聚氨酯廢料製備活性碳之酸性固體催化劑應用於甲基藍吸附以及果糖脫水

Abstract

聚氨酯聚合廢料（Polyurethane Poly Waste），一種被高度關注的廢棄物，主要原因為此廢棄物可以藉由熱裂解或其他熱化學回收與處理的方式得到富含碳的固體產物，具有相當大的潛力開發有價值的材料。本研究使用富含碳的固體產物製備活性碳，並利用此活性碳分別應用於吸附廢水中的亞甲基藍，以及催化果糖脫水生成5-羥甲基糠醛（5-hydroxymethylfurfural, 5-HMF）。本研究所使用的活性碳利用兩種製備方式，產出不同特性的活性碳，分別是兩步熱解後活化的PA-800-2 和一步直接活化A-800-2。在吸附亞甲基藍的應用中，A-800-2 的吸附能力與PA-800-2 相比之下，因高比表面積有高吸附量的相互關係，前者有較高的比表面積2860 m²/g 而後者僅1406 m²/g ，吸附量的結果分別對應到437 mg/g 與373 mg/g 的吸附量。在催化反應的應用之中，A-800-2 會先將表面的羥基透過矽烷類化合物修飾，再以烷基磺內酯化合物進一步修飾，讓表面產生磺酸官能基而形成一種酸性的固體磺酸化催化劑，此催化劑進行果糖的脫水反應表現良好的催化活性，果糖在水溶液中脫水後生成5-羥甲基糠醛。綜合前述兩種應用，本研究所製備出的活性碳，發展出合適且永續的方式應用聚氨酯聚合廢料，有效地提升聚氨酯聚合廢料的價值。

Polyurethane (PU) waste, a significant polymer waste of environmental concern, can be valorized through thermochemical recycling processes like pyrolysis. The resulting solid residue, rich in carbon, presents an opportunity for the development of valuable materials. This study investigates the potential of this residue to prepare activated carbon for two applications: adsorption of methylene blue from wastewater and catalysis of fructose dehydration to 5- hydroxymethylfurfural ( 5- HMF) . Activated carbons were prepared using two methods: two- step pyrolysis followed by activation (PA-800-2) and one- step direct activation (A-800-2) . The adsorption capacities of A-800-2 and PA-800-2 for methylene blue were evaluated. A-800-2 exhibited a higher adsorption capacity (437 mg/g) compared to PA-800-2 (373 mg/g), likely due to its larger surface area (2860 m²/g) compared to PA-800-2 (1406 m²/g). Additionally, A-800-2 was further modified to prepare a sulfonated solid acid catalyst by interaction of alkyl sultone and silane onto hydroxyl groups of the material. This catalyst exhibited catalytic activity in the fructose dehydration reaction to 5- hydroxymethylfurfural ( 5-HMF) in aqueous solution. This sustainable approach offers a promising pathway for the valorization of PUPW.