<p>In general, the research focuses on sequestration of naphthenic acids (NAs) from simulated oil sands process water (OSPW) conditions using engineered copolymers known as &beta;-cyclodextrin-based polyurethanes. The thesis research is divided into two main parts; <i>i)</i> synthesis and characterization of &beta;-cyclodextrin-based polyurethanes, and <i>ii)</i> sorption studies of the copolymer materials with NAs from aqueous solutions.</p> <o>In the first part, &beta;-cyclodextrin (&beta;-CD) was crosslinked with five types of linker molecules, respectively, under various synthetic conditions. The various diisocyanates investigated as linkers include the following: 1,6-hexamethylene diisocyanate (HDI), 4,4'-dicyclohexylmethane diisocyanate (CDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate (PDI) and 1,5-naphthalene diisocyanate (NDI). The polyurethanes (PUs) were systematically designed at different mole ratios of monomers by maintaining &beta;-CD and varying the relative mole ratio of diisocyanate monomer from unity to greater values. Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTS), solid state ¹³C CP-MAS NMR, solution state ¹H/¹³C NMR spectroscopy, thermogravimetric analysis (TGA), elemental analysis (CHN), nitrogen porosimetry, and a dye-based (p-nitrophenol; PNP, and phenolphthalein; phth) sorption method were used to characterize the copolymer materials. In general, the &beta;-CD PUs were insoluble in water except for &beta;-CD crosslinked with HDI at the 1:1 mole ratio which was moderately water soluble. All techniques show complementary results about the structural and compositional characterization, particularly for the estimation of the ratios between the co-monomers. The optimal preparation of copolymer materials for sorption-based applications occurs for &beta;-CD/linker monomer mole ratios from 1:1 to 1:3. There is a maximum limit of the crosslinking density which is ~ 1:7 (&beta;-CD:linker) according to the steric effects of the substituents in the annular region of &beta;-CD. Also, the copolymers were generally found to be mesoporous with relatively low surface area (BET; ~10¹ m²/g) and they appear to exhibit swelling in aqueous solution due to hydration as observed from the estimation of the dye-based surface areas using PNP. The surface accessibilities of the &beta;-CD inclusion sites ranged between 1-100%, as evidenced by the decolourization of phenolphthalein (phth) due to the formation of 1:1 &beta;-CD/phth inclusion complexes.</p> <p>In the second part, the inclusion of NAs and its surrogates with three well known types of cyclodextrin (&alpha;-, &beta;-, and &gamma;-CD) was confirmed using negative ion mode electrospray ionization (ESI). The CDs were found to form well-defined 1:1 inclusion complexes. The binding constant (K2) of NAs and its surrogates inclusion with &beta;-CD was determined indirectly using the spectral displacement technique and were found to be 10³-10⁴ M^-1 (surrogates) and ~ 10⁴ M^-1 (NAs), respectively. Furthermore, the binding constants were found to increase with an increase of the lipophilic surface area (LSA) of the surrogates. The sorption results of NAs with three different types of &beta;-CD materials (i.e. &beta;-CD PU, &beta;-CD crosslinked with epichlorohydrin (EP) and a silica-based mesoporous material containing &beta;-CD), showed &beta;-CD PU had a greater affinity. The sorption capacity (~ 0 - 75.5 mg NAs/g copolymer) and binding affinity (~10³ - 10⁴ M^-1) of &beta;-CD PUs varied due to the nature of linker monomer and the mole ratio of the co-monomers. Aromatic-based copolymers showed high sorption binding affinity while aliphatic-based copolymers showed a relatively high sorption capacity at the co-monomer ratio. Finally, Syncrude-Derived NAs showed fluorescent characteristics which contradict the classic definition of NAs. Further studies using UV-Vis and fluorescence emission spectroscopy showed potential development of an analytical method that can be used to quantify NAs in OSPW for <i>in-situ</i> field applications.

