Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species

Wang, Wenlong; Wu, Qian-Yuan; Huang, Nan; Wang, Ting; Hu, Hong-Ying

doi:10.1016/j.watres.2016.04.015

Cited by 367 publications

(106 citation statements)

References 40 publications

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“…Chlorine is highly selective, and its reactivity was proven to be related to the chemical structure (functional group and dissociation) of organic materials [30]. Only 2.2% CBZ was degraded by chlorination under 10 mg/L chlorine after 5 min in the present work, and the negligible chlorination efficiency of CBZ is in accordance with the results reported in different water matrices [31][32][33]. The other target MPs exhibited specific degradation efficiency values ranging from 28.2% to 77.4%, and E3 was most sensitive to chlorine.…”

Section: Occurrence Of Micropollutants In Reclaimed Watersupporting

confidence: 91%

“…The pH had a negligible influence on the degradation of NAP. Previous studies demonstrated that lower concentrations of OH· and Cl· but a higher concentration of ClO· formed at higher pH levels [21,31,33]. With increasing pH, the decreasing concentrations of OH· and Cl· could be responsible for the decreased removal efficiencies of the 7 MPs, while the enhancement of ClO· could contribute to the accelerated degradation of MPs, such as CLA, DCF, IBP, and Indo.…”

Section: Effect Of Phmentioning

confidence: 97%

“…As mentioned above, both chlorination and UV irradiation are selective, and the reactivity relates to the properties (chemical structure, molar absorption coefficient, and quantum yield) of organic materials, which result in low degradation efficiency for some MPs. Potent nonselective oxidizing agents, including OH· and Cl·, can be generated during the UV-chlorine process [31], which can react with MPs and result in the significant enhancement of removal efficiency. Based on the above results, it is suggested that the UV-chlorine treatment has potential practical application in removal of MPs from real reclaimed water.…”

Section: Degradation Of Micropollutantsmentioning

confidence: 99%

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Degradation of Micropollutants by UV–Chlorine Treatment in Reclaimed Water: pH Effects, Formation of Disinfectant Byproducts, and Toxicity Assay

Wang

Ying

Минг

et al. 2019

Water

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The utilization of reclaimed water is a reliable and sustainable approach to enhance water supply in water-deficient cities. However, the presence of micro-organic pollutants (MPs) in reclaimed water has potential adverse effects on aquatic ecosystems and human health. In this study, we investigated the occurrence of 12 target MPs in the influent and reclaimed water collected from a local wastewater treatment plant, and the ultraviolet (UV)-chlorine process was applied to analyze its ability to remove MPs. The results showed that all 12 MPs were detected in both the influent and the reclaimed water, with the concentrations ranging from 25.5 to 238 ng/L and 8.6 to 42.5 ng/L, respectively. Over 52% of all the target MPs were readily degraded by the UV-chlorine process, and the removal efficiency was 7.7% to 64.2% higher than the corresponding removal efficiency by chlorination or UV irradiation only. The degradation efficiency increased with the increasing initial chlorine concentration. The pH value had a slight influence on the MP degradation and exhibited different trends for different MPs. The formation of known disinfectant byproducts (DBPs) during the UV-chlorine process was 33.8% to 68.4% of that in the chlorination process, but the DBPs' formation potentials were 1.3 to 2.2 times higher. The toxicity assay indicated that UV-chlorine can effectively reduce the toxicity of reclaimed water.

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Section: Occurrence Of Micropollutants In Reclaimed Watersupporting

confidence: 91%

Section: Effect Of Phmentioning

confidence: 97%

Section: Degradation Of Micropollutantsmentioning

confidence: 99%

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Degradation of Micropollutants by UV–Chlorine Treatment in Reclaimed Water: pH Effects, Formation of Disinfectant Byproducts, and Toxicity Assay

Wang

Ying

Минг

et al. 2019

Water

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“…Accordingly, it is expected that an increase in chlorine dose enhances pollutant degradation through augmentation of radical production. In fact, some researchers reported that the degradation of carbamazepine, methylene blue, and trimethoprim were enhanced by an increase in chlorine dose [21,51,82,83]. However, free chlorine acts as a radical scavenger by reactions of R 1 , R 2 , and R 3 in Table 1 and Fig.…”

