• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.519-525
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• 2008

Biodegradation of toluene, styrene and hydrogen sulfide as model compounds of volatile organic compounds and odor from waste gas was investigated experimentally in a biotrickling filter. This study focussed on the description of experimental results with regard to operating conditions. The effect of varying $H_2S$ load rate and inlet concentration was investigated under autotropic and mixotropic environmental conditions. The $H_2S$ removal efficiencies of greater than 99% were achieved at $H_2S$ loads below $10g/m^3{\cdot}hr$ for each environment. It was observed that the maximum elimination capacity of mixotrophic filter was achieved a little greater than the one of autotrophic filter. The biofiltration of toluene and styrene in trickling bed was examined under different gas flow rates, load rates, and inlet concentrations. Below $40g/m^3{\cdot}hr$ of toluene loading, the elimination capacity and loading were identical and it was completely destroyed. In high loading of toluene, the biotrickling filter was operated at its maximum elimination capacity. In the inlet concentration of 0.2, 0.5, and $1.0g/m^3$, the maximum elimination capacity of toluene showed 40, 45, and $60g/m^3{\cdot}hr$, respectively. After a short adaptation period, it was demonstrated that the results of styrene in originally toluene adapted bioreactor was similar with the ones of toluene. However, the performance of filer for styrene is generally a little lower than for toluene. The operating conditions (including liquid flow rate etc.) allowing the highest removal efficiency should be determined experimentally for each specific case.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.639-645
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• 2016

We herein report efficient triplet-triplet annihilation upconversion (TTA-UC) achieved in various non-toxic and non-volatile vegetable oils as a UC media using platinum-octaethylporphyrin (PtOEP) and 9,10-diphenylanthracene (DPA) as a sensitizer and acceptor, respectively. Green-to-blue UC was readily achieved from PtOEP/DPA solution in vegetable oils with the quantum yield of 8% without any deoxygenation process. The UC efficiency was found to be significantly dependent on the contents of unsaturated hydrocarbon in vegetable oils and viscosity of the solution, as well. Though the Stern-volmer constant and quantum yield in vegetable oils were measured to be lower than those measured in the deaerated organic solvent, the quenching efficiency was still high enough to be 93%. In the sunflower oil, the UC threshold intensity ($I_{th}$) was approx. $100mW/cm^2$, which is far larger than the sunlight intensity, but we believe that the UC achieved in non-toxic and air-saturated media was still highly applicable to nontraditional visualization techniques such as bioimaging.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.527-532
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• 2005

Ionic polymer metal composites (IPMC) are soft polymeric smart materials having large displacement at low voltage in air and water. The polymeric electrolyte actuator consists of a thin and porous membrane and metal electrodes plated on both faces, in impregnation electro-plating method. The response and actuation of actuator are governed. Among many factors governing the activation and response of IPMC actuator, the surface electrode plays an important role. In this study, the well-designed modification of electrode surface was carried out in order to improve the chemical stability well as electromechanical characteristics of the IPMC actuator. We employed Ion Beam Assisted Deposition (IBAD) method to prepare the topologically homogeneous thin surface electrode. After roughing the surface of Nafion membrane in order to get a larger surface area, the IPMC was prepared by impregnation for electro-plating and re- coating on the surface through traditional chemical deposition, followed by an additional surface treatment with high conductive metals with IBAD. It was observed that our IPMC specimen shows the enhanced surface electrical properties as well as the improved actuation and response characteristics under applied electric field.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.451-457
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• 2006

