• Journal of Korean Society of Water and Wastewater
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• v.36 no.2
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• pp.59-79
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• 2022

Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, including their current status of research and development. Advanced oxidation processes (AOPs) such as ozonation and UV/H₂O₂ and adsorption processes using powdered (PAC) and granular activated carbon (GAC) were mainly discussed with focusing on process principles for the micropollutant removal, effect of process operation and water matrix factors, and technical and economic feasibility. Pilot- and full-scale studies have shown that ozonation, PAC, and GAC can achieve significant elimination of various micropollutants at economically feasible costs(0.16-0.29 €/m³). Considering the current status of domestic WWTPs, ozonation and PAC were found to be the most feasible options for the enhanced sewage effluent treatment. Although ozonation and PAC are all mature technologies, a range of technical aspects should be considered for their successful application, such as energy consumption, CO₂ emission, byproduct or waste generation, and ease of system construction/operation/maintenance. More feasibility studies considering domestic wastewater characteristics and WWTP conditions are required to apply ozonation or PAC/GAC adsorption process to enhance sewage effluent treatment in Korea.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.917-925
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• 2006

The aim of our research was to apply experimental design methodology in the optimization of photocatalytic degradation of azo dye(Reactive orange 16). The reactions were mathematically described as a function of parameters amount of $TiO_2(x_1)$, and dye concentration($x_2$) being modeled by the use of the Box-Behnken method. The results show that the responses of color removal(%)($Y_1$) in photocatalysis of dyes were significantly affected by the synergistic effect of linear term of $TiO_2(x_1)$ and dye concentration($x_2$). Significant factors and synergistic effects for the $COD_{Cr}$, removal(%)($Y_2$) were the linear term of $TiO_2(x_1)$ and dye concentration($x_2$). However, the quadratic term of $TiO_2(x_1^2)$ and dye concentration($x_2^2$) had an antagonistic effect on $Y_1$ and $Y_2$ responses. Canonical analysis indicates that the stationary point was a saddle point for $Y_1$ and $Y_2$, respectively. The estimated ridge of maximum responses and optimal conditions for $Y_1:(X_1,\;X_2)$=(1.11 g/L, 51.2 mg/L) and $Y_2:(X_1,\;X_2)$=(1.42 g/L, 72.83 mg/L) using canonical analysis was 93% and 73%, respectively.

• Korean Journal of Materials Research
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• v.30 no.8
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• pp.383-392
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• 2020

In this paper, AgCl/Ag₃PO₄/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag₃PO₄/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag₃PO₄/diatomite composite under visible light are evaluated. In the AgCl/Ag₃PO₄/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag₃PO₄/diatomite remains at 95 % of the original level, much higher than that of pure Ag₃PO₄ (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag₃PO₄/diatomite composites can be attributed to the synergistic effect of Ag₃PO₄, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO₂ and H₂O. Even more remarkably, AgCl/Ag₃PO₄/diatomite can maintain above 95 % photo-degradation activity after five cycles.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.381-398
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• 1975

Present work was executed to evaluate effects of adjuvants. stabilizers. moisture. pH and heavy metals on the stability of Fenitrothion in the emulsifiable concentrate. In addition, susceptibility ' of Fenitrothion in various formulations, to UV-irradiation has been also examined. The results are summarized as follows; 1. Xylene and benzene were found to be satisfactory solvents for Fenitrothion emulsifiable concentrate. As expected, polar sol vents such as aliphatic alcohols considerably reduced stability of the pesticides. 2. Of the two non-ionic emulsifiers, an alkyl aryl type Sorpol-1200, in contrast to sorbitan type Tweens, substantially reduced decomposition of Fenitrothion in the emulsifiable concentrates. Moisture and pH of emulsifiers. in the ranges studied. affected little if any. on the stabi ity of the Fenitrothion during the experiment periods. 3. Maleic anhydride, p-toluene sulfonic acid, sulfosalicylic acid, maleic anhydride-sulfosalicylic acid reduced decomposition of Fenitrothion in the emulsifiable concentrate. Addition of organic acids, however, increased liability of Fenitrothion in the emulsifiable concentrate. 4. Presence of either zinc or copper metals in the emulsifiable concentrate containing Tween-80 as a emulsifier, reduced stability of the Fenitrothion. 5. UV-irradiation, as expected, brought decomposition of Fenitrothion. The liability of Fenitrothion formulations decreased in the order, wettable powder ${\gg}$ dust > emulsifiable concentrate.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.203-207
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• 2009

