Preparation method for biomass-based carbon membrane

The invention discloses a preparation method for a biomass-based carbon membrane. The preparation method is characterized in that a modified starch and modified cellulose blended polymer membrane is prepared from starch and cellulose which are adopted as raw materials; and carbon membranes having different mean pore diameters and pore diameter distribution, high mechanical strength, developed pore structure and good separation performance and used for achieving different separation purposes are prepared by changing the substitution degrees, additive amounts and carbonization conditions of modified starch and modified cellulose. The preparation method for the separation carbon membrane, which is low in preparation cost, simple in production process, easy for industrialization and pollution-free, can be used for preparing the carbon membranes with different separation purposes.