Hydrodynamic cavitation as a tool to control macro-, micro-, and nano-properties of inorganic materials

Emerson, Sean C.; Krausz, Ivo Michael; Moser, William R.

doi:10.1557/jmr.2001.0481

Cited by 26 publications

(16 citation statements)

References 10 publications

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“…Research in the past two decades has demonstrated immense promise of hydrodynamic cavitation reactors for intensification of various physical and chemical processes such as degradation of dyes, 1 hydrolysis of oils, 2 degradation of recalcitrant pollutants and wastewater treatment, 3,4 nanosynthesis, 5,6 potable water disinfection, 7 and microbial cell disruption. 8,9 The literature on application of hydrodynamic cavitation for process intensification is quite vast and references cited above are only a few representative studies.…”

Section: Introductionmentioning

confidence: 99%

Flow regime maps and optimization thereby of hydrodynamic cavitation reactors

2012

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Hydrodynamic cavitation reactors are known to intensify diverse physical and chemical processes. In this article, flow regime maps have been proposed that give an overview of the operation of hydrodynamic cavitation reactor for different combinations of design and process parameters. These maps are based on simulations of cavitating flow using mathematical model that couples continuum mixture model with diffusion limited model. Specific flow regimes have been identified depending on the energetics of the collapse of cavitation bubble as sonophysical, sonochemical, and stable oscillatory (no physical or chemical effect). The radial motion of the bubble in the cavitating flow is governed by the mean and turbulent pressure gradients, which in turn, are decided by the design parameters. An analysis of variations in the pressure gradients in the cavitating flow with design parameters has been given. The flow regime maps form a useful tool for identification of most optimum set of design parameters for hydrodynamic cavitation reactor for a physical or chemical process. © 2012 American Institute of Chemical Engineers AIChE J, 58: 3858–3866, 2012

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Section: Introductionmentioning

confidence: 99%

Flow regime maps and optimization thereby of hydrodynamic cavitation reactors

2012

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“…Although light emission from hydrodynamic cavitations was observed in the 1960's [4], the chemical effects of hydrodynamic cavitation have only been properly investigated since 1993 [5][6][7][8][9]. Hydrodynamic cavitation has been recently employed in the preparation of nanostructured materials [10,11], the removal of chemicals from wastewater treatment [12][13][14][15][16][17][18][19], water disinfection [20], and the degradation of polymers [21,22].Chlorocarbons consist of chloromethane, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, and 1,1,1-trichloroethane. Carbon tetrachloride and chloroform are among the most widespread contaminants in surface and underground water, and in tap water treated by chlorination.…”

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confidence: 99%

Degradation of Chlorocarbons Driven by Hydrodynamic Cavitation

Ondruschka

Bräutigam

2007

Chem Eng & Technol

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To provide an efficient lab-scale device for the investigation of the degradation of organic pollutants driven by hydrodynamic cavitation, the degradation kinetics of chloroform and carbon tetrachloride and the increase of conductivity in aqueous solutions were measured. These are values which were not previously available. Under hydrodynamic cavitation conditions, the degradation kinetics for chlorocarbons was found to be pseudo first-order. Meanwhile, C-H and C-Cl bonds are broken, and Cl 2 , Cl . , Cl -and other ions released can increase the conductivity and enhance the oxidation of KI in aqueous solutions. The upstream pressures of the orifice plate, the cavitation number, and the solution temperature have substantial effects on the degradation kinetics. A decreased cavitation number can result in more cavitation events and enhances the degradation of chlorocarbons and/or the oxidation of KI. A decrease in temperature is generally favorable to the cavitation chemistry. Organic products from the degradation of carbon tetrachloride and chloroform have demonstrated the formation and recombination of free radicals, e.g., CCl 4 , C 2 Cl 4 , and C 2 Cl 6 are produced from the degradation of CHCl 3 . CHCl 3 and C 2 Cl 6 are produced from the degradation of CCl 4 . Both the chemical mechanism and the reaction kinetics of the degradation of chlorocarbons induced by hydrodynamic cavitation are consistent with those obtained from the acoustic cavitation. Therefore, the technology of hydrodynamic cavitation should be a good candidate for the removal of organic pollutants from water. IntroductionCavitation is the formation, growth, and implosive collapse of gas or vapor-filled bubbles in liquids [1]. Turbulent flow, laser, electrical discharge, boiling, radiolysis, and ultrasonic irradiation can cause cavitational bubbles. The collapse of cavities generates extreme energy for chemical and mechanical effects. It has been experimentally estimated that extreme conditions exist inside the medium for an extremely short time, e.g., temperatures of about 5000°C and pressures of ca. 50-100 MPa exist inside the collapsing cavity [2,3].Hydrodynamic cavitation is produced by pressure variations in a flowing liquid due to the geometry of the system. It can simply be generated by a rotating propeller blade, high-speed homogenizer and jet fluidizer (e.g., the high-velocity passage of the liquid through a constriction such as a throttling valve, orifice plate, and venturi). Although light emission from hydrodynamic cavitations was observed in the 1960's [4], the chemical effects of hydrodynamic cavitation have only been properly investigated since 1993 [5][6][7][8][9]. Hydrodynamic cavitation has been recently employed in the preparation of nanostructured materials [10,11], the removal of chemicals from wastewater treatment [12][13][14][15][16][17][18][19], water disinfection [20], and the degradation of polymers [21,22].Chlorocarbons consist of chloromethane, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetra...

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“…It was known that acoustic cavitation from sonication possibly produces a series of mechanochemical effects, such as high shear forces, micro-jets, shock wave and cavitation bubbles which are capable of inducing dramatic changes in product morphology [19,20]. In the current system under sonication, it was believed that high shear forces and cavitation bubbles created by sonication retarded the magnetic attraction between the prickly spheres and subsequent fusing growth and finally resulted in dispersed prickly spheres [21,22].…”

Section: Resultsmentioning

confidence: 99%