The concern of seriousness and harmful effects of environmental pollution is rising by the various water pollutions, appearances of new micro-noxious substances and increase of sustainable pollutants. The method is suggested that can effectively increase the removal of organic substances and several pollutants using a coagulation process. The experiment for characteristics of $ZrSiO_4$ (zirconium silicate) as a coagulation-aid was carried out for application to coagulation process with domestic wastewater and lake water, and the removal rate of the organic substances depending on a dosage was evaluated by PDA (Photometric Dispersion Analyzer) in this study. Zeta-potential of zirconium silicate solution was -32.22 mv at pH 7 and the lower negative(-) charge was detected in the more acidic conditions. Absorbance on $UV_{254}$ presented higher when zirconium silicate was added than in a domestic wastewater itself. Besides, the results by PDA experiment represented that injection of zirconium silicate could promote growing of floc. Tests for coagulation process were conducted by three ways which are pre-injection, co-injection and post-injection of zirconium silicate with alum. Accordingly, removal efficiency of organic substances increased over 15% in co-injection than in using of alum as a sole reagent. When a 20 mg/L of alum was used with a 10 mg/L of zirconium silicate, the removal efficiency was high up to 90%. Removal efficiency of $COD_{Cr}$ was improved more than 15% in case of dosage of coagulant either PAC (Poly aluminium chloride) or PACS (Poly aluminium chloride Silicate) together with zirconium silicate. As a result, the removal efficiency of $COD_{Cr}$ were 5~10% higher in a co-injection of zirconium silicate with a coagulant than a pre-injection and a post-injection but it of soluble substances was lower in a co-injection.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.3
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• pp.225-236
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• 2012

In this study, the cellular protective effects on HaCaT cells and human erythrocytes and antioxidative effects of P. tricuspidata stem extracts were investigated. The ethyl acetate ($50{\mu}g/mL$) and aglycone fraction ($25{\mu}g/mL$) of P. tricuspidata stem extracts doesn't show any characteristics of cytotoxicity. When HaCaT cells were treated with 10 mM $H_2O_2$ and $30{\mu}M$ rose bengal, the ethyl acetate ($6.25{\sim}50{\mu}g/mL$) and aglycone ($6.25{\sim}25{\mu}g/mL$) fraction protected the cells against the oxidative damage in a concentration dependent manner. The P. tricuspidata stem extracts showed more prominent cellular protective effect than (+)-${\alpha}$-tocopherol, known as lipid antioxidant at $10{\mu}g/mL$. The ethylacetate fraction of P. tricuspidata stem extracts ($18.5{\mu}g/mL$) showed more free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC5_{50}$). Reactive oxygen species (ROS) scavenging activity ($OSC_{50}$) of P. tricuspidata stem extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system was investigated using the luminol-dependent chemiluminescence assay. The ethyl acetate ($1.72{\mu}g/mL$) and the aglycone fraction ($1.53{\mu}g/mL$) showed similar ROS scavenging activity of L-ascorbic acid ($1.50{\mu}g/mL$). These results indicate that extract/fractions of P. tricuspidata stem extracts can function as natural cytoprotective agents and antioxidants in biological systems, particularly skin exposed to UV radiation by protecting cellular membrane against ROS.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.1
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• pp.57-65
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• 2012

In the present study, the antioxidative properties, inhibitory activity on tyrosinase, and active components of Eriobotrya japonica (E. japonica) leaf extract were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) of extract/fraction of E. japonica leaf was in the order 50 % ethanol extract ($22.625{\mu}g/mL$) < ethyl acetate fraction (6.75) < deglycosylated aglycone fraction (5.06). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of fraction/extracton ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system using the luminol-dependent chemiluminescenceassay were investigated. $OSC_{50}$ of the ethyl acetate fraction, deglycosylated aglycone fraction, and ethanol extract were 0.75, 0.79, and $1.61{\mu}g/mL$, respectively. The cellular protective effects of E. japonica leaf extract on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The protective effects of extract/fraction of E. japonica leaf were increased in a in a concentration dependent manner ($5{\sim}50{\mu}g/mL$). Especially, ${\tau}50$ of ethyl acetate fraction at concentrations of $10{\mu}g/mL$ and $50{\mu}g/mL$ showed the most protective effects at 390.8 min and 1471.5 min. The inhibitory effect ($IC_50$) on tyrosinase of E. japonica leaf extracts was higher than arbutin, known as a skin-whitening agent. The order of inhibitory effects was acetate fraction ($75.25{\mu}g/mL$) < 50 % extract (74.1) < deglycosylated aglycone fraction (43.35). TLC of the ethyl acetate fraction showed 7 bands (EJL 1 - EJL 7). HPLC of the aglycone fraction exhibited 2 peaks, kaempferol and quercetin. The amounts of kaempferol and quercetin were 53.7 and 46.3 %. respectively. Therefore, The amounts of kaempferol and its glucoside were a little bit higher than quercetin and its glucoside in E. japonica leaf extract. Accordingly, these findings suggest that extracts/fractions of E. japonica leaf can function as antioxidants in biological systems, especially skin exposed to UV radiation, and protect cellular membranes against ROS. Thus, the extract/fraction of E. japonica leaf may be used in novel functional cosmetics as antioxidants against skin photoaging.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.217-226
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• 2016

