• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.11
• /
• pp.965-974
• /
• 2009

This study evaluated the degradation efficiency of malodorous sulfurized-organic compounds by utilizing N- and Sdoped titanium dioxide under visible-light irradiation, and examined the catalyst deactivation and regeneration. Catalyst surface was characterized by employing Fourier-Transform-Infrared-Red (FTIR) spectra. The visible-light-driven photocatalysis techniques were able to efficiently degrade low-level dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) with degradation efficiencies exceeding 97%, whereas they were not effective regarding the removal of high-level DMS and DMDS, with degradation efficiencies of 84 and 23% within 5 hrs of photocatalytic processes. As compared with DMS, DMDS which containes one more sulfur element revealed quick catalyst deactivation. Catalyst deactivation was confirmed by the equality between input and output concentrations of DMD or DMDS, the obsevation of no $CO_2$ generation during a photocatalytic process, and the FTIR spectrum peaks related with sulfur ion compounds, which are major byproducts formed on catalyst surfaces. The mineralization efficiency of DMS at 8 ppm, which was a peak value during a photocatalytic process, was calculated as 144%, exceeding 100%. The catalyst regenerated by high-temperature calcination exhibited higher catalyst recovery efficiency (53 and 58% for DMDS and DMS, respectively) as compared with dry-air and humid-air regeneration processes. However, even the calcined method was unable to totally regenerate deactivated catalysts.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2002.05b
• /
• pp.279-280
• /
• 2002

$TiO_2$의 흡착에 의한 폐수처리는 거의 없으며, 본 실험의 T 산업 폐수에 평균 65mg/L 포함된 다량의 Cl￣ 이온은 광산화 반응의 억제제(inhibitor)로서 작용하는 것으로 사료되었다. 암모니아성 질소가 초기 40 mg/L에서 운전시간 24 시간 후에는 60 mg/L까지 증가함을 알 수 있었으며, 질산성 질소의 농도는 15 mg/L 까지 증가하였다. ${PO_4}^{3-}$ 의 농도 변화는 거의 없었으며 1 mg/L 이하의 낮은 농도로 존재하였으며, 무기탄소 양은 매우 소량으로 거의 변화가 없었다. 운전기간 동안 pH 2.4 ～ 2.6으로 수렴하였고 반응속도의 변화는 거의 없었으며, CODcr에 대한 $BOD_{5}$의 분율은 반응이 진행될수록 증가하는 것으로 보아 난분해성의 폐수가 광촉매 반응 후 생물학적 처리가 가능한 폐수로 변화되었음을 알 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.77-77
• /
• 2003

산업화에 따라 각종 산업분야에서 유기 용제의 사용이 증가하게 되었고 대기오염, 수질오염 등의 상태가 심각해져가고 있는 실정이다 그러나 다양해진 오염물질을 처리하는 데 있어서 기존의 산화처리방법은 한계에 달하였고 새로운 처리공정으로 최근 고급산화법(AOP : Advanced Oxidation Process)에 대한 연구가 활발하게 진행되고 있다. 이에 본 연구에서는 대기환경 및 인체에 심각한 영향을 주는 VOCs(Voletail Organic compounds)중 BTEX(Benzene, Toluene, Ethylbenzene, Xylene)를 다양한 형태의 광촉매제를 이용하여 기상 광분해한 후 이에 대한 최적의 분해 조건과 분해율을 비교하고자 하였다. 순환식의 자체 제작한 기상광반응장치를 이용하여, CVD법으로 TiO$_2$ 입자를 알루미나 비드위에 코팅한 볼과 같은 방법으로 유리기판위에 코팅한 판상의 광촉매제 그리고 결정성이 각기 다른 루틸상과 아나타제 그리고 아나타제/루틸 혼합상의 TiO$_2$ 분말을 직접 이용하여 VOCs 농도와 종류, 광원의 종류 및 세기를 변화시켜 PID(Photo ionization Detector)방식의 순환식 VOCs 측정기를 이용하여 광분해율을 실시간으로 측정하였다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2001.11a
• /
• pp.48-49
• /
• 2001