<p>In general, the research focuses on sequestration of naphthenic acids (NAs) from simulated oil sands process water (OSPW) conditions using engineered copolymers known as &beta;-cyclodextrin-based polyurethanes. The thesis research is divided into two main parts; <i>i)</i> synthesis and characterization of &beta;-cyclodextrin-based polyurethanes, and <i>ii)</i> sorption studies of the copolymer materials with NAs from aqueous solutions.</p> <o>In the first part, &beta;-cyclodextrin (&beta;-CD) was crosslinked with five types of linker molecules, respectively, under various synthetic conditions. The various diisocyanates investigated as linkers include the following: 1,6-hexamethylene diisocyanate (HDI), 4,4'-dicyclohexylmethane diisocyanate (CDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate (PDI) and 1,5-naphthalene diisocyanate (NDI). The polyurethanes (PUs) were systematically designed at different mole ratios of monomers by maintaining &beta;-CD and varying the relative mole ratio of diisocyanate monomer from unity to greater values. Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTS), solid state ¹³C CP-MAS NMR, solution state ¹H/¹³C NMR spectroscopy, thermogravimetric analysis (TGA), elemental analysis (CHN), nitrogen porosimetry, and a dye-based (p-nitrophenol; PNP, and phenolphthalein; phth) sorption method were used to characterize the copolymer materials. In general, the &beta;-CD PUs were insoluble in water except for &beta;-CD crosslinked with HDI at the 1:1 mole ratio which was moderately water soluble. All techniques show complementary results about the structural and compositional characterization, particularly for the estimation of the ratios between the co-monomers. The optimal preparation of copolymer materials for sorption-based applications occurs for &beta;-CD/linker monomer mole ratios from 1:1 to 1:3. There is a maximum limit of the crosslinking density which is ~ 1:7 (&beta;-CD:linker) according to the steric effects of the substituents in the annular region of &beta;-CD. Also, the copolymers were generally found to be mesoporous with relatively low surface area (BET; ~10¹ m²/g) and they appear to exhibit swelling in aqueous solution due to hydration as observed from the estimation of the dye-based surface areas using PNP. The surface accessibilities of the &beta;-CD inclusion sites ranged between 1-100%, as evidenced by the decolourization of phenolphthalein (phth) due to the formation of 1:1 &beta;-CD/phth inclusion complexes.</p> <p>In the second part, the inclusion of NAs and its surrogates with three well known types of cyclodextrin (&alpha;-, &beta;-, and &gamma;-CD) was confirmed using negative ion mode electrospray ionization (ESI). The CDs were found to form well-defined 1:1 inclusion complexes. The binding constant (K2) of NAs and its surrogates inclusion with &beta;-CD was determined indirectly using the spectral displacement technique and were found to be 10³-10⁴ M^-1 (surrogates) and ~ 10⁴ M^-1 (NAs), respectively. Furthermore, the binding constants were found to increase with an increase of the lipophilic surface area (LSA) of the surrogates. The sorption results of NAs with three different types of &beta;-CD materials (i.e. &beta;-CD PU, &beta;-CD crosslinked with epichlorohydrin (EP) and a silica-based mesoporous material containing &beta;-CD), showed &beta;-CD PU had a greater affinity. The sorption capacity (~ 0 - 75.5 mg NAs/g copolymer) and binding affinity (~10³ - 10⁴ M^-1) of &beta;-CD PUs varied due to the nature of linker monomer and the mole ratio of the co-monomers. Aromatic-based copolymers showed high sorption binding affinity while aliphatic-based copolymers showed a relatively high sorption capacity at the co-monomer ratio. Finally, Syncrude-Derived NAs showed fluorescent characteristics which contradict the classic definition of NAs. Further studies using UV-Vis and fluorescence emission spectroscopy showed potential development of an analytical method that can be used to quantify NAs in OSPW for <i>in-situ</i> field applications.