The investigation of adsorptive performance on modified multi-walled carbon nanotubes by mechanical ball milling

Different lengths of short multi-walled carbon nanotubes (MWNTs) were prepared by mechanical ball milling over 12 h. TEM observation indicated that the extent of shortening and opening of MWNTs increased on prolonging the milling time. The short nanotubes with length of 100-200 nm were obtained after ball milling for 30 h. The adsorptive performance for aniline in aqueous solution indicated that the adsorptive capacity of short open-ended MWNTs increased obviously from 15 to 36% compared to the unmilled MWNTs. The measurements of pore size distribution proved that the inner pore diameter of 3 nm remains constant and the aggregated pore diameter decreased obviously after ball milling. The increasing and expanding of hystersis loop in N2 adsorption-desorption isotherms confirmed that the capillarity plays an important role in adsorption on the milled short MWNTs.