Degradation of chlortoluron during UV irradiation and UV/chlorine processes and formation of disinfection by-products in sequential chlorination

Guo, Zi-Bo; Lin, Yi-Li; Xu, Bin; Huang, He; Zhang, Tianyang; Tian, Fuyang; Gao, Naiyun

doi:10.1016/j.cej.2015.07.074

Cited by 76 publications

(16 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, chlorine can react with HO• and Cl• (reaction (3.1–3.4)), acting as scavenger of these reactive radicals [ 19 , 22 , 23 ].

At lower chlorine dosage (0.1 ∼ 1.0 mM), the enhanced generation rate of reactive radicals was greater than the increased scavenging rate by the added chlorine dosage, resulting in the increase of steady-state concentrations of reactive radicals [ 24 ]. At higher chlorine dosage (1.0 ∼ 2.0 mM), the enhanced generation rate of radicals from the increase of chlorine dosage was counterbalanced by its radical scavenging effect.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways

Tang¹,

Shi²,

Liu³

et al. 2018

R. Soc. open sci.

View full text Add to dashboard Cite

As a potential endocrine disruptor, clofibric acid (CA) was investigated in this study for its degradation kinetics and pathways in UV/chlorine process. The results showed that CA in both UV photolysis and UV/chlorine processes could be degraded via pseudo-first-order kinetics, while it almost could not be degraded in the dark chlorination process. The observed rate constant (kobs) in UV photolysis was 0.0078 min−1, and increased to 0.0107 min−1 combining with 0.1 mM chlorine. The kobs increased to 0.0447 min−1 with further increasing the chlorine dosage from 0.1 to 1.0 mM, and reached a plateau at higher dosage (greater than 1.0 mM). The higher kobs was obtained at acid solution rather than basic solution. Moreover, the calculated contributions of radical species to kobs indicated that the HO• contributed significantly to CA degradation in acidic conditions, while the reactive chlorine species and UV direct photolysis dominated in neutral and basic solution. The degradation of CA was slightly inhibited in the presence of HCO3− (1 ∼ 50 mM), barely affected by the presence of Cl− (1 ∼ 200 mM) and greatly suppressed by humic acid (0 ∼ 5 mg l−1). Thirteen main degradation intermediates and three degradation pathways of CA were identified during UV/chlorine process.

show abstract

“…On the other hand, chlorine can react with HO• and Cl• (reaction (3.1–3.4)), acting as scavenger of these reactive radicals [ 19 , 22 , 23 ].

Section: Resultsmentioning

confidence: 99%

“…HOCl has a higher quantum yields at 254 nm than OCl − (1.45 versus 0.97) [ 25 ]. On the other hand, OCl − scavenges HO• with much higher rate constant (8.8 × 10 9 M −1 s −1 ) than HOCl (8.46 × 10 4 M −1 s −1 ) [ 24 ]. In other words, HOCl is a mild free radical scavenger contrast to OCl − .…”

Section: Resultsmentioning

confidence: 99%

Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways

Tang¹,

Shi²,

Liu³

et al. 2018

R. Soc. open sci.

View full text Add to dashboard Cite

show abstract

“…Hydroxyl radicals and reactive chlorine species (e.g., • Cl and • Cl 2 − ) are the primary reactive species during the UV/chlorine AOP, and the contributions of • Cl 2 – are negligible due to its generally less reactivity with organic substances . Meanwhile, many studies have reported the application of the UV/chlorine process, the roles of • OH and • Cl in the degradation of pollutants have not been distinguished except for the case of benzoic acid .…”

Section: Resultsmentioning

confidence: 99%

Degradation of Atenolol with Electrochemical Oxidation at Mixed Metal Oxide Electrodes Assisted by UV Photolysis

Zhu

Dong

Zhou

2018

CLEAN Soil Air Water

View full text Add to dashboard Cite

Electrochemical oxidation has drawn considerable research attention for the destruction of organic contaminants. This study utilizes the combination of electrolysis and the UV photolysis process to degrade the β‐blocker atenolol (ATL). The results show that the combination of electrolysis and UV photolysis is superior to a single process alone based on the removal rates of ATL and electrical efficiency per order (EE/O). In situ electrogenerated chlorine is confirmed to be responsible for ATL degradation with NaCl electrolytes, and mixed metal oxide (MMO) anodes play a more significant role in the generation of active chlorine than platinum (Pt) anodes. Moreover, reactive species (hydroxyl radical •OH and chlorine radical •Cl) mainly contributed to ATL degradation during the photo‐electrolysis process. Increasing the concentration of NaCl electrolytes and applied current densities can enhance the ATL degradation. Finally, major intermediate products are identified, and a possible degradation pathway of ATL is proposed during the photo‐electrolysis processes. This study demonstrate that the photo‐electrolysis process can be considered as a potential technology for the destruction of pharmaceutical pollutants in water.

show abstract

“…The method of generating RC seen in Equation (9). A number of studies have shown that RCS has a weak a oxidize electron-rich organics [38,41,42]; thus, it is speculated that •OH is conve active chlorine species with a weaker oxidization ability by the increase in Cl − co tion, which slows down the degradation rate of Trp. Because the concentration of Cl − in natural water is typically 1-100 mg/L, the effect of different concentrations of Cl − on the UV degradation of Trp was also investigated.…”

Section: Effect Of Water Matrixmentioning

confidence: 99%

Degradation of Tryptophan by UV Irradiation: Influencing Parameters and Mechanisms

Zhang

Fei

et al. 2021

Water

View full text Add to dashboard Cite

The chlorination of dissolved amino acids can generate disinfection by-products (DBPs). To prevent the formation of DBPs, we examined the UV-induced degradation of tryptophan (Trp). In order to further understand the impact of UV disinfection on Trp, the effects of initial concentrations of Trp, pH, temperature, concentrations of NO3−, HCO3− and Cl− on Trp removal were investigated, and a degradation mechanism was also proposed. The results demonstrated that degradation fitted a pseudo first-order reaction kinetic model. The degradation of Trp was mainly caused by direct UV degradation. The apparent rate constant kobs decreased with the increase in initial Trp concentration and increased with increases in pH and temperature. The thermal degradation activation energy was 19.65 kJ/mol. Anions in water also had a significant influence on the degradation of Trp. HCO3− and NO3− contributed to the kobs of Trp, but Cl− inhibited the degradation rate. By electron paramagnetic resonance (EPR) spectroscopy, ·OH was proven to be formed during the degradation of Trp by UV. Based on the intermediate products of C11H15NO3, C10H15N and C9H13N detected by LC-MS-MS, the degradation pathway of Trp was speculated.

show abstract

Degradation of chlortoluron during UV irradiation and UV/chlorine processes and formation of disinfection by-products in sequential chlorination

Cited by 76 publications

References 45 publications

Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways

Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways

Degradation of Atenolol with Electrochemical Oxidation at Mixed Metal Oxide Electrodes Assisted by UV Photolysis

Degradation of Tryptophan by UV Irradiation: Influencing Parameters and Mechanisms

Contact Info

Product

Resources

About