Comparison of UV/PDS and UV/H2O2 processes for the degradation of atenolol in water

UV/H₂O₂ and UV/peroxodisulfate (PDS) processes were adopted to degrade a typical β-blocker atenolol (ATL). The degradation efficiencies under various operational parameters (oxidant dosage, pH, HCO^?₃, humic acid (HA), NO^?₃, and Cl^?) were compared. Principal factor analysis was also performed with a statistical method for the two processes. It was found that increasing the specific dosage of the two peroxides (peroxide]₀/ATL]₀) ranging from 1:1 to 8:1 led to a faster degradation rate but also higher peroxide residual. Within the pH range 3–11, the optimum pH was 7 for the UV/PDS process and elevating pH benefitted the UV/H₂O₂ process. The presence of HCO^?₃, HA, and Cl^? adversely affected ATL oxidation in both processes. The NO^?₃ concentration 1–3 mmol/L accelerated the destruction of ATL by the UV/PDS process, but further increase of NO^?₃ concentration retarded the degradation process, contrary to the case in the UV/H₂O₂ process. The rank orders of effects caused by the six operational parameters were pH ≈ specific dosage > HA]₀ > NO^?₃]₀ > HCO^?₃]₀ > Cl^?]₀ for the UV/H₂O₂ process and specific dosage > pH > HA]₀ > NO^?₃]₀ > HCO^?]₀ >Cl^?]₀ for the UV/PDS process. The UV/PDS process was more sensitive to changes in operational parameters than the UV/H₂O₂ process but more efficient in ATL removal under the same conditions.