Abstract:

The possible use of ozone and advanced oxidation processes (AOP) to degrade and eliminate lignin compounds from aqueous solutions, and the determination of the required ozone dose are the primary objectives of this study. The influence of the oxidation methods on the subsequent biological decomposition of the by-products was also investigated.During ozonisation of the alkalilignin aqueous solutions, the polymer is degraded to a degree depending on the ozone dose. Lignin content decreased by about 40 to 96.6% at an ozone dose of 0.1 and 3.6 mgO3/mgCOD, respectively, accompanied by a drop of COD in the range of 8.8 - 69.6%. An ozone dose of about 1 mgO3/mgCOD is required to reduce the lignin content by more than 80%; at such a dose, the reduction of COD was about 35%. Lignin proved to be a substance that is practically insusceptible to biodegradation under the test conditions. An increase of the susceptibility to biodegradation of the lignin disintegration products could have been observed at an appropriately high dose of ozone.