PURPOSES : The increase in particulate matter due to increased air pollutant emissions has become a significant social issue. According to the Ministry of Environment, air pollutants emitted from large-scale businesses in 2022 increased by 12.2% compared to the previous year, indicating that air pollution is accelerating owing to excessive industrialization. In this study, TiO2, which is used to reduce airborne particulate, was used. The TiO2 coating fixation and dynamic pressure coating-type TiO2 fixation methods were used to solve the material peeling phenomenon caused by gravity, which is a limitation when the TiO2 penetration method is applied to a vertical concrete structure along the road. The long-term durability and performance were analyzed through environmental resistance and NOx removal efficiency evaluation experiments. These analyses were then assessed by comparing the NOx removal efficiency with the dynamic pressure permeationtype TiO2 fixation method used in previous studies. METHODS : To evaluate the long-term durability and performance of the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation method for vertical concrete structures, specimens were manufactured based on roadside vertical concrete structures. Environmental resistance tests such as the surface peeling resistance test (ASTM C 672) and freeze-thaw resistance test (KS F 2456) were conducted to evaluate the long-term durability. To evaluate the long-term performance, the NOx removal efficiency of TiO2 concrete owing to road surface deterioration during the environmental resistance test was evaluated using the NOx removal efficiency evaluation equipment based on the ISO 22197-1 standard. This evaluation was compared and analyzed using the dynamic pressure infiltration TiO2 fixation method. RESULTS : The long-term durability of the TiO2 coating fixation and dynamic pressure coating TiO2 fixation methods were evaluated using environmental resistance tests. During the surface peeling resistance test, the TiO2 material degraded and partially detached from the concrete. However, the NOx removal efficiency was ensured by the non-deteriorated and fixed TiO2 material. The long-term performance was confirmed through a freeze-thaw resistance test to evaluate the NOx removal efficiency after 300 cycles of surface deterioration. The results showed that when the TiO2 coating fixation and dynamic pressure infiltration TiO2 fixation methods were applied to vertical concrete structures, the durability of the structure was not compromised. In comparison to the dynamic pressure infiltration TiO2 fixation method, the NOx removal efficiency observed during the surface peeling resistance test was lower, while the freeze-thaw test exhibited notably higher removal efficiency. CONCLUSIONS : To solve the material peeling phenomenon caused by gravity, the long-term durability and performance were evaluated by applying the TiO2 coating fixation and dynamic pressurized coating TiO2 fixation methods to vertical concrete specimens. Long-term durability was confirmed through environmental resistance tests, and long-term utility was secured by measuring the NOx removal efficiency according to surface degradation. These findings show that implementing the TiO2 coating fixation method and dynamic pressure coating TiO2 fixation methods on-site effectively reduce NOx.

This study is aimed at improving the plasma resistance of Al2O3 ceramics on which plasma resistant YAS(Y2O3- Al2O3-SiO2) frit is melt-coated using a simple heat-treatment process. For this purpose, the results of phase analysis and microstructural observations of the prepared YAS frits and the coating layers on the Al2O3 ceramics according to the batch compositions are compared and discussed with regard to the results of plasma resistance test. The prepared YAS frits consist of crystalline or amorphous or co-existing crystalline and amorphous phases according to the batch compositions, depending on the role and content of each raw material. The prepared YAS frit is melt-coated on the densely sintered Al2O3 ceramics, resulting in a dense coating layer with a thickness of at least ~ 80 m. The YAS coating layer consists of crystalline YAG(Y3Al5O12), Y2Si2O7, and Al2O3 phases, and YAS glass phase. Plasma resistance of YAS coated Al2O3 ceramics is strongly dependent on the content of the YAG(Y3Al5O12) and Y2Si2O7 crystalline phases in the coating layer, especially on the content of the YAG phase. Comparing the weight loss of YAS coating ceramics with values obtained for commercial Y2O3, Al2O3, and quartz ceramics, the plasma resistance of the YAS coating ceramics is 6 times higher than that of quartz, 2 times higher than that of Al2O3, and 50 % of the resistance of Y2O3.

현대인의 눈높이에 맞는 친환경적인 고급품질의 인조진주 제품개발이 세계의 악세사리 및 생활용품 시장에서 요구되고 있다. 본 연구는 고품질의 인조진주 제품을 경제적으로 대량생산하기 위한 방법으로 유기안료를 인조진주 제조용 친환경 무기안료로 대체하고 기존 제조 방식에서 사용하는 주재료였던 니트로셀룰로오스를 우레탄 바인더로 대체하여 광택도가 73.4%에서 86.7%로 증가하였으며 CVD 마감처리 후에는 96%의 높은 광택도를 가졌다. 색차분석 결과 CVD 코팅으로 인하여 빛의 간섭효과 때문에 a*와 b*값이 각각 +37.7에서 +31.9로, +24.5에서 +14.2로 감소하면서 다양한 색을 발현하여 영롱한 빛깔의 인조진주가 제조되었다. 마감 증착된 고품질의 인조진주의 내화학성, 광택도, 색차계, 표면 거칠기, 내마모성, 중금속함량검사, 염수분무테스트 등을 분석하여 품질향상 및 인체 무해성을 확인하였다.

