Kinetic Model for UV/H2O2 Degradation of 5-Methoxypsoralen

• Published in: Russian physics journal 2016-08, Vol.59 (4), p.552-561
• Main Authors: Tchaikovskaya, O. N., Bryantseva, N. G., Carrasco, J. L. Gómez, Krayukhina, V. S., Almagro, M. D. Murcia, Gómez, M. Gómez
• Format: Article
• Language: English
• Subjects: Compound A; Condensed Matter Physics; Decay rate; Ethanol; Exposure; Hadrons; Heavy Ions; Irradiation; Kinetics; Lasers; Mathematical and Computational Physics; Mathematical models; Nuclear Physics; Optical Devices; Optics; Photodegradation; Photonics; Physics; Physics and Astronomy; Theoretical
• ISSN: 1064-8887; 1573-9228
• DOI: 10.1007/s11182-016-0805-9

The influence of H 2 O 2 on the photodegradataion of 5-methoxypsoralen (5-MOP) in ethanol and in waterethanol solutions upon exposure to KrCl excilamp radiation (λ rad = 222 nm) and XeBr excilamp radiation (λ rad = 283 nm) is investigated. A kinematic model of photodegradation of the investigated molecule is constructed. The addition of H 2 O 2 resulted in a weak increase of the decay rate of 5-MOP in ethanol exposed to KrCl excilamp radiation. In water-ethanol solutions the addition of H 2 O 2 altered the mechanism of decay of 5-MOP irradiated by the KrCl excilamp in comparison with irradiation by the XeBr excilamp. It has been shown that upon exposure to XeBr excilamp radiation in the presence of H 2 O 2 , the primary photoproduct of the transformation of 5-MOP in the reaction corresponding to the first-order kinetic model is formed both in ethanol and in the water-ethanol solutions. Maximum removal of 5-MOP takes place for the ratio of initial concentrations [5-MOP]:[H 2 O 2 ] = 1:3 after 60 min irradiation. It is found that irradiation by the XeBr excilamp the decay rate of 5-MOP is 5 times higher in the water-ethanol solutions in comparison with ethanol. Upon exposure to KrCl excilamp radiation the mechanism of 5-MOP decay corresponds to a pseudo-firstorder kinetic model. The nature of the dependence of the decay rate of 5-MOP on the irradiation time for the ratio of initial concentrations [5-MOP]:[H 2 O 2 ] = 1:24 indicates that during decay of the initial compound a photoproduct appears in the system which decays during the irradiation time into secondary compounds. Efficient removal of 5-MOP under this irradiation takes place for the ratio of initial concentrations [5-MOP]:[H 2 O 2 ] = 1:10 after 60 min irradiation.