Fecha de publicación: 08/01/2021 Fuente: Wipo Tobacco Agriculture The invention relates to a preparation method of Mg/Ca loaded modified tobacco stalk biochar, which comprises the following steps: adding tobacco stalk powder into an MgCl2 solution, adding egg shellpowder, stirring, drying for the first time, pyrolyzing, cleaning, drying for the second time, pulverizing and screening to obtain the Mg/Ca loaded modified tobacco stalk biochar. The Mg/Ca loaded tobacco stalk metal biochar composite material is prepared through MgCl2 pretreatment and egg shell doping, the Mg/Ca biochar composite material has high adsorption capacity on HPO4 under the condition of high pH, the problem that the adsorption capacity of single metal Mg-loaded biochar is reduced under the condition of high pH is successfully solved, and the pH adaptability of the single metalMg-loaded biochar is improved. The test result can provide reference for preparation of a low-cost metal biochar composite material, provide technical guidance for phosphorus removal of an alkaline water body, and also provide a new thought for disposal of wastes with high Ca content and mixed treatment of the wastes.2->