Degradation Of Organic Pollutants By Ultraviolet/Ozone In High Salinity Condition: Non-Radical Pathway Dominated By Singlet Oxygen

In this work, the combined ultraviolet ozone process (UV/O-3) was applied for organic contaminant (Reactive Blue K-GL, RB) degradation in high salinity. The degradation rates of RB in both O-3 and UV/O-3 systems were enhanced by NaCl (the k increased from 0.080 to 0.116 to 0.132 and 0.267 min(-1) respectively), while mineralization rate varied at different salt conditions. In addition, UV irradiation promoted the degradation efficiency of RB with the presence of salt. Singlet oxygen (O-1(2)) was the primary active species in the UV/O-3 system. The quenching experiments and signal intensity of O-1(2) corresponded well to the mineralization of RB. Under conditions of high salinity and high pH, O-3 has high mass transfer coefficient (k(La), 3.303 min(-1)) and self-decomposition (k(d), 0.600 min(-1)), which further promoted the formation of O-1(2) for mineralization of RB. Furthermore, UV/O-3 system was efficient in real textile wastewater treatment (CODCr removal rate 91.7% and decolorization rate 98.7%). (C) 2020 Elsevier Ltd. All rights reserved.