• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.503-509
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• 2014

The carbon/porous silica composite membrane was fabricated in a simple manner, which could be successfully for the simultaneous separation and production of chiral epoxides and 1,2-diols, based on their differences in hydrophilic/hydrophobic natures. The chiral Co(III)-$BF_3$ salen catalyst adopted in the membrane reactor system has given the very high enantioselectivity and recyclability in hydrolysis of terminal epoxides such as ECH, 1,2-EB, and SO. The optically pure epoxide and the chiral catalyst were collected in the organic phase after hydrolysis reaction. The hydrophilic water-soluble 1,2-diol product hydrolyzed by chiral salen diffused into the aqueous phase through the SBA-16 or NaY/SBA-16 silica composite layer during the reaction. The water acted simultaneously as a reactant and a solvent in the membrane system. One optical isomer was obtained with high purity and yield, and furthermore the catalysts could be recycled without observable loss in their activity in the continuous flow-type membrane reactor.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.768-774
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• 2014

SI process is a thermochemical process producing hydrogen by decomposing water while recycling sulfur and iodine. Various technologies have been developed to improve the efficiency on Section III of SI process, where iodine is separated and recycled. EED(electro-electrodialysis) could increase the efficiency of Section III without additional chemical compounds but a substantial amount of $I_2$ from a process stream is loaded on EED. In order to reduce the load, a crystallization technology prior to EED is considered as an $I_2$ removal process. In this work, $I_2$ particle sinking behavior was modeled to secure basic data for designing an $I_2$ crystallizer applied to $I_2$-saturated $HI_x$ solutions. The composition of $HI_x$ solution was determined by thermodynamic UVa model and correlation equations and pure properties were used to evaluate the solution properties. A multiphysics computational tool was utilized to calculate particle sinking velocity changes with respect to $I_2$ particle radius and temperature. The terminal velocity of an $I_2$ particle was estimated around 0.5 m/s under considered radius (1.0 to 2.5 mm) and temperature (10 to $50^{\circ}C$) ranges and it was analyzed that the velocity is more dependent on the solution density than the solution viscosity.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.806-811
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• 2016

Organosolv pretreatment is the process to frationation of lignocellulosic feedstocks to enhancement of enzymatic hydrolysis. This process has advantages that organic solvents are always easy to recover by distillation and recycled for pretreatment. The chemical recovery in organosolv pretreatment can isolate lignin as a solid material and carbohydrates as fermentable sugars. For the economic considerations, using of low-molecular-weight alcohols such as ethanol and methanol have been favored. When acid catalysts are added in organic solvent, the rate of delignification could be increased. Mineral acids (hydrochloric acid, sulfuric acid, and phosphoric acid) are good catalysts to accelerate delignification and xylan degradation. In this study, the biomass was pretreated using 40~50 wt% ethanol at $170{\sim}180^{\circ}C$ during 20~60 min. As a results, the enzymatic digestibility of 2-stage pretreatment of rigida using 50 wt% ethanol at $180^{\circ}C$ was 40.6% but that of 1-stage pretreatment was 55.4% on same conditions, therefore it is shown that the pretreatment using mixture of the organosolv and catalyst was effective than using them separately.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.567-573
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• 2012

Compared with the natural marble, the artificial marble has the advantages of excellent appearance, high degree of finish, even color, fine pressure and wear resistance, bear erosion and weathering, etc. It can be widely used in kitchen countertops, bath vanity tops, table tops, furniture, reception desks, etc. However, large amounts of artificial marble waste such as scraps or dust have been generated from sawing and polishing processes in artificial marble industry. Waste from artificial marble industry is increasing according to demand magnification of luxurious interior material. Artificial marble wastes can be recycled as aluminum oxide used as raw materials in electronic materials, ceramics production, etc., and methyl methacrylate(MMA) which become a raw material of artificial marble by pulverization, pyrolysis and distillation processes. The characteristics of artificial marble wastes was analyzed by using TGA/DSC and element analysis. Crude aluminum oxide was obtained from artificial marble waste by pulverization and thermal decomposition under nitrogen atmosphere. In this work, Box-Behnken design was used to optimize the pyrolysis process. The characteristics of crude aluminum oxide was evaluated by chromaticity analysis, element analysis, and surface area.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.1
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• pp.21-29
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• 2024

In this study, EMC(Epoxy molding compound) waste from the semiconductor molding process is recycled and synthesized into silica nanoparticles, which are then applied as abrasive materials contains CMP(Chemical mechanical polishing) slurry. Specifically, silanol precursor is extracted from EMC waste according to the ultra-sonication method, which provides heat and energy, using ammonia solution as an etchant. By employing as-extracted silanol via a facile sol-gel process, uniform silica nanoparticles(e-SiO₂, experimentally synthesized SiO₂) with a size of ca. 100nm are successfully synthesized. Through physical and chemical analysis, it was confirmed that e-SiO₂ has similar properties compared to commercially available SiO₂(c-SiO₂, commercially SiO₂). For practical CMP applications, CMP slurry is prepared using e-SiO₂ as an abrasive and tested by polishing a semiconductor chip. As a result, the scratches that are roughly on the surface of the chip are successfully removed and turned into a smooth surface. Hence, the results present a recycling method of EMC waste into silica nanoparticles and the application to high-quality CMP slurry for the polishing process in semiconductor packaging.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.3
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• pp.57-66
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• 2024

