Arsenic-polluted cultivated land stabilizer, preparation method and application thereof

The invention provides an arsenic-polluted cultivated land stabilizer and a preparation method and application thereof.The preparation method comprises the steps that dried red mud powder and biomass are mixed according to the mass ratio of 1: (2-5), and a mixture is obtained; the mixture is placed in a nitrogen atmosphere for thermal decomposition, and modified biochar is prepared; reacting sulfuric acid with the red mud to generate a leaching solution; performing ultrasonic compounding on the modified biochar and the leaching solution at normal temperature, and dehydrating and drying to obtain the arsenic-polluted cultivated land stabilizer. The arsenic-polluted cultivated land stabilizer prepared by the invention comprises red mud and biomass, wherein the mass ratio of the red mud to the biomass is 1: (2-5). The biomass is agricultural waste including one or more of walnut shells, straw, coconut shells and bagasse. After the soil is treated by the stabilizer, the content of available arsenic in the soil is