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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Effects of triangular multi-orifice plates with venturi tube on degradation ofhydrophilic and hydrop...
Effects of triangular multi-orifice plates with venturi tube on degradation ofhydrophilic and hydrophobic mixing pollutants
Author : ZHIYONG DONG (1) & ZHEN ZHANG (2)
ABSTRACT
Hydrodynamic cavitation is a novel technique that has been found to be substantially application in wastewater
treatment, especially in degradation of refractory pollutants. Cavitation means phenomena of formation, growth and
collapse of cavitatin bubbles. Microjets and shock waves due to collapse of cavitation bubbles can release high intensity
energy, which generate strong oxidation conditions of chemical process such as hydroxyl radical (OH*) and hydrogen
peroxide (H2O2). This paper experimentally studied effects of the hydrodynamic cavitation due to triangular multi-orifice
plates with Venturi tube on degradation of hydrophilic and hydrophobic mixing pollutants. The different combinations of
triangular multi-orifice plates with Venturi tube to generate hydrodynamic cavitation were carried out. A mixture of pnitrophenol
(PNP) and nitrobenzene was prepared for hydrophilic and hydrophobic mixing wastewater in the
hydrodynamic cavitation reactor, and the degradation rates due to the hydrodynamic cavitation were analyzed by an
ultraviolet spectrophotometer. Effects of different flow velocities, cavitation numbers, orifice numbers, orifice sizes, initial
wastewater concentrations and wastewater circulation cycles (treatment time) through the cavitation reactor on
degradation of the hydrophilic and hydrophobic mixture were experimentally investigated. The experimental results
showed that the higher initial flow velocity is, the greater the rate of degradation reaches, and as the reaction
progresses, effect of the initial velocity on the degradation rate is more apparent; with the increase in the circulation
cycle, cavitation number of the mixture increases, reaching a certain cycle, the degradation rate tends to be stable;
degradation rate is affected by the initial concentration, exhibiting a variation in increase first and then decrease, and an
optimal initial concentration corresponding to the maximum degradation rate exists; under the condition of the same
orifice size, the more orifice number is, the greater the degradation rate reaches; and at the same orifice number, the
larger orifice size results in higher turbulence intensity and shear stress, thus causing more intense cavitation and
greater degradation rate.
File Size : 452,868 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 19/08/2015
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