There is growing interest in the use of high performance anaerobic digestion (AD) processes for the production of biogas at wastewater treatment facilities to offset the energy demands associated with wastewater treatment. Recuperative thickening (RT) is a promising technique which involves recycling a portion of the digested solids back to the incoming feed. In general there exists a significant number of knowledge gaps in the field of RT because the studies that have been conducted to date have almost exclusively occurred in pilot or full scale trials; this approach greatly limits the amount of process optimization that can be done in a given trial. In this work, a detailed and comprehensive study of RT processes was conducted at the lab scale; a demonstration of the optimization of polymer assisted dewatering is given and biogas production and quality monitored. Two custom designed digesters (capacity = 1.5 L) were operated in parallel with one acting as a ‘control’ digester and the other operating under a semi-batch RT mode; both digesters were also operated in parallel under RT with alternative polymer flocculants. There were no significant changes in the overall biogas methane composition; however the RT digester had an average biogas productivity over two times higher than the control one. It was found that the recycling of the polymer flocculant back into the RT digester resulted in a significant improvement in dewatering performance. At the highest polymer concentration tested, all polymer flocculants demonstrated equivalent dewatering performance achieving over 6 times lower CST’s than the control; at lower polymer concentrations the 4516 polymer flocculant had superior dewatering performance. Thus, there exists an opportunity to decrease the overall consumption of polymer flocculants through judicious selection of the flocculant and the dose that is used both for the thickening and end-stage dewatering processes in RT digesters.

Thesis

Master of Applied Science (MASc)

In wastewater treatment (WWT), solid wastes are treated using a technique called anaerobic digestion (AD) which involves the conversion of solids in biogas by anaerobic bacteria. Biogas is a mixture of mostly methane and carbon dioxide and can be used as a fuel source for energy production. There’s growing interest in the use of high performance AD processes for the production of biogas at WWT facilities to offset the energy demands associated with WWT. Recuperative thickening (RT) is a promising technique which involves recycling a portion of the digested solids back to the digester. In this work, a detailed and comprehensive study of RT processes was conducted at the lab scale; a demonstration of the optimization of polymer assisted dewatering is given and biogas production and quality monitored. Two 1.5 L custom designed digesters were operated in parallel one as a ‘control’ and the other operating under a semi-batch RT.

The oil sands industry is currently facing a challenge by regulators to develop dewatering technologies that can halt any further growth in the massive size of existing tailings ponds and also reclaim the contents of those ponds. The most recent technology involves in-tank and/or in-line addition of flocculants followed by a dewatering step (e.g. centrifugation, thin-lift dewatering). This work has focused on three different dewatering technologies. Firstly, a high-throughput method was developed to investigate the effects of ionic composition adjustment on MFTs dewatering through a centrifugation process. As a result, it was found that samples with different concentrations and valency of cations had different settling kinetic and higher concentrations and valency of cations caused faster settling. Also, changes in the ionic composition of samples suggest that there is a strong interaction (ion exchanging) between MFTs and added solution. Secondly, the effects of different factors (e.g. freezing time and temperature) on freeze-thaw dewatering of MFTs were studied using a temperature monitoring setup. It was found that partial freezing causes less dewatering compared to complete freezing after thawing. Finally, a lab-scale unit of low-speed rotary filtration was built and it was implemented to dewater polymer amended MFTs. By using this unit, effects of different factors were investigated on the dewatering efficiency of the rotary filtration unit through a DOE study. The DOE results showed that the flocculation conditions have a big impact on performance of the rotary filtration and for some of the DOE conditions, cakes were formed with more than 47 wt% which couldn’t be reached by just gravity settling of polymer amended MFTs. Also, freeze-thaw of the cakes after rotary filtration could increase the solids content.

Thesis

Master of Applied Science (MASc)

The oil sands industry has been challenged by regulators to develop dewatering technologies that can stop any further growth in the massive size of existing tailings ponds and also reclaim the contents of those ponds. The current dewatering technologies have different challenges that were tried to address in this study. At the first part of the research, it was tried to develop a method for rapid investigation of the effects of salt addition followed by a mechanical method (centrifugation) on dewaterability of MFTs. In the second part it was tried to investigate freeze-thaw as a natural dewatering technique and also to investigate the possibility of mechanizing this process. In the last part, an alternative dewatering technology (rotary filtration), that is predicted to be cheaper than centrifugation, was used to dewater MFTs (amended by polymer). Therefore, a lab-scale version was made and used for polymer amended MFTs dewatering. By using this technology the solids content of MFT had around 20 wt% increase (compare to the untreated MFTs).

