Preparation method of magnesium intercalation montmorillonite modified biochar composite material

The invention discloses a preparation method of a magnesium intercalation montmorillonite modified biochar composite material, and relates to a preparation method of a montmorillonite modified biochar composite material. The method aims at solving the technical problem that an existing method for controlling fertilizer nutrient release through biochar is tedious in operation. The preparation method comprises the following steps: mixing the calcium-based montmorillonite and the modifier, adding deionized water, heating, stirring, carrying out suction filtration, and drying to obtain sodium montmorillonite; mixing the sodium montmorillonite with an organic pillared agent, adding deionized water, heating, stirring, washing and drying to obtain modified montmorillonite; the modified montmorillonite and MgCl2. 6H2O are mixed, deionized water is added, and magnesium intercalation montmorillonite is obtained through heating stirring, suction filtration, washing and drying; and mixing the magnesium intercalated montm