Preparation method and application of heavy metal passivation material for contaminated soil

The invention belongs to the technical field of soil heavy metal passivation, and discloses a preparation method and application of a contaminated soil heavy metal passivation material. The method comprises the following steps: enabling attapulgite to react with gamma-aminopropyltriethoxysilane, so as to prepare amino modified attapulgite; the amido modified attapulgite and dimethyl maleate are subjected to a reaction, and attapulgite-iminosuccinic acid dimethyl ester is prepared; the preparation method comprises the following steps: carrying out a reaction on attapulgite-dimethyl iminosuccinate and dimethyl maleate, so as to prepare attapulgite-tetramethyl secondary amino disuccinate; after the attapulgite-tetramethyl secondary amino disuccinate reacts with a sodium hydroxide aqueous solution, the pH value is adjusted to be 2-3, and attapulgite-secondary amino disuccinic acid is prepared; the method comprises the following steps: crushing straws and aquatic wastes, and mixing the crushed straws and aquatic w