Degradation of PET Microplastics by Controlled Microbial & Photocatalytic, MoO3, Exposure

Polyethylene Terephthalate (PET) plastic is a material widely used to manufacture common household items like clothing and water bottles. Unfortunately, millions of tons of microplastic PET waste matriculate into our environment annually, resulting from dumped wastewater and litter. Microplastic PET fibers are extremely difficult to hydrolyze and can release chemicals, creating a potential for toxicity in seafood that has unknown consequences on human health. This research is a comparative study of the chemical and biological degradation of PET microplastics by photocatalytic and microbial means. The chemical degradation process was performed with the use of the photocatalyst, MoO3, under visible light irradiation for sixty hours with PET in water. The biodegradation process was initiated by an incubation period of soil media with microplastic discs analyzed for degradation every eight weeks. The photocatalytic degradation of PET was analyzed with atomic force microscopy (AFM) and by measuring the changes in the contact angle of a water droplet on its surface to evaluate its hydrophilic nature. The biodegradation process is ongoing but has not yet shown progress in breaking the fundamental groups of the PET polymer. Our results from the photocatalytic degradation show an increase in the hydrophilic nature of the PET surface and average surface roughness, suggesting that chemical degradation is an effective method for PET microplastic waste removal. Furthermore, there are limitations to photocatalytic degradation of PET in wastewater treatment and more research needs to be done to establish parameters for exposure time when using MoO3 as a photocatalyst in water.