EFFECTS OF NATURAL ORGANIC MATTER ON PHOTOLYTIC AND PHOTOCATALYTIC DECOMPOSITION OF PHARMACEUTICALS

Abstract

Pharmaceuticals and personal care products (PPCPs) are of serious concern in the aquatic environment due to the widespread occurrence and potential toxicity to aquatic organisms. Photolysis and TiO2 photocatalysis are promising techniques for the elimination of PPCPs. Photolysis and TiO2 photocatalysis of two common PPCPs including tetracycline (TC) and ciprofloxacin (CIP) were investigated using UVA light-emitting diodes (UVA/LED) as the light source. The UVA/LED/TiO2 system could be energy-efficiently applied (0.58-4.89 kWh/m3/order) for rapid decomposition (0.0769-0.6596 min-1) of TC/CIP. The effect of background natural organic matter (NOM) on photolytic and photocatalytic decomposition of TC/CIP was studied because NOM is the predominant light absorber in natural waters and it can generate/scavenge reactive radicals under irradiation. Results showed that NOM could affect reaction kinetics, the formation of reactive species and the formation of transformation products of TC and CIP during photolysis and photocatalysis.