The 6 major modification methods of bentonite, a general lecture, you will understand after reading it!

The modification operation of bentonite is usually used to treat the surface of natural bentonite through three methods such as physical, chemical and mechanical, and change the physical or chemical properties of the bentonite surface according to the required purpose, so as to meet the application of bentonite in different technical fields, and can also improve the function and use value of bentonite itself.

What are the most common bentonite modification methods? Through sorting, Xiaobian found that there are five modification methods: acid modification, roasting and calcination method, sodium method, salt modification method, organic modification method, etc. Let's take a closer look.

1. Sodium modification method

In the practical application of bentonite, it is found that the exchange capacity of Ca2+ in calcium-based soil is much lower than that of Na+, so calcium-based soil is often sodified before being put into market use. Commonly used sodium agents are NaF, Na2CO3, NaCl, NaNO3, NaSO, etc.

2. Roasting activation modification method

The roasting activation modification method is to calcine bentonite at different temperatures for a certain period of time. This calcination causes the bentonite to lose the water on the surface, the bound water in the skeleton structure, and the organic pollutants in the pores, resulting in an increase in air rate and a more loose structure, which ultimately increases the adsorption of bentonite.

3. Organic modification method

The principle of organic modification method makes bentonite organic and obtains organic composite bentonite. This modification method completely changes bentonite from hydrophilic and oleophobicity, which is called lipophilic hydrophobicity. Organic modification is used to enhance the ability of bentonite to remove organic matter by increasing the interlayer distance of bentonite.

4. Inorganic modification method

The principle of the inorganic modification method is similar to the organic modification method, which is mainly through the swelling characteristics of bentonite and the interlayer cation exchangeability of bentonite, which are the two characteristics of natural bentonite. After inorganic modification of natural bentonite, the spacing between layers is significantly increased, which can also improve the adsorption effect.

5. Inorganic/organic composite modification method

The principle of inorganic/organic composite modification method is based on two characteristics of bentonite: 1. the layer gap of bentonite is relatively large, and 2. the cationic exchangeability of bentonite. The method is to use an inorganic polymer to stretch out the interlaminar domain of bentonite to make the spacing larger, and then change the surface properties of bentonite through an activator.

The commonly used preparation method is to treat bentonite with polyhydroxy cations, so that the interlaminar domain of bentonite increases, resulting in charge reversal, and then organic surface activator is added to change its surface properties.