Thin-film nanocomposite (TFN) reverse osmosis (RO) membranes have drawn keen attention to overcome the limitations in polymeric desalination membranes. However, preparation of TFN-RO membranes using conventional protocol involves problems such as a waste of expensive nanomaterials and inaccurate control of loading amount. In this work, we suggest a new protocol of TFN-RO membranes through pre-adsorption of carbon nanotubes (CNTs) on the support layer using spray coating. SEM images of spray coated supports showed well-dispersed adsorption of CNTs compared with those using conventional method. RO performances of TFN membranes using spray coating were comparable to conventionally prepared membranes. Thus, this new protocol is useful to prepare TFN membranes in terms of cost-efficiency.

최근 먹는물 수질 기준 강화에 따라 정수처리시설에 고분자 나노여과(Nanofilatration, NF)막이 도입되고 있으나, 화학 세정으로 인한 막의 주기적인 교체가 불가피하다. 반면, 세라믹 막은 강한 물리/화학적 내구성을 지니고 있으나, NF막 제조 기술의 한계로 상용화되지 못하고 있다. 연구에서는 알루미나-지르코니아 나노물질을 여과코팅 방법으로 세라믹 막의 평균 공극 크기를 감소시켰고, SEM-EDX, 분획분자량, 자연유기물, 염(CaCl2) 제거를 통해 막의 특성 변화를 분석하였다. 제조된 막은 분획분자량이 400 Da.이고, Suwannee river 자연유기물과 염의 제거율이 각각 92%와 58%였다. 이취미 물질인 지오스민 제거평가 결과, 실험조건에서 65%의 지오스민이 제거됨을 확인하였다.

We report on a unique fabrication technique, DSC for high performance PA TFC RO membranes. DSC allows the simultaneous and continuous spreading of two reactive monomer solutions to create an unsupported PA layer, which is then adhered onto a porous support to form a membrane. DSC facilitates the characterization of the PA layer structure by easily isolating it. The DSC-PA layer exhibits a thinner and smoother structure with a more wettable and less negatively charged surface than one prepared via conventional interfacial polymerization (IP). DSC enables the formation of an extremely thin (~9 nm) and dense PA layer using a very low MPD concentration, which is not feasible by conventional IP. Importantly, the DSC-assembled membrane shows the excellent water flux and NaCl rejection, exceeding both the IP control and commercial RO membranes.

최근 원전해체, 원전사고 등으로 인한 수계 내 방사성물질 제거 기술로 고분자 소재의 분리막이 사용되고 있지만 고에너지 광선으로 막의 변형 및 파손이 중요한 문제점 중 하나이다. 무기계열의 세라믹막은 강한 내구성을 지니며, 기 존의 한외여과막 수준의 표면 공극 크기를 나노여과막 수준으로 개질할 경우 방사선 물질 제거에 효과적이다. 본 연구에서는 알루미나-지르코니아 나노물질 을 여과코팅 방법으로 세라믹막 표면을 나노여과막 수준으로 개질을 하였고, SEM-EDX, 분획분자량, 오염 전 투수량을 통해 막의 특성 변화를 확인하였다. 제조된 세라믹 나노여과막의 방사선물질 제거 평가로 우라늄(Uranyl nitrate hexahydrate) 2 mg/L 수용액을 사용하였고, ICP-MS 분석결과 40% 제거율을 확인하였다.

입자 크기가 약 16 및 5 nm인 두 다른 크기의 TiO2 나노입자들과 titanium tetraisopropoxide (TTIP) binder 와 ethanol 용매만으로 제조된 코팅액을 사용하여 130 oC 저온 열처리로 ITO/PEN substrate 위에 메조다공성 TiO2 박막들을 형성하였다. 이들 TiO2/ITO/PEN 박막들을 활용한 유연 염료감응 태양전지들을 제작하여 광변환 특성을 비교 연구하였다. 크기가 다른 두 TiO2 나노입자들을 각각 단독으로 사용하여 제작된 cell들의 경우에 크기가 16 nm 인 TiO2 나노입자 cell이 5 nm인 나노입자 cell에 비해 박막의 porosity가 훨씬 크고 같은 질량에서 표면적이 훨씬 넓어 광변환 효율이 훨씬 높으나 염료 흡착량에 대해 상대적으로 작은 광전류는 입자간의 연결성에 기인되며 큰 입 자에 작은 입자를 10% 정도 혼합한 경우에 표면적 증가와 함께 입자간의 연결성을 강화시켜 큰 입자 단독으로 제작 된 cell에 비해 광변환 효율이 크게 증가됨을 확인하였다.