Section: Effect Of Chlorine Dosementioning

confidence: 95%

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

Kishimoto

2019

J. of Wat. & Envir. Tech.

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The photolysis of chlorine by ultraviolet radiation (UV/chlorine) produces HO˙ and Cl˙, part of which further transforms into reactive chlorine species (RCS) like Cl 2˙− and ClO˙. These radicals are responsible for the advanced oxidation effect of UV/chlorine processes. Recently, UV/chlorine processes gather much attention from researchers and practitioners and published papers on UV/chlorine processes have drastically increased, which were thoroughly reviewed in this paper for understanding the state of the art of these technologies. Fundamental studies elucidate that acidic conditions are favorable to UV/chlorine processes through a change in quantum yield of chlorine photolysis, equilibrium shifts of radical species, and a change in radical scavenger effect of free chlorine. Comparative studies reveal that UV/chlorine processes are usually more energy-efficient than UV/hydrogen peroxide and UV/ persulfate processes. Although unfavorable byproducts formation by RCS reactions is apprehended, application researches in real waters show that UV/chlorine processes do not enhance disinfection byproducts formation very much. Since UV irradiation and chlorination are widely used unit operations, a barrier to install an UV/chlorine process into a conventional process is not high. It is desired to develop and optimize a whole process combined with other unit processes for maximizing benefits in water treatment in the future. CONTENTS INFLUENTIAL FACTORSEffect of pH Effect of chlorine dose Effect of halide ion Effect of alkalinity Effect of natural organic matter (NOM) Effect of UV light source LP-UV/chlorine process MP-UV/chlorine process Excimer-UV/chlorine process UV-LED/chlorine process Solar/chlorine process Comparison with other UV-based AOPs PROCESS VARIATIONS

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“…15 Wu et al compared the change in the acute toxicity of a trimethoprim solution at different reaction times in the chlorination and UV/chlorine processes, and found that the acute toxicity resulting from UV/chlorine was lower than that from direct chlorination, with the same removal rate of trimethoprim. 16 Additionally, UV irradiation can effectively inactive chlorine-tolerant pathogenic microorganisms (e.g., Cryptosporidium parvum and Giardia lamblia) and is oen used in conjunction with chlorine in a complementary manner.…”

mentioning

confidence: 99%

Kinetics and mechanistic investigation into the degradation of naproxen by a UV/chlorine process

Gao

Chu

et al. 2017

RSC Adv.

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In this study, UV irradiation combined with chlorine (UV/chlorine) was used to degrade naproxen (NPX), a typical non-steroidal anti-inflammatory drug (NSAID) widely used for the treatment of symptoms associated with inflammation, in water. Compared with UV irradiation alone and direct chlorination, the UV/chlorine process shows a synergistic effect on NPX degradation. The effects of different factors, including the chlorine dose, solution pH, and the presence of Cl À , HCO 3 À or humic acid (HA), on NPX degradation in the UV/chlorine process were investigated. The results indicated that the degradation of NPX followed pseudo-first-order kinetics in all cases, and the rate constant increased as the chlorine dose increased and decreased as the pH increased. The effects of the water matrix on UV/chlorine treatment were species-dependent. The NPX degradation rate was inhibited by the presence of HCO 3 À and HA but significantly improved by Cl À . LC/MS/MS analysis indicated that NPX decomposition in the UV/chlorine process was associated with decarboxylation, demethylation and hydroxylation. These results indicate that the UV/chlorine process is a promising technology for the treatment of water polluted by emerging contaminants, such as NPX. However, UV/chlorine can notably enhance the formation of disinfection by-products compared to direct chlorination, which should be carefully considered when integrating this process into drinking water treatment schemes.

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Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species

Cited by 367 publications

References 40 publications

Degradation of Micropollutants by UV–Chlorine Treatment in Reclaimed Water: pH Effects, Formation of Disinfectant Byproducts, and Toxicity Assay

Degradation of Micropollutants by UV–Chlorine Treatment in Reclaimed Water: pH Effects, Formation of Disinfectant Byproducts, and Toxicity Assay

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

Kinetics and mechanistic investigation into the degradation of naproxen by a UV/chlorine process

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