Enhanced free-radical generation by shrinking microbubbles using a copper catalyst

Li, Pan; Takahashi, Masayoshi; Chiba, Kaneo

doi:10.1016/j.chemosphere.2009.07.062

Cited by 137 publications

(110 citation statements)

References 15 publications

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“…Fig. 6 shows that the fluorescence signal of HTA was observed in air-microbubble water but not in air-macrobubble water, which once again supported the conclusion of Takahashi et al [22] and Li et al [26]. Compared with macrobubble-ozonation, the fluorescence intensity of the samples in ozone microbubble water was significantly higher than that in ozone macrobubble water, indicating a greater amount of hydroxyl radicals generated during microbubble-ozonation.…”

Section: Hydroxyl Radicalssupporting

confidence: 77%

“…A great amount of chemical energy is released in a few microseconds due to the accumulation of high concentrations of ions on the gas-liquid interface of the collapsing microbubble, which causes the generation of hydroxyl radicals under high temperature and pressure [22]. Takahashi et al [22] and Li et al [26] tested the generation of hydroxyl radicals from collapsing micro-bubbles by electron spin-resonance (ESR). Chu et al [10] proved that the existence of hydroxyl radicals in ozone microbubble water with fluorescence detection.…”

Section: Hydroxyl Radicalsmentioning

confidence: 99%

“…The Young-Laplace equation can be applied to calculate the internal pressure of the bubble [25]. (2)), the internal pressure of a 1 μm bubble is 3.85 times than that of 1 mm bubble [26]. According to the Henry's Law, high internal pressure of the bubble results in improved dissolution in water [25].…”

Section: Ozone Gas Holdupmentioning

confidence: 99%

See 2 more Smart Citations

Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry

Zheng

Wang

Tao

et al. 2015

Journal of Hazardous Materials

106

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Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry, Journal of Hazardous Materials http://dx.doi.org/10.1016/j.jhazmat. 2015.01.069 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis work investigated microbubble-ozonation for the treatment of a refractory wet-spun acrylic fiber wastewater in comparison to macrobubble-ozonation. COD cr , NH 3 -N, and UV 254 of the wastewater were removed by 42%, 21%, and 42% respectively in the microbubble-ozonation, being 25%, 9%, and 35% higher than the removal rates achieved by macrobubble-ozonation at the same ozone dose. The microbubbles (with average diameter of 45 μm) had a high concentration of 3.9 × 10 5 counts/mL at a gas flow rate of 0.5 L/min. The gas holdup, total ozone mass-transfer coefficient, and average ozone utilization efficiency in the microbubble-ozonation were 6.6, 2.2, and 1.5 times higher than those of the macrobubble-ozonation. Greater generation of hydroxyl radicals and a higher zeta potential of the bubbles were also observed in the microbubble ozonation process. The biodegradability of the wastewater was also significantly improved by microbubble-ozonation, which was ascribed to the enhanced degradation of alkanes, aromatic compounds, and the many other bio-refractory organic compounds in the wastewater. Microbubble-ozonation can thus be a more effective treatment process than traditional macrobubble-ozonation for refractory wastewater produced by the acrylic fiber manufacturing industry.

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Section: Hydroxyl Radicalssupporting

confidence: 77%

Section: Hydroxyl Radicalsmentioning

confidence: 99%

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Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry

Zheng

Wang

Tao

et al. 2015

Journal of Hazardous Materials

106

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“…On the other hand, metal catalysis increases the hydroxyl radical generation from ozone in aqueous solution. Several effectual reports suggested the catalytic oxidation reactions [11][12][13][14]. Khuntia et al (2013) determined the enhancement of OH· radical generation from ozone for the catalytic ozonation using four common metal ions.…”

Section: Fig 4 Effect Of Ph On As(iii) Oxidation With Ozone At 20°cmentioning

confidence: 99%

“…However, the exact mechanism of the ·OH radical generation under strong acidic condition is precisely not known. Li et al investigated the generation of hydroxyl radicals by microbubbles at acidic pH and confirmed the generation of hydroxyl radicals at pH 2 [13]. On the other hand, another brief description of ozone is catalytic ozonation using metalion and it is a promising method to enhance the hydroxyl generation from ozone.…”

Section: Introductionmentioning

confidence: 99%

Arsenic removal from waste water by ozone oxidation combined with ferric precipitation

Zhang

Yang

2017

Mong. J. Chem.

