KOSEN 한인과학기술자네트워크

>아래의 자료는 산업기술정보원(http://www.kiniti.re.kr)을 통해 검색된 자료입니다. 웹을 통해 원문 신청이 가능합니다. 참고해 보시기 바랍니다. > >* 확장 SBH 모델에 의한 오존 자기 분해의 반응 속도론적 검토, 森岡崇行; 星川寬;, 水道協會雜誌 (JPN) 63(11); P28-40; 1994 > >* 확장 SBH 모델을 응용한 브롬산 이온 생성의 반응 속도론적 기초 검토, Nobukatu,S.; Masaki,I.; Takeo,M.;, 水環境學會誌 : (JPN) 22(11); P7-14; 1999 > >참고로 영문 keyword를 적어주시면 해외 영문DB를 통해서 검색하는데 도움이 될 것 같습니다. > > >>안녕하세요 >>오존은 강산화제로서 반응물이 없어도 초순수에서 점차 감소한다고 하는데 이를 알기 위해 오존의 자가분해속도를 구해서 그 속도상수를 찾아야 한다고 하는데 잘 모르겠군요 >>어떻게 해야 하는지 궁금합니다. 실험방법을 가르쳐 주시거나 참고문헌을 알고 싶습니다. ---------------------------------------------------------------------- Kinetics of ozonation of naphthalene and anthracene Wang, Peter C. (Mississippi State Univ) Matta, Hanna B. | Kuo, Chiang-Hai Source: Journal of the Chinese Institute of Chemical Engineers v 22 n 6 Nov 1991 p 365-371 0368-1653 Abstract: This research used a stopped-flow spectrophotometer system to study the kinetics of the ozonation of naphthalene and anthracene in aqueous solutions. The kinetics of the naphthalene-ozone reaction is second order overall and first order with respect to the concentration of each reactant. The second-order rate constant increases from 850 to 3,750 l-script /M-s as the pH value changes from 3 to 7 at 25°C. The ozonation reaction proceeds at a moderate rate, and the rate increases with the temperature and the pH value of the solution. Anthracene reacts with ozone at an extremely fast speed; the half-life of anthracene is no more than a few milliseconds. The reaction is first order with respect to the concentrations of both anthracene and ozone. The ozonation rate of anthracene depends only slighly on pH and temperature, and at 25°C, the second-order rate constant is 2.78 × 107 l-script /M-y in distilled water. In English 20 Refs. EI92050490087 Ozonization of ethanolamine in aqueous medium Parisheva, Z. (Technical Univ of Plovdiv) Demirev, A. Source: Water Research 34 4 Mar 2000 Elsevier Science Ltd p 1340-1344 0043-1354 Abstract: The destruction of ethanolamine by ozonation in aqueous medium was studied. The effectiveness of ozonation was estimated by the degree of conversion α [%], and by the rate constant, k [min-1], which was calculated from a first-order kinetic equation. The activation energy of the process was calculated from the rate constant vs temperature relationship according to the Arrhenius equation. The effect of pH of the medium and temperature, T, on the effectiveness of ozonation was investigated. It was established that ozonation of ethanolamine is most effective at T = 283 K and pH = 11.0. Under these conditions the rate constant has its high value 0.118 min-1. At pH = 11.0 the effect of the temperature on the rate constant is stronger which can be explained with the high value of the activation energy of the process. The amount of the residual ozone in gaseous phase was determined and the possibility of its decomposition on a catalyst of higher nickel oxide was studied. The effect of the amount of catalyst on the decomposition of the residual ozone was examined. The quantity of the catalyst needed for the complete decomposition of the residual gaseous ozone was estimated by the achieved degree of conversion of residual ozone α = 100%. In English 13 Refs. Kinetic and mechanistic study of ozonation of three dichlorophenols in aqueous solutions Qiu, Yongqiang (Mississippi State Univ) Zappi, Mark E. | Kuo, Chiang-Hai | Fleming, Elizabeth C. Source: Journal of Environmental Engineering v 125 n 5 May 1999 ASCE p 441-450 0733-9372 Abstract: This research investigates the kinetic parameters associated with the ozonation of 2,3-, 2,4-, and 2,5-dichlorophenols (DCPs) in aqueous solutions at 25 °C. The overall ozonation kinetics of each DCP was found to be first order with respect to each reactant concentration (i.e., DCP and ozone). Among the three isomers studied, the ozonation of 2,5-DCP was the fastest with the overall rate constant varying from 68,500 to 7,750,000 M-1 s-1 within a pH range of 2.1 to 5.0. The overall rate constant increased with pH because of the increase in the degree of dissociation of the DCP molecules to dichlorophenoxide ions. The electrophilic addition of ozone at the ortho and para positions of the molecular and ionic forms of the DCPs was postulated to be the likely mechanism for the degradation of the DCPs to chlorobenzenediols, monochlorophenols, chlorocyclohexadienediones, ethylacetate, heptanone, carboxylic