Upcycling polyamide containing post-consumer Tetra Pak carton packaging to valuable chemicals and recyclable polymer
Upcycling polyamide containing post-consumer Tetra Pak carton packaging to valuable chemicals and recyclable polymer
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DOI：
10.1016/j.wasman.2021.06.031
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发表时间：
2021-07-09
期刊：
影响因子：
8.1
通讯作者：
Bai, Xianglan
中科院分区：
文献类型：
--
作者：
Chen, Xiaolin;Luo, Yixin;Bai, Xianglan
每年有数十亿吨消费后的利乐纸盒作为土地和海洋废物被丢弃，造成严重的环境问题和资源损失。纸箱废弃物的回收利用受到其多材料组成和回收产品价值低的阻碍。在这项研究中，一种新的升级循环的纸箱进行了调查。将由纸、聚烯烃和聚酰胺组成的消费后纸箱在含有10-20 mM酸的210-230 ° C四氢呋喃中直接转化，以通过选择性分解纸级分产生高达19.2%的左旋葡萄糖酮和8.6%的糠醛。剩余的固体含有大部分完整的聚乙烯和聚酰胺，但也有一小部分的纸衍生炭分离使用solventdissolution方法。二甲苯可溶部分是类似于原始聚乙烯的回收聚合物，这通过其官能团、热解产物的组成和熔体流变学结果来验证。二甲苯不溶性部分是聚酰胺和纸衍生的炭的混合物。在热解时，产生己内酰胺作为唯一的主要蒸气产物。剩余的热稳定的纸衍生炭可以用作高质量的固体燃料。总的来说，所展示的回收方法可能会最大限度地提高从纸箱废物中回收的产品的价值。
Billion tons of post-consumer Tetra Pak cartons are discarded annually as land and ocean wastes, creating significant environmental problems and resource losses. Recycling of the carton wastes is hindered by its multimaterial compositions and low values of the recycled products. In this study, a novel upcycling of the cartons was investigated. A post-consumer carton consisting of paper, polyolefin, and polyamide was directly converted in 210-230 degrees C tetrahydrofuran containing 10-20 mM acid to produce up to 19.2% of levoglucosenone and 8.6% of furfural by selectively decomposing paper fraction. The remaining solids containing mostly intact polyethylene and polyamide but also a smaller fraction of paper-derived char were separated using a solventdissolution method. The xylene-soluble fraction was a recycled polymer similar to the original polyethylene, which was verified by its functional groups, the composition of the pyrolysis products, and the melt rheology results. The xylene-insoluble fraction was a mixture of polyamide and paper-derived char. Upon pyrolysis, caprolactam was produced as the only major vapor product. The remaining, thermally stable paper-derived char could be used as a high-quality solid fuel. Overall, the demonstrated recycling method could potentially maximize the values of the products recovered from carton wastes.