Water, 6. Treatment by Oxidation Processes

Lutze, Holger V.

doi:10.1002/14356007.o28_o17.pub2

Cited by 3 publications

(3 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Above pH 7, the rate decreases strongly, while below pH 6, this decrease is moderate. The lowest pH value measured at 3.45 shows a slight increase compared to higher pH values, which can be due to the formation of Cl 2 at pH < 4 . Modeling the data also shows a very low reaction rate of neutral Cz, while the expectation is that k (Cz H + ,HOCl) ≤ k (Cz,HOCl) .…”

Section: Resultsmentioning

confidence: 99%

Reaction of Chlorine Dioxide with Saturated Nitrogen-Containing Heterocycles and Comparison with the Micropollutant Behavior in a Real Water Matrix

Abdighahroudi

Mutke

Jütte

et al. 2022

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

Chlorine dioxide (ClO2) is a very selective oxidant that reacts with electron-rich moieties such as activated amines and thus can degrade specific N-containing micropollutants. N-containing heterocycles (NCHs) are among the most frequent moieties of pharmaceuticals. In this study, the reactions of ClO2 with ritalinic acid and cetirizine, two abundant micropollutants, and model compounds representing their NCH moiety were investigated. The pH-dependent apparent reaction rates of all NCHs with ClO2 were measured and modeled. This model showed that neutral amines are the most important species having reaction rates between 800 and 3200 M–1 s–1, while cationic amines are not reactive. Ritalinic acid, cetirizine, and their representative model compounds showed a high stoichiometric ratio of ≈5 moles ClO2 consumption per degraded ritalinic acid and ≈4 moles ClO2 consumption per degraded cetirizine, respectively. Investigation of chlorine-containing byproducts of ClO2 showed that all investigated NCHs mostly react by electron transfer and form above 80% chlorite. The reactions of the model compounds were well comparable with cetirizine and ritalinic acid, indicating that the model compounds indeed represented the reaction centers of cetirizine and ritalinic acid. Using the calculated apparent reaction rate constants, micropollutant degradation during ClO2 treatment of surface water was predicted for ritalinic acid and cetirizine with −8 to −15% and 13 to −22% error, respectively. The results indicate that in ClO2-based treatment, piperidine-containing micropollutants such as ritalinic acid can be considered not degradable, while piperazine-containing compounds such as cetirizine can be moderately degraded. This shows that NCH model compounds could be used to predict micropollutant degradation.

show abstract

Section: Resultsmentioning

confidence: 99%

Reaction of Chlorine Dioxide with Saturated Nitrogen-Containing Heterocycles and Comparison with the Micropollutant Behavior in a Real Water Matrix

Abdighahroudi

Mutke

Jütte

et al. 2022

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is worth mentioning the safety hazards of monochloramine production. Monochloramine is a common water treatment chemical produced onsite at hospitals, food and beverage facilities, and hotels; however, if reaction conditions are not carefully controlled, NCl 3 (explosive) can be coproduced . Important factors to consider include pH, temperature, concentration of reactants, and source of NH 3 .…”

mentioning

confidence: 99%

“…Despite the advantages of monochloramine, use of NH 2 Cl at scale poses practical challenges. This includes hazards associated with monochloramine accumulation, storage of large reagent quantities (up to 40 Vol), and instability of reagent (half-life of 50–100 h) . Perhaps for these reasons, monochloramine is typically made on site.…”

mentioning

confidence: 99%

Expanding Access to Remdesivir via an Improved Pyrrolotriazine Synthesis: Supply Centered Synthesis

Paymode¹,

Cardoso²,

Agrawal³

et al. 2020

Org. Lett.

View full text Add to dashboard Cite

Pyrrolotriazine 1 is an important precursor to remdesivir. Initial results toward an efficient synthesis are disclosed consisting of sequential cyanation, amination, and triazine formation beginning from pyrrole. This route makes use of highly abundant, commoditized raw material inputs. The yield of triazine was doubled from 31% to 59%, and the synthetic step count was reduced from 4 to 2. These efforts help to secure the remdesivir supply chain.

show abstract

Determination of free chlorine based on ion chromatography—application of glycine as a selective scavenger

2020

Self Cite

View full text Add to dashboard Cite

Free available chlorine (FAC) is the most widely used chemical for disinfection and in secondary disinfection; a minimum chlorine residual must be present in the distribution system. FAC can also be formed as an impurity in ClO2 production as well as a secondary oxidant in the ClO2 application, which has to be monitored. In this study, a new method is developed based on the reaction of FAC with glycine in which the amine group selectively scavenges FAC and the N-chloroglycine formed can be measured by ion chromatography with conductivity detector (IC-CD). Utilizing IC for N-chloroglycine measurement allows this method to be incorporated into routine monitoring of drinking water anions. For improving the sensitivity, IC was coupled with post-column reaction and UV detection (IC-PCR-UV), which was based on iodide oxidation by N-chloroglycine resulting in triiodide. The method performance was quantified by comparison of the results with the N,N-diethyl-p-phenylenediamine (DPD) method due to the unavailability of an N-chloroglycine standard. The N-chloroglycine method showed limits of quantification (LOQ) of 24 μg L−1 Cl2 and 13 μg L−1 Cl2 for IC-CD and IC-PCR-UV, respectively. These values were lower than those of DPD achieved in this research and in ultrapure water. Measurement of FAC in the drinking water matrix showed comparable robustness and sensitivity with statistically equivalent concentration that translated to recoveries of 102% for IC-CD and 105% for IC-PCR-UV. Repeatability and reproducibility performance were enhanced in the order of DPD, IC-CD, and IC-PCR-UV. Measurement of intrinsic FAC in the ClO2 application revealed that the N-chloroglycine method performed considerably better in such a system where different oxidant species (ClO2, FAC, chlorite, etc.) were present.

show abstract

Water, 6. Treatment by Oxidation Processes

Cited by 3 publications

References 58 publications

Reaction of Chlorine Dioxide with Saturated Nitrogen-Containing Heterocycles and Comparison with the Micropollutant Behavior in a Real Water Matrix

Reaction of Chlorine Dioxide with Saturated Nitrogen-Containing Heterocycles and Comparison with the Micropollutant Behavior in a Real Water Matrix

Expanding Access to Remdesivir via an Improved Pyrrolotriazine Synthesis: Supply Centered Synthesis

Determination of free chlorine based on ion chromatography—application of glycine as a selective scavenger

Contact Info

Product

Resources

About