Enhanced photocatalytic inactivation of Cylindrospermopsis raciborskii by modified TiO2/Ag3PO4: Efficiency and mechanism

To effectively inhibit the emerging harmful algae Cylindrospermopsis raciborskii, modified TiO2/Ag3PO4 (T-P25/A) with oxygen vacancies was successfully synthesized by tea polyphenol (TP) reduction and chemical deposition methods for algae removal under visible light. The creation of oxygen vacancies affected the band structure of P25 and improved the photocatalytic performance of the T-P25/A composite. The photogenerated holes (h(+)) and superoxide radicals (center dot O-2(-)) are dominant reactive species in the photocatalytic system of T-P25/A, which yielded a 91.75 % inactivation rate to Cylindrospermopsis raciborskii (cyanobacteria cells) after 5 h of visible light irradi-ation. This degradation rate was about 1.5 and 1.7 times that of P25/A and Ag3PO4, respectively. Furthermore, the algal inactivation mechanism by T-P25/A under visible light was indicated by changes in morphological characteristics, cellular content degradation, oxidative species accumulation, and enzyme activity. This research provides valuable information about applicational prospects for the inactivation of harmful algal cells in real water bodies.

Automated summary

Modified TiO2/Ag3PO4 (T-P25/A) with oxygen vacancies was synthesized through tea polyphenol reduction and chemical deposition methods, effectively inhibiting the growth of harmful algae Cylindrospermopsis raciborskii under visible light. The creation of oxygen vacancies improved the photocatalytic performance of T-P25/A, leading to a 91.75% inactivation rate to Cylindrospermopsis raciborskii after 5 hours of visible light irradiation. The algal inactivation mechanism by T-P25/A was demonstrated through changes in morphological characteristics, cellular content degradation, oxidative species accumulation, and enzyme activity.