Temperature-assisted UV/H2O2 oxidation of concentrated linear alkylbenzene sulphonate (LAS) solutions

This study demonstrates the importance of reaction temperature on the UV/H2O2 process. Oxidation reactions have been carried out on 1 g L−1 solutions of linear alkylbenzene sulphonates (LASs) in the range from ambient to 80 °C. Use of these conditions could be justified as they often represent the thermal conditions in which some polluted effluents are discharged.At an intermediate temperature of 60 °C and using small amounts of hydrogen peroxide LAS removal is significantly improved due to a more efficient use of the oxidant. This is mainly due to the enhancement of the radical reaction rate constant, as it does the quantum yield of the LAS.The use of more severe operating conditions, temperatures of 80 °C and high amounts of peroxide is necessary if the aim is to improve biodegradability. Only in that case intensified oxidation makes possible the removal of aromatic intermediates.

• We work with high reaction temperatures in the UV/H2O2 system.
• The oxidations have been carried out on 1 g L−1 solutions of LAS.
• This work has focused in the determination of the optimal operating conditions.
• The intermediates, the biodegradability and mineralisation are studied.
• The effect of temperature on same kinetic parameters is studied.