초록 ▼

연구개발결과
-촉매 코팅 필터
본 연구과제 수행 결과, 기상합성공정을 이용하여 바나듐, 망간과 같은 비귀금속계 전이금속 산화물을, 높은 비표면적을 가지는 기상합성 나노입자 지지체에 담지시킨 촉매를, 코디어라이트 하니콤에 코팅하여 촉매를 제조하는 기술을 개발하였다. 귀금속 계열 촉매를 담지시켜 사용하는 기존 방식의 산화촉매 산화의 경제성이 낮은 문제점을 해결하기 위해 본 연구에서는 비귀속계 전이금속을 담지하여 경제성을 획기적으로 향상시키는 동시에 비표면적 및 활성을 증가시키고 작은 기공을 갖는 나노크기의 촉매 입자를 제조함

연구개발결과
-촉매 코팅 필터
본 연구과제 수행 결과, 기상합성공정을 이용하여 바나듐, 망간과 같은 비귀금속계 전이금속 산화물을, 높은 비표면적을 가지는 기상합성 나노입자 지지체에 담지시킨 촉매를, 코디어라이트 하니콤에 코팅하여 촉매를 제조하는 기술을 개발하였다. 귀금속 계열 촉매를 담지시켜 사용하는 기존 방식의 산화촉매 산화의 경제성이 낮은 문제점을 해결하기 위해 본 연구에서는 비귀속계 전이금속을 담지하여 경제성을 획기적으로 향상시키는 동시에 비표면적 및 활성을 증가시키고 작은 기공을 갖는 나노크기의 촉매 입자를 제조함으로서 저온에서 VOCs 및 NOx 등 대기오염물질 분해 활성을 나타내는 나노 촉매코팅 필터 기술을 개발하였다.
개발 기술의 실용화, 제품화를 목표로 벤치스케일 규모의 촉매 합성 및 코팅장치와 촉매 평가 장치를 구축하여 파일럿 규모의 촉매 합성 및 코팅 장치를 구축하여 소각로 대기오염 배출 시설에 실증규모 촉매 평가 시설을 구축하여 촉매 필터의 성능을 검증하였다. 기업과 함께 현장 적용 연구를 공동으로 수행함으로서 나노촉매소재 시스템 개발을 가속화 할뿐 아니라 기술 선점을 보다 효과적으로 달성한 것으로 판단된다. 이 연구개발 기술이 활용될 국내 에어필터 및 공기 청정기 관련 시장은 건강 및 환경에 대한 관심이 높아짐에 따라 크게 성장하고 있어 관련 소재 수요도 함께 증가할 것으로 예상된다.
- 바이오 파울링
수중 플라즈마 방전 및 친환경적 용매를 적용하여 바이오파울링 오염 저감을 극대화 시킬 수 있는 최적 분리막 친수화 표면 개질/코팅 기술을 개발하였다. 개발된 분리막을 표면 분석한 결과 분리막 표면에 20 nm 내외의 매우 얇은 개질/코팅 층을 형성하여 분리막의 몰폴로지에 거의 영향을 주지 않음을 확인하였다. Bench-scale 규모 분리막 시스템에 적용하여 실제 하수슬러지에 대한 연속 투과 실험 결과 본 연구에서 개발된 분리막의 경우 상용화된 친수성 PVDF 분리막 대비 투과유량, 바이오파울링 내오염성, 분리막 세정 주기 모두 향상된 것을 확인하였다. 상기 결과에 의거하여 본 연구에서 개발된 분리막을 실증 규모 MBR 적용 수처리 시스템에 적용 시 경제적 이윤을 평가한 결과 전체 운영비의 약 40% 저감 효과가 가능한 것으로 산출되었다.

