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, HCO3-, humic acid （HA）, NO3- , 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/H 2O2 process. The presence of HCO3- , HA, and Cl adversely affected ATL oxidation in both processes. The NO3- concentration 1-3 mmol/L accelerated the destruction of ATL by the UV/PDS process, but further increase of NO3- 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 〉 [NO3-]0 〉 [HCO3-]0 〉 [Cl-]0 for the UV/H2O2 process and specific dosage 〉 pH 〉 [HA]0 〉 [NO3-]0 〉 [HCO3-]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.