Thermodynamic study on the reactivity of trace organic contaminant with the hydroxyl radicals in waters by advanced oxidation processes

This paper is to investigate the degradation abilities of various chlorinated aliphatics, benzene and its derivatives in order to treat organic polluted wastewaters efficiently by advanced oxidation processes (AOPs). A thermodynamic method is proposed to calculate the standard molar Gibbs energy of formation for aqueous organic species. Using the method proposed, the standard molar Gibbs energies of formation for 31 aqueous organic species are obtained. Moreover, the molar Gibbs energy change of reaction Δ_r G_m⁰ for the organic species with hydroxyl radicals is calculated from the standard molar Gibbs energy of formation for aqueous organic species to determine the degradation order of ease for the organic species. New photocatalytic experiments are carried out for the model verification. The calculation results of the model agree with the available and new experimental results. This work shows that the thermodynamics of the degradation reaction for the organic pollutants in AOPs can find the corresponding relationships with the degradation reaction rate by experimental measurements. The work in this paper represents a success of thermodynamics for the application in environmental area.