RNA aptamers that bind to a wide range of targets with high affinity and specificity have been identified via the in vitro systematic evolution of ligands by exponential enrichment (SELEX). However, the process is quite unpredictable due in part to binding that occurs not only on the targets themselves but also on any of the other functional groups, moieties, or surfaces. Recent modelling work has shown that this level of “background binding” is a key parameter in the performance of aptamer selection processes. One strategy to minimize the amount of background binding is to pre-block those possible binding sites with a non-amplifiable nucleic acid molecule, such as yeast tRNA. It is also known that binding buffer conditions have strong effect on the binding affinity of nucleic acids. However, there are no detailed studies and little quantitative information available to guide the design of aptamer selection processes. In this study, the binding ability of yeast tRNA, which has comparable size with most RNA aptamer libraries, on both silicon dioxide and poly (ethylene terephthalate glycol) (PET-G) surfaces was studied using Quartz Crystal Microbalance with Dissipation (QCM-D). Silicon dioxide surface is a commonly used substrate for QCM-D tests on the adsorption behaviour of different nucleic acid. PET-G is a commonly used polymer substrate for the fabrication of microfluidic devices, which are advanced techniques for aptamer selection. The presence of specific divalent cations, for example Mg2+ over Ca2+, in binding buffers greatly enhanced the binding of yeast tRNA on silicon dioxide surfaces and PET-G surfaces. Proper NaCl concentration (100 mM) and MgCl2 concentration (5 mM) is necessary to enhance yeast tRNA binding on both surfaces. Yeast tRNA binding ability on silicon dioxide surfaces show more dependence on binding buffer pH than on PET-G surfaces.

Thesis

Master of Applied Science (MASc)

Micro-scale processing (MSP) techniques are miniaturized version of upstream and downstream conventional unit operations that are designed to accelerate the pace of bioprocess design and development. Previous ‘dead end’ filtration studies have demonstrated the usefulness of this concept for membrane filtration processes. However, these experiments were performed without stirring which is the most common strategy to control the effects of concentration polarization and fouling on filtration performance. In this work, the pressure-driven stirred conditions of a conventional stirred-cell module were integrated with a 96-well filter plate to develop a high throughput technique called ‘stirred-well filtration’ (SWF). The design allowed for up to eight constant flux filtration experiments to be conducted at once using a multi-rack programmable syringe pump and a magnetic lateral tumble stirrer. An array of pressure transducers was used to monitor the transmembrane pressure (TMP) in each well. The protein sieving behavior and fouling propensity of Omega™ ultrafiltration membranes were assessed via a combination of hydraulic permeability measurements and protein sieving tests in constant filtrate flux mode. The TMP profile during filtration of bovine serum albumin (BSA) solution was strongly dependent on the stirring conditions – for example the maximum TMP in the stirred wells were an average of 7.5, 3.8, and 2.6 times lower than those in the unstirred wells at filtrate fluxes of 12, 36, and 60 LMH (5, 15, and 25 μL/min) respectively. The consistency of the data across different wells for the same stirring condition was very good. To demonstrate the effectiveness of the SWF technique, the eight tests for a simple 2² factorial design-of-experiments (DOE) test with duplicates was run to evaluate the effect of solution pH and salt concentration on protein filtration. The combination of SWF with statistical methods such as DOE is shown to be an effective strategy for high-throughput optimization of membrane filtration processes.

