Anatoxin-a degradation by using titanium dioxide

Highlights: • TiO2 photocatalysis efficiently degrades neurotoxic anatoxin-a. • Several toxin decomposition products were noted with m/z ratio from 156.11 to 216.1. • Photocatalyst can damage cyanobacterial cells and degrade the released toxin. • Homogenization of cyanobacterial cells accelerates degradation of toxin. • Decomposition products were not toxic to T. platyurus. Advanced oxidation processes, such as using titanium dioxide (TiO₂) photocatalysis, are being developed to reduce or eliminate the toxicity of treated water. In this study, the removal of purified anatoxin-a (ANTX-a), live Dolichospermum flos-aquae cells, and a cell extract of this organism under UV-A/TiO₂ photocatalysis, creation of decomposition products and their toxicity were investigated. Total degradation of purified ANTX-a from the initial concentration of 10 mg·L⁻¹ with the addition of TiO₂ under UV-A irradiation was achieved in 30 min. Under these conditions several decomposition products were noted with m/z ratio from 156.11 to 216.1. Analysis of the completely degraded ANTX-a sample using Thamnotoxkit F™ toxicity test showed that it was no longer toxic. TiO₂ photocatalysis was also efficient in the decomposition of the living cyanobacterial cells. Degradation of their cell structures and degradation of released toxin was also achieved in 30 min. Earlier homogenization of cyanobacteria culture significantly accelerated degradation of ANTX-a to 10 min.