Silica gel can be used as a desiccant and can be reused

Silica gel can be used as a desiccant and can be reused. Silica gel is a porous material having a different particle size which is suitably dehydrated from a silicic acid gel mSiO2·nH2O. It has an open porous structure, a large specific surface area (surface area per unit mass), and can adsorb many substances. It is a good desiccant, adsorbent and catalyst carrier. The adsorption of silica gel is mainly physical adsorption, which can be regenerated and reused. Adding acid to an alkali metal silicate (such as sodium silicate) solution, acidifying it, adding a certain amount of electrolyte to stir, to form a silicic acid gel; or adding acid or a thicker sodium silicate solution Ammonium salts can also form silicic acid gels. The silicic acid gel is allowed to stand for a few hours to be aged, and then the soluble salt is washed away with hot water, dried at 60 to 70 ° C and activated at about 300 ° C to obtain a silica gel. The silicic acid gel is immersed in a cobalt chloride solution, then dried and activated to obtain a color-changing silica gel. When it is used as a desiccant, it is blue before water absorption, and turns red after water absorption. The degree of water absorption can be seen from the change of color, and whether regeneration treatment is required. Silica gel is also widely used in steam recovery, petroleum refining and catalyst preparation. Silicone can also be used as a mobile phone case with extremely high drop resistance