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As a typical wide-band-gap semiconductor, BiPO 4 (BPO) has a great potential for photocatalytical degradation of highly stable benzene (C 6 H 6 ) that has been regarded as a priority hazardous VOC substance in the indoor atmosphere. Hexagonal (H-BPO), monoclinic (M-BPO), and their mixture phase BiPO 4 (M/H-BPO) were selectively synthesized to study the effect of BPO phase structure on the degradation of C 6 H 6 . The samples were characterized by several techniques, including X-ray diffraction, FTIR spectroscopy, UV–vis diffuse reflection spectroscopy, N 2 absorption-desorption measurements, scanning/transmission electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the monoclinic phase was a thermodynamically stable phase. The band gap energy of H-BPO, M-BPO, and M/H-BPO was 3.74, 3.93 and 3.86 eV, respectively. A transformation from rice-like hexagonal BPO to monoclinic phase nanorods was realized through varying the hydrothermal temperature and the composition of the solvent. The degradation of C 6 H 6 was closely associated with the crystalline phase of BPO and the mineralization rates decreased in order of M– (7.3) > M/H– (1.51) > H-BPO (0.51 μmol·h −1 ·m −2 ). The rates were higher than that of well-known P25 (0.34 μmol·h −1 ·m −2 ). The highest activity of M-BPO could be ascribed to its intrinsic distortion of PO 4 tetrahedron and the largest band gap structure. OH, O 2 − , and photoinduced holes were the major oxidation species accounting for the destruction of C 6 H 6 . [ABSTRACT FROM AUTHOR]

[Display omitted] • Co–CeO 2 was used to activate the PMS for degrading PET plastics. • The degradation rate reached 91.61 % in 6 h after adding 1 mL H 2 O 2 and 5 mM PMS. • Several factors, such as pH and anions, were considered. • SO 4 − played a crucial role in the degradation, compared to OH, O 2 −, and 1O 2. • The possible mechanism of photocatalysis/PMS degradation of PET was proposed. Polyethylene terephthalate (PET) plastic, widely used for packaging owing to its excellent properties, has become a major contributor to plastic waste, for which satisfactory recycling and upgrading treatment technologies are lacking. In this study, Co-doped CeO 2 was used as a photocatalyst to degrade PET plastics in water, and PET degradation was measured according to the weight loss rate. Peroxymonosulfate (PMS) addition to the photocatalytic system enabled the degradation of 53.82 ± 4.48 % of PET plastics, highlighting the excellent PET plastic degradation capability of the photocatalytic PMS system. The study investigated the effects of the catalyst-to-plastic ratio, PMS concentration, initial pH, inorganic anions, humic acid concentration, and hydrogen peroxide (H 2 O 2) addition on the catalytic oxidation system. Contrast experiments revealed that H 2 O 2 addition to the photocatalysis/PMS oxidation system further improved the PET plastic degradation efficiency (91.61 ± 1.50 %). Liquid product analysis, electron paramagnetic resonance, and free radical quenching experiments confirmed that SO 4 − played the most significant role in PET degradation. Finally, a possible mechanism for the degradation of PET plastics in water using the photocatalysis/PMS oxidation system was proposed. [ABSTRACT FROM AUTHOR]