Degradation of Diquat in aqueous solution: Transformation product identification and hydrolysis pathway investigation

In aquatic environments, hydrolysis is an important degradation method. The hydrolysis of Diquat was studied under different conditions in aqueous solution. The hydrolysis half-life of Diquat was strongly influenced by water pH and temperature, while different water types exhibited contrasting effects. According to the mass spectrometry date, six major hydrolysis transformation products (HTPs) were determined. The primary hydrolysis mechanism of Diquat involved N-C bond cleavage, hydroxylation, addition reaction, pyridine ring-opening and methylation. These results lay a further foundation for assessment of environmental risks and at the same time contribute to the explanation of Diquat's behavior in water environments.