Magnetic soil remediation agent for soil heavy metal pollution, preparation method and use thereof

A magnetic soil remediation agent for soil heavy metal pollution, prepared by using a remediation agent framework material and a magnetic core material as raw materials, and a heavy metal collector as a modifier;

• the remediation agent framework material is silicon dioxide activated by a strong alkali;
• the remediation agent framework material is prepared according to the following method:
• SiO2 powder is used as raw material, adding solid NaOH according to a mass ratio of SiO2:NaOH of 1:(0.1-0.15), then roasted, cooled and pulverized;
• and an excess NaOH is washed off so that a pH of the remediation agent framework material is 6.5-8.5;
• the magnetic core material comprises magnetic materials Fe3O4 and γ-Fe2O3, and a mass ratio of Fe3O4 and γ-Fe2O3 is (1.5-2):1;
• the modifier comprises ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid trisodium salt (NTA), (S,S)-ethylenediamine-N,N-disuccinic acid trisodium salt (EDDS), and mercaptoethylamine, and a mass ratio of EDTA:NTA:EDDS:mercaptoethylamine in the modifier is 1:(0.05-0.1):(0.1-0.2) (0.2-0.3);
• a mass ratio of the remediation agent framework material, the magnetic core material, and the modifier is 1:(0.05-0.1):(0.005-0.01), and the remediation agent framework material, the magnetic core material, and the modifier are uniformly mixed in proportion, precipitated, filtered, heated for drying and pulverized to obtain the magnetic soil remediation agent.