.59({\times}10^{-2}min^{-1})$ under argon at a concentration of $200{\mu}M$ of NHCs. The rate of hydroxyl radicals(${\bullet}{OH}$) formation from water is $19.8{\mu}M\;min^{-1}$ under argon and $14.7{\mu}M\;min^{-1}$ under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ${\bullet}{OH}$ radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ${\bullet}{OH}$ radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent $[Fe^{2+}]$ accelerates the decomposition. This is probably due to the regeneration of ${\bullet}{OH}$ radicals from hydrogen peroxide, which would be formed from recombination of ${\bullet}{OH}$ radicals and which may contribute a little to the decomposition.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.171-176
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• 2003

The sonolytic decomposition of NHCs, such as atrazine［6-chloro-N-ethyl-N＇ -(1-methylethyl)-1,3,5-triazine-2,4-diamine］, simazine( 6-chloro-N,N＇ -diethyl-l ,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N＇-triethyl-l,3,5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range 1.06∼2.07 (x10/sup -3/ min/sup -1/) under air and 1.30∼2.59(x10/sup -3/ min/sup -1/)under argon at a concentration of 200μM of NHCs. The rate of hydroxyl radicals(·OH) formation from water is 19.8μM min/sup -1/ under argon and 14.7 μM min/sup -1/ under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ·OH radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ·OH radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent ［Fe/sup 2＋/］ accelerates the decomposition. This is probably due to the regeneration of ·OH radicals from hydrogen peroxide, which would be formed from recombination of ·OH radicals and which may contribute a little to the decomposition.