Dongguan Zhuoyuan Desiccant Co., Ltd. focuses on various desiccants, drying rods, deodorants, anti-rust products, anti-mold tablets and other environmentally friendly products
电话TEL:+86 137-1270-0858

12 yearsVarious desiccant products

Meet the EU ROSH standardFactory direct salesQuality Assurance
4Company dynamics

The principle of discoloration of silica gel


The color-changing silica gel is an indicator absorbent with high added value and high technical content. It is made of fine-pored silica gel with high activity adsorption material and belongs to the advanced adsorption desiccant. The main feature of color-changing silica gel is that it has a strong adsorption effect on the water in the medium (such as air or industrial gas).

The color-changing principle of color-changing silica gel is also very simple. The main component of color-changing silica gel is cobalt chloride, which is highly toxic. By absorbing water vapor in the air, the original blue color changes from blue to light red as the absorbed water content increases. It can display different colors by changing the amount of cobalt chloride crystal water, and the color changes with the humidity.

Currently, color-changing silica gel can be divided into three types: blue silica gel desiccant, cobalt-free orange silica gel desiccant and cobalt-free blue silica gel desiccant .

1. The main reason for the discoloration of blue silica gel desiccant is the existence of cobalt chloride, which has the characteristic of water absorption from blue to pink.

2. The discoloration of the cobalt-free orange silica gel desiccant is mainly due to the existence of methyl violet. Methyl violet will change color due to the change of pH. It uses methyl violet to occur in the range of pH 0.13~0.5 The principle of "yellow-green".

3. The main reason for the discoloration of the cobalt-free blue silica gel desiccant is Congo red. Congo red is used as an acid-base indicator. The decolorization range is 3.5~5.2, alkaline is red, and acid is blue and purple. . The color-changing silica gel absorbs water vapor or other organic substances in the medium during use, which reduces the adsorption capacity of the color-changing silica gel. It can be reused after regeneration. In order to increase the drying speed of the silica gel, the quicklime can be divided into upper and lower layers or layers. Placing silica gel between the upper and lower layers of quicklime has the advantages of simple operation, cost saving, and fast effect.

Dongguan Zhuoyuan Desiccant Co., Ltd. © Copyright