Dissertation

Master of Applied Science (MASc)

Membrane filtration processes are widely utilized across different industrial sectors for biological and environmental separations. Examples of the former are sterile filtration and protein fractionation via microfiltration (MF) and ultrafiltration (UF) while drinking water treatment, tertiary treatment of wastewater, water reuse and desalination via MF, UF, nanofiltration (NF) and reverse-osmosis (RO) are examples of the latter. A common misconception is that the performance of membrane separation is solely dependent on the membrane pore size, whereas a multitude of parameters including solution conditions, solute concentration, presence of specific ions, hydrodynamic conditions, membrane structure and surface properties can significantly influence the separation performance and the membrane’s fouling propensity. The conventional approach for studying filtration performance is to use a single lab- or pilot-scale module and perform numerous experiments in a sequential manner which is both time-consuming and requires large amounts of material. Alternatively, high-throughput (HT) techniques, defined as the miniaturized version of conventional unit operations which allow for multiple experiments to be run in parallel and require a small amount of sample, can be employed. There is a growing interest in the use of HT techniques to speed up the testing and optimization of membrane-based separations. In this work, different HT screening approaches are developed and utilized for the evaluation and optimization of filtration performance using flat-sheet and hollow-fiber (HF) membranes used in biological and environmental separations. The effects of various process factors were evaluated on the separation of different biomolecules by combining a HT filtration method using flat-sheet UF membranes and design-of-experiments methods. Additionally, a novel HT platform was introduced for multi-modal (constant transmembrane pressure vs. constant flux) testing of flat-sheet membranes used in bio-separations. Furthermore, the first-ever HT modules for parallel testing of HF membranes were developed for rapid fouling tests as well as extended filtration evaluation experiments. The usefulness of the modules was demonstrated by evaluating the filtration performance of different foulants under various operating conditions as well as running surface modification experiments. The techniques described herein can be employed for rapid determination of the optimal combination of conditions that result in the best filtration performance for different membrane separation applications and thus eliminate the need to perform numerous conventional lab-scale tests. Overall, more than 250 filtration tests and 350 hydraulic permeability measurements were performed and analyzed using the HT platforms developed in this thesis.

Thesis

Doctor of Philosophy (PhD)

Membrane filtration is widely used as a key separation process in different industries. For example, microfiltration (MF) and ultrafiltration (UF) are used for sterilization and…

The treatment of municipal, industrial and agricultural wastewater produces a semi-liquid mixture known as sludge. The costs associated with pumping, transporting, treating, storing, and disposing of sludge are significant. Therefore, sludge dewatering techniques are employed to increase the solids content of the material by separating the solid and liquid components, thus reducing the overall volume requiring further handling. Non-mechanical dewatering methods require large areas of land and favorable climatic conditions, while mechanical dewatering technologies require significant capital investment and ongoing operation and maintenance by highly trained personnel. Due to these shortcomings, the conventional methods of sludge dewatering are not applicable to scenarios where: the quantity of sludge is small, there is limited budget, there are land restrictions, or dewatering is performed seasonally. An alternative approach that has recently attracted considerable attention is the use of dewatering fabrics; specially engineered textiles supplied in the form of very large bags into which the sludge is pumped. The concept itself is simple, pressure inside the bag pushes the free water through the fabric while the solid material is retained within. Unfortunately, these products have exhibited poor dewatering performance for certain feed materials. In this work, a series of ‘next-generation’ engineered dewatering fabrics featuring elongated ‘slit’ pores were produced using laser cutting techniques. A comprehensive analysis of the effect of the filter properties on dewatering performance was performed using sludge sourced from two different operations: municipal wastewater treatment and precious metal mining.

Thesis

Master of Applied Science (MASc)

In recent years, the use of engineered dewatering fabrics has emerged as a viable alternative to conventional methods of sludge dewatering in numerous application areas including municipal wastewater, mining, and pulp and paper. Previous studies have focused on the development of empirical ratios between dewatering performance and the porous properties of the textile material. The limitation of this approach is that the latter is difficult to characterize using currently available techniques due to the complex, nonuniform pore structure of conventional woven and nonwoven dewatering fabrics. In this study, a series of dewatering fabrics were produced using advanced microfabrication techniques featuring well-defined slit-pore geometries. Full-factorial design-of-experiment frameworks were employed to evaluate the effects of slit-pore dimensions and slit-pore spacing on cake layer development and key dewatering performance metrics. Laboratory scale dewatering performance tests were performed using both anaerobic digested sludge from the Woodward Avenue Wastewater Treatment Plant in Hamilton, Ontario and metal precipitate sludge from a nickel-copper mine in Ontario, Canada. The results from this study provide new insights into the importance of the cake layer in geotextile…

