椰殼纖維（Coconut husk）是一種豐富的木質纖維素（lignocellulosic）農業工業副產物，具有高度的永續生物精煉（biorefinery）應用潛力。本研究建立一套兼具環境友善與高效率之椰殼纖維資源化技術，結合深共熔溶劑（Deep Eutectic Solvent, DES）預處理與微波輔助技術，以提升纖維素回收效率並製備高附加價值奈米纖維素。首先，比較不同以膽鹼氯化物（Choline chloride）為基礎之DES系統於生質分離中的效能，其中以膽鹼氯化物–乳酸（ChCl/LA）系統表現最佳，纖維素回收率達62.4%，木質素去除率達56.2%。
進一步將微波照射整合至最佳化DES預處理程序，可於10分鐘內顯著提升生質分離效率，使纖維素回收率提高至82.4%，半纖維素去除率達64.0%，木質素去除率達70.5%。所得富含纖維素之固體經球磨（Ball milling）製備奈米纖維素，其產率高達82.8%。隨後透過磷酸化（Phosphorylation）與羧基化（Carboxylation）進行表面功能化修飾，成功引入更多活性官能基，並利用傅立葉轉換紅外線光譜（FTIR）、掃描式電子顯微鏡暨能量散射光譜（SEM-EDX）、穿透式電子顯微鏡（TEM）、X光繞射分析（XRD）、動態光散射（DLS）、比表面積分析（BET）及熱重分析（TGA）等技術進行完整之材料特性鑑定。
結果顯示，所製備之奈米纖維素粒徑約為20–50 nm，經表面功能化修飾後具有較佳之膠體穩定性與比表面積。在所有吸附材料中，以磷酸化奈米纖維素對釩離子（Vanadium ions）展現最佳吸附效能；於最佳操作條件下，其去除率高達99.57%，主要歸因於表面磷酸官能基密度增加、活性吸附位點提升及靜電吸引作用增強。
整體而言，本研究所建立之微波輔助DES預處理技術可有效提升纖維素可及性，並大幅縮短處理時間、降低化學藥劑使用量及能源消耗。本研究成功建立一套符合綠色生物精煉理念之永續資源化技術，將椰殼纖維廢棄物轉化為高附加價值功能性奈米纖維素，展現其於廢水處理、資源回收及循環生物經濟等領域之廣泛應用潛力。

Coconut husk is an abundant lignocellulosic agro-industrial residue with significant potential for sustainable biorefinery applications. This study developed an environmentally friendly strategy for the valorization of coconut husk through deep eutectic solvent (DES)-based pretreatment integrated with microwave irradiation for efficient cellulose recovery and nanocellulose production. Initially, different choline chloride-based DES systems were evaluated for biomass fractionation, where the choline chloride–lactic acid (ChCl/LA) system exhibited the highest cellulose recovery (62.4%) and lignin removal (56.2%). Integration of microwave irradiation with the optimized DES significantly enhanced biomass fractionation, increasing cellulose recovery to 82.4%, while achieving 64.0% hemicellulose removal and 70.5% lignin removal within 10 min of treatment. The cellulose-rich fraction was subsequently converted into nanocellulose through ball milling with a high yield of 82.8%. Surface functionalization by phosphorylation and carboxylation successfully introduced additional active functional groups, as confirmed by FTIR, SEM-EDX, TEM, XRD, DLS, BET, and thermal analyses. The synthesized nanocellulose exhibited particle sizes of approximately 20-50 nm and improved colloidal stability after functionalization. Among all adsorbents, phosphorylated nanocellulose demonstrated superior adsorption performance for vanadium ions, achieving a maximum removal efficiency of 99.57% under optimized operating conditions owing to the increased density of phosphate functional groups and enhanced electrostatic interactions. The integrated microwave-DES pretreatment effectively improved cellulose accessibility while minimizing processing time and chemical consumption. Overall, this study demonstrates a sustainable green biorefinery approach for converting coconut husk waste into high-value functional nanocellulose with excellent potential for wastewater treatment, resource recovery, and circular bioeconomy applications.

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