• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.146-154
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• 2019

In this study, alkoxysilane-functionalized amphiphilic polymer (AFAP), which have hydrophilic segment and hydrophobic segment functionalized by alkoxysilane group at the same backbone, was synthesized and used as a dispersant and control agent for reaction rate in the preparation of colloidally stable organic-inorganic (O-I) hybrid sols. After reaction with fluorosilane compounds, fluorinated O-I hybrid sols were prepared and coated onto glass substrate to form hydrophobic O-I hybrid coating films through low-temperature curing process. Surface hardness and hydrophobicity of cured coating films were varied with type of solvent and composition of AFAP and fluorinated alkoxysilane compounds. At appropriate solvent and composition of fluorinated alkoxysilane compounds, O-I hybrid coating film having high transparency and surface hardness could be prepared, which could be applicable to cover window of solar cell and displays.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.49-53
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• 2005

This paper presents a multi-scale hybrid simulation for the design of a catalytic multi-tubular reactor with high performance. The multi-tubular reactor consists of shell and a large number of tubes in which various catalytic chemical reactions occur. To consider fluid dynamics in the shell-side and kinetics in the tube-side at the same time, commercial CFD package and process simulation tool are coupled. This hybrid approach allowed us to predict many kinds of meaningful results such as tube center temperature profile, heat transfer coefficients on the tube wall, temperature rise of cooling medium, pressure drop through shell and tube side, concentration profile of each chemical species along the tube, and so on., and to achieve the optimal reactor design.

• Polymer(Korea)
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• v.34 no.5
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• pp.405-409
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• 2010

New sol-gel precursors having the ability to protect iron against corrosion were synthesized and used to prepare organic-inorganic hybrid coatings based on epoxy. Bisphenol A epoxy was modified with 3-isocyanatopropyltriethoxysilane to improve the compatibility, and water and HCl were used as catalysts for sol-gel process. Various coating formulations were prepared depending on the type of sol-gel precursors and the amount of each ingredient, and cast on iron substrates by dip-coating and thermally cured. Corrosion protection properties of coated iron were studied by a salt spray test and electrochemical impedance spectroscopy under 0.1 M NaCl electrolyte. Hybrid coatings containing anticorrosive functional group exhibited excellent corrosion protection on iron, compared to that of typical hybrid coatings. From electrochemical impedance spectroscopy, the hybrid coatings containing anticorrosive functional group could maintaine the initial impedance after 500 h, while the impedance of hybrid coatings without them started to decrease after 24 h.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.272-278
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• 2013

The hybrid system composed of a photocatalytic reactor and a biofilter was operated under various operating conditions in order to treat malodorous waste air containing ammonia which is a major air pollutant emitted from composting factories and many publicly owned treatment works. Total ammonia removal efficiency of the hybrid system was maintained to be ca. 80% even though its inlet loads were increased at a higher operating stage according to an operating schedule of the hybrid system. The ammonia removal efficiency of photocatalytic reactor was decreased from 65% to 22% as ammonia inlet loads to photocatalytic reactor were increased. In spite of same inlet loads of ammonia to the photocatalytic reactor, the ammonia removal efficiency of photocatalytic reactor with lower ammonia concentration of fed-waste air was higher than that with higher ammonia concentration of fed-waste air. To the contrary, during the first half of the hybrid system operation the ammonia removal efficiency of a biofilter was quite suppressed while, despite of increased ammonia inlet loads, the ammonia removal efficiency of the biofilter was continuously increased to 78% and reached the ammonia removal efficiency similar to what Lee et al. attained. The maximum ammonia elimination capacity of the photocatalytic reactor was observed to be ca. 16 g-N/$m^3$/h. In an incipient stage of hybrid system run, the ammonia elimination capacity of the biofilter showed little sensitivity against ammonia inlet loads to the hybrid system. However, in the 2nd half of its run, the ammonia elimination capacity of the biofilter was increased abruptly in case of high ammonia inlet loads to the hybrid system. In 6th stage of hybrid system run, total ammonia inlet load attained at ca. 80 g-N/$m^3$/h corresponding to 16 g-N/$m^3$/h of ammonia elimination capacity of the photocatalytic reactor. Then, the remaining ammonia inlet load to the 2nd and main process of the biofilter and its elimination capacity was expected and shown to be ca 64 g-N/$m^3$/h and ca 48 g-N/$m^3$/h, respectively. The ammonia elimination capacity of the biofilter was close to 1,200 g-N/$m^3$/day of the maximum elimination capacity of the investigation performed by Kim et al.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.100-115
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• 2022