Aevitas is an industrial wastewater treatment plant that receives about 300 m3/day of mixture of wastewater from different industries. The chemical oxygen demand of higher 600 ppm and the variety of the chemical constitution of industrial wastewater are two significant problems on Aevitas. Therefore, there is a strong need for developing advanced analytical techniques that can identify the specific compounds that are the source of COD. During 10 months, about 75 industrial samples were characterized using a battery of tests including GC/MS, COD, TOC, and pH to identify the chemicals that are main source of COD in the industrial wastewaters. Results showed that the COD of 87% of 75 provided samples from Aevitas plant was higher than 600. At the first step of process design, activated carbon was used to eliminate the identified organic chemicals from the wastewaters. The maximum and minimum of COD removal (depends on the chemical composition) of the wastewaters were obtained as 94 and 24%, respectively. Moreover, the amount of COD and TOC that can be adsorbed on the surface of 1 gram of the activated carbon were 25 and 7 mg, respectively. Although activated carbon is capable to reduce the COD, its capacity of adsorption is limited. To overcome this problem an alternative process, membrane filtration was applied for COD removal. Two types of crossflow NF (NF270, NF90, NFX, NFW, NFS, TS80, XN45, and SXN2_L) and RO (BW60 and TW30) membranes in two modules of the spiral wound and flat sheet were used. The filtration results of 11 different industrial wastewaters showed that NF90, TS80, NFX, and NFS were effective in COD removal. However, in terms of output flux NFX and NFS flat sheet were better than others were. Similar to the activated carbon process, the COD removal in filtration process was between 30 and 90%. The obtained results can be used to scale up the membrane filtration process at Aevitas.

Thesis

Master of Chemical Engineering (MChE)

Aevitas is an industrial wastewater treatment plant, which is situated at the City of Brantford. Every day, this plant receives about 15 trucks of the mixture of wastewaters from many different industries. The input wastewater into the plant should be treated and meet the environmental standard so that it can be discharged into a municipal wastewater plant. Currently, the maximum allowable chemical oxygen demand (COD) for discharging the treated wastewater from Aevitas to the municipal wastewater treatment plant is 600 ppm. Despite the fact, the current system in Aevitas is not efficient to meet this criterion. Thus, we strive to design efficient processes to overcome the problem. To this end, 75 samples were collected from Aevitas to observe the kind of chemicals that are the source of COD and then, two processes including activated carbon adsorption and membrane filtration were used for further reduction of COD. Although activated carbon can reduce the COD, the limited adsorption capacity was a major concern for its long-term application, especially if…

Despite the long history of topical eye drops and their use in delivering therapeutic agents to the anterior of the eye, efficient sustained delivery continues to be an elusive goal. The robust and effective clearance mechanisms that the eye is endowed with are significant delivery challenges and result in short drug residence times and low ocular bioavailability. The work carried out in this thesis focused on developing, synthesizing and characterizing silicone hydrogels and evaluating their potential as drug eluting inserts for more effective delivery of ocular pharmaceuticals. The first strategy (Chapter 2) focused on incorporating a novel hydrogel additive, hyaluronic acid, to promote hydrogel-drug ionic interactions that can function to increase drug loading and subsequent release dosage. Hydrogels composed of a hydrophilic monomer, N,N-dimethlacrylamide (DMA) or 2-hydroxyethyl methacrylate (HEMA), and a hydrophobic monomer, methacryloxypropyltris(trimethylsiloxy)silane (TRIS), were used as model contact lenses. By combining ionic interactions with molecular imprinting techniques within a single hydrogel, it was shown that this can produce a compound effect on drug uptake and release. Although greater control over release dosage was achieved, there was limited capacity for these materials to delivery timolol for extended periods with drug release occurring rapidly over a period of 1-2 days. However, there were clear differences in the release duration from the p(DMA-co-TRIS) and p(HEMA-co-TRIS) hydrogel formulations. Therefore, the second study (Chapter 3) aimed to better understand the relationship between the hydrogel chemical composition and the resultant material properties on the drug release characteristics. A range of hydrogels were synthesized with varying hydrophilic and hydrophobic monomers, which were then characterized by their water content, transparency, optical haze and surface wettability. The previous generation materials were evolved by incorporating a modified siloxy methacrylate TRIS(OH), a methacrylated polydimethylsiloxane macromonomer (mPDMS) and a polymerizable silicone surfactant (ACR). The properties of the hydrogels were dramatically affected by the nature and relative contribution of hydrophobic and hydrophilic monomers. The release of dexamethasone (DEX), an anti-inflammatory medication, was shown to vary significantly depending on the hydrogel formulations; often displaying faster release in high water content materials and slow release in low water content hydrogels. The mechanism of diffusion for lipophilic DEX in these hydrogel systems appeared to be through the internal aqueous network channels within the bulk. Over the range of hydrogels formulations that were tested, the release from them varied from approximately seven days to greater than two weeks.

