5:15 PM - 7:15 PM
[HCG19-P01] Erosion Model from PET macro- to microplastics due to River Sediment Transport
Keywords:PET, River sediments, erosion
Who has not seen a careless hand throw a plastic bottle in a channel, a river, which would conveniently flow out of sight? But, have you ever wonder what was happening to that bottle downstream. In the present contribution, I investigated the surface of PET plastics mixed with sediments, in order to quantify and understand the mechanical degradation mechanisms, leading to the generation of microplastics. How much microplastic is being generated, how fast would the plastic desegregate under the sole mechanical action, and are we dealing with one or different processes (in other words, do microplastic erode at the same pace all along)? The methodology is based on the combination of Laboratory experiments on microplastics to create a progressive abrasion over time, combined with SEM (Scanning Electron Microscope) mapping of the surfaces, and a combined physical and statistical model.
Results have shown a progressive slimming and lightening of the 5 mm x 5 mm square PET plastic over time, with a first rapid erosion with decreased rate. Using SEM, the author could define that the first layer was being “peeled off” before an underlying layer, more resistant revealed a slower and different degradation process, with small impact craters growing over time, signaling a different crystalline structure in the PET material.
From this laboratory analysis, a simple model relating the abrasion rate of plastic over time based on its intrinsic molecular structure in relation with the energy of the sediment transport system was generated. The control of the erosion parameter was created using the SEM maps of the surface and the density of “impacts” and peeled-off surfaces. This part was introduced as a statistical sample of the process to describe using a simple Monte Carlo Simulation. Thus, based on the sediment transport energy system and data on PET plastics, it is possible to define amount of microplastics being generated.
Results have shown a progressive slimming and lightening of the 5 mm x 5 mm square PET plastic over time, with a first rapid erosion with decreased rate. Using SEM, the author could define that the first layer was being “peeled off” before an underlying layer, more resistant revealed a slower and different degradation process, with small impact craters growing over time, signaling a different crystalline structure in the PET material.
From this laboratory analysis, a simple model relating the abrasion rate of plastic over time based on its intrinsic molecular structure in relation with the energy of the sediment transport system was generated. The control of the erosion parameter was created using the SEM maps of the surface and the density of “impacts” and peeled-off surfaces. This part was introduced as a statistical sample of the process to describe using a simple Monte Carlo Simulation. Thus, based on the sediment transport energy system and data on PET plastics, it is possible to define amount of microplastics being generated.