In this study, integrated hybrid system (IHS) composed of two alternatively-operating UV/photocatalytic reactor (AOPR) process and biofilter processes of a biofilter system having two units (i.e., R_up and R_dn) with an improved design (R reactor) and a conventional biofilter (L reactor) was constructed, and its transient behavior was observed to perform the successful treatment of waste air containing ethanol and hydrogen sulfide (H₂S). At the IHS-operating stages of HA1, HA2 and HA3T of reversed feed direction, the AOPR process showed not only ethanol-removal efficiencies of 55, 50 and 45%, respectively, but also H₂S-removal efficiencies of 70, 60 and 37%, respectively. In particular, a drastic decrease of H₂S-removal efficiency at the stage of HA3T was observed due to a doubling of H₂S-inlet concentration fed to AOPR from 10 ppmv to 20 ppmv at the stage of HA3T. The order of ethanol-breakthroughs and the order of the magnitude of ethanol-removal efficiencies at the sampling ports of each unit of R reactor at the stages of HA1, HB1, HA2, HB2, and the first half of HA3T, were reversed, respectively, at the stages of the second half of HA3T and HB3T. In case of H₂S, R reactor did not show H₂S-breakthrough as prominent as the ethanol-breakthrough, but showed the trend similar to the ethanol-breakthrough.

• Polymer(Korea)
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• v.37 no.1
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• pp.34-40
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• 2013

Commercially available polyamide thermoplastic elastomer (PA-TPE) was blended with hybrid filler which was prepared by means of the reaction between polyhedral oligomeric silsesquioxane (POSS) containing amine group and toluene diisocyanate (TDI)-caprolactam (CL) to explore the effect of blending the hybrid filler with the TPE. The chemical structure of the filler was identified by using FTIR and $^1H$ NMR. The composites, PA-TPE/POSS-(TDI+CL), which were the blends of TDI+CL modified POSS filler and PA-TPE up to 7 wt%, showed better elastic recovery delivered from lower tension setting compared to the PA-TPE and the PA-TPE/octaphenyl POSS blend. In addition the tensile strength and the initial modulus increased with increasing the hybrid filled content. Consequently it was assumed that the POSS-(TDI+CL) filler was a suitable material for enhancing strength and modulus without loss of elastic properties for the original PA-TPE.

• Korean Journal of Optics and Photonics
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• v.27 no.2
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• pp.73-80
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• 2016

In this paper, we report the results of a study on the design and fabrication of a light-guiding plate (LGP) using a hybrid light-emitting diode (LED) and sunlight source that can be applied to a photobioreactor. LGP patterns for the LED source were designed and engraved on an LGP, together with previously reported patterns for a sunlight source. A control system for the hybrid LGP was designed to maintain the output photon flux density (PFD) from the LGP at a constant value. When the target value of the output PFD was set to $70{\mu}E/(m^2{\cdot}s)$, the error range of the output PFD was found to be within ${\pm}2%$.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.116-124
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• 2022