We synthesized phase pure CrN having surface areas up to $47m^2/g$ starting from $CrCl_{3}$ with $NH_{3}$. Thermal Gravimetric Analysis coupled with X-ray diffraction was carried out to identify solid state transition temperatures and the phase after each transition. In addition, the BET surface areas, pore size distributions, and crystalline diameters for the synthesized materials were analyzed. Space velocity influenced a little to the surface areas of the prepared materials, while heating rate did not. We believe it is due to the fast removal of reaction by-products from the system. Temperature programmed reduction results revealed that the CrN was hardly passivated by 1% $O_{2}$. Molecular nitrogen was detected from CrN at 700 and $950^{\circ}C$, which may be from lattice nitrogen. In temperature programmed oxidation with heating rate of 10 K/min in flowing air, oxidation started at or higher than $300^{\circ}C$ and resulting $Cr_{2}O_{3}$ phase was observed with XRD at around $800^{\circ}C$. However the oxidation was not completed even at $900^{\circ}C$. CrN catalysts were highly active for n-butane dehydrogenation reaction. Their activity is even higher than that of a commercial $Pt-Sn/Al_{2}O_{3}$ dehydrogenation catalyst in terms of volumetric reaction rate. However, CrN was not active in pyridine hydrodenitrogenation.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.565-568
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• 1998

Amphipathic compounds (bis-sulfonate Gemini type) with double or triple long chain alkyl groups were prepared by the reaction of N-(long chain acyl)diethanolamine diglycidyl ethers with fatty alcohols, followed by the reaction with propanesultone. All these new Gemini type surfactants were soluble in water and showed much better micelle forming ability and lowering surface tension than sodium dodecyl sulfonate with one sulfonate group. cmc and ${\Upsilon}$ cmc values of the triple-chain compounds were still much smaller than those of the corresponding double-chain compounds with two common alkyl groups. The efficiency of adsorption at the water/air interface ($pC_{20}$) of these surfactants was very high. Their foaming properties, wetting ability toward a felt chip, and lime-soap dispersing requirement (LSDR) were measured. Their initial foaming properties were high but showed good low foam stability, wettability and LSDR.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1164-1173
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• 1996

Treating methods and characteristics of waste from a nuclear fuel powder conversion plant were studied. To recovery or treat a trace uranium in liquid waste, the ammonium uranyl carbonate(AUC) filtrate must be heated for $CO_2$ expelling, essentially. Uranium content of final treated waste solution from fuel powder processes for a heavy water reactor(HWR) could be lowered to 1 ppm by the lime treatment after the ammonium di-uranate(ADU) precipitation by simple heating. Otherwise, in case of the waste from fuel powder processes for a pressurized light water reactor(PWR), it is result in 0.8 ppm as a form of uranium peroxide such as $UO_4{\cdot}2NH_4F$ compounds. Optimum condition was found at $101^{\circ}C$ by the simple heating method in case of HWR powder process waste. And in case of PWR powder process waste, optimum condition could be obtained by precipitating with adding hydrogen peroxide and adjusting at pH 9.5 with ammonia gas at $60^{\circ}C$ after heating the waste In order to expelling $CO_2$. As the characteristics of recovered uranium compounds, median particle size of ADU was increased with pH increasing in case of HWP waste. Also, in case of uranium proxide compound recovered from PWR waste, the property of $U_3O_8$ power obtained after thermal treatment in air atmosphere was similar to that of the powder prepared from AUC conversion plant.

• Journal of Surface Science and Engineering
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• v.12 no.3
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• pp.207-216
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• 1979

Environmental pollution or contaminations caused by various kinds of pollutants have become one of most serious problems of our time. Environ mental pollution is the unfavoralble alteration of our surroundings, through direct or indirect effects of changes in energy patterns, rediation levels, chemical and physical constitution and abundances of organisms. These changes may affect humans directly or through their supplies of water and of agicultural and other biological products, their physical objects or possessions, or their opportunities for recreation and appreciation of nature. Pollutants that meet the criteria of this definition of environmental pollution are numerous: gases (such as sulfur dioxide and nitrogen oxides) and paniculate matter (such as smoke particles, lead aerosols, and asbestos) in the atmosphere; pesticides and radioactive isotopes in the atmosphee and in waterways; sewage, organic. chemicals, and phosphates in water; solid wastes on land; excessive heating (thermal pollution) of rivers and lakes; and many others. Some of these pollutants are introduced into the environment naturally, others by human actions, and most in both ways. Our major concer is with environmental pollution resulting wholly or largely as a by-product of human activities, because these can be controlled most readily. Environmental pollution cannot be solved by science and technology alone. It should be handled by an interdisciplinary approach with combined methods of science and technology as wen as social science disciplines for the better solution of this critical problem. In this respect, introducing "Environmental Science," a new scientific approach for the solution of environmental problems, which is now widely accepted by most developed countries of the world will be very helpful for systematization of theoretical basis for a new scientific approach to environmental pollution. Environmental science is "the study of all systems of air, land, water, energy, and life that surround Man. It includes all sciences directed to the system-level of understanding of the environment, drawing especially upon such disciplines as meteorology, geophysics, oceanography, and ecology, and utilizing to the fullest knowledge and techniques developed in such fields as physics, chemistry, biology, mathematics and engineering as well as many social science disciplines, such as economics, such as economics, law, political science and public administration." The components of this discipline are not new, for they are drawn from existing areas of science within biology chemistry, physics, and geoscience. What is really new about environmental science, however, is it siewpoint - its orientation to global problems, its conception of the earth as a set of interlocking, interacting systems, and its interest in Man as a part of these systems.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.372-376
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• 1998

