RHDS 촉매는 코크와 황 화합물 그리고 금속인 바나듐이 표면에 침적되어 비활성화가 된다. 이러한 오염물을 제거하기 위해서 먼저 폐 RHDS 촉매에 묻어있는 중질유분의 세정, 코크와 황 화합물을 고온 배소 처리한 후, 과량으로 침적되어 있는 바나듐의 침출량을 조절하기 위하여 0.5, 1 wt% 옥살산 수용액을 이용하여 초음파 교반기에서 50 ℃, 10 sec 동안 교반하여 NOx 저감을 위한 SCR 촉매로의 적용 가능성을 확인하고자 하였다. 재생처리 한 RHDS 촉매의 성분은 XRF 를 사용하여 분석하였고, 상압 고정층 연속 흐름 반응기 상에서 NOx 저감 성능을 측정하였다. 옥살산 수용액 0.5 wt%, 10 sec 동안 초음파 침출한 촉매가 가장 안 정적인 NOx 저감 성능을 보였으며, 375 ℃ 이상의 고온에서는 상용 촉매와 동등 수준의 NOx 저감 성능을 확인할 수 있었으나 저온영역 200 ℃에서 250 ℃까지는 상용 촉매보다 낮은 NOx 저감 성능을 보였다. 따라서 폐 RHDS 촉매를 재생처리 한 후 분말로 메탈 코로게이트 지지체에 워시코팅한 촉매는 상용 SCR 촉매로서 이용 가능함을 확인하였다.

In this study, we investigate the deformation behavior of Hf44.5Cu27Ni13.5Nb5Al10 metallic glass powder under repeated compressive strain during mechanical milling. High-density (11.0 g/cc) Hf-based metallic glass powders are prepared using a gas atomization process. The relationship between the mechanical alloying time and microstructural change under phase transformation is evaluated for crystallization of the amorphous phase. Planetary mechanical milling is performed for 0, 40, or 90 h at 100 rpm. The amorphous structure of the Hf-based metallic glass powders during mechanical milling is analyzed using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Microstructural analysis of the Hf-based metallic glass powder deformed using mechanical milling reveals a layered structure with vein patterns at the fracture surface, which is observed in the fracture of bulk metallic glasses. We also study the crystallization behavior and the phase and microstructure transformations under isothermal heat treatment of the Hf-based metallic glass.

This study examined the physical and chemical properties of soil in Jang-San wetland in Busan Metropolitan City. The wetland covers wide and flat area comparing to its outside. The samples of the wetland soil were collected and analyzed in order to identify the profiles and chemical properties. According to the analyses of soil moisture and particle size distribution, the wetland soil mostly belongs to sandy loam with the soil moistures of 14.9-153.2%. The soil profiles are configured with O, A, B, and C horizons from the land surface. The organic matter content (2.38-16.7%) at most sampling locations decreases downwardly with the highest at 0-20 cm depth. The organic matter content has a good positive relationship with soil moisture content. According to X-ray diffraction analysis, the wetland soils contain quartz and feldspar (the main components of rhyolite porphyry) as well as montmorillonite, gibbsite, and kaolinite (the weathered products of feldspar). The wetland soil displays the highest iron concentration (average 22,052 mg/kg), indicating oxidation of iron. High concentrations of potassium (average 17,822 mg/kg) and sodium (average 5,394 mg/kg) originate from the weathering of feldspar. Among anions, sulfate concentration is highest with average 9.21 mg/kg that may originate from sulfate minerals and atmosphere.