• Journal of Korean Society of Water and Wastewater
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• v.32 no.1
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• pp.27-35
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• 2018

The stability of liquid ferrate(VI) produced by an innovative method was confirmed and the degradation characteristics of cyclic compounds(Benzene, Aniline, Toluene, 1,4-Dioxane) by liquid ferrate(VI) were investigated under the same reaction conditions. When it was compared with the ferrate manufactured by the wet oxidation method, the liquid ferrate was more stable. And the stability of liquid ferrate was tested at the storage temperature. As a result, only 17.7% of liquid ferrate(VI) has decomposed at the storage temperature($4^{\circ}C$) for 28 days. Among the cyclic compounds, the aniline was rapidly degraded compare to other cyclic compounds, which seems to be due to the electron-donating ability of the substituent, $-NH_2$ group. Especially, when 1,4-dioxane was compared with benzene, the decomposition rate of 1,4-dioxane was lower than that of benzene, suggesting that oxygen atoms hinder the electrophilic reaction. Among 4 cyclic compounds, it was observed that aniline has the highest rate constant than those of other cyclic compounds.

• Journal of Environmental Science International
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• v.15 no.1
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• pp.67-75
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• 2006

The degradation of Rhodamine B (RhB) in water was investigated in laboratory-scale experiments, using five advanced oxidation Processes (AOPs) $UV/H_2O_2$, lenten, photo-lenten, $UV/TiO_2,\;UV/TiO_2/H_2O_2$. The photodegradation experiments were carried out in a fluidized bed photoreactor equipped with an immersed 32 W UV-C lamp as light source. initial decolorization rate and COD removal efficiency were evaluated and compared. The results obtained showed that the initial decolorization rate constant was quite different for each oxidation process. The relative order of decolorization was: photo-fenton > $UV/TiO_2/H_2O_2$ > fenton > $UV/H_2O_2$ > $UV/TiO_2$ > UV > $H_2O_2$. The relative order of COD removal was different from decolorization: photo-fenten ${\fallingdotseq}$ $UV/TiO_2/H_2O_2\;>\;UV/TiO_2\;>\;fenton\;>\;UV/H_2O_2$. The Photo-lenten and $UV/TiO_2/H_2O_2$ processes seem to be appropriate for decolorization and COD removal of dye wastewater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.122-124
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• 2002

The removal capacity of zero-valent iron for Cr(Ⅵ) was evaluated using batch kinetic tests. The rate constants for zero-valent iron dramatically increased as initial Cr(Ⅵ) concentration decreased. Generally, the reaction rates of Cr(Ⅵ) with zero-valent iron were faster than that of a biotic degradation of Cr(Ⅵ), and furthermore the reaction rates were inversely proportional to the initial Cr(Ⅵ) concentrations. After certain reaction time elapsed. no further decrease of Cr(Ⅵ) was observed, indicating a loss of iron reactivity. The loss of iron reactivity was primarily due to the passivation of iron surfaces with iron-Cr precipitates, but the reactivity of iron was recovered by adding iron-reducing bacteria. Even though the addition of bacteria itself removed Cr(Ⅵ), the combination of iron-reducing bactera and oxidized iron significantly enhanced the reaction rate for Cr(Ⅵ) removal. The results from column tests also confirmed that the innoculation of iron-reducing bacteria to the column containing completely oxidized iron partially enhanced the recovery of the iron reactivity.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.2
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• pp.75-83
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• 1990

An experiment was conducted with three ruminally and intestinally cannulated non-lactating cows of Finnish Ayrshire breed, to assess the ruminal degradation characteristics of oat (Avena sativa), rye (Secale cereale) and rice (Oryza sativa) straw by the nylon bag technique, and the subsequent post-ruminal degradation of their rumen-undegraded residues by using the mobile bag technique, respectively. The straw samples were untreated or treated with aqueous $NH_3$ or with urea solution in cold or hot water. The untreated straw samples were milled or chopped, and the treated straw samples were chopped. The constant values a, b, and c were computed according to the exponential equation, where a = intercept of degradation curve at time 0, b = potentially degradable material, c = rate of degradation of band (a+b) = maximum potential degradability (asymptote). It was found that nitrogen contents of chemically treated straw were markedly increased by both $NH_3$ and urea treatments. Milling the samples attributed to a remarkable loss at 0 h incubation time as compared to chopping of the respective samples. However, chemical treatment markedly improved the b value and the subsequent (a+b) values for dry matter, organic matter, neutral-detergent fiber, and acid-detergent fiber of the samples. Furthermore, temperature of the water used in the urea solutions was considered essential, since urea in hot water rather than in cold water seemed to enhance the overall degradability. The disappearance of rumen-incubated straw residues from the mobile bags ranged from 4.5 to 9.6% for the parameters measured. On average, the OM disappearance from bags was clearly higher for the residues of urea treated straw compared to those of ammonia treated straw, but the disappearance of NDF tended, however, to be higher on the ammonia treatment.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.390-394
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• 1992

Some enzymatic characteristics of the aflatoxin degrading factor produced extraceIlularly by Aspergillus awamori var. fumeus were investigated. When aflatoxin B1 was incubated with the culture filtrate of A. awamori var. fumeus. 60% of it was degraded within an hour. The degradation rate decreased with time and there was virtually no degradation after one hour. The apparent Michaelis constant ($K_m$) determined by Lineweaver-Burk plot was $10.2{\mu}M$. The optimum degradation was observed at $30^{\circ}C$ and pH 5. For the degradation, molecular oxygen seemed to be required. The degradation was enhanced by the $Co^{2+}$. but was inhibited by many other ions like $Fe^{2+}$, $Ca^{2+}$. $Mg^{2+}$, $Zn^{2+}$,$Cu^{2+}$, and $Ba^{2+}$, The presence of either KeN or metyrapone inhibited the reaction while that of $NaI0_4$ cytochrome C or NADPH showed no effect.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.10
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• pp.888-893
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• 2016

