Advisor(s)
Abstract(s)
The degradation by gamma radiation of four phenolic compounds (gallic acid, protocatechuic acid, vanillic acid
and syringic acid) present in cork wastewaters was studied in several treatment conditions. The irradiations were
performed under different pH (natural, 3, 7 and 10) and atmospheres (aerated, N2O and O2) for isolated and
aqueous mixture solutions of standard phenolic acids. The degradation of the compounds was higher in isolated
than in the mixture solutions indicating a protective effect in the quaternary mixture solution. The saturation
with N2O promoted the highest degradation rates for all phenolic acids in the mixture. However, at natural pH
and in air it was achieved degradation efficiencies>50% for gallic, vanillic and syringic acids in isolated and
mixture solutions for a treatment dose of 20 kGy. It was verified that some of the compounds are a degradation
product of the others, for example gallic acid was found to be a radiolytic product of syringic, vanillic and
protocatechuic acids. Two different compounds were identified as radiolytic products of the studied phenolic
acids, and their fragmentation pathways were proposed. The results highlighted that ionizing radiation could be
used as clean technology for pollutants degradation using doses of 20 kGy.
Description
Keywords
Cork wastewaters Gamma radiation Phenolic acids Radiolytic degradation
Citation
Madureira, J.; Barros, L.; Melo, R.; Cabo Verde, S.; Ferreira, Isabel C.F.R.; Margaça, F. M.A. (2018). Degradation of phenolic acids by gamma radiation as model compounds of cork wastewaters. Chemical Engineering Journal. ISSN 1385-8947. 341, p. 227-237