Photolysis of fumonisin B1 under simulated solar irradiation in aquatic environment

Abstract

Given that the presence of fumonisin as a potentially carcinogenic com­pound in the aqueous medium was confirmed, it is very important to find a method for its effective removal. In this study, the degradation efficiency of fumonisins in aqueous media was investigated by direct and indirect photolysis under simulated solar irradiation (SSI). The initial pH value had a significant effect on the kinetics of fumonisin B1 (FB1) degrada­tion, with the highest efficacy observed at pH 4.0 (88%), and the lowest at pH 10.0 (21%) during the 180 min of irradiation. Under these experimental conditions, FB1 photolysis in the first degradation period follows pseudo-first-order kinetics. In comparison to direct photolysis, indirect photolysis using H2O2 had an inhibitory effect on the degradation of FB1. Namely, 24% of FB1 was degraded during 180 min of irradiation at pH 8.0, while 74% was degraded by direct photolysis for the same period of time. In the case of the application of indirect photolysis using S2O82- at pH 4.0, the degradation efficiency of FB1 (91%) was similar as in the case of direct photolysis (88%), at the same pH, as well as for the same period of time. Considering the degradation efficiency, it was concluded that in both cases only direct photolysis was performed, probably because SSI does not contain suitable wave­lengths for sulfate radical (SO4•-) formation. Based on this, we can conclude that direct photolysis at pH 4.0 is practically the most suitable treatment for FB1 removal under SSI.

Keywords

• advanced oxidative processes
• mycotoxins
• photodegradation
• water