Degradation of organic ultraviolet filter diethylamino hydroxybenzoyl hexyl benzoate in aqueous solution by UV/H2O2
2015
Gong, Ping | Yuan, Haixia | Zhai, Pingping | Dong, Wenbo | Li, Hongjing
Steady-state and transient-state photolysis experiments were conducted to investigate the degradation of organic ultraviolet filter diethylamino hydroxybenzoyl hexyl benzoate (DHHB) in the aqueous solution by UV/H₂O₂. Results showed that the obvious degradation of DHHB was not observed under UV irradiation (λ = 254 nm), and the DHHB degradation was conducted due to the oxidation by hydroxyl radical (HO·). While the H₂O₂ concentration was between 0.05 and 0.10 mol L⁻¹, the highest DHHB degradation efficiency was obtained. The lower solution pH favored the transformation of DHHB, and the coexisting Cl⁻ and NO₃ ⁻ ions slightly enhanced the conversion. The degradation of DHHB by HO· followed a pseudo-first-order kinetic model with different initial DHHB concentrations. By intermediate products during DHHB oxidation and laser flash photolysis spectra analysis, a primary degradation pathway was proposed.
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