Fenton-like photocatalyzed degradation of dibutyl phthalate with goethite and carboxylic acids

Detailed investigation of photocatalyzed degradation of dibutyl phthalate (DBP), an endocrine disrupter, in the presence of alpha-FeOOH (goethite) and different carboxylic acids is the focus of this study. To get a better insight into the efficiency of the degradation, the influence of different parameters, such as concentration of total Fe and Fe(II), dissolved oxygen, DBP concentration, pH and salinity is investigated. The reaction mechanism consists of several interrelationship steps. The first step is the chemical reaction of carboxylic acid groups of the organic acids with hydroxyl groups of the alpha-FeOOH and a charge transfer upon illumination generating Fe(II). The second step is the release of Fe(II) into the solution followed by H2O2 oxidation to form highly photoactive hydroxyl complex of iron(III) and OH. Simultaneously, the superoxide radical O-2(-) and hydroperoxyl radical is formed in acidic solutions in presence of carboxylic acids as well. This mechanism explains the genesis of different reactive species oxidizing DBP. From the variety of the studied carboxylic acids (oxalic, citric, salicylic, pyruvic, maleic, and fumaric), oxalic acid is the best Fe-ligand for the photoreductive dissolution of goethite. Concentrations of the total amount of Fe and its dissociated forms Fe(II) as well as oxygen and hydroxyl radicals play a fundamental role in efficiency of DBP degradation. The photodegradation of DBP with goethite and the use of suitable carboxylic acids under optimized reaction conditions could be an efficient process for decontamination of polluted waters.

Automated summary

This study focuses on the detailed investigation of photocatalyzed degradation of dibutyl phthalate (DBP) in the presence of alpha-FeOOH and different carboxylic acids. The influence of various parameters on the degradation efficiency is examined, and the reaction mechanism involving the formation of reactive species and Fe-ligands is explained. Overall, the photodegradation of DBP with goethite and suitable carboxylic acids under optimized conditions proves to be an efficient process for decontaminating polluted waters.