Date of Defense
27-11-2025 7:30 AM
Location
F1-1077
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Chemical Engineering
College
COE
Department
Chemical and Petroleum Engineering
First Advisor
Prof. Mohammednoor Al Tarawneh
Keywords
Halogenated plastic wastes, co-pyrolysis, NBFRs, PVC, PTFE, metal oxides, halogen capture, mechanism, hydro-defluorination, DFT, TG-IR-GCMS.
Abstract
Plastic waste handling is a daunting task due to the presence of halogenated polymers, specifically those cluttered with bromine (Br), chlorine (Cl), and fluorine (F). Halogenated plastics can be mixed with other polymers in the general plastic waste, particularly in the recycling stream. Brominated flame retardants (BFRs) are mainly present in e-waste and from the use of flame retardants in household items, textiles, and furniture. Plastics from discarded electronics often contain significant levels of bromine and chlorine, predominantly from flame retardants and plasticizers. Being the most deployed thermoplastic worldwide, waste polyvinyl chloride (PVC) generation is expected to increase by about 80% over the next couple of decades. Per- and polyfluoroalkyl substances (PFAS), considered as the ‘forever chemicals’, are found mainly in firefighting gear, specifically in firefighting foams, and also in countless consumer goods like non-stick coatings, stain-resistant fabrics, and food packaging.
The conventional treatment of these waste plastics such as open incineration and landfilling leads to toxic pollutants seepage deep into aquifers and the emission of highly toxic and corrosive halogen-bearing gases, such as HBr, HCl, and HF, in addition to other persistent organic pollutants (POPs) such as polyhalogenated dibenzo-p-dioxins and polyhalogenated dibenzofurans, and hence poses a significant threat to both environmental and human health. In adherence to the Stockholm Convention treaty (2004), studies are underway to mitigate the POPs due to their potential health hazards. In the line of inquiry, critical analysis of the obstacles and prospects associated with many degradation techniques on the halogenated polymer has been performed, assessing based on the degradation efficiency, treatment upscaling, pollution control, and feasibility. Though many treatments show promising results, they also entail drawbacks. The thermal treatment exploiting various metal oxides is considered the most executable technique for halogenated polymer valorization coupled with mineralization/metal extraction due to its intuitive operational feasibility and potential scalability. Strategies for combating the soaring halogenated polymeric wastes, studied herein tap into promoting a circular economy approach for their sustainable disposal and recycling.
This dissertation presents a comprehensive investigation and collectively highlights the significance of pyrolysis using readily available metal oxide additives as a viable, scalable, and environmentally sound solution for managing halogenated polymeric waste. The research demonstrates the remarkable capacity of these additives to act as in-situ dehalogenation agents, effectively capturing toxic acidic gases and converting them into benign products and solid metal halides that are retained in the residual char. Outcomes reported in this study are instrumental to designing and operating a thermal recycling facility contaminated with high loads of mixed halogenated waste plastics.
Included in
THERMO-CHEMICAL RECYCLING OF WASTE PLASTICS CONTAINING HALOGENATED POLYMERS (Br−, Cl−, F−) USING POTENTIAL ADDITIVES
F1-1077
Plastic waste handling is a daunting task due to the presence of halogenated polymers, specifically those cluttered with bromine (Br), chlorine (Cl), and fluorine (F). Halogenated plastics can be mixed with other polymers in the general plastic waste, particularly in the recycling stream. Brominated flame retardants (BFRs) are mainly present in e-waste and from the use of flame retardants in household items, textiles, and furniture. Plastics from discarded electronics often contain significant levels of bromine and chlorine, predominantly from flame retardants and plasticizers. Being the most deployed thermoplastic worldwide, waste polyvinyl chloride (PVC) generation is expected to increase by about 80% over the next couple of decades. Per- and polyfluoroalkyl substances (PFAS), considered as the ‘forever chemicals’, are found mainly in firefighting gear, specifically in firefighting foams, and also in countless consumer goods like non-stick coatings, stain-resistant fabrics, and food packaging.
The conventional treatment of these waste plastics such as open incineration and landfilling leads to toxic pollutants seepage deep into aquifers and the emission of highly toxic and corrosive halogen-bearing gases, such as HBr, HCl, and HF, in addition to other persistent organic pollutants (POPs) such as polyhalogenated dibenzo-p-dioxins and polyhalogenated dibenzofurans, and hence poses a significant threat to both environmental and human health. In adherence to the Stockholm Convention treaty (2004), studies are underway to mitigate the POPs due to their potential health hazards. In the line of inquiry, critical analysis of the obstacles and prospects associated with many degradation techniques on the halogenated polymer has been performed, assessing based on the degradation efficiency, treatment upscaling, pollution control, and feasibility. Though many treatments show promising results, they also entail drawbacks. The thermal treatment exploiting various metal oxides is considered the most executable technique for halogenated polymer valorization coupled with mineralization/metal extraction due to its intuitive operational feasibility and potential scalability. Strategies for combating the soaring halogenated polymeric wastes, studied herein tap into promoting a circular economy approach for their sustainable disposal and recycling.
This dissertation presents a comprehensive investigation and collectively highlights the significance of pyrolysis using readily available metal oxide additives as a viable, scalable, and environmentally sound solution for managing halogenated polymeric waste. The research demonstrates the remarkable capacity of these additives to act as in-situ dehalogenation agents, effectively capturing toxic acidic gases and converting them into benign products and solid metal halides that are retained in the residual char. Outcomes reported in this study are instrumental to designing and operating a thermal recycling facility contaminated with high loads of mixed halogenated waste plastics.