• 청정기술
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• 제10권4호
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• pp.195-201
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• 2004

기능성 고분자와 셀룰라아제가 화학적으로 결합된 수식 셀룰라아제를 이용하여 폐신문용지(Old Newsprint, ONP)의 탈묵공정에 적용하였다. 수식 셀룰라아제 중의 셀룰라아제는 섬유의 피브릴화(fibrillation)를 촉진시켜 잉크입자의 박리를 향상시켰으며, 수식 셀룰라아제 중의 수식 고분자가 탈묵공정에서 분리된 잉크입자를 부상제거하는 새로운 탈묵 공정이 완성되었다. 수식 셀룰라아제를 이용한 공정은 극소량의 수식 셀룰라아제의 사용으로 인장강도, 백감도(brightness), 백색도(whiteness)를 포함한 물리적 성질을 기존 탈묵공정에서의 그것보다 향상시켰다. 잉크와 섬유의 결합은 저장 기간이 증가함에 따라 더욱 강해지고, 기존의 방법으로는 잉크입자 제거가 어려운 반면, 수식 셀룰라아제를 이용한 공정은 잉크입자 제거에 매우 탁월한 효과를 나타내었고, 약 1년간의 보존 기간을 가진 폐신문용지의 탈묵 효과를 41% 향상시켰다. 또한 이 공정은 황변현상을 제거했으며, 섬유의 피브릴화를 촉진시켜 재생지의 물리적 성질인 인장강도와 내부결합도를 향상시켰다.

• 상하수도학회지
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• 제32권5호
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• pp.399-409
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• 2018

Prussian blue is known as a superior material for selective adsorption of radioactive cesium ions; however, the separation of Prussian blue from aqueous suspension, due to particle size of around several tens of nanometers, is a hurdle that must be overcome. Therefore, this study aims to develop granule type adsorbent material containing Prussian blue in order to selectively adsorb and remove radioactive cesium in water. The surface of granular activated carbon was grafted using a covalent organic polymer (COP-19) in order to enhance Prussian blue immobilization. To maximize the degree of immobilization and minimize subsequent detachment of Prussian blue, several immobilization pathways were evaluated. As a result, the highest cesium adsorption performance was achieved when Prussian blue was synthesized in-situ without solid-liquid separation step during synthesis. The sample obtained under optimal conditions was further analyzed by scanning electron microscope-energy dispersive spectrometry, and it was confirmed that Prussian blue, which is about 9.7% of the total weight, was fixed on the surface of the activated carbon; this level of fixing represented a two-fold improvement compared to before COP-19 modification. In addition, an elution test was carried out to evaluate the stability of Prussian blue. Leaching of Prussian blue and cesium decreased by 1/2 and 1/3, respectively, compared to those levels before modification, showing increased stability due to COP-19 grafting. The Prussian blue based adsorbent material developed in this study is expected to be useful as a decontamination material to mitigate the release of radioactive materials.

• 한국농공학회논문집
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• 제58권6호
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• pp.23-30
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• 2016

Soil loss is an accompanying phenomenon of hydrologic cycle in watersheds. Both rainfall drops and runoff lead to soil particle detachment, the detached soil particles are transported into streams by runoff. Here, a sediment-laden water problem can be issued if soil particles are severely detached and transported into stream in the watershed. There is a need to estimate or simulate soil erosion in watersheds so that an adequate plan to manage soil erosion can be established. Universal Soil Loss Equation (USLE), therefore, was developed and modified by many researchers for their watersheds, moreover the simple model, USLE, has been employed in many hydrologic models for soil erosion simulations. While the USLE has been applied even in South-Korea, the model is often regarded as being limited in applications for the watersheds in South-Korea since monthly conditions against soil erosion on soil surface are not capable to represent. Thus, the monthly USLE factors against soil erosion, soil erodibility and crop management factors, were established for four major watersheds, which are Daecheong-dam, Soyang-dam, Juam-dam, and Imha-dam watersheds. The monthly factors were established by recent fifteen years from 2000 to 2015. Five crops were selected for the monthly crop management factor establishments. Soil loss estimations with the modified factors were compared to conventional approach that is average annual estimations. The differences ranged from 9.3 % (Juam-dam watershed) to 28.1 % (Daecheong-dam watershed), since the conventional approaches were not capable of seasonally and regionally different conditions.