Green and Low-Energy Preparation Method for Cellulose Nanofibers Based on Cold Plasma

Abstract

Disclosed is a green and low-energy preparation method for cellulose nanofibers based on cold plasma. The preparation method comprises the following steps: (1) uniformly mixing cellulose with a FeSO4 solution, so that FeSO4 is immersed into cellulose, and then performing cold plasma treatment under atmospheric-pressure air to obtain oxidized cellulose, the water in the FeSO4 solution being subjected to cold plasma treatment; and (2) washing and suction filtering the oxidized cellulose obtained in step (1), and then carrying out mechanical fibrillation treatment to obtain the cellulose nanofibers (CNF). According to the invention, the cold plasma and the FeSO4 catalyst are compounded to construct a highly oxidizing environment that oxidizes cellulose and obtain CNFs by means of mild mechanical dispersion treatment. The whole process is carried out at normal temperature. The method is simple and mild, and does not require other non-environment-friendly chemicals. Meanwhile, the energy consumption of the nanocrystallization process is significantly reduced, the obtained CNF is uniformly dispersed, and the yield is higher.

1 : A green and low-energy preparation method for cellulose nanofibers (CNFs) based on cold plasma, comprising the following steps:
 (1) uniformly mixing cellulose with a FeSO 4  solution, so that FeSO 4  is immersed into the cellulose, and then performing cold plasma treatment under atmospheric-pressure air to obtain oxidized cellulose; and   (2) washing the oxidized cellulose obtained in step (1), and carrying out suction filtration and mechanical fibrillation treatment to obtain the CNFs.   
     
     
         2 : The method according to  claim 1 , wherein water in the FeSO 4  solution in step (1) is subjected to cold plasma treatment. 
     
     
         3 : The method according to  claim 2 , wherein the preparation of the FeSO 4  solution in step (1) comprises the following steps:
 treating deionized water with the cold plasma under the atmospheric-pressure air, and then dissolving a FeSO 4  catalyst into the deionized water to obtain the FeSO 4  solution.   
     
     
         4 : The preparation method according to  claim 3 , wherein the cold plasma treats the deionized water at an operating voltage of 120-160 kV for 1-5 min. 
     
     
         5 : The preparation method according to  claim 1 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-160 kV for 45-90 min. 
     
     
         6 : The preparation method according to  claim 1 , wherein a mass ratio of FeSO 4  to the cellulose in step (1) is 1-4:100. 
     
     
         7 : The preparation method according to  claim 1 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-140 kV for 60-90 min; and a mass ratio of FeSO 4  to the cellulose is 3-4:100. 
     
     
         8 : The preparation method according to  claim 1 , wherein a concentration of FeSO 4  in the FeSO 4  solution in step (1) is 0.1 wt %-0.4 wt %. 
     
     
         9 : The preparation method according to  claim 1 , wherein a mixing time in step (1) is 10-20 min. 
     
     
         10 : The preparation method according to  claim 1 , wherein in step (2), the oxidized cellulose is treated under an ultrasonic condition of 600 W at a concentration of 0.5 wt %-2 wt % for 90 min to obtain the CNFs. 
     
     
         11 : The preparation method according to  claim 2 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-160 kV for 45-90 min. 
     
     
         12 : The preparation method according to  claim 3 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-160 kV for 45-90 min. 
     
     
         13 : The preparation method according to  claim 4 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-160 kV for 45-90 min. 
     
     
         14 : The preparation method according to  claim 2 , wherein a mass ratio of FeSO 4  to the cellulose in step (1) is 1-4:100. 
     
     
         15 : The preparation method according to  claim 3 , wherein a mass ratio of FeSO 4  to the cellulose in step (1) is 1-4:100. 
     
     
         16 : The preparation method according to  claim 4 , wherein a mass ratio of FeSO 4  to the cellulose in step (1) is 1-4:100. 
     
     
         17 : The preparation method according to  claim 2 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-140 kV for 60-90 min; and a mass ratio of FeSO 4  to the cellulose is 3-4:100. 
     
     
         18 : The preparation method according to  claim 3 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-140 kV for 60-90 min; and a mass ratio of FeSO 4  to the cellulose is 3-4:100. 
     
     
         19 : The preparation method according to  claim 4 , wherein in step (1), the cold plasma treats the cellulose at an operating voltage of 120-140 kV for 60-90 min; and a mass ratio of FeSO 4  to the cellulose is 3-4:100. 
     
     
         20 : The preparation method according to  claim 4 , wherein in step (2), the oxidized cellulose is treated under an ultrasonic condition of 600 W at a concentration of 0.5 wt %-2 wt % for 90 min to obtain the CNFs.