Interfacial effect of extremely low frequency electromagnetic fields (EM-ELF) on the vaporization step of carbon dioxide from aqueous solutions of body simulated fluid (SBF).
Spontaneous processes in an aqueous solution of body simulated fluid (SBF) were monitored in closed vessel for a period of 1 month at 310 K, at atm pressure, and initial pH of 7.2, both with and without exposure to a square pulsed extremely low frequency electromagnetic fields (EM-ELF) of 250 microT, repeated at 75 Hz. The most important findings are that the SBF surface tension (gamma), evaluated under the EM-ELF field, is lower than the corresponding value measured without EM-ELF at any time. Furthermore, the pH of the exposed SBF is always more basic than that of the unexposed solution. As a consequence, when the EM-ELF is applied, calcium phosphate salts do not precipitate from the SBF solution for a period as long as 30 days. Behind all these experimental evidences there is only one mechanism: the vaporisation from the SBF-air interface of the CO(2)(aq) dissolved into the aqueous electrolyte solution. Thermodynamic analysis of these results establish that, at any given time, the difference, Delta, between the measured surface tensions with and without EM-ELF applied, gives the work of the electromagnetic forces to change the extent at which the CO(2)(aq) adsorbs at the liquid-air interface. It has been demonstrated that the work supply per second and per unit of area by the electromagnetic forces, 3.73 x 10(-10) mJ/s cm(2), is very near to the experimental slope in the plot Delta vs. t 1.7 x 10(-10) mJ/s cm(2). This leads to the conclusion that the EM-ELF fields have an interfacial effect on the concentration value of the CO(2) (aq) at the SBF-air interface. Because of that, the EM-ELF field is enhancing the CO(2) vaporisation rate; thus any other steps, which are a consequence of this mechanism, are changing. These results allow explanation of previous experiments concerning the precipitation of calcium carbonate from flowing hydrogen carbonate aqueous solution in the temperature range 353-373 K at a pressure of 0.1 MPa under the effect of static magnetic fields.
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Dipartimento di Edilizia, Urbanistica e Ingegneria dei Materiali, Universita degli Studi di Genova, Genova, Italy. dabe@unig.it
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D000327:Adsorption; D001826:Body Fluids / Q000737:chemistry* / Q000528:radiation effects*; D002245:Carbon Dioxide / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D004559:Electric Wiring; D004574:Electromagnetic Fields; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D012996:Solutions; D013499:Surface Properties / Q000528:radiation effects; D013500:Surface Tension / Q000528:radiation effects; D014835:Volatilization / Q000528:radiation effects; D014867:Water / Q000737:chemistry*
D012996:Solutions; D014867:Water; D002245:Carbon Dioxide