Although biodegradable straws are widely used, they are often unsuitable for disposal in open environments and cannot be recycled in the same manner as conventional plastic straws. Hence, an effective disposal method needs to be developed. Herein, the thermochemical conversion of biodegradable straws made mostly of polylactic acid (PLA) was considered, and the effects of CO₂ on the characteristics of thermochemical products produced from biodegradable straws were explored. The thermochemical conversion of the biodegradable straw in CO₂ atmosphere yielded more non-condensable gases than the thermochemical conversion in N₂ owing to an enhanced thermal cracking of volatiles at 800 °C. At temperatures > 600 °C in CO₂, the reverse water-gas shift reaction considerably increased the CO selectivity. Using CO₂ in the thermochemical conversion decreased yields of char and wax, which was attributed to CO₂ enhancing thermal cracking of volatiles evolved during the thermochemical conversion and C–H and O–H bonds present in the feedstock. The CO₂ thermal agent promoted the cleavage of the polymeric bond of PLA to produce up to 14-fold more lactic acid (the monomer of PLA) than that produced with N₂ agent, while it suppressed radical reactions to produce fewer phenyls and polycyclic aromatic hydrocarbons. Thermochemical treatment in a CO₂ environment has a significant feature of upcycling biodegradable plastic waste, such as biodegradable straws.

尽管可生物降解的吸管被广泛使用，但它们通常不适合在开放环境中处理，并且不能以与传统塑料吸管相同的方式回收。因此，需要开发一种有效的处理方法。在此，考虑了主要由聚乳酸（PLA）制成的可生物降解秸秆的热化学转化，并探讨了CO ₂对可生物降解秸秆生产的热化学产品特性的影响。由于在 800 °C 下挥发物的热裂解增强，在 CO ₂气氛中可生物降解秸秆的热化学转化比在 N _{2中的热化学转化产生更多的不凝性气体。}在温度 > 600 °C 的 CO _2中，反向水煤气变换反应显着提高了CO的选择性。在热化学转化中使用 CO ₂会降低炭和蜡的产率，这归因于 CO ₂增强了热化学转化过程中产生的挥发物的热裂解以及原料中存在的 C-H 和 O-H 键。CO _{2热剂促进 PLA 的聚合键断裂，产生的乳酸（PLA 的单体）比用 N 2}剂产生的乳酸（PLA 的单体）多 14 倍，同时抑制自由基反应产生更少的苯基和多环芳烃碳氢化合物。CO _{2中的热化学处理}环境具有对可生物降解塑料废物进行升级回收的显着特征，例如可生物降解的秸秆。