Abstract: Spherical activated carbon has high adsorption efficiency and can be separated from the solution easily，but due to its broadspectrum adsorption，the application has certain limitations.Membrane separation is an excellent selective separa tion method.Combining the high efficiency adsorption of spherical activated carbon with the high efficiency selectivity of membrane separation technology could realize the wider utilization of spherical activated carbon.The surface of spherical ac tivated carbons was coated with polyvinyl butyral（PVB） as film forming substance，and the process of decolorization of poly saccharides was simulated by using dextran and monascus red pigment as the adsorbent of two different relative molecular masses.The effects of PVB with different relative molecular masses and concentrations on the adsorption process of coated spherical activated carbon were investigated.Then，the process was analyzed by adsorption kinetics and equilibrium.In single component adsorption，the maximum amount of dextran adsorbed decreased by up to 67.1%，while the minimum amount of monascus red decreased by only 14.8%.In two component adsorption process，the adsorption selectivity of the two component increased by 114.8%，indicating that the coated activated carbon has achieved great improvement in selective adsorption.

Key words: coated spherical activated carbon；PVB；adsorption；selectivity