Removal of alkylphenols from polluted sites using surfactant-assisted soil washing and photocatalysis.

Background And Purpose: Surfactant-assisted soil washing and photocatalysis are well-known remediation processes of environmental concern. The application of photocatalysis to treat soil washing extracts containing 4-methylphenol, 4-ethylphenol and 4-tert-butylphenol in the presence of nonionic (C(12)E(8) and C(12)E(23)) and anionic (SDS) surfactants and some of their binary mixtures was investigated in this work by studying the pollutants degradation in the presence of TiO(2) dispersions irradiated with simulated solar light.

Materials And Methods: Clean soil samples were spiked with the investigated alkylphenols.

High-performance liquid chromatography coupled to ultraviolet diode array detection and electrospray ionization mass spectrometry for the analysis of intermediates produced in the initial steps of the photocatalytic degradation of sulfonated azo dyes.

High-performance liquid chromatography coupled to ultraviolet diode array detection and electrospray ionization mass spectrometry was applied to monitor the photocatalytic degradation mediated by TiO2 of three sulfonated monoazo dyes (Orange I, Orange II, and Ethylorange) present in aqueous solution. Photobleaching, organic carbon, nitrogen and sulfur evolution were also followed during the process. Delayed carbon mineralization was observed with respect to both dyes disappearance and photobleaching, due to the formation of transient intermediate compounds which were in turn completely degraded.

Intermediate distributions and primary yields of phenolic products in nitrobenzene degradation by Fenton's reagent.

Nitrobenzene thermal degradation was investigated using the Fenton reagent in different experimental conditions. Reaction products were analyzed by HPLC, GC-MS, LC-MS and IC. The products obtained at different nitrobenzene conversion degrees show that degradation mainly involves successive hydroxylation steps of the aromatic ring and its subsequent opening followed by oxidation of corresponding aliphatic compounds.

Photocatalytic oxidation of methyl-orange in aqueous suspension: comparison of the performance of different polycrystalline titanium dioxide.

The photocatalytic oxidation of methyl-orange (C14H14N3SO3Na) dye was carried out in aqueous suspensions of polycrystalline TiO2 irradiated with artificial light until its complete mineralization was achieved. The performances of two widely used semiconductor powders were studied for comparison purposes. The dependence of dye photo-oxidation rate on various experimental parameters, including substrate concentration, semiconductor amount, and pH was investigated by using both catalysts.

Azo-dyes photocatalytic degradation in aqueous suspension of TiO2 under solar irradiation.

The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C14H14N3SO3Na) and orange II (C16H11N2SO4Na), is reported.