Optimization of nimesulide oxidation via a UV-ABC/HO treatment process: Degradation products, ecotoxicological effects, and their dependence on the water matrix.

Nimesulide (Nim) degradation in ultrapure water (UW) and municipal sewage (MS) via UV-ABC/HO was investigated. The variables included in the experimental design were time, initial Nim, and initial HO concentrations. Resulting decreases in Nim concentration (monitored by high performance liquid chromatography (HPLC) using a photodiode array detector operating at a maximum UV absorbance of 300 nm), mineralization (from total organic carbon (TOC) measurements), and ecotoxicity (assays employing the bioindicators Daphnia similis, Artemia salina, and Allium cepa) were also studied.

Degradation of 4-aminoantipyrine by electro-oxidation with a boron-doped diamond anode: Optimization by central composite design, oxidation products and toxicity.

Electro-oxidation with electrogenerated HO (EO-HO) was applied to treat acidic aqueous solutions of 4-aminoantipyrine (4-AA), a persistent drug metabolite of dipyrone, in sulfate medium. Trials were made using a boron-doped diamond anode in the presence of HO electrogenerated on site. A 2 central composite design (CCD) was employed to evaluate the effect of four independent variables, namely current density (j), pH, 4-AA concentration and electrolysis time, on the percentages of degradation and mineralization, as well as on mineralization current efficiency (MCE).

Tolfenamic acid degradation by direct photolysis and the UV-ABC/HO process: factorial design, kinetics, identification of intermediates, and toxicity evaluation.

This study employed direct UV-ABC photolysis and the UV-ABC/HO process to investigate the degradation of tolfenamic acid (TA), a common anti-inflammatory drug used in both human and veterinary medicine. A 2 factorial design with added center point was used to evaluate the effect of three independent variables-namely, HO concentration ([HO]), TA concentration ([TA]), and experiment time (time)-on TA degradation and HO photolysis during UV-ABC/HO treatment using a high-pressure mercury vapor lamp (photon flux of 2.6307 × 10 J s) as the UV irradiation source.

Photo-Fenton treatment of valproate under UVC, UVA and simulated solar radiation.

The abatement of valproic acid sodium salt (VA) via photo-Fenton process was investigated to evaluate the effect of irradiation type. Three different light sources have been used: UVA (black light blue lamps, BLB reactor), UVC (UVC reactor) and simulated sunlight in a Solarbox (SB). Using the highest concentrations of Fe (10mgL) and HO (150mgL), 100% of VA degradation was observed in BLB and UVC devices, and 89.

Abatement of the inhibitory effect of chloride anions on the photo-Fenton process.

The inhibition of the photo-Fenton (Fe2+/Fe3+, H2O2, UV light) degradation of synthetic phenol wastewater solutions by chloride ions is shown to affect primarily the photochemical step of the process, having only a slight effect on the thermal or Fenton step. Kinetic studies of the reactions of oxoiron (IV) (FeO2+) with phenol indicate that, if FeO2+ is formed in the photo-Fenton degradation, its role is probably minor. Finally, it is shown that, for both a synthetic phenol wastewater and an aqueous extract of Brazilian gasoline, the inhibition of the photo-Fenton degradation of the organic material in the presence of chloride ion can be circumvented by maintaining the pH of the medium at or slightly above 3 throughout the process, even in the presence of significant amounts of added chloride ion (0.