超高温和高温厌氧条件下聚乳酸塑料的降解

用批次实验研究了聚乳酸塑料在厌氧消化条件下的降解特性。结果表明,提高处理温度和氨氮浓度可以显著促进聚乳酸分解为乳酸。当聚乳酸作为唯一的基质时,其转化为甲烷的速度缓慢,60 d后甲烷转化率为11.7%。将聚乳酸与餐厨垃圾混合消化则可以促进聚乳酸转化,60 d后的转化率为49.8%。如果将聚乳酸在80 ℃条件下预处理,然后再进行厌氧消化,则22 d后的转化率为81.8%。混合消化和超高温预处理都可以改善聚乳酸的可降解性,其中超高温预处理的促进效果尤为明显。

Polylactide biodegradation under thermophilic and hyperthermophilic anaerobic digestion condition

The biodegradation of polylactide (PLA) under anaerobic digestion condition was evaluated by batch experiments. It was found that increasing temperature and ammonia concentration can promote the transformation of PLA to lactic acid. When the PLA was treated under thermophilic (55 ℃) anaerobic digestion, it was difficult for it to be converted to methane gas. After 60 days treatment, the net methane conversion ratio of the PLA was only 11.7%. Co-digestion of the PLA and kitchen garbage (KG) promoted the biodegradation of the PLA, which reached a methane conversion ratio of 49.8% after 60 days treatment. With hyperthermophilic (80 ℃) pretreatment, the biodegradation of PLA was promoted greatly, and the net methane conversion ratio of the PLA was 81.8% after 22 days in the following thermophilic anaerobic digestion.