Study on anaerobic degradation performance of biodegradable plastics in food waste compost
Four typical biodegradable plastics PLA,PBAT,PBS and starch mixtures were selected to evaluate the anaerobic degradation performance 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 films during degradation.The results has shown that four types of biodegradable plastics undergo varying degrees of degradation in anaerobic food waste compost,but the trend 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%,respectively.Similarly,no matter PLA or PBAT,there is microbial enzyme catalytic oxidation,which promotes degradation;the difference is that the PLA film undergoes a rapid bulk hydrolysis process,while the PBAT film undergoes a surface corrosion degradation process.This work provides a scientific basis for the environmental safety evaluation of large-scale application of biodegradable plastics and the feasibility of recycling and anaerobic composting.