• Environmental Engineering Research
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• v.23 no.1
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• pp.1-9
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• 2018

The degradation of methylene blue (MB) in an aqueous solution by nano-metallic particles (NMPs) was studied to evaluate the possibility of applying NMPs to remove MB from the wastewater. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the synthesized NMPs before and after the reaction. The effects of the NMP dosage, the initial pH, the initial concentration of MB and the amount of $H_2O_2$ on the MB degradation outcomes were studied. The highest removal rate of MB was achieved to be 100% with an initial MB concentration of 5 mg/L, followed by 99.6% with an initial concentration of 10 mg/L under the following treatment conditions: dose of NMP of 0.15 g/L, concentration of $H_2O_2-100mM$ and a temperature of $25^{\circ}C$. The SEM analysis revealed that the nano particles were not spherical in shape. FTIR spectra shows occurrence of metal oxides on the surfaces of the NMPs. The XPS analyses results represent that Fe, Zn, N, Ca, C and O were occurred on the surfaces of the NMPs. The degradation of MB was suitable for the pseudo-first-order kinetics.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1589-1595
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• 2010

In order to effective degradation of organic dye both under visible light or ultrasonic irradiation, the MWCNTs (multiwalled carbon nanotube) deposited with Fe and $TiO_2$ were prepared by a modified sol-gel method. The Fe/$TiO_2$-MWCNT catalyst was characterized by surface area of BET, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) and ultraviolet-visible (UV-vis) spectroscopy. The low intensity visible light and low power ultrasound was as an irradiation source and the methylene blue (MB) was choose as the model organic dye. Then degradation experiments were carried out in present of undoped $TiO_2$, Fe/$TiO_2$ and Fe/$TiO_2$-MWCNT catalysts. Through the degradation of MB solution, the results showed the feasible and potential use of Fe/$TiO_2$-MWCNT catalyst under visible light and ultrasonic irradiation due to the enhanced formation of reactive radicals as well as the possible visible light and the increase of ultrasound-induced active surface area of the catalyst. After addition of $H_2O_2$, the MB degradation rates have been accelerated, especially with Fe/$TiO_2$-MWCNT catalyst, in case of that the photo-Fenton reaction occurred. The sonophotocatalysis was always faster than the respective individual processes due to the more formation of reactive radicals as well as the increase of the active surface area of Fe/$TiO_2$-MWCNT catalyst.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.299-305
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• 2000

Degradation behavior of the three commercial biodegradable polymers, namely poly(3-hydroxybutyrate) (PHB) Sky-Green/sup R/ (SG) and Mater-Bi/sup R/ (MB) was investigated using bacteria isolated from activated sludge and farm soil. Three PHB degrading bacteria, three SG degrading bacteria and one MB degrading bacteria were isolated. The PHB degrading bacteria were identified to be Flavimonas oryzihabitans, Corynebacterium pseudodiphtheriticum and Micrococcus diversus, while Pseudomonas vesicuraris, Pasteurlla multocida and Flavobacterium odoratum were identified as SG degrading bacteria. As for MB, Pseudomonas vesicuraris was isolated. The shake flask test for 28 days indicated that the rate of biodegradation of PHB, SG and MB in terms of weight loss were about 44∼69% 25∼32% and 29% respectively. The surface morphology of PHB, SG andMB films before and after degradation by microorganisms in an activated sludge soil was observed under SEM, demonstrating that the film surface had a very porous structure, and that microorganisms colonized heavily on the film surface. TOC and pH variation as a result of abiotic hydrolysis, or microbial growth in the absence of the polymers were compared to those due to degradation by F. oryzihabitans. Abiotic hydrolysis of PHB was three times as fast as that of SG and MB. Addition of yeast extract to the basal liquid medium accelerated the biodegradation of the polymers. Biodegradation of PHB was always faster than that of SG and MB irrespectively of the presence of yeast extract in the basal liquid medium.

• Journal of Mushroom
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• v.20 no.2
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• pp.86-91
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• 2022

Pleurotus eryngii, a white rot fungus, produces two extracellular lignin-degrading enzymes, laccase and manganese peroxidase (MnP). Owing to these enzymes, P. eryngii efficiently degrades synthetic chemicals such as azo, phthalocyanine, and triphenyl methane dyes. In this study, we investigated the degradation processes of four aromatic dyes, congo red (CR), methylene blue (MB), crystal violet (CV), and malachite green (MG), by P. eryngii under solid and liquid culture conditions. CR and MG were the most quickly degraded under solid and liquid culture conditions, respectively. However, compared to CR, CV, and MG, MB was not degraded well under both culture conditions. The activities of ligninolytic enzymes (laccase and MnP) were also investigated. Laccase was identified to be the major enzyme for dye degradation. A positive relationship between decolorization and enzyme activity was observed for CR, MB, and CV degradation. In contrast, decolorization of MG ensued after high enzyme activity. These results indicate that the degradation process differs between MG and the other aromatic dyes. Therefore, P. eryngii could be a potential tool for the bioremediation of synthetic aromatic dye effluent.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.5-12
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• 2017

Effects of operating parameters such as activated carbon dose, gaseous $O_3$ concentration and pH on the properties of methylene blue(MB) degradation in a catalytic ozonation were investigated through a series of batch experiments. Activated carbon catalyzed the self-decomposition of ozone, generating $OH{\cdot}$, thus promoting MB degradation. Thus the increase of activated carbon dose enhanced the MB and TOC removal. The higher gaseous ozone concentration injected, the promoted MB and TOC removal obtained through the enhanced mass transfer. The MB removal was not significantly affected by the variation of aqueous pH. Catalytic ozonation can be considered as an efficient alternative in treating refractory pollutants in textile wastewater with faster and higher dye and TOC removal compared with ozonation and adsorption.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.518-524
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• 2013

