| Abstract
| - Semibatch wet air oxidation (WAO) experiments were conducted on aqueous solutions of linearalkylbenzene sulfonates (LAS) at various pH's, to determine whether acidic and/or basic pHaffects the rate and extent of the degradation and desulfonation of LAS and its refractorysulfonated intermediates. It was found that acidic pH increases the removal of TOC, COD, andLAS, as well as increasing desulfonation. Acid catalysis of the desulfonation and aromatic ringcleavage reactions is thought to be responsible. Conversely, the WAO of LAS and its intermediateswas less effective at high pH. It is hypothesised that this is due to radical scavengers and thedominance of the superoxide radical in the alkaline environment. Desulfonation might also beautocatalyzed in unmodified LAS WAO reactions by reaction products, as acid is a product ofLAS WAO reactions. Experiments were conducted at 240 °C at neutral (unmodified) and alkalinepH's to compare WAO in the presence and “absence” of this acid. Desulfonation occurred to thesame extent at both pH's, indicating that it was not significantly autocatalyzed by the acidgenerated during WAO.
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