Chemical effects of ultrasound on aqueous solutions. Formation of hydroxyl radicals and hydrogen atoms

Makino, Keisuke; Mossoba, Magdi M.; Riesz, Peter

doi:10.1021/j100231a020

Cited by 504 publications

(225 citation statements)

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“…As shown in Fig. 2 (a), pure water adding 500 mM DMPO was treated by ultrasound for 5 min, and the typical EPR spectrum of hydroxyl free radical (hyperfine coupling constants: a N = a H = 14.9 G) was observed, which is in agreement with many previous studies [6,8,11]. By contrast, we did not find EPR spectrum of hydroxyl free radical in other stock solutions.…”

Section: Evidence For the 1-hydroxylethyl Free Radical Formation In Ssupporting

confidence: 92%

“…The reason is that ethanol, as a hydroxyl free radical scavenger, has the ability to react with hydroxyl free radicals leading to the formation of the novel 1-hydroxylethyl free radical [8,15], and thus resulted in the disappearance of hydroxyl free radical in solutions with ethanol, i.e. ethanol is a substrate for the hydroxyl free radical and therefore competes with the spin trap [8], which can also be confirmed by the EPR spectra shown in Fig. 2 (c) and Fig.…”

Section: Evidence For the 1-hydroxylethyl Free Radical Formation In Smentioning

confidence: 99%

“…Besides the hydroxyl radicals produced by ultrasound in aqueous solution [6], some other free radicals are also generated by ultrasonic waves in some organic liquids [7]. In addition, some species of the above-mentioned free radicals may react with the dissolved substances thus leading to produce secondary radicals [8]. As a consequence, a chain of chemical reactions could be induced by the free radicals generated by ultrasonic waves.…”

Section: Introductionmentioning

confidence: 99%

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Free radical generation induced by ultrasound in red wine and model wine: An EPR spin-trapping study

Zhang

Shen

Fan

et al. 2015

Ultrasonics Sonochemistry

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Direct evidence for the formation of 1-hydroxylethyl radicals by ultrasound in red wine and air-saturated model wine is presented in this paper. Free radicals are thought to be the key intermediates in the ultrasound processing of wine, but their nature has not been established yet. Electron paramagnetic resonance (EPR) spin trapping with 5,5-dimethyl-l-pyrrolin N-oxide (DMPO) was used for the detection of hydroxyl free radicals and 1-hydroxylethyl free radicals. Spin adducts of Hydroxyl free radicals were detected in DMPO aqueous solution after sonication while 1-hydroxylethyl free radical adducts were observed in ultrasound-processed red wine and model wine. The latter radical arose from ethanol oxidation via the hydroxyl radical generated by ultrasound in water, thus providing the first direct evidence of the formation of 1-hydroxylethyl free radical in red wine exposed to ultrasound. Finally, the effects of *Corresponding author. Tel.: +86 29 85310517; fax: + 86 29 85310517. E-mail address: qinganzhang@snnu.edu.cn (Q.A. Zhang). ultrasound frequency, ultrasound power, temperature and ultrasound exposure time were assessed on the intensity of 1-hydroxylethyl radical spin adducts in model wine.

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Section: Evidence For the 1-hydroxylethyl Free Radical Formation In Ssupporting

confidence: 92%

Section: Evidence For the 1-hydroxylethyl Free Radical Formation In Smentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Free radical generation induced by ultrasound in red wine and model wine: An EPR spin-trapping study

Zhang

Shen

Fan

et al. 2015

Ultrasonics Sonochemistry

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“…The nature of the radicals formed in the sonolysis of water depends on the dissolved gas in the solvent: if Ar is present in the aqueous solution, OH · and H · radicals are detected [97,98], and H 2 O 2 and H 2 are formed from the radical recombinations. After the initial cleavage of water, 80% of the OH · and H · radicals formed have been reported to recombine in the cavity [99].…”

Section: Influence Of the Dissolved Gasmentioning

confidence: 99%

Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

González-Garcı́a

Sáez

Tudela

et al. 2010

Water

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As one of several types of pollutants in water, chlorinated compounds have been routinely subjected to sonochemical analysis to check the environmental applications of this technology. In this review, an extensive study of the influence of the initial concentration, ultrasonic intensity and frequency on the kinetics, degradation efficiency and mechanism has been analyzed. The sonochemical degradation follows a radical mechanism which yields a very wide range of chlorinated compounds in very low concentrations. Special attention has been paid to the mass balance comparing the results from several analytical techniques. As a conclusion, sonochemical degradation alone is not an efficient treatment to reduce the organic pollutant level in waste water.

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“…Several effects of ultrasound related to the electrochemical processes have been reported such as enhancement of the mass transport at the electrode [34], ultrasoundinduced surface effects [35] and generation of active radical species [36]. In water, the sonochemical formation of OH · radicals is followed by recombination of hydrogen peroxide [37] or by the activation of carbon surfaces [38].…”

Section: Controlled Potential Electrolysis Influence Of the Phmentioning

confidence: 99%

Electrosynthesis of hydrogen peroxide via the reduction of oxygen assisted by power ultrasound

González-Garcı́a

Banks

Šljukić

et al. 2007

Ultrasonics Sonochemistry

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The electrosynthesis of hydrogen peroxide using the oxygen reduction reaction has been studied in the absence and presence of power ultrasound in a non-optimized sonoelectrochemical flow reactor (20 cm cathodic compartment length with 6.5 cm inner diameter) with reticulated vitreous glassy carbon electrode (30 x 40 x 10 mm, 10 ppi, 7 cm 2 cm -3 ) as the cathode. The effect of several electrochemical operational variables (pH, volumetric flow, potential) and of the sono-electrochemical parameters (ultrasound amplitude and horn-to-electrode distance) on the cumulative concentration of hydrogen peroxide and current efficiency of the electrosynthesis process have been explored. The application of power ultrasound was found to increase both the cumulative concentration of hydrogen peroxide and the current efficiency. The application of ultrasound is therefore a promising approach to the increased efficiency of production of hydrogen peroxide by electro-synthesis, even in the solutions of lower pH (< 12). The results demonstrate the feasibility of at-site-of-use green synthesis of hydrogen peroxide.

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Chemical effects of ultrasound on aqueous solutions. Formation of hydroxyl radicals and hydrogen atoms

Cited by 504 publications

References 0 publications

Free radical generation induced by ultrasound in red wine and model wine: An EPR spin-trapping study

Free radical generation induced by ultrasound in red wine and model wine: An EPR spin-trapping study

Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

Electrosynthesis of hydrogen peroxide via the reduction of oxygen assisted by power ultrasound

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