Extraction of cellulose nanofibrils from pine sawdust by integrated chemical pretreatment
Extraction of cellulose nanofibrils from pine sawdust by integrated chemical pretreatment
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DOI：
10.1016/j.heliyon.2024.e25355
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发表时间：
2024-01
期刊：
影响因子：
4
通讯作者：
Xiaran Miao;Wenqiang Hua;Yiwen Li;Fenggang Bian;Tiqiao Xiao
中科院分区：
文献类型：
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作者：
Xiaran Miao;Wenqiang Hua;Yiwen Li;Fenggang Bian;Tiqiao Xiao
降低能耗是提取纤维素纳米纤维(CNF)的化学前处理工业化的主要挑战。本研究采用碱性/酸性-亚氯酸盐/TEMPO-氧化剂组合预处理法对松木木屑中的CNF进行了纳米原纤化处理。碱性和酸性亚氯酸盐处理有效地消除了WS中存在的非纤维素成分，导致单个细胞层的分层，以及形成这些层的纤维素纤维束和纤维素微纤维内的内部结构膨胀。纤维素微纤维内CNF的间距从3.7 nm增加到5.5 nm。这些松散堆积的层次结构促进了试剂的渗透，导致了速度氧化剂反应过程中比表面积的增加，从而加快了反应速度。WS在温和的条件下(70℃，1h)在非常稀薄的溶液中(1%NaOH和0.5%NaClO2)进行预处理，显著缩短了反应速度(从3h缩短到30h)，反应试剂的消耗也更低(与WS直接氧化相比，消耗的量是直接氧化法的四分之一，以实现相同程度的纤维素纳米原纤化)。
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).