The invention discloses a method for sustainably preparing nanometer
cellulose in an environment-friendly and economic mode. The preparing method includes the following steps that 1,
cellulose raw materials and
organic acid are hydrolyzed and esterified; 2, the treated
cellulose is prewashed in a centrifugal
sedimentation mode, the
organic acid is separated to be continuously recycled, washed cellulose suspension liquid is dialyzed, and then reacted acid and accessory substances are removed; 3, the dialyzed suspension liquid is separated to obtain small-particle cellulose nanometer crystals; 4, cellulose
solid precipitated on a lower layer of the suspension liquid is treated through a high-pressure
homogenizer or an ultrasonication physical
machine to obtain colloidal cellulose nanometer fibrils. According to the method, in the preparing process, the
modified cellulose raw materials are synchronously hydrolyzed and esterified through relative-safety and environment-friendly food-grade
organic acid; compared with inorganic strong acid, the used organic acid is low in
corrosion performance, high in
boiling point, small in reaction pressure and easy to control and operate, and the cellulose nanometer crystals with the stable quality and the cellulose nanometer
fibril products with the stable quality can be obtained at the same time.