生物降解塑料在厨余垃圾堆肥中厌氧降解性能研究

Study on anaerobic degradation performance of biodegradable plastics in food waste compost

选取4种典型生物降解塑料PLA、PBAT、PBS和淀粉混合物,通过自主搭建厌氧生物降解性能检测平台,进行为期290天的厨余垃圾堆肥中厌氧降解性能评估。进一步通过监测PLA、PBAT薄膜降解过程中形貌尺寸、失重、分子量和结构变化,研究了厌氧降解过程机制。研究表明4种生物降解塑料在厌氧厨余垃圾堆肥中发生不同程度降解,但矿化率变化趋势都是先快后趋于缓慢,其中PLA最快,然后是PBS和淀粉混合物,PBAT最慢,在290天后累积矿化率依次分别达到33.8%,27.3%,20.1%和12.7%。相同的是,无论PLA还是PBAT,都存在微生物酶催化氧化作用,进而促进降解;不同的是,PLA薄膜经历快速本体水解过程,而PBAT薄膜经历表面腐蚀降解过程。本工作为生物降解塑料大面积推广应用的环境安全性评价,以及回收并厌氧堆肥处理可行性提供科学依据。

Four typical biodegradable plastics PLA,PBAT,PBS and starch mixtures were selected to evaluate the anaerobic degradation pe rformance in food waste compost for 290 days on self-built anaerobic biodegradability detection platform.The mechanism of anaerobic degradation process was further studied by monitoring the morphology,size,weight loss,molecular weight and structural changes of PLA and PBAT fi lms during degradation.The results has shown that four types of biodegradable plastics undergo varying degrees of degradation in anaerobic food waste compost,but the tre nd of mineralization rate changes is first fast and then tends to slow down.Among them,PLA is the fastest,followed by PBS and starch mixture,and PBAT is the slowest,with the cumulative mineralization rate reaching the degradation platform after 290 days,which are 33.8%,27.3%,20.1%and 12.7%,res pectively.Similarly,no matter PLA or PBAT,there is microbial enzyme catalytic oxidation,which promotes degradation;the difference is that the PLA film underg oes a rapid bulk hydrolysis process,while the PBAT film undergoes a surface corrosion degradation process.This work provides a sc ientific basis for the environmental safety evaluation of large-scale application of biodegradable plastics and the feasibility of recycling and anaerobic composting.