• 상하수도학회지
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• 제20권1호
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• pp.115-121
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• 2006

The purpose of this study was to investigate applicability of pretreatment on the existing biological treatment for domestic wastewater reclamation. From Jar Tests, it was found that optimum dosage of coagulant was PAC 0.5mg/L and $FeCl_3$ 180mg/L for urban sewage. In this study, PAC 0.5mg/L was selected considering sludge production and the amount of coagulant required. In a continuous experiment performed with combining chemical coagulation and biological treatment, a considerable removal efficency was obtained in term of BOD, SS, T-N, T-P and ABS. When the raw sewage was supplied into the pre-chamical treatment facility, the removal of BOD and SS was 48.3% and 81.1%. However T-N removal was very low which means T-N consists of $NH_3-N$ mostly. T-P was almost completely recluced by the chemical addition. The effluent BOD & SS was 57~76 and 21~43mg/L, which could reduce the size of biological treatment facility. From the cost estimation pre-chemical treatment could save around half of the area required for biological treatment with post ceagulation.

• 접착 및 계면
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• 제14권3호
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• pp.146-159
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• 2013

본 연구에서는 $350^{\circ}C$에서 4 min 이내로 빠르게 등온 안정화공정을 통해 얻어진 레이온직물의 화학조성, 물리적 특성, X-선 회절 패턴, 열안정성 그리고 직물 형상에 미치는 초음파세척 및 화학전처리의 영향을 조사하였다. 안정화공정 동안 레이온직물에서 발생하는 중량감소와 열수축을 줄이고 안정화반응을 촉진시키기 위하여 안정화공정 전에 레이온직물을 먼저 초음파 세척하고 $NH_4Cl$, $Na_3PO_4$, $H_3PO_4$ 및 $ZnCl_2$로 화학전처리 공정을 수행하였다. 결과는 초음파세척 및 화학전처리가 안정화된 레이온직물의 중량감소, 열수축, 미세구조 변화, 탄소함량, 열안정성, 및 직물 형상에 영향을 주었으며, 사용한 안정화시간과 화학전처리제의 종류에 의존하였다.

• 한국환경과학회지
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• 제14권7호
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• pp.683-689
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• 2005

The consecutive combination process of a biological process as the pre-treatment and a chemical process as the post-treatment is applied for the dyeing wastewater. The poor efficiency of biological treatment using pure oxygen makes the chemical treatment cost high. It is necessary to improve the efficiency of biological treatment in order to reduce the cost of chemical treatment. The purpose of this paper is to find the minimum dose of chemical reagent to fit the Discharged Water Quality Standards for the different biological treatment effluents. Results revealed that the minimum dosage of Fenton's reagent lead to save the cost of chemical treatment based on the guideline dose in the treatment plant. The possible maximum saving reagents was up to $70\%$ for the effluent of the pilot plant packed with the carrier imbedded microorganisms which were selected from the present treatment plant.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.43-44
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• 2009

Fabrics for Digital Textile Printing (DTP) are different from it of general textile printing. It is necessary to pre-treatment of chemical agents for desired quality. But this process does not correspond with simplification of DTP processing. In this research, we pre-treated of cotto is necessary to pre-treatment of chemical agents for desired quality. But this process does not correspond with simplification of DTP processing. In this research, we pre-treated of cotton fabric for DTP by atmosphere plasma treatment and we understood that pre-treatment of fabric by atmosphere plasma treatment was more simple DTP process.