Master of Applied Science (MASc)

Industrial wastewater treatment using conventional treatment technologies is becoming challenging day-by-day due to presence of ‘newer’ refractory compounds, lower treatment efficiencies and stricter environmental laws. Combination of conventional treatment techniques with modern treatment technologies like membrane filtration or advanced oxidation processes (AOPs) has shown promise in achieving high efficiencies. In this work we have worked towards development of a membrane nanofiltration unit to treat coagulation-flocculation pretreated IWW from a specialized treatment facility. More specifically, state-of-the-art TiO2 ceramic NF membranes with low molecular weight cut off (MWCO) (200, 450, 750, 8500 Da) purchased from Inopor Gmbh were tested on 6 different IWW samples due to their superior chemical stability, higher flux and high fouling resistance along with 3 commercial polymer NF membranes (NF90, NFX, NFS) for comparison purposes. Additionally, wastewater characterization dataset including composition analysis using Gas-chromatography Mass-spectroscopy (GC-MS) is leveraged to build data driven models for membrane performance prediction. ‘200 Da’ ceramic NF membrane was able to reject significant COD with an average rejection of 77% and 60% for two IWW samples with permeate flux between 5-15 LMH at 100-120 psi trans-membrane pressure (TMP). ‘200-Da’ membrane was also found to achieve more flux than ‘450 Da’ membrane while rejecting more COD at the same time. ‘200 Da’ membrane also showed lower flux decline than polymer membranes. Additionally, the ceramic NF membranes were found to be easily chemically cleanable restoring wastewater flux after fouling. Since polymer NF membranes were found to reject at higher COD rejection efficiencies (60-90%) and permeate flux, further improvement in ceramic membranes is needed to treat at higher efficiencies. 200 Da, NF90 and NFX membranes were found to be promising to reduce COD below target (600 mg/L) and should be studied further for this application.

Thesis

Master of Applied Science (MASc)

Conventional technologies for Industrial wastewater (IWW) treatment include biological treatment, coagulation, flocculation, adsorption and filtration. Many industries produce IWW with high concentration of biologically toxic organics ruling out the option of biological treatment. Moreover, with stricter regulatory laws in place for effluent discharge, adoption of new treatment technologies is needed. Nanofiltration (NF) is one such treatment technology that has seen a lot of growth in the past decade since its advent in 1980s. Polymer nanofiltration has been successfully used in applications such as dye removal in textile industry, as a pre-treatment method in desalination plants, for organic solvent nanofiltration in pharmaceutical industry and many more. More recent development of ceramic nanofiltration membranes has seen a lot of interest from researchers around the world due to their superior physical and chemical robustness, fouling resistant properties and higher…