폴리설폰막 위에 친수성 고분자를 Layer-by-Layer법으로 코팅하여 복합막을 제조하였다. FE-SEM 분석을 통하여 복합막 표면과 기공 내 코팅층을 확인하였다. 또한 100 ppm NaCl 용액에 대한 복합막의 투과성능 평가를 실시하였다. 복합 막 제조를 위한 코팅 고분자는 PVSA, PEI, PAA, PSSA, PSSA_MA를 사용하였다. 폴리설폰막 표면에 8,000 ppm PAA (이 온세기 0.35) 수용액을 3분 동안 코팅한 뒤 10,000 ppm PEI 수용액을 4분 동안 코팅하였다. 그 결과 PAA-PEI 복합막의 투과 도는 101 LMH, 제거율은 66.7%로 가장 좋은 투과성능을 나타내었다. PAA-PEI 복합막의 투과성능은 도레이케미칼의 NE 4040-70 (투과도 = 30 LMH, 염 배제율 = 40~70%) 제품과 유사한 성능을 보여주는 우수한 투과 특성을 나타내었다.

극성 기체인 CO2를 분리하기 위해 UiO-66과 PVC-g_POEM을 사용하여 Membrane을 만들었다. UiO-66(MOFs)는 높은 수분 안정성뿐 아니라, 강산 및 강염기 수용액 하에서도 안정된 구조를 유지한다. 또한 다양한 용매에 사용할 수 있는 장점을 가지고 있다. 본 연구에서는 PVC-g-POEM 고분자 매트릭스에 높은 비표면적을 갖는 UiO-66 입자를 분산하여 Mixed Matrix Membrane을 제조하였다. 분리막 두께에 변화시키며, 다양한 이성분계 혼합기체에 대한 투과 실험을 실시하였다. 합성된 MMM의 결정상은 XRD로, 두께 및 표면 등은 SEM을 통해 분석하였으며, 기체 투과 실험에서 투과된 기체의 조성은 GC를 이용하여 분석하였다.

중공사막 지지체에 계면중합반응을 통해 막을 형성하여 복합막을 제조하였으며 복합막의 성능평가를 위해 코팅용액의 농도, 코팅시간 및 건조온도 등을 변화시켜 실험을 수행하였다. PART 1 실험에서는 PVAm과 -NH 작용기를 갖는 수용상의 PEI, -COCl작용기를 갖는 유기상의 Trimesoyl chloride 사이의 계면중합 반응을 통해 복합막을 제조하였다. PART 2 실험에서는 PEI를 piperazine(PIP)으로 대체하여 계면중합반응을 하였다. PART 1에서는 PVAm 10,000ppm과 PEI 4,000ppm을 혼합하였을 때 투과도와 배제율 측면에서 가장 좋은 결과를 보였으며 PART 2에서는 PVAm과 PIP의 농도가 높아짐에 따라 투과도는 감소하고 배제율은 증가하는 결과를 얻었다.

We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensin measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as 100 oC. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from 60 oC to 200 oC. It is supposed from these results that the ptype oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.

Anti-reflection coating films have used to increase the transmittance of displays and enhance the efficiency of solar cells. Hydrophobic anti-reflection coating films were fabricated on a glass substrate by sol-gel method. To fabricate an anti-reflection film with a high transmittance, poly ethylene glycol (PEG) was added to tetraethyl orthosilicate (TEOS) solution. The content of PEG was changed from 1 to 4 wt% in order to control the morphology, thickness, and refractive index of the SiO2 thin films. The reflectance and transmittance of both sides of the coated thin film fabricated with PEG 4 wt% solution were 0.3% and 99.4% at 500 nm wavelength. The refractive index and thickness of the thin film were n = 1.29 and d = 105 nm. Fluoro alkyl silane (FAS) was used for hydrophobic treatment on the surface of the anti-reflection thin film. The contact angle was increased from 13.2˚ to 113.7˚ after hydrophobic treatment.

Thermal barrier coatings(TBCs) are being applied in many industrial fields such as thermal power generation, aviation and seasonal fields. ZrO2-Y2O3(8%) thermal spray coating powders are commercially used as thermal-barrier coating materials to protect against oxidation and corrosion of heat-resistant alloys at elevated temperatures. Currently, ZrO2-Y2O3(8%) thermal-spray powder is made using the industrial co-precipitation process, which is very complex and requires a lot of time. In this study, orthorhombic ZrO2 and Y2O3 powders were fabricated by mechanical mixing, which is more economical than the co-precipitation process. A tetragonal, yttria-stabilized zirconia(YSZ) coating-layer was produced by plasma spraying, using orthorhombic ZrO2-Y2O3(8%) powder. Our experimental results indicate that ZrO2-Y2O3(8%) mixed powder can be used economically in industry because it is no longer necessary to make this powder by liquid and gas-phase methods.