Kinetic study of hydroxyl radical formation in a continuous hydroxyl generation system

Wang, Xin; Zhang, Long

doi:10.1039/c8ra08511k

Cited by 45 publications

(26 citation statements)

References 21 publications

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“…Unlike free chlorine, hydroxyl radicals are the strongest commonly used electrochemically generated disinfectant but require the most energy to produce due to high oxidation potential ( Figure 2 ). 55 , 65 , 89 , 90 In addition to being one of the strongest oxidants, hydroxyl radicals are also some of the shortest lived oxidants. 33 , 91 The combination of high oxidation potential and low lifetime (<1 μs) makes it difficult to measure the OH • concentration in solution, particularly in the presence of other reactive oxygen species (ROS), and colorimetric assays and indicator compounds are often used to indirectly measure OH • dose.…”

Section: Electrochemical Disinfectionmentioning

confidence: 99%

Electrochemical Disinfection in Water and Wastewater Treatment: Identifying Impacts of Water Quality and Operating Conditions on Performance

Hand

Cusick

2021

Environ. Sci. Technol.

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Electrochemical disinfection—a method in which chemical oxidants are generated in situ via redox reactions on the surface of an electrode—has attracted increased attention in recent years as an alternative to traditional chemical dosing disinfection methods. Because electrochemical disinfection does not entail the transport and storage of hazardous materials and can be scaled across centralized and distributed treatment contexts, it shows promise for use both in resource limited settings and as a supplement for aging centralized systems. In this Critical Review, we explore the significance of treatment context, oxidant selection, and operating practice on electrochemical disinfection system performance. We analyze the impacts of water composition on oxidant demand and required disinfectant dose across drinking water, centralized wastewater, and distributed wastewater treatment contexts for both free chlorine- and hydroxyl-radical-based systems. Drivers of energy consumption during oxidant generation are identified, and the energetic performance of experimentally reported electrochemical disinfection systems are evaluated against optimal modeled performance. We also highlight promising applications and operational strategies for electrochemical disinfection and propose reporting standards for future work.

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Section: Electrochemical Disinfectionmentioning

confidence: 99%

Electrochemical Disinfection in Water and Wastewater Treatment: Identifying Impacts of Water Quality and Operating Conditions on Performance

Hand

Cusick

2021

Environ. Sci. Technol.

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“…The concentration of H 2 O 2 in microdroplets has been detected at 30 μM (Lee et al, 2019). Typically, working concentrations of H 2 O 2 for disinfection range from 188 mM to 8 M (0.4-30%) (Brudzynski et al, 2011;Wang and Zhang, 2018). OHÁ can effectively damage the bacterial cell envelope given its high oxidation potential (2.80 V) (Finnegan et al, 2010) and nonselectivity.…”

Section: Resultsmentioning

confidence: 99%

Spraying Small Water Droplets Acts as a Bacteriocide

et al. 2020

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Disinfectants are important for arresting the spread of pathogens in the environment. Frequently used disinfectants are often incompatible with certain surfaces, expensive and can produce hazardous by-products. We report that micron-sized water droplets can act as an effective disinfectant, which were formed by spraying pure bulk water with coaxial nebulizing airflow. Spraying for 20 min onto Escherichia coli and Salmonella typhimurium on stainless-steel discs caused inactivation of over 98% of the bacteria. Control experiments resulted in less than 10% inactivation (water stream only and gas only) and 55% inactivation with 3% hydrogen peroxide. Experiments have shown that cell death results from cell wall destruction. We suggest that the combined action of reactive oxygen species present in water droplets (but not in bulk water) along with the droplet surface charge is responsible for the observed bactericidal activity.

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“…The energy of such water-hydroxyl clusters ОН*(Н 2 О) n (where n=2-30), and, accordingly, its reactivity is much higher than that of ordinary water clusters that form around its ionic dissociates (Н + , ОН -), for example Н + (H 2 O) n . The redox potential of the OH * hydroxyl radical reaches 2.8 V [5], while that for atomic oxygen is 2.42 V, and ozone is 2.07 V. From this fact it follows that both uncoupled electron of an oxygen atom, and, to a greater extent, an active hydrogen atom or formed during internal dissociation of a hydroxyl radical by an ionic "mechanism" a proton changes the structural and energy parameters of the electron shells of water molecules as a result of contact (penetration). Since the system consisting of excited oxygen and hydrogen atoms is metastable, it can be assumed that the electron of the hydrogen atom periodically transfers to the free orbit of the electron shell of the oxygen atom.…”

Section: Theoretical Substantiation Of the Activation Processes Of Tementioning

confidence: 99%

Clustering of protons as the main factor in increasing the activity of leaching solutions at their electrochemical and photochemical processing

Rasskazova

2020

E3S Web Conf.

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The theoretical substantiation for the proton clustering process during electrochemical and photochemical processing of technological solutions is provided in the paper. This process provides a significant increase in the efficiency of leaching of gold from refractory ores. It was proposed that the chemical processes in aqueous solutions occur not only due to electronic (interelectronic) interactions, but also as a result of proton-electron interactions. The hypothesis is substantiated. Proton-electron interactions play an important role in the destruction and formation of chemical bonds between the solvent and the solute, as well as between dissolved substances. Compounds with a polymer-like structure can be formed during the electrolysis of aqueous solutions of different reagents, containing oxygen dimers (O-O). Hydrated cluster shell of active water molecules is formed around these polymer-like compounds. A metastable region of clustered protons is formed. Water-gas emulsion is formed during electrolysis and irradiatin with UV light. Highly active oxidants such as atomic oxygen, superoxide radical ion, ozone, and hydroxyl radical are synthesized in the gas bubbles. These compounds intensify protonation processes during hydration. The results of experiments on column activation leaching of dispersed gold from large-volume sample of refractory ore from the Pogromnoye deposit prove the validity of the theoretical substantiations.

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Kinetic study of hydroxyl radical formation in a continuous hydroxyl generation system

Abstract: A novel and simple apparatus for the continuous generation of hydroxyl radicals has been constructed for the first time.

Cited by 45 publications

References 21 publications

Electrochemical Disinfection in Water and Wastewater Treatment: Identifying Impacts of Water Quality and Operating Conditions on Performance

Electrochemical Disinfection in Water and Wastewater Treatment: Identifying Impacts of Water Quality and Operating Conditions on Performance

Spraying Small Water Droplets Acts as a Bacteriocide

Clustering of protons as the main factor in increasing the activity of leaching solutions at their electrochemical and photochemical processing

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