Researcher(s)
- Evan Phillips, Chemical Engineering, University of Florida
Faculty Mentor(s)
- Dongxia Liu, Chemical & Biomolecular Engineering, University of Delaware
- Song Luo, Chemical & Biomolecular Engineering, University of Delaware
Abstract
Zeolites are silica based porous structures that are hydrothermally stable, biosafe, cheap, and can either be synthesized or found naturally occurring in nature. These reasons have made it very attractive for use in catalysis. Commercially, zeolites are used in the petrochemical industry, mainly in oil refining, as well as in some catalytic converters to treat NOx-containing exhausts from vehicles. As of recently, zeolites have been used experimentally to degrade and recycle plastic waste, converting long polymer chains into more useful hydrocarbons. However, zeolites aren’t always well suited for long polymer chains, and can run into many issues (e.g., low selectivities, and coke formation) during the recycling process. We attempted to address these issues in three ways: 1. Addition of more alumina in the framework; 2. Creating more mesopores in between zeolite nanosheets through our novel vapor phase pillarization (VPP) method; and, 3. Introducing a bifunctionality mechanism. For the purposes of this discussion, we limited our scope to the first two solutions above, and how they apply to two different zeolite structures, MFI and FER.
For the MFI structure, the effect of alumina sites on our VPP method was studied. For the FER structure, the effect of the intercalation temperature (for silica source used to form pillars between zeolite nanosheets) on VPP-based pillarization was researched. We then used our pillared MFI zeolite to conduct a depolymerization reaction of LDPE plastic granules, and saw a 98.6% conversion into low molecular weight hydrocarbons, with an 85% yield of liquid products. The results we obtained give us a greater insight into these processes, and will provide an easily replicable and more efficient method for plastic waste deconstruction.