Photooxidation and subsequent biodegradability of recalcitrant tri-alkyl phosphates TCEP and TBP in water.
Biodegradable organic carbon (BDOC) from OH radical oxidation (UV-H2O2) of the recalcitrant industrial anti-foaming agents and flame retardants, tri-n-butyl phosphate (TBP) and tris(2-chloroethyl) phosphate (TCEP), was quantified with respect to the fraction of the TBP or TCEP photooxidized. For 50-96% contaminant oxidation via OH, BDOC was similar in solutions of either compound, and ranged from 0.25 to 0.5 mg L(-1) (TBP0 and TCEP0 = 5 mg L(-1)). In addition, for this contaminant oxidation range, complete dehalogenation of TCEP was observed, along with a significant change in pH. Oxidation of TCEP results in both H+ and Cl(-) release, while the TBP mineralization pathway results in CO2, H2O, H+, and PO4(3-). For low microg/L levels of TCEP contamination in treated surface waters, UV-H2O2 oxidation of TCEP or TBP would not be expected to impact pH or chloride concentrations, however, a portion of the TCEP or TBP oxidation products, likely in non-halogenated aldehyde form, would become an available carbon source for bacterial growth in storage, distribution, or during further physical treatment.
Watts
Michael J
MJ
Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, USA.
Linden
Karl G
KG
D000085:Acetates / Q000528:radiation effects; D001673:Biodegradation, Environmental; D002712:Chlorides / Q000032:analysis; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D009930:Organic Chemicals / Q000528:radiation effects*; D010755:Organophosphates / Q000737:chemistry* / Q000528:radiation effects; D010084:Oxidation-Reduction; D012996:Solutions; D014466:Ultraviolet Rays; D014867:Water
D000085:Acetates; D002712:Chlorides; D009930:Organic Chemicals; D010755:Organophosphates; D012996:Solutions; D014867:Water; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide