General Route to Nanocrystalline Oxides by Hydrodynamic Cavitation

Abstract

We have developed the WPI cavitational materials process for the production of phasepure, nanostructured materials. Hydrodynamic cavitation is generated mechanically using a high-pressure fluid system. The method begins with a precipitant stream that experiences a large pressure drop (21 000 psi ambient) across a patented geometry interaction chamber. Due to the large pressure drop, bubbles are formed and collapse, causing localized heating of the solvent. In addition, the precipitate undergoes a high degree of mechanical shear in the interaction chamber. This paper deals with the application of this novel technique to the synthesis of several nanostructured oxides. The nanophase oxides are characterized using transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Select area diffraction patterns of the dried (110 °C) oxide samples in this study show distinct rings indicating nanosized particles. This is corroborated by peak breadth measurements in the X-ray diffraction patterns of the calcined samples. A comparison is made between cavitation syntheses and classical coprecipitation.

Photocatalysis of methylene blue on titanium dioxide nanoparticles synthesized by modified sol-hydrothermal process of TiCl4

“…Sunstrom et al [16] reported a similar XRD pattern for TiO 2 prepared by the hydrodynamic cavitation method. The particle size calculations were found to be around 5-17 nm.…”

Composite Polylactic-Methacrylic Acid Copolymer Nanoparticles for the Delivery of Methotrexate

“…In hydrodynamic cavitation processing, nanoparticles are generated through the formation and release of gas bubbles within the sol-gel solution that is rapidly pressurized within a supercritical drying chamber and exposed to cavitational disturbances and high temperature heating [52]. The erupted hydrodynamic bubbles are responsible for nucleation, growth, and quenching of the nanoparticles with the particle size controlled by adjusting the pressure and the solution retention time in the cavitation chamber.…”

Degradation of Chlorocarbons Driven by Hydrodynamic Cavitation

“…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.…”

“…The efficacy of hydrodynamic cavitation reactors has been conclusively shown to be better than ultrasonic bath reactors [8,9,29]. However, earlier investigations on the chemical effects of hydrodynamic cavitation were carried out at very high upstream pressure (10-150 MPa) [7,10] or at pilot-plant scale (50-100 L) [29,30]. In this investigation, chloroform and carbon tetrachloride were destructed at quite low upstream pressure (0.1-0.7 MPa) within a labscale circulating reactor (2.4 L).…”