Preparation method of complex modified montmorillonite

The invention discloses a preparation method of complex modified montmorillonite. The method adopting sodium montmorillonite as a raw material and a chelating agent diethylenetriamine as a modifier comprises the following steps: adding a diethylenetriamine solution into a sodium montmorillonite suspension, stirring and reacting the diethylenetriamine solution and the sodium montmorillonite suspension under a 20-80 DEG C water bath condition for 2-24 h, carrying out suction filtration, and washing and drying the obtained reaction product to obtain the modified montmorillonite, wherein the moleof the diethylenetriamine is 80-120% of the cation exchange capacity of the sodium montmorillonite. The modified montmorillonite obtained through the method can effectively adsorb Pb (II), Cd (II) andother toxic heavy metal ions in an aqueous solution as an adsorbent, and has a high adsorption efficiency, the adsorption rate can reach 98.4% or more when the initial concentration of Pb ions is less than 100 mg/L, the modif