The effects of dissolved organic matter on the decomposition of di-n-butyl phthalate by ozone/hydrogen peroxide process

The effects of the dissolved organic matter (DOM) on the ozone decay and the di-n-butyl phthalate (DBP) decomposition during ozone/hydrogen peroxide (O₃/H₂O₂) process were investigated (DBP-d₄ was used instead of DBP). Four surface waters, two secondary municipal sewage effluents (SMSEfs) and Suwannee river natural organic matter were used as DOM. The ozone decompositions in the DOM solutions were separated by instantaneous ozone consumption and slower ozone decay. The effect of H₂O₂ addition on the ozone decay was clearly observed at slower ozone decay. Ozone decomposition rate at slower ozone decay increased linearly with H₂O₂ dose. DBP-d₄ was exponentially decreased with ozone consumption. Ozone consumption required to decompose 90% of DBP-d₄ ((ΔO₃)_90%) in SMSEFs was higher than those in surface waters. The (ΔO₃)_90% per DOC of DOM values were from 22 to 23 μmole/mgC for SMSEFs and from 10 to 17 μmole/mgC for surface waters. The (ΔO₃)_90% values were correlated to specific ultraviolet absorbance at 254 nm (SUVA₂₅₄) for surface waters.