The basics of oxidants in water treatment. Part A: OH radical reactions

Sonntag, Clemens von

doi:10.2166/wst.2007.383

Cited by 37 publications

(20 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High pH values (due to free OH -ions) promote both the ozone (O 3 ) decomposition in HO • radicals (see Eqs. (5)(6)) and the displacement of the ammonia equilibrium (NH 3 /NH 4 + ) toward NH 3 (see Eq. (3)).…”

Section: Resultsmentioning

confidence: 99%

“…(1,2), Table 1), the major secondary oxidant coming from the ozone decomposition. The stability of ozone and its decomposition in HO • radicals largely Downloaded by [University of Illinois Chicago] at 09:20 25 November 2014 depends on the chemical composition of the aqueous phase, especially its pH, the type and the content of natural organic matter and its alkalinity [2,5]. Towards the end of the Seventies, Singer and Zilli (1975) and Hoigné and Barder (1978) -cited in [4] -focused their research on the effect of the non-dissociated ozone in the process of the ammonia oxidation and discovered that ammonia reacts with ozone only when is non-protonated (that is when ammonia is in the form NH 3 ) and NO 3 -is the product.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental study on the abatement of ammonia and organic carbon with ozone

Ruffino

Zanetti

2012

Desalination and Water Treatment

View full text Add to dashboard Cite

A B S T R AC TAmmonia and organic carbon are commonly widespread substances both in municipal and in industrial wastewaters and are usually treated having recourse to biological processes. This work presents some preliminary results useful for the design of an oxidation treatment using ozone which has effect on both ammonia and organic carbon. In the fi rst part of the paper the oxidation of relatively low concentrations of ammonia (20 mg/l) by means of ozone and halides (chloride, bromide) was investigated with the aid of on-purpose made solutions. The experimental fi ndings pointed out that the reaction rate of an oxidation process involving ammonia and ozone (or ozone and halides) is different from a zero-order kinetics and is affected by the presence of free OH -ions. In fact high pH values promote both the ozone (O 3 ) decomposition in HO • radicals and the displacement of the ammonia equilibrium (NH 3 /NH 4 + ) toward NH 3 . Chloride was found to have no effect on the ammonia oxidation, on the other hand, the joined effect of ozone and bromide results in a more effective and faster reaction, which generates lower amounts of nitrate in comparison with the oxidation due to the only ozone and/or HO • radicals. In the second part of the work the oxidation of organic carbon (as potassium hydrogen phthalate) with ozone or bromide/ozone was investigated. In the process of the ozonation of organic carbon, bromide has no effect on the reaction rate, but it seems to slow down the process because of the competition between the oxidation of the potassium hydrogen phthalate and the formation of HOBr. The obtained results show that the oxidation stops when the residual concentration of organic carbon reaches a value equal to about 50% of the initial value.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study on the abatement of ammonia and organic carbon with ozone

Ruffino

Zanetti

2012

Desalination and Water Treatment

View full text Add to dashboard Cite

show abstract

“…The OER is the ratio between the dose necessary in hypoxic and the dose necessary in normoxic conditions to produce the same biological effect. The microscopic reason of the increased sensitivity in the presence of oxygen mainly is the quenching of the DNA damage mechanism mediated by free radicals, the so-called indirect damage [ 15 ].…”

Section: Biological Effects and Oxygen Enhancement Ratiomentioning

confidence: 99%

Clinical Evidence and Radiobiological Background of Particle Radiation Therapy

Tinganelli

Durante

Helm

2016

Current Clinical Pathology

View full text Add to dashboard Cite

“…Enzymatic phenol oxidation starts with initial attack of the phenolic nucleus by an electron resulting in the formation of free phenoxy radicals (von Sonntag, 2007). The unpaired electron of the phenoxy radical can resonate across different positions as exemplified in Fig.…”

Section: Formation Pathways Of the Coupling Productsmentioning

confidence: 99%