The kinetics of the photocatalytic degradation of Fenuron (3-phenyl-1,1-dimethylurea) in aqueous
suspension of several semiconductors irradiated at 365nm has been investigated. The kinetics of the
reaction is well described by the Langmuir-Hinshelwood model showing that the degradation reactions occur
on the semiconductors particles surface. The primary photoproducts were identified by RMN and GC/MS.
The main initial reaction is hydroxylation in ortho and para position with respect to the urea function. The
rate of the photocatalytic degradation increases upon addition of small amounts of hydrogen peroxide, but
is slightly reduced by chloride ions.

Ouarda  Brahmia

Abdelaziz  Boulkamh

Tahar  Sehili

Jean-Pierre  Aguer

Claire  Richard

Kinetics of photocatalytic decomposition of Fenuron over <svg style="vertical-align:-3.27605pt" height="15.675" version="1.1" viewBox="0 0 32.512501 15.675" width="32.512501" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.537)"><path id="x54" d="M592 498l-30 -3q-13 63 -31 89q-13 19 -33.5 25.5t-75.5 6.5h-70v-493q0 -60 16 -75.5t86 -19.5v-28h-286v28q68 4 83.5 19.5t15.5 75.5v493h-62q-60 0 -83 -7t-33 -24q-12 -17 -32 -90h-29q10 116 12 180h20q10 -16 21 -20.5t34 -4.5h395q19 0 28.5 5t21.5 20h21&#xA;q2 -89 11 -177z" /></g><g transform="matrix(.017,-0,0,-.017,8.868,11.537)"><path id="x69" d="M135 536q-20 0 -35 15.5t-15 35.5q0 22 15 37t36 15t35.5 -15t14.5 -37q0 -21 -15 -36t-36 -15zM252 0h-220v26q48 5 59 17t11 63v206q0 47 -9 58t-54 18v24q78 12 142 39v-345q0 -51 11.5 -63t59.5 -17v-26z" /></g><g transform="matrix(.017,-0,0,-.017,13.424,11.537)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g><g transform="matrix(.012,-0,0,-.012,26.125,15.613)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g></svg> in aqueous solution

Photolysis of phenol and p-chlorophenol exposed to KrCl- and Nd-YAG laser light is studied
by electron spectroscopy and fluorescence and quantum chemical techniques. The decrease of the quantum
yield of phenol fluorescence with increase in the excitation energy is not related to dynamic changes in
the intramolecular photophysical processes; rather this is a result of increased photoreaction efficiency.
Chlorine substitution for para-state of phenol is shown to strengthen the OH-bond in excitation into the
long wavelength absorption band.

O. Tchaikovskaya

I. Sokolova

O. Bazyl

V. Swetlichnyi

T. Kopylova

G. Mayer

N. Sultimova

The fluorescence analysis of laser photolysis of phenols in water

The photochemical behaviour of many aromatic pesticides (mainly herbicides) are compared and
the main reactions are separated in three different classes: 1- reactions involving carbon-halogen bond; 2 -
other reactions involving the aromatic ring; 3 - reactions of the aliphatic moiety. It appears that the nature of
the substituents and their relative positions on the ring play a major role in the orientation of the reaction. The
molecular and ionic forms of ionisable molecules may have different photochemical behaviour. A wavelength
effect is observed with some compounds. The case of mecoprop [2-(4-chloro-2-methylphenoxy)-propanoic
acid] is presented as an example.The irradiation of herbicides in aqueous solution may lead to the formation of photochemical intermediates
more toxic to microorganisms than the initial substrate.

P.  Boule

L.  Meunier

F.  Bonnemoy

A.  Boulkamh

A.  Zertal

B.  Lavedrine

Direct phototransformation of aromatic pesticides in aqueous solution

The use of the computer to simulate light induced chemical processes has given access to
a detailed description of the molecular motion and mechanism underlying the reactivity of organic and
bio-organic chromophores. Thus, different computational strategies and tools can now be operated like
&#8220;virtual spectrometers&#8221; to characterize the photoinduced molecular deformation and reactivity of a given
chromophore. Furthermore, a systematic computer investigation of a wide range of photochemical organic
reactions during the last decade, has lead to novel concepts that allow the chemist to formulate the mechanism
of a photochemical reaction in a rigorous way and with a language which is familiar to chemists.In this review we will revise some basic mechanistic concepts which have emerged in the novel field of
computational photochemistry. These comprise the concept of conical intersection funnels, photochemical
paths, path branching and selectivity. Recent work in the field of biological photoreceptors has demonstrated
that computational chemistry can be successfully applied to photobiological problems. Here we will revise the
results of the photoisomerization path mapping of the protonated Schiff base of retinal, the chromophore of
rhodopsin proteins. These studies have produced the &#8220;two-state two-mode model&#8221; which provides a description
of the photon-induced molecular motion in the isolated retinal chromophore. Such model represents
a substantial revisionof the previous models for the primary event invisioninan imals and light driven
proton-pumping in halobacteriae.

Marco  Garavelli

Fernando  Bernardi

Michael A. Roob

Massimo  Olivucci

Computer simulation of photoinduced molecular motion and reactivity

In the last decade the sol-gel process became a promising method to synthesize materials in
form of coatings, nanoscale powders and porous systems. Several products or devices made with such a
process already exist on the market. This paper briefly reviews the state of the art in the development of
electrochromic coatings and devices and nanocrystalline solar cells achieved during the last decade using
sol-gel derived pure and doped niobium pentoxide.

Michel A. Aegerter

Michael Schmitt

Yeping Guo

Sol-gel niobium pentoxide coatings: Applications to photovoltaic energy conversion and electrochromism

About this journal

International Journal of Photoenergy publishes original research and review articles focused on all areas of photoenergy, including photochemistry and solar energy utilization.

Journal profile

Meet the editorial board

Chief Editor, Giulia Grancini, is based at the University of Pavia, Italy. Her current research work aims at solving the stability and toxicity issues of developing multi-dimensional hybrid interfaces as lego-bricks for a new efficient, stable, and environmentally-friendly solar technology.

Editor spotlight

Submit your proposal

Do you think there is an emerging area of research that really needs to be highlighted? Or an existing research area that has been overlooked or would benefit from deeper investigation? Raise the profile of a research area by leading a Special Issue.

Special Issues

Author guidelines

Editorial board

Databases and indexing

International Journal of Photoenergy - Table of contents 2002

International Journal of Photoenergy | Hindawi

title

International Journal of Photoenergy publishes original research and review articles focused on all areas of photoenergy, including photochemistry and solar energy utilization.

description

https://images.hindawi.com/journals/ijp/ijp.banner.jpg

twitter:card

twitter:description

twitter:site

twitter:title

twitter:url

twitter:image