Application of several advanced oxidation processes for the destruction of terephthalic acid (TPA)

Terephthalic acid (TPA) is widely applied as a raw material in making polyester fiber, polyethylene terephthalate (PET) bottles, polyester films, etc. TPA is toxic and is known to act as endocrine disruptor. TPA wastewater is traditionally treated by biological process and this study aims to evaluate the effectiveness of several advanced oxidation processes on TPA removal. The oxidation processes studied were: UV–TiO 2, UV–H 2O 2, UV–H 2O 2–Fe, O 3, O 3/Fe, O 3/TiO 2, UV–O 3–H 2O 2–Fe and UV–O 3–H 2O 2–Fe–TiO 2. The results indicate that the time required for the complete destruction of 50 ppm of TPA can be minimized from 10 h using UV–TiO 2 system, to less than 10 min by UV–H 2O 2–Fe–O 3 system. Some of the likely organic intermediates identified during TPA destruction include, benzoquinone, benzene, maleic acid and oxalic acid. Possible destruction pathway of TPA has been proposed. TPA degradation by various systems was also analyzed based on the reaction kinetics and operating costs.