| Abstract
| - The semibatch wet air oxidation (WAO) of 1600 mg L-1 of a linear alkylbenzene sulfonate (LAS)known as sodium dodecylbenzene sulfonate (SDBS) was investigated, for varying oxidationtemperature from 180 to 240 °C and pressure from 3.05 to 6.55 MPa. The major reaction productsidentified were low-molecular-weight volatile fatty acids (VFAs) such as formic and acetic acids,sulfonated aromatics, and sulfate. For 120-min WAO at 1.5 MPa oxygen partial pressure, atemperature increase from 180 to 240 °C led to increases in the liquid-phase LAS removal from79 to 100%, in the COD removal from 23 to 70%, and in the desulfonation of the LAS moleculefrom 7.4 to 57% of the total theoretical sulfate. Increasing the overall oxidation pressure from3.05 to 6.55 MPa had little effect on the overall TOC and COD degradation, but increased thedesulfonation. On the basis of these results, a reaction mechanism is proposed. Sulfonatedaromatic WAO intermediates accumulated under the conditions used, indicating that, to achievefurther organic degradation, more effective desulfonation conditions will be required.
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