Extraction of cellulose nanofibrils from pine sawdust by integrated chemical pretreatment
Xiaran Miao,
Wenqiang Hua,
Yiwen Li,
Fenggang Bian,
Tiqiao Xiao
Affiliations
Xiaran Miao
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
Wenqiang Hua
Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
Yiwen Li
Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
Fenggang Bian
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China; Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China; Corresponding author. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.
Tiqiao Xiao
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China; Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China; Corresponding author. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.
Reducing energy consumption is major challenge in the industrialization of chemical pretreatments for the extraction of cellulose nanofibrils (CNF). In this study, an integrated chemical pretreatment with alkaline/acid-chlorite/TEMPO-oxidant was used for the nano-fibrillation of CNF from pine sawdust (WS). The alkaline and acid-chlorite pretreatments effectively eliminated the non-cellulosic components present in WS, resulting in the delamination of individual cell layers and swelling of the internal structures within the cellulose fiber bundles and cellulose microfibrils that form these layers. The spacing between CNF within the cellulose microfibrils increased from 3.7 nm to 5.5 nm. These loosely packed hierarchical structures facilitated the penetration of the reagent, which led to an increase in the specific surface area during the TEMPO-oxidant reaction and consequently accelerated the reaction rate. The WS was pretreated in a very dilute solution (1 % NaOH and 0.5 % NaClO2) under mild conditions (70 °C for 1 h), which resulted in a significant reduction of the TEMPO reaction time (from 3 h to 30 min) and a lower consumption of the reaction reagent (one fourth of the amount consumed compared to the direct oxidation of WS to achieve the same degree of cellulose nano-fibrillation).