The main purpose of specialized industrial wastewater treatment facilities is to treat incoming wastewater loads from various industries which do not have the capability of treating their wastewater on site. Accordingly, specialized industrial wastewater treatment facilities face a challenge in quickly identifying optimal treatment options for the varying incoming wastewater loads they receive. With the new discharge limits set by the federal Wastewater System Effluent Regulations (WSER) and a compliance deadline by 2020, it became crucial for such facilities to optimize their processes and ensure having a method to determine optimal treatment options and conditions to meet the new discharge limits. One such limit is the Chemical Oxygen Demand (COD), which is representative of the amount of organic matter present in a solution. Polymer flocculation is a common mechanism used for solid-­liquid separation in industrial wastewater treatment. While many previous research studies have been previously conducted on polymer flocculation and industrial wastewater treatment, there seems to be a lack in studies that focus on running experiments in a rapid high-­ throughput manner and using samples that vary in composition and come from different generators/sources. In this work, a high-­throughput method was implemented to investigate several aspects in the polymer flocculation area on various wastewater samples obtained from a specialized industrial wastewater treatment facility. Using this method, the optimum polymer flocculant type, dosage and concentration were successfully identified for several wastewater samples. In addition to that, scale-­up experiments were done in the v facility on various wastewater tanks to compare the performance of undiluted and diluted polymer flocculant. Diluted polymer flocculant was proven to successfully treat wastewater tanks to a level safe enough for discharge and just as good as undiluted polymer flocculant while using less “neat” polymer flocculant volumes. Moreover, possible cost savings and a better treated water quality were also achieved by implementing multi-­staged polymer flocculation concept for industrial wastewater on a small scale. This work also focused on testing the FBRM as an in-­line method for particle size distribution measurements in industrial wastewater. However, even after an optimization attempt, it did not work well on the samples tested. Another in-­line method that was also tested was UV spectroscopy. This method was proven to successfully work as a method to determine optimum polymer flocculant dose and could be a promising in-­line tool. Finally, bentonite was used as a flocculation aid along with polymer flocculants and design of experiments (DOE) methods were implemented to almost successfully reduce the COD, which as mentioned is an important water quality parameter, in automotive industrial wastewater samples with initial average COD of 77,000 ppm to the safe discharge limit (i.e. 600 ppm)

Thesis

Master of…

In 2012, mandatory effluent quality standards were established in Canada as part of the Wastewater Systems Effluent Regulations (WSER) with compliance deadlines starting in 2020. Maintaining the treatment process efficacy to meet these new stringent discharge regulations is extremely challenging at treatment facilities that treat wastewater from multiple industries due to the high variation in the composition of the incoming feed to the process. In this work, application of two new analytical tools, PeCOD® and Liquid Chromatography-Organic Carbon Detection (LC-OCD), for measurement and characterization of industrial wastewater organic pollution respectively, has been investigated. Organic pollution is commonly measured as Chemical Oxygen Demand via the dichromate method (CODCr) which requires 2-3 hours to complete. Thus this method is not suitable for applications that require rapid and frequent pollution monitoring. The Photoelectrochemical Oxygen Demand (peCOD) is an alternative parameter of organic pollution that can be measured in approximately 15 minutes via a method that utilizes the high oxidation potential of UV-irradiated TiO2 nano-particulates. Herein peCOD suitability to replace CODCr for analysis of industrial wastewater was investigated. The results indicated that for both untreated (i.e. incoming) and treated (i.e. effluent) industrial wastewater samples, peCOD results are lower than CODCr results. However, for the effluent samples, the two methods’ results are strongly correlated. Containing hard to oxidize materials (i.e. macromolecules) and high concentrations of chloride and nitrogenous compounds were identified as potential causes of difference between the results of the two methods. When there is variation in the composition of the incoming wastewater to a treatment process, information about the wastewater composition is required for process optimization. Thus optimization cannot be based solely on bulk measurements of organic pollution (e.g. COD). In this study, a novel combination of LC-OCD analysis with Design-Of-Experiments (DOE) methods was used to optimize the Fenton Advanced Oxidation (AO) treatment conditions in terms of chemical reagent concentrations, to develop statistical models of the process, and to identify potential mechanisms of COD removal.

