Removal of saccharin by UV/persulfate process: Degradation kinetics, mechanism and DBPs formation

A comparative study on the degradation of iohexol and diatrizoate during UV/persulfate process: kinetics, degradation pathways and iodinated disinfection by-products

“…The degradation rate of iohexol slightly decreased with the increase of pH, whereas the degradation of diatrizoate gradually increased to the maximum as the pH increased from 5 to 7, and then slightly decreased as the pH further increased to 9. In the UV/PS process, SO 4 •− is the main reactive radical under acidic and neutral conditions, 30 9)), 34 whereas the generated HO• may be further scavenged by OH − in solution to form O• − with lower redox potential (eqn (10)), 35,36 which may decrease the rate of iohexol and diatrizoate degradation by the UV/PS process.…”

“…In the UV/PS process, SO 4 · − is the main reactive radical under acidic and neutral conditions, 30 thus increasing the degradation rate of ICM under acidic and neutral conditions. With pH > 7, both SO 4 · − and HO· radicals will be present in the UV/PS oxidation process, and OH − in solution may react with SO 4 · − to form HO· and SO 4 2− (eqn (9)), 34 whereas the generated HO· may be further scavenged by OH − in solution to form O· − with lower redox potential (eqn (10)), 35,36 which may decrease the rate of iohexol and diatrizoate degradation by the UV/PS process.SO 4 · − + OH − → SO 4 2− + HO·HO· + OH − → H 2 O + O· − …”

Powdered activated carbon (PAC)-assisted peroxymonosulfate activation for efficient urea elimination in ultrapure water production from reclaimed water

“…This can be attributed to the fact that excessive free radicals may scavenge themselves or convert into other species with weaker redox potentials through reactions with S 2 O 8 2− (Eqs. 2 – 4 ) 33 , 34 . In summary, the results highlight the importance of optimizing the PAC and PMS dosage for efficient urea degradation.…”

Powdered Activated Carbon (Pac)-Assisted Peroxymonosulfate Activation for Efficient Urea Elimination in Ultrapure Water Production from Reclaimed Water

“…2-4). 31,32 In summary, the results highlight the importance of optimizing the PAC and PMS dosage for e cient urea degradation. The ndings suggest that the synergistic effect between PMS and PAC, plays a crucial role in achieving high urea removal e ciency.…”

“…which have a low redox potential (2.30 V, k = 3.6 10 5 ). 32 In contrast, the presence of CO 3 2signi cantly inhibited urea removal. When CO 3 2co-exists, the carbonate radicals (CO 3 -•) which have a low redox potential (1.63 V) could be formed.…”