Internal mass transfer during osmotic dehydration of gingers in sugar solution was examined as a function of concentration, temperature and immersion time of those solutions using moisture loss, sugar gain, molality and rate parameter. Influence of osmotic dehydration on browning reaction and texture properties of air dried rehydrated was also evaluated. Increasing the concentration and temperature of sugar solutions increased moisture loss, sugar gain, molality and rate parameter. Water loss and sugar gain were rapid in the first 3 min and then changed gentle slope. Moisture loss during osmotic dehydration using a sugar solution $(60\;Brix,\;80^{\circ}C)$ with 18 min immersion time was 40.05 g moisture/100 g wet ginger which was 52% reduction of initial moisture content in ginger (83.02%, wet basis). The changes of rate parameter were more affected by temperature than by concentration of sugar solution. Minimum browning degree (O.D.=0.027) was carried out by osmotic dehydration in sugar solution $(40\;or\;50\;Brix,\;80^{\circ}C)$ with 15 min immersion time compared to control (O.D.=0.132). Influence of osmotic dehydration on puncture forces of 3 min rehydrated ginger in boiling water were $22{\sim}34%$ of reduction, while blanching treatment had not affected compared to those of control.

• Journal of the Korean earth science society
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• v.23 no.5
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• pp.416-423
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• 2002

The concentrations of dimethylsulfide (DMS) and carbon disulfide (CS$_2$) were measured concurrently with relevant environmental parameters at Kosan, Cheju during Apr 2001. Results of our analysis indicate that the combined temporal variations of both DMS and CS$_2$ record three distinctible patterns that are separable from each other. For instance, DMS behaved very similarly to CS$_2$ during the 1st (5${\sim}$18 Apr) and 3rd period (23${\sim}$26 Apr). The pronouncingly high concentration of CS$_2$ was maintained during the first period, but DMS values peaked mostly during the third period. It was furthermore striking to find that changes in DMS levels occurred in an opposite direction relative to CS$_2$ during the 2nd period. Although most of these variabilities appear to be associated with the interaction of source/sink processes and the air parcel movement, certain aspects of their behavior are found to be highly complicated enough to account for.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.123-127
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• 2012

In order to develop eco-friendly biopesticide, an entomopathogenic bacterium Photorhabdus temperata M1021 has been lyophilized via freeze-drying along with protective agents such as skim milk, starch, sodium alginate, glucose and sodium glutamate to protect cells from lysis. Freeze-drying powder of P. temperata M1021 containing 7% skim milk (w/v) showed highest survival rate of 63% among all the protective agents used in trials. Furthermore, the freeze-dried microbial powder showed 75% of survival rate after stored at $4^{\circ}C$ for 4 weeks at air contact conditions. Injection toxicity of the freeze-dried sample was tested against larvae of Galleria mellonella. A dose of $2.0{\times}10^1$ cells of P. temperata M1021 killed 100% of the G. mellonella larvae within 4 days after injection. Moreover, $2.0{\times}10^0$ cells caused 50% mortality within the 4 days after injection. Freeze-dried P. temperata M1021 strains exhibited effective insecticidal activity and could be a better candidate for being used as a biopesticide.