• 대한환경공학회지
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• 제22권7호
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• pp.1263-1271
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• 2000

Alum을 이용한 응집 과정에서 탁도 및 유기물 제거와 응집 floc의 특성을 파악하였다. 본 실험에서 구한 탁도 제거영역을 Amitharajah의 연구결과와 비교했을 때 sweep floc 및 charge neutralization의 제거영역이 낮은 pH 영역으로 이동하였는데 그 원인은 원수에 포함된 유기물 농도가 다른데서 찾을 수 있다. 대체적으로 탁도 및 유기물($UV_{254}$와 TOC)의 제거영역은 비슷하였으나 탁도 제거에 비해 낮은 pH에서 유기물 제거의 효과가 높았다. Floc의 특성은 AIA, SALLS 방법을 이용하여 volume diameter과 fractal dimension을 측정하였다. AIA 방법에 비해 SALLS 방법의 측정이 용이하고 신뢰성도 높았다. SALLS 방법을 이용하여 floc을 측정한 결과 sweep floc 영역의 floc이 charge neutralization 영역의 floc 보다 fractal dimension과 평균 직경이 크게 측정되었으며, 오염물질의 제거율이 높을수록 floc의 fractal dimension과 평균 직경도 크게 나타났다.

• 상하수도학회지
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• 제9권4호
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• pp.63-72
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• 1995

The mean velocity gradient, G, has been used as a principal design and operation parameter for flocculation unit. This paper questions that significance. The physical and qualitative meaning of collision efficiency factors of each transport mechanism (Brownian motion, fluid shear, and differential sedimentation) are reviewed. The overall collision frequency function is calculated by summing up the collision frequency function of each mechanism. In the collision of two particles of different size, a diagram showing the dominant region in which each mechanism is important is developed and the meaning of the diagram is discussed. The primary ramification of this curvilinear, heterodisperse approach is that G is found to be not nearly so important. Previous experimental work in which the role of G has been examined is reviewed in light of this finding.

• Macromolecular Research
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• 제9권5호
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• pp.285-291
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• 2001

The polysulfone(PSf)/polyethersulfone(PES) blend membranes were prepared by an immersion precipitation method. N-methyl-2-pyrrolidone(NMP) was used as a solvent and water as a nonsolvent. The composition of the coagulation bath and the dope polymer concentration as well as the blend ratio of two polymers were varied. The membrane morphologies were interpreted on the basis of the phase diagram of the PSf/PES/NMP/water system. As the solvent content in the coagulation bath increased in the single polymer system, the number of macrovoids decreased and the morphology was changed from finger-like to cellular structure. In the given bath condition phase separation occurs earlier for the solutions of PSf/PES blend than for those of single polymer. A horizontally layered structure and horizontal protuberances inside the macrovoid were observed for the membranes formed from PSf/PES blend solutions. This peculiar structure formation can be interpreted by a PSf-rich/PES-rich phase separation followed by a polymer-rich/polymer-lean phase separation during the exchange of solvent and nonsolvent.

• 한국물환경학회지
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• 제24권6호
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• pp.682-689
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• 2008

The purpose of this study was to find out the variation between molecular size distribution (MSD) of natural organic matter (NOM) in raw waters after different water treatment processes like conventional process (coagulation, flocculation, filtration) followed by advanced oxidation process (ozonation, GAC adsorption). The MSD of NOM of Suji pilot plant were determined by Liquid Chromatography-Organic Carbon Detection (LC-OCD) which is a kine of high-performance size-exclusion chromatography (HPSEC) with nondispersive infrared (NDIR) detector and $UV_{254}$ detector. Five distinct fractions were generally separated from water samples with the Toyopearl HW-50S column, using 28 mmol phosphate buffer at pH 6.58 as an eluent. Large and intermediate humic fractions were the most dominant fractions in surface water. High molecular weight (HMW) matter was clearly easier to remove in coagulation and clarification than low molecular weight (LMW) matter. Water treatment processes removed the two largest fractions almost completely shifting the MSD towards smaller molecular size in DW. No more distinct variation of MSD was observed by ozone process after sand filtration but the SUVA value were obviously reduced during increase of the ozone doses. UVD results and HS-Diagram demonstrate that ozone induce not the variation of molecular size of humic substance but change the bond structure from aromatic rings or double bonds to single bond. Granular activated carbon (GAC) filtration removed 8~9% of organic compounds and showed better adsorption property for small MSD than large one.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.655-668
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• 2009

본 총설에서는 수정진동자 센서의 원리와 질량, 점성, 점탄성의 변화에 기초한 수정진동자 센서의 응용에 관하여 고찰하였다. 수정진동자의 기본원리와 공진주파수-공진저항 다이어그램에 관하여 상세히 기술하였다. 카본을 피막한 가스센스, 혈액응고를 이용한 센스, 전기화학분석, 결정화 분석 등에 관한 응용 예를 소개하였다. 이러한 연구 결과를 토대로 새로운 바이오센서나 화학센서 개발 가능성에 관하여 고찰하였다.