Abstract ▼

Ⅳ. Results
We developed a synthesis process for single and composite nanocatalysts by improving the chemical vapor condensation process. Our team has also manufactured nanocatalysts with diverse colors without coagulation by building on prior research into evaporation temperature, reaction temper

Ⅳ. Results
We developed a synthesis process for single and composite nanocatalysts by improving the chemical vapor condensation process. Our team has also manufactured nanocatalysts with diverse colors without coagulation by building on prior research into evaporation temperature, reaction temperature, particle resident time within a reactor, reaction gas ratio, concentration of precursor and particle collecting methods and other conditions in an effort to further improve the surface characteristics of nanocatalysts proposed in other studies. The physico-chemical properties of synthesized (CVC process) catalysts were analyzed by various techniques, including XRD, TEM, BET and XPS which are the best techniques for understanding the characteristics of materials. The synthesized catalysts showed smaller particle size, larger surface area, higher purity, and less agglomeration in comparison to catalysts of the same composition produced from other methods (conventional TiO₂-Degussa P25).
The specific surface area (SSA) of TiO₂ particles synthesized by vapor-phase synthesis (CVC) was three times larger (ca. 150 m²/g) than that of conventional TiO₂ particles. Also, when the CVC-TiO₂ catalyst was used as a support material and impregnated with various metal catalysts such as V₂O₅, the SSA increased six times (ca. 300 m²/g) more than commercial catalysts. Adding metal components to a commercial TiO₂ particle can reduce particle pore size and enable pore blocking. Consequently, the metal on synthesized nanocatalysts is dispersed well, creating a monodisperse of spherical shapes with diameters <10 nm, thus increasing the SSA. TEM mapping images photographed in this study also confirmed the monodisperse of metal. CVC-TiO₂ particles were found to have anatase content over 97% of its total components with a very small rutile phase. Also, the ratio of their hydroxyl group (OH), which increases photocatalytic activity on the catalyst surface, was over 32%, which is more than twice that of commercial catalysts Further examination was conducted on the low temperature oxidization ability of air pollutants using CVC-synthesized nanocatalysts, as well as the catalytic decomposition of VOCs (toluene), NOx and 1,2-dichlorobenzene (1,2-DCB) over CVC-synthesized nanocatalysts. First, in testing the removal of nitric oxide (NOx), the synthesized catalyst showed up to 99% conversion efficiency in the lower temperature range (~250℃), which was superior to the maximum conversion ratio of 90% demonstrated by the commercial catalyst (~300℃). The commercial catalyst showed a sufficient removal efficiency at 300℃, but the CVC-synthesized catalyst showed over 80% of removal efficiency at 200℃, indicating a shift in reaction temperature to lower temperatures. In the case of 1,2-DCB decomposition testing, a 90% efficiency was shown at a 200℃ reaction temperature, while removal efficiency increased two times compared with the commercial nanocatalyst. The results from our prior tests suggest that this increased efficiency is due to the larger SSA value and higher V⁵⁺ content of the CVCsynthesized catalyst.
In the decomposition testing of VOCs (toluene), an excellent removal efficiency was also shown in the overall reaction temperature range, especially near room temperature.
Using CVC-synthesized nanocatalysts, overall conversion was good against pollutants compared with commercial catalysts, where the toluene oxidization ability was over 90% (under 40℃). Previous research has indicated a technical limitation at around 100℃ reaction temperatures. Catalytic activity is different depending on the types of impregnated metal dispersion and of metal crystal phases. Furthermore, the issue of catalyst poisoning has yet to be resolved.
As a result of membrane surface characterization, a modification of PVDF MF membrane by coating in liquid carbon dioxide using PEGDA, PEGMA, and Pd precursor as monomer showed that PEGDA, PEGMA, and Pd nanoparticles were successfully coated in the membrane surface while the stable oxygen or Pd concentration along the membrane bulk showed the successful coating in the pores.
Membrane surface characterization(XPS, FTIR, SIMS, contact angle, SEM, AFM, etc) indicated the underwater discharge plasma-induced crosslinking reaction of hydrophilic groups in various chemicals(< M.W 100 g/mol) such as acrylate, ammonia, sodium azide onto the membrane surfaces were occurred extensively. The morphology of the surface-modified/-coated membranes was almost identical to that of the pristine membrane.
The permeation flux of the protein(BSA) solution and WWTP sludge though the surface-modified membranes was consistently higher(> 50%) than the pristine hydrophilic PVDF membrane, which resulted in much lower membrane fouling resistance values compared with that of the pristine hydrophilic PVDF membrane.
Cross-flow continuous fouling experiments showed that the underwater discharge plasma-induced surface-modified/-coated MF PVDF membranes were notably less(> 50%) susceptible to biofouling which resulted in lower membrane cleaning frequency than the commercially available hydrophilic PVDF membrane.