Fe(III) promoted LAS (linear alkylbenzenesulfonate) removal from waters.

The mechanisms of the interactions between Fe(III) aquacomplexes and surfactants were investigated; three alkylbenzenzsulfonates, two surfactants (octylbenzenesulfonate (OBS) and dodecylbenzenesulfonate (DBS)), and a shorter derivative (ethylbenzenesulfonate (EBS)) were studied. The results with OBS show evidence for three different ways in which Fe(III) interferes with the surfactant: the widely described flocculation process, complexation of Fe(OH)2+ (aquacomplexes) by the surfactant, and a redox reaction. The formation of a weak complex is maximum for a ratio of three between the monomeric aquacomplex [FeOH(H2O)5]2+ and OBS.

Phototransformation of methabenthiazuron in the presence of nitrate and nitrite ions.

The influence of nitrate and nitrite ions on the degradation of methabenzthiazuron upon irradiation using artificial solar light has been investigated. The rate of degradation of methabenzthiazuron (1 microM) was accelerated by NO3- (0.1 mM) by a factor of 10.

Photodegradation of chlorinated pesticides dispersed on sand.

The photochemical behaviour of several chlorinated pesticides, namely 4-chloro-2-methylphenoxyacetic acid (MCPA), dichlorophen (DCPH), flamprop-methyl (FPM) and vinclozolin (VCZ) is studied on various kinds of sand: Fontainebleau sand (almost pure silica), Touggourt sand (coloured sand from Sahara) and Jijel sand (dark marine sand). The photodegradation of MCPA is more rapid on Fontainebleau sand than on the two others, because the former is almost colourless pure silica and the others adsorb on the internal surface of the reactor. The degradation rate decreases in the order MCPA, DCPH, FPM, VCZ.

Photolysis of aqueous solutions of aniline-2,5-disulfonic acid: steady state and laser flash photolysis studies.

The photochemical behaviour of aniline-2,5-disulfonic acid (ADSA) in aqueous solutions upon excitation at 254 nm, 310 nm and 334 nm has been studied. A specific phototransformation into o-anilinesulfonic acid (o-AS) via a desulfonation process was observed. Such a reaction was efficiently inhibited by molecular oxygen.