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What is the discoloration principle of magic silica gel desiccant

The main component of the color changing desiccant is cobalt chloride, which has very strong toxicity, but at the same time, it has a strong adsorption capacity for water vapor in the air. Interestingly, there is blue transparent silica gel before moisture absorption. As the moisture absorption gradually reaches saturation, it will turn into light red. At present, there are three color changing silica gel desiccants: blue silica gel desiccant, cobalt free orange silica gel desiccant and cobalt free blue silica gel desiccant.


Discoloration principle of blue silica gel desiccant: CoCl2 (blue) + 6H2O (light red) = CoCl2 · 6H2O; Anhydrous cobalt dichloride is transparent blue and turns into light red irregular crystal after absorbing water. Under heating, it can be decomposed into cobalt chloride for reuse. As silica gel desiccant for packaging, it is widely used in precision instruments, leather, shoes, clothing, food, medicine and household appliances.


Discoloration principle of cobalt free orange silica gel desiccant: methyl violet changes in color due to the change of pH value (acidity and alkalinity), while cobalt free orange silica gel desiccant uses the principle of changing from orange to dark green in the range of pH 0.13 ~ 0.5, but its function is the same. It has strong moisture absorption energy and is also a recycling environmental protection desiccant material.


Discoloration principle of cobalt free blue silica gel desiccant: Congo red itself is used as acid-base indicator. The discoloration range is 3.5 ~ 5.2. The alkali state is red and the acid state is blue purple. At present, this desiccant is rarely used, and the Yellow turns red.


Quicklime desiccant is mainly used in the market to crosslink polypropylene sodium with stable chemical properties. At 25 ℃ and 80% relative humidity, the adsorbed water vapor capacity can give full play to the product's adsorption performance, which is 10-20 times the water absorption ratio of ordinary silica gel desiccant. Due to non chemical processing composition, it has more advantages in environmental protection and cost than silica gel desiccant, The content of heavy metals is lower than the international environmental protection standard, which is the best choice in line with the market demand.