{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/78546"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/78546","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"Opportunities to Improve Air Pollution Control by Exploiting Unique Properties of Porous Polymers","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Ghafari, Mohsen"],"institution":"State University of New York at Buffalo","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Atkinson, John","Civil, Structural and Environmental Engineering"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-10-26T02:55:11Z","date_published":"2018-10-26T02:55:11Z","updated_at":"2026-07-27T19:05:12Z","subjects":["environmental engineering"],"languages":["eng"],"rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10477/78546","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Atkinson, John","Civil, Structural and Environmental Engineering"]},{"key":"dc:creator","label":"Author","values":["Ghafari, Mohsen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-10-26T02:55:11Z","2018","2018-08-01 22:00:37"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Text","Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["environmental engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/10477/78546"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","Adsorption and catalytic reactions have long been used to control air pollution and water contamination. Decades of research in this broad arena motivated the production of a variety of materials. However, preparation of a material that is flexible enough to be tailored with user-defined properties for specific applications has always been a challenge. Activated carbon (AC) and zeolites are the two most commonly applied porous materials for these applications because of their low cost. However, irreversible adsorption of organic compounds, surface reactivity with gas impurities, co-adsorption of moisture, and formation of hydrophilic functional groups during synthesis and use justifies continued research into alternative materials.Porous polymers represent a new class of materials that continue to gain traction in recent years because of their tunable physical and chemical properties that allow them to be tailored for specific applications. While porous polymers have long been used in membrane separations, drug delivery, biomolecule supports, cell scaffolds, chromatography packing materials, and many others, they are considered new in the fields of adsorption and catalysis.In this work, polymers are used as adsorbents and catalysts to address the challenges associated with the use of traditional porous materials (AC and zeolites). First, commercial hydrophobic porous polymers were applied as NO oxidation catalysts to overcome water co-adsorption in fossil fuel combustion flue gas. Volatile organic compound (VOC) adsorption and desorption performance of commercial and lab-modified polymers was then investigated to evaluate their application as adsorbents for air pollution control. Finally, amine functionalized polymers were tested for aqueous phase phenol adsorption to identify adsorption mechanisms associated with individual amine groups while improving overall polymer adsorption capacity.Commercial styrenic polymers with different levels of cross-linking were tested as NO oxidation catalysts, for the first time, under dry and humid conditions. This work specifically shows that polymers outperform AC under humid conditions not only due to their higher hydrophobicity but also due to their higher resistance to oxidation that allows them to resist increases in hydrophilicity during use. Furthermore, improved performance by hyper-cross-linked polymers over low-cross-linked polymers shows that increasing the degree of cross-linking (i.e., providing narrower pores) improves steady-state NO conversion. However, established hyper-cross-linking processes deposit hydrophilic groups and may make the polymers more susceptible to water adsorption and NO2 reduction. This work is the first investigation to suggest and justify a potential solution to the water co-adsorption challenge for low-temperature NO oxidation. In doing so, this contribution to the fields of air pollution control and materials engineering develops updated NO oxidation reaction mechanisms for the polymeric catalysts and identifies the chemical stability of polymer surfaces.To improve adsorption and catalytic performance of hydrophobic polymers, a one-step post-synthesis hyper-cross-linking technique was developed to increase micropore volume of polymers without sacrificing their intrinsic hydrophobicity. Different dichloroalkanes were applied as external cross-linkers using the Friedel-Crafts reaction to bridge phenyl rings in commercial styrenic polymers, bypassing the chloromethylation step that is shown to be the cause of hydrophobicity loss. Additionally, using different length dichloroalkane cross-linkers allows tailoring of pore size distributions, with short cross-linkers generating narrower pores and long cross-linkers generating wider pores. Advantages of this method include an ability to prepare porous