Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1002/ceat.200800634
Title (Primary) On the role of water in dielectric heating with radio-waves
Author Roland, U.; Kopinke, F.-D.
Source Titel Chemical Engineering & Technology
Year 2009
Department TUCHEM
Volume 32
Issue 5
Page From 754
Page To 762
Language englisch
Keywords Dielectric heating; Microwaves; Radio waves; Soil decontamination; Water; Zeolites
Abstract Beside the classical mechanism of orientation polarization which is sufficient to explain dielectric heating of aqueous liquids, a number of additional aspects have to be considered when humid solids are heated by microwaves or radio waves. The large relative dielectric constant of water can lead to shielding and, therefore, attenuation of the electrical field in humid matrices. The shielding effect is influenced by the geometric arrangement of compartments with varying humidity. On the other hand, the large dielectric loss of water results in an effective heating. As shown by modeling of appropriate experiments, the dielectric loss factor is significantly changed for water which is in intimate contact with surfaces. The dielectric loss factor is much larger for water in the surface layers compared with the bulk phase. For some solids dielectric heating is based on a completely different mechanism which is also influenced by water. The dominant mechanism leading to dielectric heating of zeolites is the migration of cations within the zeolite framework. Water has a strong effect on the dielectric loss factor, most likely by hydration or modifying the electrostatic interactions of cations with the lattice.
Persistent UFZ Identifier
Roland, U., Kopinke, F.-D. (2009):
On the role of water in dielectric heating with radio-waves
Chem. Eng. Technol. 32 (5), 754 - 762 10.1002/ceat.200800634