▎ 摘　　要

NOVELTY - Preparing modified biochar comprises (i) mixing and filtering the peanut shell powder and the graphene oxide suspension to obtain the peanut shell powder impregnated with the graphene oxide suspension, where the volume ratio of the peanut shell powder to the graphene oxide suspension is (50-100) g: (0.8-1.2) l, (ii) mixing the peanut shell powder impregnated with the graphene oxide suspension with nano silicon dioxide to obtain a mixture, where the mass ratio of the peanut shell powder impregnated with the graphene oxide suspension to the nano-silicon dioxide is (80-120): (0.25-0.5), (iii) mixing the mixture with water to obtain a mixture, where the mass ratio of the mass of the mixture to water is (0.8-1.2) kg: (12-18)l, and (iv) carbonizing the mixture to obtain a hydrated carbon, and drying the obtained hydrated carbon, where the carbonization temperature is 180-200 degrees C and the carbonization time is 16-20 hours. USE - The method is useful for preparing modified biochar. ADVANTAGE - The biochar has porosity and large specific surface area, good adsorption capacity, and reduces the activity of soil heavy metals in the soil. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (i) modified biochar prepared according to above mentioned method; (ii) biochar-containing composite material, comprising the modified biochar, the polyvinyl alcohol, the chitosan, and the Rhodotorula sphaeroides; and (iii) microbial soil repairing agent, comprising 5-7 pts. wt. composite material, 50-65 pts. wt. Bacillus megatherium microbial inoculum, 20-35 pts. wt. modified oyster shell powder, 30-45 pts. wt. humic acid and 15-25 pts. wt. sodium alginate.