Difference in polystyrene oxo-biodegradation behavior between copper phthalocyanine modified TiO2 and ZnO paint photocatalyst systems

An oxo-biodegradation of polystyrene (PS) film was performed with copper phthalocyanine modified ZnO (CuPc-ZnO)/polyethylene oxide (PEO)/methyl linoleate (ML) and CuPc-TiO2/PEO/ML paint photocatalyst systems. Difference in the behavior between them was studied in the photodegradation and biodegradation stages, respectively. The CuPc modification brought about the improvement of the photodegradation activity. The smaller particle ZnO (50 nm) showed the less activity due to the ZnO dissolution process. The activity of the CuPc-ZnO/PEO/ML was higher than that with the CuPc-TiO2/PEO/ML. These systems highly contributed to the initial photodegradation stage. In the biodegradation stage, the dissolved CuPc-ZnO did not inhibit the fungus growth. The fungus was same species regardless of the kind of the photocatalyst system. The respirometric biodegradation profiles showed that the mineralization value reached at the same constant value around the 16 days. However, the initial biodegradation behavior was different.