Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis

Kobayashi, Yoshimi; Hayashi, Makoto; Yoshino, Fumihiko; Tamura, Muneaki; Yoshida, Ayaka; Ibi, Haruna; Lee, Masaichi-Chang-il; Ochiai, Kuniyasu; Ogiso, Bunnai

doi:10.2334/josnusd.56.35

Cited by 12 publications

(5 citation statements)

References 27 publications

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“…The fluorescence intensities of all the components were decreased by the combined ultrasound/H 2 O 2 treatment, and aromatic protein II appeared to be completely eliminated. It has been found that ultrasonic irradiation accelerates H 2 O 2 dissociation, releasing more free radicals than would otherwise be released (Kobayashi et al, 2014 ). The free radicals released will promote the oxidation of organic matter.…”

Section: Resultsmentioning

confidence: 99%

Recovery of Phosphorus From Swine Manure by Ultrasound/H2O2 Digestion, Struvite Crystallization, and Ferric Oxide Hydrate/Biochar Adsorption

et al. 2018

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Swine manure is potentially harmful to the environment but is also a readily accessible local source of phosphorus (P) for agricultural use. Decreasing the environmental impact of swine manure and recovering P from swine manure have been a challenge for a long time. In this study, an integrated process involving ultrasound/H2O2 digestion, struvite crystallization, and ferric oxide hydrate (HFO)/biochar adsorption was used to recover P from swine manure. The ultrasound/H2O2 treatment effectively solubilized the swine manure and converted organic P and other sparingly soluble P species into soluble phosphate. The struvite crystallization process allowed 85% of the available P to be recovered at pH 10.0 using a Mg:P molar ratio of 1.4 and a stirring rate of 150 rpm. HFO was loaded onto biochar synthesized by pyrolyzing ground corncob. The mechanism through which P was adsorbed was investigated by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The adsorption of P by the HFO/biochar followed pseudo-second-order kinetics and was primarily controlled by chemical processes. The maximum amounts of P adsorbed were 225.08–242.21 mg/g. Thermodynamic calculations indicated that the adsorption of P was endothermic and spontaneous and increased the degree of disorder in the overall system. P mass balance calculations indicated that 90.4% of the total P was recovered as struvite and P-saturated HFO/biochar.

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Section: Resultsmentioning

confidence: 99%

Recovery of Phosphorus From Swine Manure by Ultrasound/H2O2 Digestion, Struvite Crystallization, and Ferric Oxide Hydrate/Biochar Adsorption

et al. 2018

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“…The plastic mixture was placed in a 3% H 2 O 2 solution and was treated in an ultrasonic bath and only the PVC sample was submerged in the flotation column at the end of the treatment . The •OH and per hydroxyl radicals (•OOH) derived from the combination of H 2 O 2 and ultrasonic energy can oxidize PVC surfaces and introduce more hydrophilic groups. , In addition, H 2 O 2 /ultrasonic irrigation can oxidize PVC from more complicated mixtures under milder conditions. ,,, In fact, •OH helps PVC to remove HCl and form CC, which is followed by the substitution of chlorine atoms to generate −OH groups (Scheme ). Then, the CC bonds are easily broken by •OOH to form −COOH and carbonyl (CO) groups.…”

Section: Surface Oxidationmentioning

confidence: 99%

“…45 The •OH and per hydroxyl radicals (•OOH) derived from the combination of H 2 O 2 and ultrasonic energy can oxidize PVC surfaces and introduce more hydrophilic groups. 59,60 In addition, H 2 O 2 /ultrasonic irrigation can oxidize PVC from more complicated mixtures under milder conditions. 52,53,61,62 In fact, •OH helps PVC to remove HCl and form CC, which is followed by the 64 Interestingly, because internal CaCO 3 migrated to the PVC surface under the effects of KMnO 4 treatment, PVC was depressed after this treatment.…”

Section: Surface Oxidationmentioning

confidence: 99%

Surface Reactions in Selective Modification: The Prerequisite for Plastic Flotation

Jiang

Zhang

Wang

2020

Environ. Sci. Technol.

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Improper disposal of waste plastic has caused much environmental pollution, but plastic recycling can reduce the amount of new and residual waste plastic in the environment through source control. Plastic flotation can separate waste plastics with similar physical and chemical properties, which suggests its promising application in plastic recycling. With the help of the different hydrophilicities waste plastic can be separated by flotation, and hydrophilization can be accomplished by surface modifications. However, no systematic studies addressing these surface reactions have been published yet, and such modifications are a prerequisite for plastic flotation. In this critical review, we not only summarize the various modification mechanisms, including physical regulation, surface oxidation, surface degradation, dechlorination, and coating, but also have reasonably added additional information for some reactions covering surface reconstruction, plastic degradation, polymer stability, wastewater treatment, soil remediation, and chemical recycling of plastic. An entirely novel concept, the “plastic gene”, is also proposed to elaborate on some contradictory results. Plastic flotation with clear surface reactions may promote plastic recycling and thereby control waste plastic at the source, save energy, and reduce microplastics. We also predict challenges for clean, efficient, and practical surface modifications and plastic flotation.

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“…For instance, it has been demonstrated that ultrasound irradiation of 1.5 % (450 mM) H 2 O 2 using a device for endodontic treatment generates hydroxyl radicals resulting in killing of E. faecalis [65]. However, the reduction of bacterial number within the treatment time of 90 s was less than 1-log.…”

Section: Sonolysis Of Watermentioning

confidence: 99%

Microbicidal Activity of Artificially Generated Hydroxyl Radicals

Sheng

Nakamura

Kanno

et al. 2015

Interface Oral Health Science 2014

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The hydroxyl radical, one of the reactive oxygen species, has one unpaired electron in the structure, so that it tends to deprive other substances of an electron which is so-called oxidation. It is known that hydroxyl radicals produced by immunological response kill invading microorganisms by the oxidation. Besides the immune system, it has been demonstrated that hydroxyl radicals play an important role in the bactericidal action of antibiotics. In this context, we have conducted a research to develop disinfection techniques utilizing artificially generated hydroxyl radicals. We adopted photolysis of H 2 O 2 , sonolysis of water and the other photo-chemical reaction as generators of hydroxyl radicals. A series of studies demonstrated that the microbicidal activity of hydroxyl radicals was sufficient to kill bacteria in an experimental biofilm as well as planktonic bacteria and fungi within a short-treatment time. In addition, the safety aspect is confirmed by an in vivo study and a literature review. Thus, it is suggested that disinfection treatment utilizing artificially generated hydroxyl radicals can be applicable to medical/dental therapy as novel disinfection treatments.

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Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against Enterococcus faecalis

Cited by 12 publications

References 27 publications

Recovery of Phosphorus From Swine Manure by Ultrasound/H2O2 Digestion, Struvite Crystallization, and Ferric Oxide Hydrate/Biochar Adsorption

Recovery of Phosphorus From Swine Manure by Ultrasound/H2O2 Digestion, Struvite Crystallization, and Ferric Oxide Hydrate/Biochar Adsorption

Surface Reactions in Selective Modification: The Prerequisite for Plastic Flotation

Microbicidal Activity of Artificially Generated Hydroxyl Radicals

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