polymers with structured pore widths and stable surface chemistry. The process is also expected to be lower cost and faster than established hyper-cross-linking methods. Adsorbent pore size distribution influences VOC adsorption capacity and kinetics, so the impact of the newly developed hyper-cross-linking method on physical adsorption and desorption performance was investigated. Adsorbates with different chemical structures and kinetic diameters were targeted to highlight the effects of changes in the polymers’ physiochemical properties on their adsorption affinity, capacity, and kinetics. Adsorbent regeneration is essential if polymers are to be competitive with established adsorbents, so this investigation also quantifies regeneration efficiency of the novel polymers at low to medium temperatures (< 100 ℃). Results show that using shorter dichloroalkane cross-linkers provides more adsorption capacity but less regeneration efficiency, particularly for large adsorbates. The findings of this work show that an appropriate external cross-linker must be selected for specific adsorbates to balance gains in adsorption capacity and reductions in regeneration efficiency.While different size cross-linkers provide control over polymer pore size distributions, in many cases, this method may not be practical due to cross-linker availability or cost. In this work, therefore, impacts on pore size distribution when using a reactive or non-reactive co-solvent for self-cross-linking 4,4′-bis(chloromethyl)-1,1′-biphenyl were studied. The reactive co-solvent (benzene) controls degree of cross-linking, while the non-reactive co-solvents (hexane and cyclohexane) affect phase separation times. Results showed that pore size distribution can be controlled using these straightforward polymer synthesis techniques, providing an opportunity to prepare tailored polymers for use in diverse separation applications.In the final stage of this research, a commercial styrenic polymer was functionalized with tertiary and quaternary amine groups to improve phenol adsorption affinity by introducing hydrogen bonding and electrostatic forces. The tertiary amine group is more effective at adsorbing phenol in near-neutral pHs while the quaternary amine group increases capacity at pH values above the pKa of phenol (9.9) due to phenol deprotonation. Amination was also applied on hyper-cross-linked polymers to increase adsorption capacity, combining physical and chemical modifications. Phenol desorption in different solvents was tested to study adsorption mechanisms and identify optimum regeneration conditions based on chemical modification. The findings of this work provide valuable information regarding polymer modifications intended to exploit individual adsorption mechanisms such that phenol removal and adsorbent regeneration are optimized."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Opportunities to Improve Air Pollution Control by Exploiting Unique Properties of Porous Polymers"]}]}],"canonical_facts":{"dc:contributor":["Atkinson, John","Civil, Structural and Environmental Engineering"],"dc:creator":["Ghafari, Mohsen"],"dc:date":["2018-10-26T02:55:11Z","2018","2018-08-01 22:00:37"],"dc:description":["Ph.D.","Adsorption and catalytic reactions have long been used to control air pollution and water contamination. Decades of research in this broad arena motivated the production of a variety of materials. However, preparation of a material that is flexible enough to be tailored with user-defined properties for specific applications has always been a challenge. Activated carbon (AC) and zeolites are the two most commonly applied porous materials for these applications because of their low cost. However, irreversible adsorption of organic compounds, surface reactivity with gas impurities, co-adsorption of moisture, and formation of hydrophilic functional groups during synthesis and use justifies continued research into alternative materials.Porous polymers represent a new class of materials that continue to gain traction in recent years because of their tunable physical and chemical properties that allow them to be tailored for specific applications. While porous polymers have long been used in membrane separations, drug delivery, biomolecule supports, cell scaffolds, chromatography packing materials, and many others, they are considered new in the fields of adsorption and catalysis.In this work, polymers are used as adsorbents and catalysts to address the challenges associated with the use of traditional porous materials (AC and zeolites). First, commercial hydrophobic porous polymers were applied as NO oxidation catalysts to overcome water co-adsorption in fossil fuel combustion flue gas. Volatile organic compound (VOC) adsorption and desorption performance of commercial and lab-modified polymers was then investigated to evaluate their application as adsorbents for air pollution control. Finally, amine functionalized polymers were tested for aqueous phase phenol adsorption to identify adsorption mechanisms associated with individual amine groups while improving overall polymer adsorption capacity.Commercial styrenic