seminar abstract book 2 - faculty of engineering _2013_2014.pdf · nov 25th, 2013 invited speaker:...

Chemical and Biochemical Engineering Graduate Seminar Committee

September 2013-April 2014

The University of Western Ontario Faculty of Engineering

Department of Chemical and Biochemical Engineering Graduate Seminar Series

Student Abstract Book

Appreciation

On behalf of the Department of Chemical & Biochemical Engineering we would like to congratulate all of the participants in this year’s series in successfully hosting an exciting weekly seminar.

The goal of the Annual Graduate Seminar series is to provide a forum for graduate students within the department of Chemical & Biochemical Engineering to discuss their research, get practice on their communication skills as well as provide opportunities for student leadership within the department. Students were involved in the organization of the program for the speakers, chaired sessions, and provided feedback on student presentations throughout the year. We would also like to sincerely thank faculty members for volunteering their time to provide feedback on student presentations.

A quick glance at the schedule indicates that we had presentations from students all of the major research areas in Chemical Engineering at Western as well as a variety of invited speakers from industry, government, and academia. Abstracts for student presentations as well as winners of the speaker of the month are included in this program.

We look forward to the continuation of the seminar series next year.

Graduate Student Seminar Committee

Chemical & Biochemical Engineering Graduate Seminar Series Committee

Thank you to the committee members who contributed to the successful organization and execution of the seminar series this year.

Sarah Williams, Ashley Johku, Maritza Gomez-Flores, Gloria Kumordzi, Ha Doan, Ghodsieh Malekshoar, Valerie Orr, Amir Kargar, Amarjeet Bassi, Anand Prakash (not pictured)

SCHEDULE FALL 2013

Date Speakers Title

Sept 16th, 2013

Dr. A. Bassi & Dr. A. Prakash

Introduction to seminar format and scientific presentations

Sept 23rd, 2013

Qasem, Alsharari Nanowires for Energy and Water Applications

Homaira Siddiqui Process Optimization for the production of bio-resins using depolymerized lignin

Sept 30th, 2013

Invited Speaker: Alison Empey (Ontario Centers of Excellence)

Oct 7th, 2013

Darryl Knight Functionalized poly(ester amide)s as vascular tissue engineering scaffolds

Sura Ali Genotoxicity and estrogencity of sulfamethoxazole and 17-β estradiol: effect of advance oxidation treatments

Oct 21st, 2013 Invited Speaker: Dr. Bill Cairns (Trojan UV)

Oct 28th, 2013

Victor Pupkevich Experimental study and scale-up of the BioGenerator

Tierney Deluzio Cyclodextrin Inclusion Compounds for Improving Oxygen Delivery for Tissue Engineering Scaffolds

Nov 4th, 2013

Shahram Amirnia Heavy Metal Adsorption by Living and Non-living Yeast Cells: Application in Environmental Biotechnology

Shanhua Huang Lignin De-polymerization for Bio-chemicals and Bio-fuels with Formic Acid

Nov 11th, 2013

Koosha Azhie Antibacterial Studies On Titania Polyurethane Nanocomposite Coatings

Raziye Samimihaghgozar

Supercritical fluid chromatography of North American ginseng extract

Nov 18th, 2013

Darcy Small Enhancement of Microalgal Biomass Production for Biofuels and High Value Products Using Static Magnetic Fields

Samindika Athapaththu Effect of Adsorption and Photocatalytic removal of Cadmium using TiO2 and Disensitized TiO2

Nov 25th, 2013 Invited speaker: Dr. Anil Kane (Patheon)

Dec 2nd, 2013 Invited speaker: Dr. Gerardo R. Fuentes

Pharmaceutical application of natural zeolites

WINTER 2014

Date Speakers Title

Jan 13th, 2014

Gureet Chandhok Multi-objective optimization approach for pretreatment of dairy manure as a feedstock for microalgal cultivation

Teresa Turnbull

The enhancement of cellulase production from Trichoderma viride and Phanerochaete chrysosporium for the enzyme degradation of anaerobically digested fibre