This study investigated the degradation of taste-and-odor compounds and toxins using dielectric barrier discharge plasma. The degradation of taste-and-odor compounds was conducted on geosmin and 2-methyl isoborneol (2-MIB), and the toxins investigated were microcystin-LR (MC-LR), microcystin-RR (MC-RR), microcystin-YR (MC-YR) and anatoxin-a. Largely depending on the type of gas fed to the plasma reactor, the degradation efficiencies of the taste-and-odor compounds decreased in order of oxygen (100%) > dry air (96%) > nitrogen (5%) for geosmin and in order of oxygen (100%) > dry air (94%) > nitrogen (2%) for 2-MIB on the basis of 150 s reaction time. This result suggests that the oxidative reactive species generated during plasma treatment, especially long-lived ozone, are mainly responsible for the degradation of these compounds. When using oxygen as the feed gas, geosmin and 2-MIB were totally degraded within 150 s, microcystins within 10 s, and anatoxin-a within 30 s. It was found that the taste-and-odor compounds and toxins were degraded more rapidly in real lake water than in distilled water.

• Journal of the Korean Ceramic Society
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• v.46 no.1
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• pp.1-9
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• 2009

Activated carbon modified with nickel (Ni-AC) was employed the for preparation of Ni-activated carbon/$TiO_2$ (Ni-AC/$TiO_2$) composites. The $N_2$ adsorption data showed that the composites had a decreased surface area compared with pristine AC. This indicated blocking of the micropores on the surface of the AC, which was further supported by observation via SEM. XRD results showed that the Ni-AC/$TiO_2$ composite contained a mixed anatase and rutile phase while the untreated AC/$TiO_2$ contained only a typical single and clear anatase phase. EDX results showed the presence of C, O, and Ti with Ni peaks on the composites of Ni-AC/$TiO_2$. Subsequently, the photocatalytic effects on methylene blue (MB) were investigated. The improved decomposition of MB showed the combined effects of adsorptions and photo degradation. In particular, composites treated with Ni enhanced the photo degradation behaviors of MB.

• Journal of Nutrition and Health
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• v.38 no.2
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• pp.104-111
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• 2005

Tumor invasion is composed of four steps: cell adhesion to the extracellular matrix, degradation of the extracellular matrix components, tumor cell motility followed by cell detachment. Matrix metalloproteinases (MMPs) are important proteinases that associated with degradation of matrix component. Epigallocatechin gallate (EGCG) is a major polyphenotic constituent of green tea. In the study, we examined the anti-invasive and MMP activity suppression effects of EGCG in MDA-MB-231 human breast cancer cells. MDA-MB-23l human breast cancer cells were cultured with various concentrations 0 - 100 μM of EGCG. EGCG significantly inhibited the cell adhesion to the fibronectin. Cell motility through gelatin filter and invasion to Matrigel were inhibited dose-dependently by EGCG treatment. EGCG also inhibited the activities of MMP-2, -9 and the amount of MMP-9 (α = 0.05). Therefore, EGCG may contribute to the potential beneficial food component to prevent the invasion and metastasis in breast cancer. (Korean J Nutrition 38(2): 104～111, 2005)

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.1-7
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• 2015

The degradation of off-flavors which is 2-Methylisoborneol (2-MIB) and geosmin by means of ultrasound (US) and pulsed ultraviolet (PUV) irradiation and its combination with catalyst (wire mesh, wire mesh coated TiO₂, and TiO₂) and additive (H₂O₂) were investigated via water system. A combination treatment of TiO₂ and H₂O₂ heterogeneity with US (24 kHz) and PUV (6000 W) has shown improved results in destroying 2-MIB and geosmin, which may be attributed to chain reactions by the enhanced formation of hydroxyl radicals (·OH) through H₂O₂ dissociation and reactive oxide ions of TiO₂ addition. Rapid degradation of off-flavors occurred within 2 min under PUV process with H₂O₂ 100 mg/L (81.5% for 2- MIB; 79.3% for geosmin) and TiO₂ 100 mg/L (83.7% for 2-MIB; 79.8% for geosmin), while compared with H2O2 100 mg/L (58.4% for 2-MIB; 58.0% for geosmin) and TiO₂ 100 mg/L (59.2% for 2-MIB; 38.5% for geosmin) within 5 min under US process. Surprisingly, the emphasis was given on the comparison with the same injected energies between PUV and US on degradation efficiency. Based on the injected energy comparison, the US provided better degradation performance under equal input power of 200 kJ with H₂O₂ 100 mg/L, while compared with H₂O₂ 100 mg/L under PUV process. Our findings suggest that US can be more effective compared to PUV for the degradation of off-flavors in aspect of energy consumptions.

• Elastomers and Composites
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• v.44 no.3
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• pp.290-298
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• 2009

In this paper, the Fe-activated carbon fiber (ACF)/$TiO_2$ composite catalysts were prepared by a sol-gel method. The synthesized photocatalysts were used for the photo degradation of Methylene blue solution under UV light. From Brunauer-Emmett-Teller measurements (BET) data, it was shown the blocking of the micropores on the surface of ACF by treatment of Fe and Ti compound. As shown in SEM images, the ferric compounds and titanium dioxides were fixed onto the ACF surfaces. The result of X-ray powder diffraction showed that the crystal phase contained a mixing anatase and rutile structure and the 'FeO+$TiO_2$' from the composites. The EDX spectra for the elemental analysis showed the presence of C, O, and Ti with Fe peaks. Degradation activity of MB could be attributed to +OH radicals derived from electron/hole pair's reactions due to photolysis of $TiO_2$ and photo-Fenton effect of Fe.