Preparation and application of hydrothermal biochar/geopolymer composite material

The invention discloses a hydrothermal biochar/geopolymer composite material preparation method, which comprises: crushing wheat straw, uniformly mixing with fly ash, adding a potassium hydroxide solution, placing into a stirring device, stirring, and curing to obtain a biochar/geopolymer composite material precursor; and performing a hydrothermal carbonization process to obtain the hydrothermal biochar/geopolymer composite material. Wherein the mixing amounts of the straw powder, the potassium hydroxide and the distilled water are respectively 5-35%, 65-85% and 30-90% of the mass of the fly ash, the hydrothermal temperature is 220-260 DEG C, the hydrothermal time is 4 hours, and the hydrothermal medium is a 0-2mol/L potassium hydroxide solution; when the prepared hydrothermal biochar/geopolymer composite material is used for adsorbing and removing lead ions in water and passivating lead in soil in situ, a good effect is shown. The method has the advantages of simple process, low cost, low energy consumption,