Jan 20th, 2014

Abdullah Dughaither Conversion of DME into olefins over HZSM-5: Effect of SiO2/Al2O3 ratio on surface chemistry and reactivity properties

Tennison Yu Characterizing a cetyl trimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) system for nanotube dispersion

Jan 27th, 2014 Invited Speaker: Dr. Tarek Elsolh

(Imperial Oil) Opportunities at imperial oil for new graduates

Feb 3rd, 2014

A S M Jahirul Islam Mazumder

Catalytic steam gasification of biomass

Ha Doan Quantification of axial mixing and the impact of internals in a counter-current liquid solids fluidized bed

Feb 10th, 2014 Ana-Maria Aguirre

Study of the effect of culture conditions and steam explosion on microalgae cell wall disruption for lipids extraction

Shan Gao Microflow structures of circulating fluidized beds

Feb 24th, 2014 Invited Speaker:

Christine Haas (Renix) Spinning Out - The Experience of Commercializing New Technology

Mar 3rd, 2014

Andrew David Wong Development of new cascade degradable polymers

Adam Golin Electrospun scaffolds for use in tympanic membrane tissue engineering

Mar 10th, 2014 Alejandro Andres Montes

Costa Factors affecting bed agglomeration in bubbling fluidized bed (BFB) boilers

Nicholas Prociw Evaluation of agglomerate stability in an industrial scale fluidized bed using a conductivity method

Mar 17th, 2014

Md Abdul Mumin Engineered quantum dots for solar-polymer films

Medhavi Gupta Comparative study of co-digestion of glucose, starch and cellulose for mesophilic biohydrogen production using anaerobic digester sludge and pure cultures

Mar 24th, 2014 Invited Speaker:

Dr. Andy Hrymak (Dean of Engineering)

Academia - Is it the right career for me?

Mar 31st, 2014 Invited speaker: Soleimani, Rasoul

Gelatin and the Soft Capsule Manufacturing Process

April 7th, 2014 Gabriela Navarro

Diffusion and partition coefficients of tar biomass gasification derived species in capillary columns

Inderpreet Sran Modification of butyl rubber for medical application

STUDENT OF THE MONTH WINNERS Two speakers were selected from each term to receive recognition for the best student presentation. The selection was based on the feedback received from both student and faculty judges. We would like to congratulate the winners on their accomplishment.

FALL 2014

Homaira Siddiqui (MESc Candidate)

“Process Optimization for the production of bio-resins using depolymerized lignin”

Tierney Deluzio (MESc Candidate)

“Cyclodextrin Inclusion Compounds for Improving Oxygen Delivery for Tissue Engineering Scaffolds”

WINTER 2014

Tennison Yu (MESc Candidate)

“Characterizing a Cetyl trimethylammonium bromide (CTAB) and Polyvinylpyrrolidone (PVP) system for nanotube dispersion”

Adam Golin (MESc Candidate)

“Electrospun scaffolds for use in tympanic membrane tissue engineering”

ABSTRACTS FALL 2013

The University of Western Ontario

Faculty of Engineering

Department of Chemical and Biochemical Engineering Graduate Seminar Series:

September 23rd, 2014

3:30-4:30pm SEB 1059

Qasem Alsharari

“Nanowires for energy and water applications”

Synthesis of well-ordered and controlled materials at nano scale is full of challenges, which increases with complexity of target materials. Synthesis of porous nanowires with high aspect ratio and high surface area comparable to nanoparticles surface area is more challenging than making nanoparticles. Supercritical CO2 is an excellent solvent to overcome some of these challenges. This work focused on copper doped titanium dioxide nanowires for sacrificial hydrogen production.

In this research aims to reduce recombination limitation and provide more red shift of catalyst active region by integrating different metals with titanium dioxide as a bimetallic and multi metallic nanowires. In addition, supercritical CO2 enabled us to produce well-dispersed metals in bimetallic and multi-metallic nanowires, which contributed to enhancement of electron-hole separation and reduction of band gap of these new nanowires making them a potential in solar and Photocatalytic applications. SEM and HRTEM images confirmed formation of porous nanowires with high aspect ratio and high metal dispersion was investigated using XPS. EELS mapping shows high dispersion of bimetallic and multi-metallic. The BET (Brunauer-Emmett-Teller) surface area, of porous doped TiO2 nanowires showed comparable surface area ranging from 48 to 80 cm2/g compared to commercial TiO2 P25 nanoparticle which has surface area about 53 cm2/g.

