With the increasing worldwide incidence of harmful cyanobacterial blooms, cylindrospermopsin (CYN), a highly toxic cyanobacterial toxin, has become a significant concern to public health and water management officials. In this study, we evaluated the removal of CYN by UV-254 nm-mediated advanced oxidation processes (AOPs), namely UV/S2O82?, UV/HSO5?, and UV/H2O2. The second-order rate constants of CYN with hydroxyl radicals and sulfate radicals were found to be comparable. However, the three processes resulted in different degradation kinetics under the same light flux, due to different properties of light utilization by the three oxidants and differences in the interaction of the radicals involved with other constituents in water. The observed pseudo-first-order reaction rate constant increased linearly with the increase of the initial oxidant concentration for all three AOPs. The presence of certain radical scavengers, especially natural organic matter (NOM), inhibited the destruction of CYN by the radicals. The presence of transition metals in tap and natural water samples, however, contributed to an enhanced treatment efficiency of CYN by UV/HSO5?. This was supported by the ICP-MS analysis of the metals in the water samples, providing the predominant copper residual of 40.6 � 3.3 �g/L in tap water samples. The results of this study suggest that the presence of transition metals in natural water sources should be considered in AOPs.  This provides us a new and feasible approach to remove CYN as well as other organic contaminants from water resources.

Destruction of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals and sulfate radicals using UV-254 nm-activation of hydrogen peroxide, persulfate, and peroxymonosulfate

244th National Meeting (2012)

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