Effects of organic acids and initial solution pH on photocatalytic degradation of bisphenol A (BPA) in a photo-Fenton-like process using goethite (α-FeOOH)

This work investigated the effects of organic acids and initial solution pH on the photodegradation of BPA in a photo-Fenton-like process using alpha-FeOOH as a catalyst. The results showed that the addition of different organic acids affected the formation of the ferric-carboxylate complexes and free radicals, which in turn varied the photodegradation efficacy. Compared with the other acids, oxalic acid (OA) was found to be the most effective in enhancing the photodegradation of BPA, which strongly depends on the OA concentration. Particularly, the addition of OA could significantly extend the working pH from an acidic to a neutral range for the photocatalytic process and thus the acidification pretreatment may not be needed. A high photocatalytic degradation of BPA occurred at pH 6.0, due to the formation of ferricoxalate complexes and (OH)-O-center dot radicals in the synergistic interactions of OA and alpha-FeOOH. This finding highlights that the oxalate-promoted photo-Fenton-like process using the alpha-FeOOH catalyst may be used for wastewater treatment without pH adjustment.