In this study, the solution plasma process was utilized with the aim of degrading synthetic dyes in water at atmospheric pressure. The experiments were conducted in a batch-type reactor consisting of a symmetric wire-wire electrode configuration with rhodamine B (RhB) as the target synthetic dye. The effects of the plasma treatment time and initial dye concentration on the RhB degradation were investigated by monitoring the change in absorbance of RhB solutions. The RhB solutions turned lighter in color and finally colorless with prolonged plasma treatment time, indicating the destruction of dye molecules. The RhB solutions were found to have degraded, following the first-order kinetic process. However, for high initial RhB concentrations, another kinetic process or factor seems to play a dominant role at the initial degradation stage. The fitted first-order rate constant decreased as the initial concentration increased. This result suggests that the degradation behavior and kinetic process of the RhB solution strongly depends on its initial concentration. The RhB degradation is considered to be due to a combination of factors, including the formation of chemically oxidative species, as well as the emission of intense UV radiation and high-energy electrons from the plasma. We believe that the solution plasma process may prove to be an effective and environment-friendly method for the degradation or remediation of synthetic dye in wastewater.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.56-62
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• 2016

A heterogeneous $Bi_2S_3/TiO_2$ composite catalyst was synthesized via a green ultrasonic-assisted method and characterized by XRD, SEM, EDX, TEM analysis. The results clearly show that the $TiO_2$ particles were homogenously coated with $Bi_2S_3$ particles, indicating that $Bi_2S_3$ particle agglomeration was effectively inhibited after the introduction of anatase $TiO_2$. The Texbrite BA-L (TBA) degradation rate constant for $Bi_2S_3/TiO_2$ composites reached $8.27{\times}10^{-3}min^{-1}$ under visible light, much higher than the corresponding value of $1.04{\times}10^{-3}min^{-1}$ for $TiO_2$. The quantities of generated hydroxyl radicals can be analyzed by DPCI degradation, which shows that under visible light irradiation, more electron-hole pairs can be generated. Finally, the possible mechanism for the generation of reactive oxygen species under visible-light irradiation was proposed as well. Our result shows the significant potential of $Bi_2S_3$-semiconductor-based $TiO_2$ hybrid materials as catalysts under visible light for the degradation of industry dye effluent substances.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1207-1213
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• 2005

In a search for bacteria capable of degrading styrene better than previously isolated strains, bacterium IS-3 was isolated from activated sludge and found to be most closely related to Pseudomonas sp. Styrene degradation by this strain was tested in liquid cultures and polyurethane-packed biofilters. In liquid cultures, the rate of styrene degradation by this bacterium increased from 24.93 to $76.53\;{\mu}mol\;g^{-1}\;DCW\;H^{-1}$ for an initial mass range from 8.7 to $34.8{\mu}mol$. The maximum styrene elimination capacity was 580-635 $g/m^{3}\cdot$h at a space velocity (SV) of 50-200/h. The critical elimination capacities guaranteeing $95\%$ removal of the input styrene were determined to be 635, 170, and 38 $g/m^{3}\cdot$h, respectively, at SVs of 50, 100, and 200/h. Kinetic analysis revealed that the maximum styrene elimination velocity ($V_{m}$) for this biofilter was 1,000 g/m$\cdot$h, and the saturation constant ($K_{m}$) was 454 ppmv. Together, these results suggest that a polyurethane biofilter containing Pseudomonas sp. IS-3 could have potential practical applications for the effective removal of styrene gas.

• Environmental Engineering Research
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• v.23 no.2
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• pp.129-135
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• 2018

The aim of this study is to assess the applicability of ferrate(VI) in the efficient treatment of aqueous waste contaminated with potassium hydrogen phthalate (KHP) which is known to be a potent endocrine disrupting chemicals. Simulated batch reactor operations were conducted at a wide range of pH (7.0 to 12.0) and molar ratios of KHP to ferrate(VI). Kinetic studies were performed in the degradation process and overall rate constant was found to be 83.40 L/mol/min at pH 8.0. The stoichiometry of ferrate(VI) and KHP was found to be 1:1. Further, lower pH values and higher KHP concentrations were favoured greatly the degradation of KHP by ferrate(VI). Total organic carbon analysis showed that partial mineralization of KHP was achieved. The presence of several background electrolytes were studied in the degradation of KHP by ferrate(VI).

• Clean Technology
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• v.23 no.4
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• pp.408-412
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• 2017

Pigment red 53:1 is a dye used in various products as a component of the inks, suspected of being carcinogenic. Thus, the environmental and occupational issues related to it are important. The enzyme-based approach with reusability has advantages to consume less energy and generate less harsh side- products compared to the conventional strategies including separations, microbe, and electrochemical treatment. The degradation of Pigment red 53:1 by the lignin peroxidase immobilized on the surface of magnetic particles has been studied. The immobilization of the peroxidase was conducted on magnetic particle surface with the treatment of polyethyleneimine, glutaraldehyde, and the peroxidase, in sequence. The immobilization was confirmed using X-ray photon spectroscopy. The absorbance peak of the pigment was monitored at 495 nm of UV/Vis spectrum with respect to time to calculate the catalytic activities of the pigment for the immobilized lignin peroxidase. For the comparison, the absorbance of the lignin peroxidase free in solution was also monitored. The catalytic rate constant values for the free lignin peroxidases and the immobilized those were 0.51 and $0.34min^{-1}$, respectively. The reusable activity for the immobilized lignin peroxidase was kept to 92% after 10 cycles. The stabilities for heat and storage were also investigated for both cases.