In this study, silicon sludge from a semiconductor packaging process is recycled to fabricate silica coated silicon-sludge and applied as a filler for an epoxy molding compound(EMC). Silicon-sludge powder(S-sludge) is treated with acid to remove metallic impurities and then coated using the sol-gel method to synthesize silica coated silicon-sludge powder(SS-sludge). The as-synthesized SS-sludge is subsequently mixed with epoxy resin, a curing agent, and carbon black to create an EMC(SS-sludge EMC). The heat dissipation properties of the EMC were examined using an IR camera. IR camera analysis confirmed that the SS-sludge EMC exhibited the highest surface temperature of 58.5℃ compared to SiO₂-based EMC. This enhancement in heat dissipation using SS-sludge EMC is attributed to the excellent thermal conductivity(150W/mK) of the silicon substrate and the presence of the silica layer on the SS-sludge surface which effectively enhances the thermal property of the EMC. Therefore, this study successfully demonstrates the recycling of silicon sludge from a semiconductor packaging process by synthesizing silica coated silicon-sludge and suggests a novel application of this material in semiconductor packaging.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.87-98
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• 2024

This study was conducted to investigate the efficiency of the filtering sets composed of fiberboards, which were fabricated with lignocellulosic fiber and cork oak bark-based activated carbon (COA), as well as traditional Korean paper handmade from mulberry trees (KP) for the filtration of PM, TVOC and HCHO. Three-layers fiberboards (WRF) were fabricated with wood fiber in its surface layers and recycled fiber/COA in its core layer using a protein-based adhesive with the resin content of 8%. Filtering sets were composed of three WRF and one sheet of KP. Concentrations of PM, TVOC and HCHO generated with the combustion of a incense in a sealed laboratory hood were reduced efficiently with the operation of air-purifier installed the filtering sets. Except for the WRF fabricated with 4%/4% resin contents, other WRF were prepared with 5%/3% and 6%/2% resin contents in surface/core layers, and then the WRF were used with KP for the fabrication of filtering sets. Filtration efficiency of the filtering sets was improved as the core-layer resin content applied in the fabrication of WRF decreased. In addition, filtration efficiency of the WRF-based filtering set fabricated with KP of 25 g/m² basis weight was higher than that with KP of 45 g/m² basis weight. Filtering sets composed of three-layers fiberboards (RWF) that recycled fiber and wood fiber/COA were used in its surface and core layers, respectively, and KP-25g showed higher filtration efficiency than those of WRF-based filtering sets. Air-inhalation equipment installed the RWF-based, WRF-based filtering sets and without filtering set were operated in small indoor and large outdoor spaces. Efficiency for filtering PM and TVOC of the RWF-based filtering sets was higher than that of other filtering sets. It is concluded that fiberboard-based filtering sets composed of RWF and KP-25g can be used as a filter for reducing the concentrations of PM and TVOC existed in indoor and outdoor spaces.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.4
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• pp.77-82
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• 2014

In Korea, length of irrigation and drain canal is about 98,638 km. In the case of 2011, dredging on the irrigation and drain canal was 7,288 km about 3,290,483 $m^3$, cost of dredging was about 5.6 billion won and cost of dredging increases every year. (Korea Rural Community Corporation, 2013). In the case of land reclamation, the problem of cross-contamination due to leachate after landfill is expected, causing saturation of the landfill site, or complaints of landfill local residents, a number of problems. The ocean landfill is possible if the items of 14 types as defined in the Sea Pollution Prevention Law contained in sediment soil, such as chromium. In terms of cost and labor, it is need to develop a technology utilizing a processing method reasonable sediments for irrigation and drainage canal. The objective of this study was to analyze the characteristics of the sediment deposited on the irrigation and drain canal. it is to provide basic data for the scheme that can be efficiently recycled sediment deposited on the irrigation and drain canal.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.70-70
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• 2011

최근 산업 발달에 의한 환경문제와 석유자원 감소에 따라 섬유시장에는 Eco-friendly 바람이 강하게 불고 있으며 리싸이클 제품이 급부상하고 있다. 폴리에스터계 고분자 제품, 그 중에서도 PET 병의 재자원화를 살펴보면 기계적, 열적으로 처리하여 물질을 바꾸지 않고서 회수하는 방법인 Mechanical Recycling과 원료를 분해하여 회수하는 방법인 Chemical Recycling이 있다. 이러한 리싸이클을 통하여 에너지 절감, 저탄소, 유해물질 감소, 환경정화 및 폐기물 감소로 환경부하가 완화되며, 자원의 효율적 재사용이 가능하다. 리싸이클 PET 섬유제품은 의류 인테리어용과 같은 한정된 용도뿐만 아니라 자동차용 부품소재 및 내장 부품 등 산업용으로도 사용가능하다. 본 연구에서는 리싸이클 PET로 제직한 직물에 정련과 호발가공을 하여 이러한 전처리에 따른 물리적 열적 특성의 변화를 비교 분석하였다. 그 결과 정련과 호발가공을 한 리싸이클 PET 직물의 인장 인열 강도가 미처리 직물과 비교하여 감소하는 결과를 보였으며 마모 파열강도는 큰 차이를 보이지 않았다. 반면에 TGA와 DSC를 이용한 열분석 결과 열적 특성 및 결정화도는 일부 차이를 나타내었다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.9-15
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• 2006

Neutral sizing is required for linerboard to solve the troubles in strength and process caused by recycled raw materials. AKD sizing efficiency can be influenced by process condition like white water quality, fines retention and so on. Therefore, this study was aimed to evaluate sizing performance of general and fast cure type AKDs using process water obtained from linerboard mill. To evaluate effect of process water quality on AKD sizing, white water was diluted with tap water at the different dilution ratios and UKP slurry was sized using the prepared water. Also, effects of inorganic and organic ion material on sizing were examined. When white water was used for stock forming, UKP sheet showed very low sizing degree. Sizing degree of sheet was increased with increase of dilution ratio because water quality was improved. Especially anionic organic material had a greater influence on AKD sizing than inorganic material. When white water quality was deteriorated, fast cure type AKD showed superior sizing performance to general type AKD.