Degradable Plastic Composite Film—A Comparison Between Photocatalytic and Biodegradation

Due to the non-biodegradable and impervious nature, accumulation of plastic wastes in the environment poses an ecological threat. Plastics are generally littered into soil and water bodies. Microorganisms play a crucial role in biodegradation of plastics. They sometimes utilize these plastics as the substrate. It is also known that sunlight degrades plastic to some extent and the degradation is enhanced by adding semiconductors in the polymer matrix to promote solar photocatalysis. In this work, composite film comprising of polyvinyl chloride (PVC), polycaprolactone (PCL, for facilitating biodegradation), and Zinc Oxide (ZnO, a semiconductor photocatalyst active under sunlight) was subjected to photocatalytic and bio-degradation separately. The microbial strain capable of degrading PVC was isolated from soil and was identified as Bacillus altitudinis. Degradation in both cases was monitored by weight loss. Maximum degradation obtained by photodegradation was 17.8% whereas maximum biodegradation was about 10%. Photodegradation was a fast process (2 h) whereas biodegradation was a complex and slow process (25 days). The degradation by photocatalytic process followed pseudo first-order kinetics.