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Abstract:The oxidation of As(III) to As(V) followed by precipitation and adsorption is thought to be the most effective process for removal of arsenic in industrial wastewater. In this work, the oxidation of As(III) to As(V) with ozone was carried out in an acidic solution. After oxidation, arsenic was removed by precipitation in an iron (III) sulfate system under ambient pressure at 90°C in acid. Batch experimental results show that ozone is quite effective in oxidizing As(III) at low pH. And more than 90% of 5g/l As(III) was removed from the acidic solution by precipitation with Fe 2 (SO 4 ) 3 in 7-8 hours. Key words: Arsenate, Arsenite, Ozone, Oxidation, Precipitation INTRODUCTIONRecently, the toxic behavior of arsenic is receiving increased attention as the arsenic pollution has been reported worldwide. Arsenic is a common element which is widely distributed throughout the rock, soil, natural water and marine environments and associated with some base and precious metals in the sulfide ores [1][2][3]. Hereupon, the mining and metallurgical industries have expended considerable research efforts to develop environmentally acceptable methodologies for the arsenic removal from waste water. Under natural conditions As is mostly found in inorganic forms as trivalent arsenite (As(III)) or as oxyanions of pentavalent arsenate (As(V)). In comparison with As(V), As(III) is high mobile and more difficult to be removed from the aqueous solution. All of the arsenic precipitation work carried out involved both ferric iron and pentavalent arsenic in solution, based on the substantially correct premise [2,4]. It is necessary to oxidize the trivalent arsenic to its pentavalent state before the arsenic removal. A lot of researchers focused on the methods for oxidation of As(III) to As(V) using different oxidants [5][6][7]8]. In several studies, ozone applications have been reported for treatment of wastewater and water, but very few studies are for oxidation of As [6][7][8][9][10]. The most characteristic chemical properties of ozone are its strong oxidizing and high standard redox potential according to the reaction conditions. It is strong oxidizing nature and its tendency to transfer an O atom with coproduction of O 2 [4]. The standard redox potentials in acid (1) and in alkaline (2) solutions are the following reactions.

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Dynamic Visualization of Free Radicals at Single Oxygen Bubbles using Chemiluminescence

Liu

Jin

et al. 2021

Chemistry An Asian Journal

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The generation of free radicals is a key process in the formation and the collapse of the bubbles in water, however, the direct and dynamic observation of the radicals in this process at single bubbles has never been achieved. Here, the hydroxyl (OH * ) and oxygen (O 2 *À ) radicals at single oxygen bubbles are continuously traced using chemiluminescence (CL), in which these radicals at the bubble react with the surrounding luminol in the solution emitting the light. Varied increase trends of luminescence are observed in the generation of a bubble, floating, short parking at the water/air interface and the final explosion, revealing the complexity in the distribution of radicals at the bubble unprecedentedly. Despite more radicals are observed at the bubble generated at a deep position under the water for the stabilization, almost the same amount of radicals are included in the bubbles that is independent on the water pressure during the production of the bubble. This rich information collected from the dynamic study of bubbles illustrates the complicated generation and distribution process of radicals at the bubbles, and will facilitate the understanding of the function about the bubbles.

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Enhanced free-radical generation by shrinking microbubbles using a copper catalyst

Cited by 137 publications

References 15 publications

Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry

Microbubble enhanced ozonation process for advanced treatment of wastewater produced in acrylic fiber manufacturing industry

Arsenic removal from waste water by ozone oxidation combined with ferric precipitation

Dynamic Visualization of Free Radicals at Single Oxygen Bubbles using Chemiluminescence

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