Photo-degradation of clofibric acid by ultraviolet light irradiation at 185 nm

摘要

As a metabolite of lipid regulators, clofibric acid (CA) was investigated in this study for itsnultraviolet (UV) degradation at monochromatic wavelength of 185nm using Milli-Q water andnsewage treatment plant (STP) effluent. The effects of CA initial concentration, solution pH, humicnacid (HA), nitrate and bicarbonate anions on CA degradation performances were evaluated.nAll CA degradation patterns well fitted the pseudo-first-order kinetic model. The results showednthat zOH generated from water photolysis by UV185 irradiation was involved, resulting in indirectnCA photolysis but contributed less to the whole CA removal when compared to the main directnphotolysis process. Acid condition favored slightly to CA degradation and other constituents innsolution, such as HA (5.0–100.0mgL21), nitrate and bicarbonate anions (1.0 £ 1023 mol L21 andn0.1 mol L21), had negative effects on CA degradation. When using real STP effluent CAndegradation could reach 97.4% (without filtration) and 99.3% (with filtration) after 1 hr irradiation,nshowing its potential mean in pharmaceuticals removal in UV disinfection unit. Mineralizationntests showed that rapid chloride ion release happened, resulting in no chlorinated intermediatesnaccumulation, and those non-chlorinated intermediate products could further be nearlyncompletely degraded to CO2 and H2O after 6 hrs.