Beta@ZIF-67复合材料的制备及对聚乳酸塑料的催化降解性能

Beta@ZIF-67 Composite for Catalytic Degradation of Polylactic Acid Plastics

以聚乳酸(PLA)为代表的可降解塑料被认为是传统石油基塑料的合适替代品.然而,PLA自然降解的时间较长,同时伴随着CO_(2)的排放.因此,升级回收PLA更有利于实现可持续发展.本文通过将沸石咪唑酯骨架(ZIF-67)生长在Beta沸石表面,制备了一种Beta@ZIF-67复合材料.该材料可以实现废弃PLA塑料的高效催化降解,在180℃下反应4 h即可将日常生活中所用PLA塑料完全转化为乳酸甲酯(产率高达76.4%).这种高催化效率得益于复合材料开放的孔道结构和较大的比表面积,以及ZIF-67(Lewis酸/碱)与Beta分子筛(Brønsted酸)所提供活性位点的协同作用.本研究为沸石分子筛复合催化剂的设计合成及用于聚乳酸塑料催化降解提供了新的途径.

Biodegradable plastics,such as polylactic acid(PLA),are preferable to traditional petroleum-based plastics.However,the natural degradation of PLA takes a long time and releases CO_(2).Therefore,upcycling PLA is a better option for achieving sustainable development.In this study,a Beta@ZIF-67 composite was developed for efficient catalytic degradation of waste PLA plastics,which was achieved by growing the zeolitic imidazolate framework-67(ZIF-67)on the surface of Beta zeolite.As a result,the real-life PLA plastics were completely converted to methyl lactate in just 4 h at 180℃with a yield up to 76.4%.The high catalytic efficiency was attributed to the composite's open pore structure,large specific surface area,and the synergistic effect of the active sites provided by ZIF-67(Lewis acid/base)and Beta zeolite(Brønsted acid).Overall,this study provides a new way for designing and synthesizing zeolite-based composite catalysts,which show promising applications in the catalytic degradation of plastics.