The destruction effect of a pulse discharge in water suspensions

Abstract

A high-energy capacitor bank (2 × 1 µF/20 kV in a Blumlein circuit) was discharged over about 3 µs through a 7 mm electrode gap in water suspensions of different materials-TiO 2 powder, wood materials (sawdust, needles)-and methylhydroxyethylcellulose dissolved in water. The Mach number of the compressional wave produced by the expanding discharge channel achieved a value of about 0.5. The destruction of added materials was tested using various methods: turbidity and covering ability of the TiO 2 -white, acid hydrolysis of beech sawdust, microbiological processes of spruce needles and molecular weight measurements of the cellulose derivative. In the used power conditions the physical destruction of materials dispersed in water (degassing and decomposition of physically bonded particles) is a dominant effect caused mainly by the compressional wave that can affect material in the whole volume. The chemical destruction probably occurs just in the vicinity or inside the plasma channel due to the action of plasma particles or energetic radiation.

Application of electrical treatments in alcoholic solvent for polyphenols extraction from grape seeds

“…However, the application of HVED results in the product fragmentation due to the propagation of shock waves and cavitational bubbles during treatment (Locke, Sato, Sunka, Hoffmann, & Chang, 2005). The product fragmentation with HVED can be controlled by the number of pulses discharges (Boussetta, 2010: 249;Mikula, Panak, & Dvonka, 1997). Fig.…”

Degradation of Organic Contaminants in Water by Pulsed Corona Discharge

“…(9) Mikula investigated the pulsed discharge in suspensions of TiO 2 powder. (10) Prior results (11,12) have shown that the photolysis in pulsed corona discharges plays an important role in degradation of organic contaminants in water. It is well known that photocatalytic oxidation is widely used for eliminating organic pollutants in waters and wastewaters.…”

Application of Pulsed Electric Energy for Lignocellulosic Biorefinery

“…Several studies have demonstrated a potential of PEE pretreatment for assistance of processing of wood and crop based lignocellulosic materials. It has been reported that the HVED-produced compression waves mechanically affects the structure of lignocellulosic particles (Mikula et al 1997). The wood materials (beech sawdust and spruce needles) were mixed with water (25 g/L) and then obtained suspensions were treated by electrical discharges.…”