Sorption isotherms for L-and D-alanine from aqueous solutions on carbon nanotubes MKN-SWCNT-S1 were constructed. It was found that the sorption of D-alanine on the investigated carbon nanotubes (CNTs) is stronger than the sorption of L-alanine. The difference in sorption can serve as the basis for their separation. The quantum chemical calculation carried out in the frame of density functional theory with dispersion corrections showed a difference in the orientation of the L-and D-alanines relative to CNTs in the adsorption process. This difference leads to a greater number of D amino acid molecules adsorbed on CNT than L-alanine on the same nanotube surface.