Author ORCID Identifier

https://orcid.org/0000-0002-0435-2308

Year of Publication

2021

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department/School/Program

Chemical and Materials Engineering

First Advisor

Dr. J. Zach Hilt

Second Advisor

Dr. Thomas D. Dziubla

Abstract

Remediation of environmental pollutants from water is one of the major challenges in the 21st century. Utilizing novel polymeric materials to accomplish this challenge has garnered a lot of interest in recent times. Flexibility in synthesizing as well as functionalizing makes them attractive for their application in pollutant remediation. This work is based on development and characterization of novel crosslinked polymeric as well as linear polymeric materials from biphenyl-based monomers, biphenyl based crosslinker and a temperature responsive monomer (Nisopropylacrylamide (NIPAAm)) for their application in remediation of toxic pollutants such as polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and iron oxide nanoparticle (IONP) waste.

First, we developed novel crosslinked polymers with the help of biphenyl-based monomers and crosslinker that have high affinity towards PCBs due the presence of pi-pi stacking interactions. Novel monomers and crosslinkers were initially synthesized by acrylation of 4,4-dihydroxybiphenyl, 4-phenylphenol, 2-phenylphenol, and the acrylated forms were identified as 44BDA, 4PPMA, 2PPMA respectively. These monomers were characterized by various techniques, including differential scanning calorimetry (DSC) for their melting temperature/freezing temperature, NMR and FTIR to confirm their structure. Subsequently, crosslinked polymer films were synthesized using 4PPMA, and 2PPMA as monomers and crosslinked with different amounts of 44BDA. These films were then characterized by studying their swelling properties in different solvents as well as their mechanical strength through the determination of their compression modulus.

These developed materials were compared with polyethylene (LDPE) to test their efficacy as a passive sampling material in real world sediment. The biphenyl polymers along with LDPE were deployed into sediments with known PCB and PAHs concentration. PCBs/PAHs were allowed to bind on them, these polymers were then retrieved to analyze the amount of PCBs and PAHs bound on them at different time interval to study the binding kinetics and compare the equilibrium binding amounts between LDPE and biphenyl based polymers.

We also developed novel polymers by incorporating the biphenyl moiety monomers (2PPMA,4PPMA) into a PNIPAAm network to develop a physically crosslink network which crosslinks due to the presence of pi-pi stacking interaction. The developed polymer were then tested for their molecular weight, swelling properties and mechanical properties.

Derivatives of these novel physically crosslinked system were used to flocculate IONPs from water. These polymers were first characterized for their lower critical solution temperature, their molecular weight as well as their zeta potential. Iron oxide nanoparticles were flocculated from a suspension by addition of these polymers as well as salt to the solution. The flocculation efficiency was studied by varying the polymer concentration, salt concentration as well as IONP concentration. Overall, functionalized polymers can be widely used for remediating toxic pollutants from the environment.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.132

Funding Information

National Institute of Environmental Health Sciences/National Institutes of Health (NIEHS/NIH) Superfund Research Project grant P42ES007380 (2016-2021)

Available for download on Thursday, May 19, 2022

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