The binary oxide adsorbent using Fe and Mn (Fe-Mn) has been prepared by precipitation method to enhance the removal of phosphate. Different amounts of chitosan, a natural organic polymer, were used during preparation of Fe-Mn as a stabilizer to protect an aggregation of Fe-Mn particles. The optimal amount of chitosan has been determined considering the separation of the Fe-Mn particles by gravity from solution and highest removal efficiency of phosphate (Fe-Mn10). The application of Fe-Mn10 increased removal efficiency at least 15% compared to bare Fe-Mn. According to the Langmuir isotherm model, the maximum uptake (qm) and affinity coefficient (b) were calculated to be 184 and 240 mg/g, and 4.28 and 7.30 L/mg for Fe-Mn and Fe-Mn10, respectively, indicating 30% and 70% increase. The effect of pH showed that the removal efficiency of phosphate was decrease with increase of pH regardless of type of adsorbent. The enhanced removal efficiency for Fe-Mn10 was maintained in entire range of pH. In the kinetics, both adsorbents obtained 70% removal efficiency within 5 min and 90% removal efficiency was achieved at 1 h. Pseudo second order (PSO) kinetic model showed higher correlation of determination (R2), suggesting chemisorption was the primary phosphate adsorption for both Fe-Mn and Fe-Mn10.

The cooking-generated particles are major indoor sources of air pollution. Recently, the performance of the range hood is focused on particle removal performance. Range hood with an auxiliary air supply system can improve the fine and ultrafine particles removal efficiency by making a supply air during cooking activities. The particles were measured in the experimental building by varying ventilation types. Only operating range hood during the cooking activities was not enough to reduce the cooking-generated particles. Despite operating range hood systems, fine and ultrafine particle concentrations were maintained when cooking was finished. The range hood with a make-up air supply system can reduce the indoor particle concentration below background conditions when those systems were operated after cooking. In this study, the assessment of cooking-generated particle removal efficiency of the range hood with an auxiliary air supply system was conducted. The removal efficiency of ultrafine particles showed trends similar to the removal efficiency of fine particles.

In this study, the porous ceramic filter was developed to be able to remove both dust and hazardous gas contained in fuel gas at high temperature. The porous ceramic filters were fabricated and used as a catalyst support. And the effects have been investigated such as the mean particle size, organic content and addition of foaming agent on the porosity, compressive strength and pressure drop of ceramic filters. With the increase of mean powder size and the organic content for the cordierite filter, the porosity was increased, but the compressive strength and pressure drop were decreased. From the results of the research, the optimum condition for the fabrication of ceramic filters could be acquired and they had the porosity of 58%, the compressive strength of 13.4 MPa and the pressure drop of 250 Pa. It was expected that this ceramic filter was able to be applied to the glass melting furnace, combustor, and dust/toxic gas removal filter.

In recent models of semiconductor manufacturing clean rooms, air washers are used to remove airborne gaseous contaminants such as NH3, SOx and organic gases introduced from outdoor air into clean room. Meanwhile, there is a large quantity of exhaust air produced from clean room. It is desirable to recover heat from exhaust air and use it to reheat outdoor air. In the present study, an experiment was conducted to investigate heat recovery, particle collection, and gas removal in a heat recovery type air washer system for semiconductor manufacturing clean rooms.

