Hydrolysis and free radial mediated degradation of phosphonates
1991
While studying the biodegradation and environmental fate of phosphonates, two almost undocumented nonbiological degradation processes acting on the stable C-P bond were observed. Under test conditions comparable to the environmental situation, phosphonates in solution are prone to a slow light-independent hydrolytic cleavage of the C-P bond(s). The process requires divalent cations, aerobic conditions, and is particularly active on N-containing phosphonates. Highest hydrolysis rates, up to 1% phosphonate-P converted to inorganic phosphate per day, were measured with the polyphosphonates. Second, C-P bonds in all phosphonates can efficiently be cleaved, also with release of orthophosphate, by means of physico-chemically generated free radicals. The riboflavin/light and Cu2+/H2O2 systems were more efficient than the Fenton reagent (Fe2+/H2O2) in this respect. Both processes are likely to contribute to the removal of xenobiotic phosphonates in the environment, particularly in the absence of photo- and biodegradation.
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