Experimental investigation on water migration mechanism of macroporous silica gel in the coupling process of moisture adsorption and electro-osmosis regeneration

Electro-osmosis regeneration (EOR) of solid desiccant is a promising alternative method for dehumidification. Macroporous silica gel (MSG) has good performance on both moisture adsorption capacity and EO effect. In this paper an experimental bench is set up to investigate the water migration character and mechanism between the air and MSG in the coupling process of moisture adsorption and EOR. Through several continuous and oft-repeated experiments under different voltages, the experimental results validate that water can be transferred to a higher relative humidity environment through MSG by EO effect. It is found that the saturated water content around the anode decreases about 1.71% and 2.76% after twice EOR processes respectively. This phenomenon means the moisture re-adsorption capacity of MSG around the anode gets weaker after EOR. Based on the experimental results, the water migration mechanism of the coupling process is analyzed. Moreover, EO effect of MSG is studied from a new perspective. The water mass induced by EO has a near linear relationship with the electric charge transport with a certain EO starting value. The coefficient between the migration water mass and quantity of electric charge is about 0.0536 g/C under the experimental condition.