Method for preparing efficient adsorbent through in-situ reaction

The invention relates to a method for preparing an efficient adsorbent through in-situ reaction. The method is characterized by firstly chemically absorbing magnesium ions in ducts and surfaces of porous materials, then adjusting the pH value to 8-11, generating magnesium hydroxide in situ and obtaining the efficient adsorbent porous magnesium oxide through calcining, wherein the adopted magnesium salts are at least one of magnesium chloride, magnesium nitrate, magnesium acetate and magnesium sulfate; the solvents of the magnesium salts are at least one of water and ethanol; the concentration of the magnesium salt solution is 5-40wt%; the calcination temperature is 300-600 DEG C; and the calcination time is 10-360min. The method has the advantages of simple needed equipment, short process flow, high preparation efficiency and low preparation cost. The prepared porous magnesium oxide has the advantages of large specific surface area, strong heavy metal ion adsorption capacity and high saturation adsorption, and has good industrial application prospects.