Effect of oxalic acid treatment on the oxidation efficiency of maize stover cellulose and controllable preparation of nanocellulose†

Corn stover was used as raw material, and purification, oxalic acid treatment, oxidation treatment, and ultrasonic treatment were performed to realize the preparation of corn stover nanocellulose with low energy consumption. The effects of oxalic acid concentration (1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt%) on the purity, morphology, crystalline structure and oxidation efficiency of corn stover cellulose during oxalic acid treatment were investigated. The controllable preparation of corn stover nanocellulose was achieved by changing the parameter conditions of ultrasonic treatment. The optimal oxalic acid treatment conditions at room temperature were determined as follows: oxalic acid concentration of 3 wt% and treatment time of 24 h. Oxidized corn stover cellulose was ultrasonically pulverized at 480 W. The average particle size of cellulose was 78.5 d nm at 80 min, which reached 9.75 d·nm at 120 min. This study realized the controllable preparation of corn stover nanofibrillar cellulose, thus providing a research basis for further improving the high value-added conversion of corn stover.