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An attempt to identify intermediate and final products of photocatalytic degradation of sodium dodecylbenzensulfonate (DBSNa) in aqueous solution was carried out. Synthetic samples of DBSNa containing TiO2 as catalyst were treated in a solar concentrator device. Samples were taken at regular intervals and analyzed by GC/MS. Two main types of signal were observed in the total ion chromatograms. The first group includes signals absent in the untreated sample that appeared during the first phases of the experiment and decreased toward the end. The second group comprised species already present in the untreated sample. There were signals in both groups probably because of stable oxygenated molecules that were accumulated to the end of treatment, indicating partial mineralization. Results clearly showed that degradation dynamic is complex. The detergent is fragmented into other products that undergo further reactions. The species distribution towards the end of the process is difficult to predict since it depends on a large number of variables including adsorption, reaction rates and the nature of the intermediate products. It is necessary to continue the study to determinate if these molecules are destroyed within the system for longer illumination times.

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The aim of this study was to investigate the characteristics and the defoamer capacity of bio-oils obtained from textile sludge pyrolysis. The pyrolysis was carried out at two temperatures: 310 and 500 8C, and the bio-oils were analyzed after 7 days and after 2 months of storage under refrigeration. The structure of the bio-oils was determined by Fourier transform infrared spectroscopy (FTIR) and the extraction of polar compounds by solid phase micro extraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS) analysis. According to the chromatography and FTIR results, aromatic hydrocarbons, amines, silicone, and organic sulphur compounds were present in the pyrolysis oils. The Bikerman test showed that 1 mL of bio-oil obtained from pyrolysis at 500 8C can break down a column of foam in less than 1 min, which is comparable to the results of commercial antifoams. According to these results, these oils can be used as defoamers, even at the textile plant itself.