Laboratory investigation of electroosmosis flow efficiency in a residual soil from gneiss

摘要

A laboratory investigation of electroosmotic flow in a residual soil from gneiss has been presented. Results indicate that flow is somewhat erratic since the electrokinetic process changes the surface chemistry of the soil. This assumption was supported by changes in pH of the electrolytes with the progress of testing. Results also indicated that current strength is proportional to the magnitude of the electrical potential gradient (epg). However, both the electroosmotic coefficient of permeability k_e and the the electroosmotic water transport efficiency k_i seems to be independent of epg. When comparisons were made of the magnitude of k_e and the hydraulic coefficient of permeability k_h, it was found that both lies within the same order of magnitude. This indicates that similar flow will take place either induced by an electrical gradient or as induced by a hydraulic gradient of the same magnitude. One might suggests that in this case, economics will prevail. For design purposes, the current cost of energy expenditure in Rio de Janeiro, Brazil, could well be presumed as US$ 0.30 per kW.h/m~3.