• 상하수도학회지
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• 제38권2호
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• pp.109-117
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• 2024

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

• Carbon letters
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• 제12권3호
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• pp.131-137
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• 2011

Kenaf fibers, cellulose-based natural fibers, were used as precursor for preparing kenafbased carbon fibers. The effects of carbonization temperature ($700^{\circ}C$ to $1100^{\circ}C$) and chemical pre-treatment (NaOH and $NH_4Cl$) at various concentrations on the thermal change, chemical composition and fiber morphology of kenaf-based carbon fibers were investigated. Remarkable weight loss and longitudinal shrinkage were found to occur during the thermal conversion from kenaf precursor to kenaf-based carbon fiber, depending on the carbonization temperature. It was noted that the alkali pre-treatment of kenaf with NaOH played a role in reducing the weight loss and the longitudinal shrinkage and also in increasing the carbon content of kenaf-based carbon fibers. The number and size of the cells and the fiber diameter were reduced with increasing carbonization temperature. Morphological observations implied that the micrometer-sized cells were combined or fused and then re-organized with the neighboring cells during the carbonization process. By the pre-treatment of kenaf with 10 and 15 wt% NaOH solutions and the subsequent carbonization process, the inner cells completely disappeared through the transverse direction of the kenaf fiber, resulting in the fiber densification. It was noticeable that the alkali pre-treatment of the kenaf fibers prior to carbonization contributed to the forming of kenaf-based carbon fibers.

• Korean Chemical Engineering Research
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• 제52권4호
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• pp.413-424
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• 2014

에너지원으로 바이오가스에 대한 잠재적 가능성이 인식되면서 최근에 바이오가스의 생산기술을 제고하고 에너지 효율을 개선하기 위한 기술개발이 지속적으로 진행되고 있다. 본 논문의 목적은 혐기성 소화 과정에서 바이오가스 생산을 증가시키기 위한 효과적이고 효율적인 슬러지 전처리 방법에 대하여 분석하였다. 이를 위해 본 논문에서는 각각의 전처리 방법의 장점과 단점을 분석하여 바이오가스 생산에 미치는 영향요인을 비교 분석하였다.

• Carbon letters
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• 제9권4호
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• pp.308-315
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• 2008

In the present study, fast isothermal stabilization processes for rayon precursor fabrics were performed at $350^{\circ}C$ and $400^{\circ}C$ within 3 minutes and the chemical and physical characteristics of the stabilized fabrics were investigated. In addition, rayon precursor fabrics were pre-treated with three different phosphorous-based flame retardants and then stabilized. The effect of flame retardants on the chemical composition, thermal shrinkage, weight change, thermal stability and XRD results was examined, comparing with those of the precursor fabrics. The result showed that the stabilization of rayon fabrics was most effective as the stabilization temperature was $350^{\circ}C$, the stabilization time was 3 min, and the pre-treatment with phosphoric acid of 1 vol%. The carbon contents of stabilized rayon fabrics were increased with increasing stabilization temperature and time, whereas the oxygen contents were decreased. Also, it is likely that the pre-treatment with phosphoric acid plays a role in retarding the change of chemical structure of rayon fabric. The XRD result was quite consistent with the result showing the effect of phosphoric acid on the chemical composition, thermal shrinkage and weight reduction of rayon fabric.

• Preventive Nutrition and Food Science
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• 제17권1호
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• pp.46-52
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• 2012

This study was performed to investigate the effects of pre-treatment and storage temperature and periods on the quality characteristics of ginger paste. The pH of the ginger paste remained constant during room temperature storage but increased with prolonged refrigerated storage periods. During five months of frozen storage, regardless of pre-treatment, the pH of most of the samples decreased slightly and then remained constant. In the color value of ginger paste stored at room temperature, the samples with and without chemical additives changed in color more prominently than fermented or pasteurized samples. Intriguingly, the color value for samples containing chemical additives changed more dramatically when stored under refrigerated conditions. However, the L, a, and b values of samples stored under frozen storage conditions did not change even after ten months. Most of the samples contained glucose and fructose, except for the fermented samples. The free sugar content of samples slowly decreased with increasing storage periods, while the organic acid content generally decreased also, regardless of sample type. Depending on pre-treatment and storage temperature, the gingerol content of the samples was either retained or decreased with prolonged storage time.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.1967-1971
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• 2013

Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs.