COMPARISON BETWEEN O-3 VUV, O-3/H2O2, VUV AND O-3 PROCESSES FOR THE DECOMPOSITION OF ORGANOPHOSPHORIC ACID TRIESTERS/

O-3/vacuum ultraviolet (VUV, ultraviolet radiation by a low pressure m ercury lamp at 185 and 254 nm), O-3/H2O2 and VUV processes rapidly dec omposed organophosphoric acid triesters (OPEs) dissolved in distilled water as compared to simple ozonation. The O-3/VUV process was the fas test of the three advanced oxidation processes (AOPs) for the decompos ition of 1 mg/l of OPEs in pH 7.5 phosphate buffer solution (0.5 mM). However the difference between the pseudo-first-order rate constants o f the O-3/VUV and O-3/H2O2 processes decreased in the condition of inc reasing OPEsw concentration, and the efficiencies of the two processes were almost the same at an initial concentration of 20 mg/l. Contrary to results in distilled water, in an effluent from a solid waste land fill site, the O-3/H2O2 process was the fastest. This is manily due to the absorption of VUV radiation by nitrate ion. WE confirmed that nit rate ion of more than a few mg/l strongly interfered with the generati on of hydroxyl (OH) radicals from VUV radiation while the O-3/H2O2 pro cess was not affected. The use of an ESR-spin trapping technique revea led that AOPs generated more OH radicals than ozonation alone, and the detection of hydrogen atom confirmed that VUV radiation directly gene rated OH radicals from water. Copyright (C) 1996 IAWQ. Published by El sevier Science Ltd.