가시광선 중합형 복합수지용 광증감제의 분해율 비교

선금주,Sun, Gum-Ju 대한치과기공학회 2011 대한치과기공학회지 Vol.33 No.4

Purpose: The purpose of this study was to know the availability of three photosensitizers, CQ, PD, DA, as a photosensitizer of dental resin composite. We want to know abortion band around visible light region for the using potential possibility as a photosensitizer for visible light cured dental composite resin. And I studied to know the relative photodecomposition ratio of three photosensitizers with or without photoinitiator, DAEM. Methods: The photodecomposition of three photosensitizers were studied by UV absorption spectroscopy in ethanol and determined by same instrument with irradiation time for relative photodecomposition. In order to study the effect of amine on photodecomposition was added the DAEM in the photosensitizer solution and the relative rate was measured by the same procedure with aove mentioned. Results: The all of three photosensitizers are absorbed around visible light region. The relative rate of decrease in absorbance incereased in the order: CQ < BD < PD. The effect of DAEM on the photodecomposition of the photosensitizers was appeared different results without DAEM. The photodecomposition rate of PD and DA decreased somewhat with the addition of amine, while that of CQ increased. The rtealtive photodecomposition rate increased in the oprder: BD ${\leq}$ CQ < PD with the addition of amine, but the differnce was not significant. Conclusion: PD and DA like CQ gives to the possibility of use as a photosensitizer for visible light cured dental composite resin by absorption around visible light region and photodecomposition in the maximum absorption wavelength. And it is showed that PD and DA are not effective decomposed with amine initiator, DAEM but CQ decomposed with DAEM effectively. This result may be due to a different mechanism operating for the decomposition of photosensitizers in the presence of amine.

Determination of diphencyprone and its photo-degradation product incompounded preparations using HPLC

Cho, Chong Woon,Kim, Kyung Tae,Park, Miyeon,Kim, Jin Seog,Lee, Jinbok,Kang, Jong Seong The Korean Society of Analytical Science 2018 분석과학 Vol.31 No.5

Diphencyprone (DPCP) is frequently used as a compounded preparation in dermatology for the treatment of alopecia and recalcitrant warts based on the immune reaction of skin allergy. However, DPCP is a non-recognized agent in Pharmacopoeia, because there are no criteria or analytical method for quality control of its powder and formulation. DPCP is unstable under light irradiation because as it easily decomposes to diphenylacetylene (DPA). This study aims to develop a simultaneous HPLC analytical method for analyzing DPCP and DPA in the raw materials and compounded preparation. The method required a C18 column ($250{\times}4.6mm$, $5{\mu}m$) at $40^{\circ}C$ with a mobile phase of (A) 0.01 M phosphoric acid in water and (B) acetonitrile at UV 220 nm. DPA conversion to DPCP in the powder and compounded preparations was accelerated after light exposure for 60 min. In addition, this resulted in different patterns depending on the wavelength of light and the formulation. That is, DPCP in compounded preparation was more unstable than that in the powder. However, the DPCP formulation in amber bottles was observed to remain stable, although the measured concentrations of DPCP were somewhat different from the nominal concentration of the compounded preparations. The control of the exact concentration is required for effective disease treatment, depending on the state of the patient. In conclusion, these results will be useful for the recognition of DPCP in Pharmacopoeia and new DPCP formulation development to prevent photodecomposition.

Photodecomposition Effect of Metal doped $Ti0_2$ System (I)

Jin, Eui,Lee, Kang-Hyeob,Kim, Young-Soon,Min, Tae-Jin,Yu, Kook-Hyun Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.2

To study photocatalytic mechanism of metal doped $Ti0_2$, we investigated photodecomposition effect, photocurrent effect and antibacterial effect. When aluminium content was 2 wt %, photodecomposition effect was better than the others. Silver doped thin films had high photocurrent efficiency and antibacterial effect. This reactions were caused by dissolved oxygen in solution and oxygen adsorbed on surface of thin films.

Ultraviolet-A (UV-A) 조사에 의한 Tetrabromobisphenol A (TBBPA)의 광분해 반응 특성

장석원(Seok Won Jang),한상국(Sang Kuk Han) 大韓環境工學會 2013 대한환경공학회지 Vol.35 No.2

모든 브롬화난연제 중 가장 많이 사용되고 있는 것은 TBBPA이다(상용화되고 있는 브롬화난연제물질 중 50%를 차지). TBBPA는 환경 중에서 유해하기 때문에 환경 중에서의 그들의 분해반응기전에 대한 연구가 흥미롭다. 본 연구에서는 UV-A(λ = 352nm) 조사에 의한 TBBPA의 광분해반응속도가 조사세기 의존적으로 증가하였다. 또한 TBBPA의 광분해반응에 의해서 2,6-dibromo-p-benzosemiquinone radical (A₂H = 2.36G, g = 2.0056)이 생성되고 그 생성반응에 singlet oxygen (1O₂)이 주요 반응 인자로서 영향을 미치는 것으로 나타났다. 한편, HA와 TBBPA의 혼합용액을 광조사하면 semiquinone radical의 전형적인 ESR 스펙트럼이 생성되었다. 그리고 HA는 TBBPA의 광분해반응속도를 농도의존적으로 감소시키는 것으로 나타났다. 또한 라디칼 생성과 광분해반응속도는 singlet oxygen (1O₂) 소거제인 sodium azide를 주입하면 감소되었다. 이러한 결과로부터, UV-A 조사에 의한 HA와 1O₂의 반응속도는 TBBPA와 1O₂의 것보다 더 빠르다는 것을 제시한다. Of all the brominated flame retardants (BFRs), TBBPA has the largest production volume (50% of the BFRs in current use). It is interest to investigate how they may degrade, because of it can pose an environmental hazard. By using UV-A (λ = 352nm), we have found that the UV-A irradiation increased the photodecomposition reaction rate of TBBPA in an intensity-dependent manner. We also observed 2,6-dibromo-p-benzosemiquinone radical (A₂H = 2.36 G, g = 2.0056) generated from TBBPA by reaction with singlet oxygen (1O₂). On the other hand, when an aqueous preparation of HA was irradiated in the presence of TBBPA, the typical spectrum of semiquinone radical was detected by electron spin resonance (ESR). And then, we have found that the photodecomposition rate of TBBPA is decreased in depend on HA concentration. Radical formation and the reactive rate of TBBPA were inhibited by sodium azide used as a singlet oxygen quencher. Therefore we report that a similar 1O₂-induced oxidation can be initiate in aqueous solutions of TBBPA dissolved in humic acid (HA) by the UV-A irradiation (λ = 352nm). From these results, we suggest that the reaction rate of HA with 1O₂ is faster than that of TBBPA with 1O₂.

연구논문 : 서남해연안해역에서 Tetrabromobisphenol A의 노출농도 및 그들의 광화학적 분해 특성

한상국 ( Sang Kuk Han ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.3

The aim of this study is to determine the exposure concentration of tetrabromobisphenol A(TBBPA) in southwestern coast and their photodecomposition rate. Also, it is to identify the radical species of the photodecomposition of TBBPA and their reactive byproducts using the electron spin resonance(ESR) method. TBBPA was not detected in any of the sea water samples from Mokpo, Gunsan, or Goheung. The sediment samples from Mokpo contained not detection(N.D)∼50.0 ng/g dry wt., while those from Gunsan contained N.D∼28.5 ng/g dry wt. and those from Goheung contained N.D∼7.3 ng/g dry wt. The photodecomposition rates were 2.56 × 10-6/hr by visible light(400 nm), 7.98 × 10-6/hr by ultraviolet light(300 nm <), and 6.78 × 10-6/hr by sunlight. Also, we confirmed that singlet oxygen and hydroxyl radicals are the key reactive oxygen species at wavelengths greater than 400 and 300 nm, respectively. This study shows that the main byproducts formed during irradiation at wavelengths above 300 nm are 2,6-dibromobenzosemiquinone radical(2,6-DBSQ·-) and g-value 2.0048 doublet spectrum.

Photodecomposition of Concentrated Ammonia over Nanometer-sized TiO2, V-TiO2, and Pt/V-TiO2 Photocatalysts

Hyung-Joo Choi,Jun-Sik Kim,강미숙 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.4

Photodecomposition of Concentrated Ammonia over Nanometer-sized TiO₂, V-TiO₂, and Pt/V-TiO₂ Photocatalysts

Choi, Hyung-Joo,Kim, Jun-Sik,Kang, Mi-Sook Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.4

To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.

Photodecomposition for high concentrated ammonia over V-TiO2s including Pt component

Min Kyu Jeon,Mi Sook Kang 한국공업화학회 2006 응용화학 Vol.10 No.2

Photocatalytic Property of Nitrogen and Nickel Codoped Titanium Oxides

김영용,정경문,황준연,안석훈,권기영 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.11

Nitrogen or nitrogen and nickel codoped TiO2s are prepared by a hydrothermal method. The doped TiO2s are applied to the photodecomposition of methylene blue (MB) under visible-light irradiation. The chemical and physical properties of catalysts are characterized by X-ray diffraction, transmission electron microscope, energy dispersive spectroscopy mapping, zeta potential, and Brunauer–Emmett–Teller. We found that nickel and nitrogen atoms are well dispersed in TiO2. While the adsorption of MB on the TiO2 surface are improved by the nitrogen doping, the photodecomposition capability of MB is barely affected by the nitrogen doping level. Particularly, the photodegradation power of the nickel and nitrogen codoped TiO2 is better than that of commercial TiO2 (Degussa P25).

Methyl orange removal over Zn-incorporated TiO₂ photo-catalyst

Kim, Y.,Lee, J.,Jeong, H.,Lee, Y.,Um, M.H.,Jeong, K.M.,Yeo, M.K.,Kang, M. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.3

This study focuses on the removal of the methyl orange (sodium p-dimethyl amino azo benzene sulfonate) of a representative dye compound in a liquid photo-system using nanometer-sized Zn-incorporated TiO<SUB>2</SUB> synthesized by a solvothermal method. The Zn-incorporated TiO<SUB>2</SUB> particles exhibited a mixed structure of anatase of TiO<SUB>2</SUB> and ZnTiO<SUB>3</SUB> with a particle size of below 20nm. The absorbance was shifted to the higher wavelength on 2.0mol% Zn-incorporated TiO<SUB>2</SUB> compared to pure TiO<SUB>2</SUB>. In the XRD pattern, the structure of ZnTiO<SUB>3</SUB> was seen at 2θ=31.75. The XPS result of O 1s confirmed that 2.0mol% Zn-TiO<SUB>2</SUB> had a higher hydrophilic property (Me-OH/Me-O=0.46) than pure TiO<SUB>2</SUB> (Me-OH/Me-O=0.25) did. Based on these results, the photodecomposition for methyl orange in liquid reaction was enhanced over Zn-incorporated TiO<SUB>2</SUB> compared with pure TiO<SUB>2</SUB>: methyl orange of 10ppm was completely decomposed after 120min over 2.0mol% Zn-incorporated TiO<SUB>2</SUB>.