This research provided single oxidation state of copper as Cu(I) which is the most active for hydrogen production.

Homaira Siddiqui

“Process optimization for the production of bio-based PF resins using de-polymerized lignin”

Using lignin as an alternative renewable feedstock for the production of bio-phenolic plywood adhesives has been of increasing interest, specifically due to the structural similarities between lignin and phenol molecules. The present research work aims at optimization of the production process of high quality bio-based phenol formaldehyde (BPF) resins to obtain optimum values of the molar ratio of formaldehyde-tophenol (F:P), phenol substitution percentage, and the relative molecular weights of de-polymerized lignin (DL). Obtained from a pulp mill in Northwestern Ontario, Kraft lignin is hydrolytically de-polymerized under different reaction severities to obtain DL products with various molecular weight ranges. Using the three-level (low, medium, and high), three factorial Box Behnken Design (BBD), the main objective is to synthesize and characterize a variety of BPF resins to attain low thermal curing temperatures and high bonding strength conditions for wood adhesives. In this presentation, the effect of the three parameters on the curing temperature and the adhesive strength of BPF resins will be examined.




October 7th, 2014

3:30-4:30pm SEB 1059

Darryl Knight

“Functionalized poly(ester amide)s as vascular tissue engineering scaffolds”

Introduction

The design of cardiovascular biomaterials focuses on biomimetic properties that are capable of eliciting specific cellular responses and directing tissue formation. In vascular tissue engineering, the ability to direct smooth muscle cells (SMCs) to acquire the quiescent, contractile phenotype following infiltration into a three-dimensional (3D) biodegradable scaffold and ensuing secretion of the extracellular matrix (ECM) remains a key challenge.1

Poly(ester amide)s (PEAs) derived from α-amino acids, diols, and diacids are promising materials due to their tunability and potential for either hydrolytic or enzymatic degradation.2 The incorporation of amino acids with functional side chains, such as L-aspartic acid, would permit the conjugation of a desired biomolecule. The immobilization of transforming growth factor β1 (TGF β1) to these scaffolds may initially improve extracellular matrix protein secretion including elastin3-5 whose absence has plagued the development of many tissue engineered blood vessels.6 TGF β1 has also been shown to upregulate contractile phenotype markers in a biostable 3D scaffold model in vitro.5 Therefore, the syntheses of these biodegradable functional PEAs and their subsequent evaluation as potential vascular scaffold materials were the primary objectives of this study.

Materials and Methods

To synthesize these aspartic acid containing PEAs, selectively protected L-aspartic acid (Z-Asp(OtBu)-OH) was coupled via carbodiimide chemistry to 1,4-butanediol followed by its hydrogenation to produce the functional monomer.7 Additional monomers based on L-phenylalanine were synthesized via the acid catalyzed condensation of these amino acids with aliphatic diols: 1,4-butanediol and 1,8-

octanediol.2,8 The functional PEAs were obtained through the interfacial polymerization of sebacoyl chloride with monomers from each of the first two steps. Finally, deprotection of the t-butyl protecting groups with trifluoroacetic acid (TFA) yielded the pendant carboxylic acid groups.

Three-dimensional fibrous PEA mats were achieved by electrospinning various concentrations of PEA solutions (5-12 wt%) in co-solvent mixtures of chloroform (CHCl3):N,N-dimethylformamide (DMF) (9:1). The fibers were collected on aluminum foil on either a static collector or on a rotating mandrel (1000 rpm).

Conjugation of TGF β1 to the surface of the pendant carboxylic acid groups of the electrospun fibrous mat was again achieved through carbodiimide chemistry (N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysulfosuccinimide (EDC.HCl/sulfo-NHS)) and confirmed using X-ray photoelectron spectroscopy (XPS) and confocal laser scanning microscopy (CLSM).