광촉매 분해반응시 광원으로서 기존의 UV램프의 사용에서 벗어나 인공적인 에너지가 필요없는 태양광을 VOCs 광분해에 solar simulator에서 타당성을 검토하고 태양광에 직접 적용하여 확인하였다. $TiO_2$-UVA 시스템에서 보다 $TiO_2$-태양광을 적용한 실험에서 분해반응속도의 증가를 보였다. 결과적으로 VOCs처리에 있어서 태양광의 적용이 가능하며 최대 4.514${\times}$$10^{-5}$ Einstein $min^{-1}$의 photon flow를 필요로 하는 광촉매분해반응에서 $TiO_2$ UVA시스템보다 태양광을 이용한 적용이 더 효과적인 것으로 사료된다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2001.05a
• /
• pp.138-139
• /
• 2001

$TiO_2$/UV 고급 산화 공정을 실제 산업 폐수에 적용하였다. 회분식 원통형 반응기에서 T산업 폐수를 광반응시킨 결과 COD 값과 TOC 값이 24시간 경과된 후 95% 이상의 제거 효율을 나타내었다. 광반응에 미치는 인자에 대한 연구에서 $TiO_2$ powder가 0.1 $g/{\ell}$ 에서 8 $g/{\ell}$까지는 투입된 광촉매의 량과 광반응속도가 비례적으로 증가되었으나 10 $g/{\ell}$ 이상에서는 광차폐효과가 나타나 광반응속도가 감소하였으며, UV 광원이 강할수록 광반응 속도는 증가하였고 초기 pH는 광촉매 반응에 영향을 미치지 않음을 알 수 있었다.

• Membrane Journal
• /
• v.23 no.3
• /
• pp.226-236
• /
• 2013

The effect of $N_2$ back-flushing period (FT) and time (BT) was compared with the previous result used PES (polyethersulfone) beads loaded with titanium dioxide photocatalyst in hybrid process of alumina microfiltration and PP (polypropylene) beads coated with photocatalyst in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). The reason of nitrogen back-washing instead of the general air back-washing method is to minimize the possible effect of oxygen included in air on water quality analysis. As decreasing FT, $R_f$ decreased and J and $V_T$ increased. Treatment efficiency of dissolved organic matters (DOM) was 82.0%, which was the higher than 78.0% of the PES beads result. This means that PP beads coated with photocatalyst was the more effective than PES beads loaded with photo-catalyst in the DOM removal. As increasing BT, the final $R_f$ decreased and the final J increased, but $V_T$ was the maximum at BT 15 sec. The average treatment efficiency of turbidity did not have any trend as changing BT. As BT increasing from 6 sec to 30 sec, the treatment efficiency of DOM increased 11.8%, which was a little higher than the result of PES beads.

• Environmental engineer
• /
• s.116
• /
• pp.46-49
• /
• 1996

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.65 no.4
• /
• pp.36-39
• /
• 2023

• Journal of Energy Engineering
• /
• v.25 no.2
• /
• pp.65-78
• /
• 2016

Initial studies of the photocatalyst has been developed from the field relating to the conversion and storage of solar energy. Recently, the study of the various organic decomposition compound and the water purification and waste water treatment by ultraviolet irradiation in the presence of light or a photocatalyst are being actively investigated. In addition, the oxidized material-carbon nanotubes, graphene-nanocomposites have been studied. Such a complex is suitable as a material constituting the solar cells and photolysis nanoelectronics, including the flexible element due to thermal and chemical stability.

• Membrane Journal
• /
• v.22 no.6
• /
• pp.441-449
• /
• 2012

Effect of humic acid (HA) with periodic nitrogen back-flushing was investigated in hybrid process of alumina microfiltration and photocatalyst for drinking water treatment. It was compared and investigated with the previous results of microfiltration water back-flushing or ultrafiltration nitrogen back-flushing in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). As results, the trends of membrane fouling were different depending on nitrogen or water back-flushing, and depending on ultrafiltration or microfiltration made with the same material. Also, the nitrogen back-flushing using microfiltration was more effective membrane fouling inhibition than ultrafiltration, and the nitrogen back-flushing was more effective than water back-flushing using the same microfiltration membrane. Turbidity treatment efficiencies were almost constant independent of HA concentration, but HA treatment efficiency was the maximum at HA 10 mg/L. From this results, it was shown that the treated water HA quality increased as increasing HA concentration, but HA could be removed the most effectively by photocatalyst beads adsorption and photo-oxidation at HA 10 mg/L.