본 연구에서는 NH(sub)4OH에 계면 활성제를 첨가한 세정액의 특성 및 세정 효과를 H(sub)2O(sub)2가 첨가된 NH(sub)4OH 세정액과 비교 연구하였다. NH(sub)4OH에 계면 활성제를 첨가한 경우 용액의 pH 및 산화 환원전위(Eh) 는 NH(sub)4OH의 값과 거의 유사하고 H(sub)2O(sub)2를 첨가한 경우에 pH는 감소하고 Eh는 증가하는 경향을 보였다. 표면장력은 계면 활성제를 첨가한 경우 약 72 dynes/cm에서 약 38dynes/cm로 감소하였으나 H(sub)2O(sub)2를 첨가한 경우에는 NH?OH 용액과 비교 거의 변화가 없었다. 실리콘 웨이퍼의 식각 속도를 측정한 결과 H(sub)2O(sub)2나 계면 활성제를 첨가하지 않은 초순수와 1 : 5(NH(sub)4OH : H(sub)2O(sub)2)의 부피비의 NH(sub)4OH용액이 첨가한 용액에 비해 최소 50배 이상의 높은 식각 속도를 보였다. 파티클 제거 실험에서 H(sub)2O(sub)2가 첨가된 NH(sub)4OH 세정액은 실험에 사용한 실리콘 표면위의 직경 0.67μm의 PSL파티클을 세정액의 온도와 무관하게 잘 제거하였으나 계면 활성제를 첨가한 NH?OH경우에 상온에서는 파티클을 제거할 수 없었으나 온도를 50˚C와 80˚C로 증가시킨 경우 H(sub)2O(sub)2가 첨가된 NH(sub)4OH와 유사한 세정 효과를 나타내었다.

Polluting gases emitted from industrial sites take compound forms consisting of gaseous and particulate phases. Localization of PTFE membrane filters has thus been initiated to remove particulate materials and mercury, which is a heavy and hazardous metallic element. More specifically, a PTFE membrane filter was fabricated by thermal laminating technology to vary porosity on the filter surface for removal of particulate materials thereon. Optimized equi-biaxial stretching ratio control enables minimization of large-size pore formation with an average pore size of 0.58 μm and improved air permeability of 8.03 cm3/cm2/sec. Various adsorbents were tested for removal of mercury vapor by surface treatment of the PTFE membrane filter. The filter’s surface was further altered using functional amine group compounds: one composed of silane coupling agent (APTMS) was found suitable as a mercury adsorbent. When ACF with a large surface area was used as support material, mercury removal efficiency increased threefold to 0.162 mg/g-ACF. Furthermore, the developed PTFE membrane filter was tested in its capacity of differential pressure and filtering efficiency using a pilot scale particulate removal unit. Stable and consistent differential pressure was maintained during long-term operation and less frequent periods of filter shutdown due to pores filling with 99.96% of particulate removal efficiency, which was more than satisfactory filtration efficiency.

The recycled washwater, which has different water quality and is produced about 5 to 20% of the total water volume treated, affects the unit operation of water treatment, especially coagulation process. However, the effects of recycled washwater on unit operation of water treatment have not been fully investigated. In this study, effects of recycled washwater on coagulation process were investigated to find the optimum coagulation condition by analyzing turbidity, UV254, TOC removal efficiencies. In addition, effects of recycled washwater on residual Al after coagulation were studied by analyzing soluble and particulate Al. The size distribution and fractal dimension of coagulated also analyzed. The recycled washwater was lower pH than the raw water. And the recycled washwater had higher UV254, TOC and residual Al concentration than the raw water. Residual Al concentration of recycled washwater was about 50 times higher than that of raw water. Optimum coagulant dosages on the blending recycled washwater and the raw water for turbidity, UV254 and Al removal were lower than that on the raw water. However, TOC removal increased by increasing coagulant dosage. The size and fractal dimension of coagulated particle produced in the blending recycled washwater were larger, which imply faster settling velocity, than those produced in the raw water only.

This study has been carried out to investigate Electrostatic Precipitator`s(ESP) performance enhancement and removal efficiency of fine particle according to (NH_4)_2SO_4 injection rate. The following conclusions are derived from the these test results : 1)For plant condition cases, according to the variation of concentration agent [(NH_4)_2SO_4] - 10ppm, 20ppm, 30ppm, 40ppm - ESP`s collection efficiency was increased to 97.74%, 98.95%, 99.04%, 99.47%, when inlet dust loading was 2g/㎥. And when inlet dust loading was 3g/㎥, that was increased to 98.19%, 99.16%, 99.23%, 99.58%. 2)It is seen from this experiments that the increasing 30ppm concentration of (NH_4)_2SO_4 increase the collection efficiency and fine particle emission control.