The invention relates to a preparation method of
biomass cellulose nanofibers with a high length-
diameter ratio, in particular to a preparation method of nano
cellulose fibers, solving the problems that nano
cellulose fibers prepared by using a traditional method for hydrolyzing
biomass cellulose with strong acid have
short length and small length-
diameter ratio, nano cellulose fibers prepared by using a mechanical shearing method are easy to mutually aggregate, and a microbial
fermentation method has high cost. The method comprises the following steps of: (1) purifying
biomass cellulose with a
benzyl alcohol solution; (2); treating with acidified
sodium chlorite; (3) treating lye; (4) treating with the acidified
sodium chlorite again; (5) treating with KOH; (6) treating with
hydrochloric acid; and (7) ultrasonically treating and
drying to obtain biomass cellulose nanofibers with high length-
diameter ratio not less than 1500,
fiber diameter from 50 nm to 300 nm, length not less than 150 um and length-
diameter ratio not less than 1500. The biomass cellulose nanofibers are mutually interwoven into a tightly wound mesh structure. The invention has low cost and is suitable for preparing nano cellulose fibers from wood, bamboo, cotton, linen and
crop straw.