Researcher(s)
- Hanna White, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Mark Blenner, Chemical and Biomolecular Engineering, University of Delaware
- Dionisios Vlachos, Chemical and Biomolecular Engineering, University of Delaware
Abstract
Plastic pollution is rapidly accumulating in the world, with polyethylene (PE) being the most abundant type of plastic waste. Traditional plastic disposal methods, such as different kinds of recycling, are inefficient and can produce a lot of heat. Another approach is using chemical oxidation. Oxidation is the essential first step of breaking hydrocarbon backbones found in polyethylene. This oxidation can be achieved through the use of low energy cold plasma. Plasma is ionized gas, such as helium and oxygen, at low temperatures that generate reactive oxygen species (ROS). These reactive oxygen species can oxidize the surface of low-density polyethylene films. This oxidized plastic can then be fed to yellow mealworms. Mealworms can rapidly consume plastic. If the partly-digested plastic is extracted from the frass of these plastic-fed mealworms, gel permeation chromatography can analyze the distribution of molecular weight chains present. When the plastic is plasma treated with both helium and oxygen, there is an increase in the amount of smaller molecular weight chains, proof of PE deconstruction. If the mealworm is removed from the experiment and the focus becomes the gut bacterial community of the mealworm, then the gut bacteria can also be treated with plasma oxidation. When the gut bacteria experiences ROS from the plasma, the bacteria enter a state of oxidative stress. In that stressed state, the gut bacteria produce their own ROS. After testing multiple plasma conditions, one condition yielded the highest cellular ROS production. If that plasma-activated bacteria is inoculated onto oxidized LDPE film, that co-treatment should result in increased PE destruction. This approach of oxidation can provide an alternative green approach to plastic disposal.