In this study, we investigated the antioxidative and cellular protective effects on HaCaT cells and erythrocytes of Moringa oleifera (M. oleifera) leaves extract and its fractions. All experiments were performed with 50% ethanol extract, ethyl acetate fraction and aglycone fraction of M. oleifera leaves. The free radical scavenging activity ($FSC_{50}$) of the extract and fractions of M. oleifera leaves were in the following order: 50% ethanol extract ($77.10{\mu}g/mL$) < ethyl acetate fraction ($20.63{\mu}g/mL$) < aglycone fraction ($17.00{\mu}g/mL$) by using the 1, 1-diphenyl-2-picrylhydrazyl. In $Fe^{3+}-EDTA/H_2O_2$ system using the luminol, reactive oxygen species (ROS) scavenging activities (total antioxidant capacity, $OSC_{50}$) of aglycone fraction ($OSC_{50}=0.63{\mu}g/mL$) was the strongest among all extracts, which was much higher than L-ascorbic acid ($1.50{\mu}g/mL$). In the $^1O_2$-induced cellular damage of erythrocytes, the cellular protective effects of 50% ethanol extract (${\tau}_{50}=46.9min$) and aglycone fraction (${\tau}_{50}=122.1min$) were higher than (+)-${\alpha}$-tocopherol (${\tau}_{50}=37.7min$), known as a lipophilic antioxidant at $10{\mu}g/mL$. After cell damage induced by $400mJ/cm^2$ UVB irradiation, the cellular protective effects of ethyl acetate and aglycone fraction of M. oleifera leaves extract were showed on the concentration from 0.20 to $1.56{\mu}g/mL$. These results suggest that M. oleifera leaves extract and its fractions can function as a natural antioxidant agent in cosmetics on skin exposed to UV radiation by protecting cellular membrane against ROS.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.25-35
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• 2008

In this study, the antioxidative effects and inhibitory effects on elastase and tyrosinase of Geranium nepalense extracts were investigated. The free radical(1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) of extract/fractions of Geranium nepalense were in the order: 50% ethanol extract(15.0 ${\mu}g/mL$)${\mu}g/mL$). ${\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities($OSC_{50}$) of some Geranium nepalense extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescense assay. The order of ROS scavenging activities were 50% ethanol extract($OSC_{50},\;0.23{\mu}g/mL$)${\mu}g/mL$)${\mu}g/mL$). Deglycosylated flavonoid fraction showed the most prominent scavenging activity. The protective effects of extract/fractions of Geranium nepalense on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Geranium nepalense extracts suppressed photohemolysis in a concentration dependent manner, particularly deglycosylated flavonoid fraction exhibited the most prominent celluar protective effect (${\tau}_{50}$, 676.7 min at 50 ${\mu}g/mL$). The inhibitory effect of aglycone fraction on tyrosinase($IC_{50}$, 70.0 ${\mu}g/mL$) and elastase ($IC_{50}$, 19.9 ${\mu}g/mL$) was very high. Aglycone fractions obtained from the deglycosylation reaction of ethyl-acetate fraction among the Geranium nepalense extracts, showed 2 bands in TLC and 2 peaks in HPLC experiments (370 nm). Two components were identified as quercetin(composition ratio, 15.3%), kaempferol(82.8%). These results indicate that extract/fractions of Geranium nepalense can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Geranium nepalense extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.2
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• pp.88-94
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• 2016

The study was carried out to examine the anti-obesity effects of 40% ethanol extract from green tea seed (GS) and quantitative determination of caffeine as its major compound. The specificity was satisfied with retention time and UV spectrum by analysis of caffeine using HPLC and comparison with standard compound. It showed a high linearity in the calibration curve with a coefficient of correlation (R²) of 0.9974. The amount of caffeine in GS was about 4.649 mg/g (0.465%) in the three times analysis, and relative standard deviation (RSD) was less than 0.452% by the validated method. The anti-obesity effects of GS were evaluated by using Oil Red O staining in 3T3-L1 adipocytes and body weight, visceral fat and lipid profiles in high fat diet (HFD)-induced C57BL/6 obese mice. Our results indicated that treatment with GS dose-dependently decreased lipid accumulation contents (p<0.001). Moreover, after oral administration for 30 days feeding with HFD-induced obses mice, GS (100 and 300 mg/kg/day) produced a significant decrease in serum total cholesterol (TC), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and visceral fat. Thus, the result of this study indicate that the GS may be a useful resource for the management of obesity.