96. Solving a chemistry problem

The amount of surfactant dye adsorption from solution can be used to estimate the specific surface area of ​​powders. With the introduction of 1 g of activated carbon in 100 ml of an aqueous solution of methylene blue, the concentration of the dye changes from the initial 1 * 10-4 mol / l to the final, equal to 6 * 10-5 mol / l. When adding 2 g of coal to the same volume of the initial solution, the equilibrium concentration was 4*10-5 mol/L. Assume that adsorption is described by the Langmuir equation, calculate Ssp of coal. The area occupied by the dye molecule on the surface is taken equal to 0.65 nm2.
Answer: 4.69 m2/g