Investigation of the Effectiveness of O2 Plasma Pretreatment for the Decomposition of (Micro)Plastics in Water

Plastic pollution is of global concern, with 57 million tons of waste produced yearly1. Microplastics pose an immediate danger. These particles serve as carriers of contaminants due to their internal composition (dyes, binders, etc.). Due to their small size $(<5 \text{mm})$, microplastics have been found in water and soil, leaving humans, animals–particularly aquatic life, and vegetation to uptake the carried contaminants. It is evident that a solution to this plastics problem, particularly microplastics in water, is required. A proposed solution is the use of non-thermal air plasma for the treatment of microplastics in water. Plasma, in water, acts as an advanced oxidation process, leading to the production of reactive oxygen species (ROS), such as OH radicals and O3. It is known that O2 plasma can decrease the contact angle of plastics, thus indicating an increase in hydrophilicity2. This allows the microplastics to disperse into the liquid phase, increasing contact with the ROS and, therefore, increasing the efficiency of the plasma treatment. To determine and quantify the effectiveness of O2 plasma pretreatment for microplastic degradation, pre-treated and control microplastics will be treated with air plasma and compared. The treated microplastic solutions will undergo GPC and ATR-FTIR analysis, to quantify average molecular weight changes and understand surface modifications to the microplastic surface. The gas and liquid phases will be analyzed using HPLC and GCMS to identify and quantify the formation of carbon products and quantify the effects of pre-treatment. The goal of this work is to quantify the effectiveness of O2 plasma pre-treatment on microplastic degradation.