Effect of ozone and ozone/activated carbon treatments on genotoxic activity of naphthalenesulfonic acids

Abstract

Naphthalenesulfonic compounds are widely used, mainly by the textile industry in the synthesis of azoic colorants. The presence of the sulfonic group is known to endow these compounds with high water-solubility and low biodegradability, although its in¯uence on their genotoxic activity is unknown. The use of energetic oxidants is recommended for the degradation of organic compounds which are refractory to biological treatment. Ozone and ozone/activated carbon have been proposed as the best alternatives to remove these compounds. The results showed that the more sulfonic groups there are on the aromatic ring of this family of contaminants, the lower is their genotoxic activity. All the compounds studied presented genotoxic activity at elevated concentrations. Ames test results indicate that DNA damage was produced by substitution of nitrogenated bases. The system based on the combined use of ozone and activated carbon was the most ef®cacious in the depuration of water containing these contaminants. This approach rapidly degraded the naphthalenesulfonic acids, eliminated their genotoxic activity and reduced their organic material content using low doses of ozone.

Degradation of recalcitrant compounds from stabilized landfill leachate using a combination of ozone-GAC adsorption treatment

“…The • OH radicals had a greater oxidizing capacity (2.80 V) than ozone (2.08 V). As a result, either by hydrogen abstraction or by electrophilic attack to double bonds, the • OH radicals-catalyzed ozone not only reacted with NH 3 -N, but also broke down other large compounds such as xenobiotic compounds, adsorptive organic halogen (AOX) and phenolic compounds in the leachate into oxidation by-products that had a smaller molecular size than the starting compounds [40]. Consequently, the by-products became more easily biodegradable, thus enabling GAC to adsorb the remaining organic materials unchanged by the ozone oxidation.…”

Oxidative Amidation of Aromatic Ethers Catalyzed by Rhodium Acetate

“…The application of ozone alone produced no reduction in the TOC concentration. As demonstrated in a previous publications,1 ozone does not present adequate oxidant potential to mineralize the organic matter. However, when ozonation was carried out in the presence of 0.1 millieq dm −3 of Fe(II) and Zn(II), a reduction in the TOC concentration was observed.…”

“…The oxidizing capacity of ozone is inadequate to produce the mineralization of dissolved organic matter,1 and its use can sometimes generate oxidation subproducts that are more toxic than the original 1, 2. Nevertheless, ozone is widely used as a purification agent in waters for human consumption and in industrial effluents 3–5…”

Biodegradation of naphthalenesulphonate polymers: the potential of a combined application of fungi and bacteria

“…Advanced oxidation processes, such as ozonation, have also been investigated for the removal of 2-NSA and its polymers; however, the observed degradation was not complete, [21,22] while results on treated samples toxicity decrease are controversial. [16,23] Conventional biological processes do not appear effective for treating water containing 2-NSAP. In fact, few works focus on the biodegradation of 2-NSA monomers using bacterial strains; the Sphingomonas sp.…”