polymers with different levels of cross-linking were tested as NO oxidation catalysts, for the first time, under dry and humid conditions. This work specifically shows that polymers outperform AC under humid conditions not only due to their higher hydrophobicity but also due to their higher resistance to oxidation that allows them to resist increases in hydrophilicity during use. Furthermore, improved performance by hyper-cross-linked polymers over low-cross-linked polymers shows that increasing the degree of cross-linking (i.e., providing narrower pores) improves steady-state NO conversion. However, established hyper-cross-linking processes deposit hydrophilic groups and may make the polymers more susceptible to water adsorption and NO2 reduction. This work is the first investigation to suggest and justify a potential solution to the water co-adsorption challenge for low-temperature NO oxidation. In doing so, this contribution to the fields of air pollution control and materials engineering develops updated NO oxidation reaction mechanisms for the polymeric catalysts and identifies the chemical stability of polymer surfaces.To improve adsorption and catalytic performance of hydrophobic polymers, a one-step post-synthesis hyper-cross-linking technique was developed to increase micropore volume of polymers without sacrificing their intrinsic hydrophobicity. Different dichloroalkanes were applied as external cross-linkers using the Friedel-Crafts reaction to bridge phenyl rings in commercial styrenic polymers, bypassing the chloromethylation step that is shown to be the cause of hydrophobicity loss. Additionally, using different length dichloroalkane cross-linkers allows tailoring of pore size distributions, with short cross-linkers generating narrower pores and long cross-linkers generating wider pores. Advantages of this method include an ability to prepare porous polymers with structured pore widths and stable surface chemistry. The process is also expected to be lower cost and faster than established hyper-cross-linking methods. Adsorbent pore size distribution influences VOC adsorption capacity and kinetics, so the impact of the newly developed hyper-cross-linking method on physical adsorption and desorption performance was investigated. Adsorbates with different chemical structures and kinetic diameters were targeted to highlight the effects of changes in the polymers’ physiochemical properties on their adsorption affinity, capacity, and kinetics. Adsorbent regeneration is essential if polymers are to be competitive with established adsorbents, so this investigation also quantifies regeneration efficiency of the novel polymers at low to medium temperatures (< 100 ℃). Results show that using shorter dichloroalkane cross-linkers provides more adsorption capacity but less regeneration efficiency, particularly for large adsorbates. The findings of this work show that an appropriate external cross-linker must be selected for specific adsorbates to balance gains in adsorption capacity and reductions in regeneration efficiency.While different size cross-linkers provide control over polymer pore size distributions, in many cases, this method may not be practical due to cross-linker availability or cost. In this work, therefore, impacts on pore size distribution when using a reactive or non-reactive co-solvent for self-cross-linking 4,4′-bis(chloromethyl)-1,1′-biphenyl were studied. The reactive co-solvent (benzene) controls degree of cross-linking, while the non-reactive co-solvents (hexane and cyclohexane) affect phase separation times. Results showed that pore size distribution can be controlled using these straightforward polymer synthesis techniques, providing an opportunity to prepare tailored polymers for use in diverse separation applications.In the final stage of this research, a commercial styrenic polymer was functionalized with tertiary and quaternary amine groups to improve phenol adsorption affinity by introducing hydrogen bonding and electrostatic forces. The tertiary amine group is more effective at adsorbing phenol in near-neutral pHs while the quaternary amine group increases capacity at pH values above the pKa of phenol (9.9) due to phenol deprotonation. Amination was also applied on hyper-cross-linked polymers to increase adsorption capacity, combining physical and chemical modifications. Phenol desorption in different solvents was tested to study adsorption mechanisms and identify optimum regeneration conditions based on chemical modification. The findings of this work provide valuable information regarding polymer modifications intended to exploit individual adsorption mechanisms such that phenol removal and adsorbent regeneration are optimized."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/78546"],"dc:language":["eng"],"dc:publisher":["State University of New York at Buffalo"],"dc:rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"dc:subject":["environmental engineering"],"dc:title":["Opportunities to Improve Air Pollution Control by Exploiting Unique Properties of Porous Polymers"],"dc:type":["Text","Dissertation"]},"updated_at":"2026-07-27T19:05:12Z"}