acids, and other by-products that were detected using gas chromatograph/mass spectrometry analysis. In English 22 Refs. EI99104861035 Kinetic and mechanistic studies of the ozonation of alicyclic amines Pietsch, Joerg (DVGW-Technologiezentrum Wasser Karlsruhe) Schmidt, Wido | Brauch, Heinz-Juergen | Worch, Eckhard Source: Ozone: Science and Engineering v 21 n 1 Feb 1999 CRC Press LLC p 23-37 0191-9512 Abstract: Studies about the ozonation of the polar and mobile alicyclic amines pyrrolidine, piperidine, morpholine and piperazine were carried out in model water at pH 7.0. According to a pseudo-first order rate law the reaction-rate constants were determined from the decrease of the amine concentration vs. the reaction time. The order of degradation of the alicyclic amines by ozone, resulting from the kinetic constants obtained, is specified. The pH value of the water, the chemical structure of the amines and their pKA values are recognized to be parameters influencing the reaction-rates of the amines. Using a radical scavenger (tert-butanol) it could be shown that the degradation of amines by ozone in neutral solution is caused by direct oxidation with the ozone molecule. According to that, the alicyclic amines are oxidized by ozone electrophilicly at the activated C-N-(pyrrolidine, piperidine, piperazine) as well as C-N- and C-O-bonding (morpholine), respectively. After cleavage of the ring system, low molecular weight compounds are formed. The amount of free amines (non-protonized species) determined by the degree of protonation of the amines plays the dominant role for the different reaction-rates of the compounds. For piperazine, as an example it was demonstrated that partly protonized species can also be oxidized by ozone. In English 22 Refs. EI99044647640 Ozonation and photodegradation kinetics of pollutant acids in wastewaters Javier Benitez, F. (Universidad de Extremadura) Beltran-Heredia, Jesus | Gonzalez, Teresa | Real, Francisco Source: Canadian Journal of Chemical Engineering v 76 n 5 Oct 1998 Can Soc for Chem Eng p 936-944 0008-4034 Abstract: The kinetics of the degradation of four phenolic acids by ozonation and polychromatic UV radiation were investigated. The acids: p-hydroxyphenylacetic, homoprotocatechuic (3,4-dihydroxyphenylacetic acid), gentisic (2,5-dihydroxybenzoic acid) and 2,3-dihydroxybenzoic, have been selected because of they constitute major pollutants present in some agro-industrial wastewaters. The p-hydroxyphenylacetic acid was initially ozonated and UV irradiated alone. Its kinetic constants and reaction orders in the ozonation process were deduced by using a model based in the film theory which takes into account the mass transfer with the chemical reaction. The quantum yields in the photodegradation process were evaluated from a simple reaction mechanism with the help of an emission model to determine the radiation flow rate absorbed. Later, in the simultaneous ozonation and UV photodegradation of the mixtures of the four acids, competitive kinetic methods were developed to determine the individual rate constants between ozone and each acid in the ozonation process, and the individual quantum yields for every acid in the photodegradation process. In English 25 Refs. EI99014537062 Comparison of ozonation kinetic data from film and Danckwerts theories Beltran, F.J. (Universidad de Extremadura) Fernandez, L.A. | Alvarez, P. | Rodriguez, E. Source: Ozone: Science and Engineering v 20 n 5 Nov 1998 CRC Press LLC p 403-420 0191-9512 Abstract: Danckwerts and film theories have been compared through the aqueous ozonation kinetic study of three organics: crotonic, cinnamic and o-hydroxycinnamic acids. At the conditions investigated, these compounds are removed from water exclusively by direct reactions with ozone and the kinetic regime of ozone absorption corresponds to a fast second order irreversible reaction. In this regime, Danckwerts theory provides wider possibilities than film theory for the determination of the rate constant and individual liquid side mass transfer coefficients. The ozonation reactor was operated as an agitated cell to determine the rate constant and as an agitated tank to obtain the mass transfer coefficient. Rate constants were found to increase with increasing pH. At pH 7 the ozone reactivity of these compounds was in the following increasing order: Cinnamic acid