Thesis

Master of Applied Science (MASc)

Many industrial facilities do not treat their wastewater on-site and instead ship it to specialized treatment facilities. Ensuring that the treated effluent meets the stringent discharge regulations is a challenging task for such facilities as the composition of the incoming feed to the treatment process changes with each shipment. In this work, application of two new analytical tools, PeCOD® and Liquid Chromatography-Organic Carbon Detection (LC-OCD), for measurement and characterization of industrial wastewater organic pollution respectively, has been investigated. The conventional method of measuring organic pollution, Chemical Oxygen Demand (COD), requires 2-3 hours to complete. Herein…

Nanoparticles (NPs) have attracted considerable attention in the field of separation science, especially in filtration studies for direct membrane integrity tests, investigating pore-size distribution, and their potential to be used as surrogates for various types of viruses encountered in water treatment and bioprocessing applications. Although the effect of adding surfactants to stabilize NP suspension have been explored for a number of different applications, there is significant variation in the amounts and types of surfactants used in filtration studies. This study used three different sizes (59, 188, and 490 nm) of fluorescent polystyrene nanoparticles (PNPs) to mimic the length, width, and aggregates of Rhabdovirus Maraba, a bullet-shape envelope virus. The PNPs were suspended in solutions with varying concentrations of the nonionic surfactant Tween 20 (0.0005% to 0.1% (v/v) in the carbonate buffer feed solution) and were tested in constant-flux filtration studies using two commercial microfiltration (MF) membranes (Durapore PVDF and MiniSart PES) with 0.22 micron pore size ratings. Results clearly demonstrate that adding a nonionic surfactant to a PNP solution will cause a shift from full retention to complete transmission during the dead-end MF of PNPs that are smaller than the pore size of an MF membrane. In a separate study, in order to have a better resemblance of virus particles in terms of surface properties, 188 nm PNPs were coated with different (lysozyme, α -lactalbumin and bovine serum albumin) proteins in order to gain similar surface properties to actual virus particles. Filtration results with one type of commercial MF membranes (Durapore PVDF) 0.22 μm pore size, clearly indicate that the transmission behavior of PNPs strongly depends on their surface properties. PNPs fully covered with BSA and α–lactalbumin could completely pass through the membranes while uncovered or partially covered PNPs resulted in no transmission or partial transmission.

Thesis

Master of Applied Science (MASc)

Nanoparticles (NPs) has been employed enormously in various applications for a variety of purposes. One of the areas that have been greatly influenced by NPs, is the field of separation science. In the pharmaceutical industry, purification of therapeutics involves a sequence of filtration and in this step, therapeutic virus filtration, sterile filtration, in particular, have been poorly studied. There is also a growing interest in the use of engineered viruses for cancer treatment due to its magnificent implication on human health. However, there are significant challenges in running filtration experiments with pathogenic substances. Therefore it has been determined that a detailed and comprehensive study of sterile filtration of virus-size NPs can benefit this area. In this work, fluorescently-labeled NPs has been used as surrogates of oncolytic viruses to extract fundamental aspects affecting the transmission of virus-sized particles through commercial microfiltration sterilizing grade membranes.

This thesis investigates the feasibility of producing activated carbon from polysaccharides. Activated carbons are high surface area solids with rich surface functionality and as a result, find use in a variety of industrial separation processes. The market for activated carbon is already established and growing but there is a huge push to find sustainable alternatives for the raw material used for its production, which is primarily coal. While there exists a significant amount of research on agricultural residues as potential replacements, there is minimal information on using polysaccharides as precursors for the production of activated carbon. Using the patented PGX process, two separate approaches were employed for the synthesis of activated carbon. The first method relied on the porous network of PGX materials to be maintained during pyrolysis while the second approach used a chemical agent to create porosity during the pyrolysis. Gas sorption analysis revealed that the PGX structure was not maintained during the pyrolysis stage hence losing all its pore network and extended surface area. Additionally, no significant variation between the PGX and non PGX variants of the chemically activated polymers was observed. However, it was revealed that the interaction between zinc chloride and pectin produced exceptionally high specific surface area (exceeding 2000 m2 g-1) activated carbon. The produced carbon had a high degree of microporosity (up to 100%) with some flexibility present in tuning the porosity. Elemental analysis revealed the carbon to have high surface functionality and preliminary adsorption test for removal of heavy metal ions from water (Pb2+ and Cd2+) showed promising results with the in-house carbon performing better than a representative commercial carbon. This study relies on statistical methods including multiple design of experiment studies and advanced characterization techniques to analyze the manufacturing process and the properties of carbon in an attempt to find the best conditions for producing activated carbon from polysaccharides.

Thesis

Master of Applied Science (MASc)