In this study, waste air containing ethanol and hydrogen sulfide, was treated by an integrated hybrid system composed of two alternatively-operating UV/photocatalytic reactor-process and biofilter processes of a biofilter system having two units with an improved design (R reactor) and a conventional biofilter (L reactor). Both a pressure drop (△p) per unit process of the integrated hybrid system and a microbe-population-distribution of each biofilter process were observed. The △p of the UV/photocatalytic reactor process turned out very negligible. The △p of the L reactor was observed to increase continuously to 4.0~5.0 mmH₂O (i.e., 5.0~6.25 mmH₂O/m). In case of R reactor, its △p showed the one below ca. 16~20% of the △p of the L reactor. Adopting such microbes-carrying biofilter media with high porosity as waste-tire crumb media, and the improved biofilter design, contributed to △p of this study, reduced by ca. 37~50% and 40~53%, respectively, from the reported △p of conventional biofilter packed with biofilter media of the mixture (50:50) of wood chip and wood bark. In addition, the △p of R reactor in this study, reduced by ca. 80% from the reported △p of conventional biofilter packed with biofilter media of the mixture (75:25) of scoria with high porosity and compost, was mainly attributed to adopting the improved biofilter design. On the other hand, in case of L reactor, the CFU counts in its lowest column was analyzed double as much as those in any other columns. However, in case of R reactor, its CFU counts were bigger by 50% than the one of L reactor and its microbes were evenly distributed at its higher and lower columns of R_dn reactor and R_up reactor. This phenomena was attributed to an even moisture distribution of 50~55% of R reactor at its higher and lower columns. Therefore, R reactor showed superb characteristics in terms of both △p and microbe-population-distribution, compared to L reactor.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.382-390
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• 2010

In this research hydrogen sulfide, ammonia and toluene were designated as the representative source of malodor and VOC, respectively, frequently generated at the compost manufacturing factory and publicly owned facilities. The optimum operating condition to treat the waste air(2 L/min) containing malodor was constructed using photocatalytic reactor/biofilter process with humidifier composed of fluidized aerobic anf anoxic reactor. The ammonia(300 ppmv) of fed-waste air was removed by 22, 55 and 23% at the stage of photocatalytic reactor, humidifier and biofilter, respectively. The toluene(100 ppmv) of fed-waste air was removed by 20, 10 and 70% at the stage of photocatalytic reactor, humidifier and biofilter, respectively. Therefore the water-soluble ammonia and the water-insoluble toluene were treated mainly at the stage of humidifier and biofilter, respectively. In addition, hydrogen sulfide(10 ppmv) was almost treated at the stage of photocatalytic reactor and its negligible trace was absorbed in humidifier so that it was not detected before biofilter process. The nitrate concentration of the process water from anoxic reactor was found lower by 3 ppm than that from fluidized aerobic reactor. Besides, the dissolved ammonia-nitrogen concentration of the process water from humidifier remained at the high value of 1,500-2,000 ppm, which may be attributed to the existence of ammonium chloride and other source of ammonium nitrogen.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.71-77
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• 2015

A fluidized biofilter was filled with Pseudomonas sp. and Bacillus cereus/thuringiensis-fixed waste-tire crumb media and was run to treat authentic textile-dyeing wastewater mixed with alkaline polyester-weight-reducing wastewater. As a result, its removal efficiency of $COD_{Cr}$ and color were 75~80% and 67%, respectively. In addition, upon constructing hybrid-recirculating system composed of the fluidized biofilter and a 450 W-UV/photocatalytic reactor, only fluidized biofilter was run bypassing UV/photocatalytic reactor at stage I. Subsequently, the hybrid system was continuously run at stage II-i, ii and iii. At stage II-i, the total removal efficiency of $COD_{Cr}$ was enhanced to be 80~85%, compared to 75% at stage I, owing to 20~30% removal efficiency of the UV/photocatalytic reactor. However, at stage II-i, the total removal efficiency of color was enhanced to be 65~70%, compared to 45~65% at stage I, even though the removal efficiency of the UV/photocatalytic reactor was tantamount to merely 0~5%. As far as the removal efficiency of fluidized biofilter of the hybrid-recirculating system is concerned, its removal efficiency of color was enhanced by the synergy effect of the hybrid-recirculating system unlike $COD_{Cr}$. Besides, despite of the increase of hybrid-recirculating system-recycle ratio, the deactivation of photo-catalytic activity was scarcely observed to eliminate the color while its irreversible deactivation was observed to eliminate $COD_{Cr}$.