The viability of the PEAs as potential vascular scaffolds was assessed through the culture of human coronary artery smooth muscle cells (HCASMCs) on the surface of 3D scaffolds and compared to 2D controls. Cell morphology was examined with CLSM and scanning electron microscopy (SEM).

For smooth muscle cell phenotype marker protein analysis via Western blot, protein lysates obtained from a radioimmunoprecipitation assay (RIPA) buffer supplemented with phenylmethylsulfonyl fluoride (PMSF) and a protease inhibitor mixture were quantified with Pierce 660 nm Protein Assay. The protein lysates were then separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE, 12%) and subsequently transferred to a nitrocellulose blotting membrane. Following blocking with 5% non-fat dried milk, the membranes were incubated overnight at 4oC with either mouse monoclonal anti-α-actin, (1:250 dilution), rabbit polyclonal calponin 1/2/3 antibody (1:250 dilution) or mouse monoclonal anti-glyceraldehyde-3- phosphate dehydrogenase (GAPDH, 1:1000 dilution). Membranes were then incubated for 1 hour in a horseradish peroxidase (HRP)-conjugated secondary antibody (1:5000 dilution) followed by enhanced chemiluminescent detection.

Results and Discussion

The structures of the aspartic acid containing PEAs were confirmed throughout the synthetic approach with nuclear magnetic resonance (NMR) spectroscopy and characterized via gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Both non-functional and aspartic acid containing PEAs could be electrospun to yield fibrous mats with average fiber diameters ranging from 100 to 500 nm, which were polymer and molecular weight dependent.

HCASMC viability on these newly synthesized PEAs was confirmed with 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The aspartic acid

containing PEAs supported HCASMC proliferation as well or better than their corresponding non-functional counterparts. CLSM and SEM images showed that the HCASMCs were well-spread on the surface of the fibers up to 4 days culture. TGF-β1 was covalently attached to the functional PEA as evidenced by the increase in elemental S in XPS and the binding of the TGF-β1 antibody. Short-term Western blot data suggest that contractile phenotype marker proteins smooth muscle α-actin and calponin were up-regulated with non-functional 3D fibrous mats compared with their corresponding 2D films. Moreover, the addition of TGF-β1 also resulted in an increase in contractile phenotype marker proteins.

The aspartic acid containing PEAs were successfully synthesized and electrospun alongside the non-functional PEAs yielding nanoscale fibrous mats, which supported HCASMC attachment and spreading further suggesting their potential use as vascular biomaterials.

References

1. Beamish, JA; He, P; Kottke-Marchant, K; Marchant, RE. Tissue Eng., Part B 2010, 16, 467. 2. Guo, K; Chu, CC; Chkhaidze, E; Katsarava, R. J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 1463. 3. Amento, EP; Ehsani, N; Palmer, H; Libby, P. Arterioscler., Thromb., Vasc. Biol. 1991, 11, 1223. 4. Lawrence, R; Hartmann, D J; Sonenshein, GE. J. Biol. Chem. 1994, 269, 9603. 5. Lin, S; Sandig, M; Mequanint, K. Tissue Eng., Part A 2011, 17, 1561. 6. Patel, A; Fine, B; Sandig, M; Mequanint, K. Cardiovasc. Res. 2006, 71, 40. 7. Atkins, KM; Lopez, D; Knight, DK; Mequanint, K; Gillies, ER. J. Polym. Sci., Part A: Polym. Chem. 2009, 47, 3757. 8. Knight, DK; Gillies, ER; Mequanint, K. Biomacromolecules 2011, 12, 2475. Acknowledgements

The authors would like to acknowledge the financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Sura Ali

“A comparative study of the effect of different advance oxidation processes on the estrogencity and genotoxicity of 17-β estradiol and sulfamethoxazole”

Advance oxidation processes (AOPs) such as ozonation, UV- ozonation and UV- H2O2 are very effective oxidative treatments for the degradation of various organic micropollutants in water, which are known as “emerging contaminants”. Their presence is a global concern because of their ability to potentially cause adverse effects in organisms at concentrations as low in the order of ng/L. They are not removed well in traditional wastewater treatment processes and enter the environment and spread throughout the water ecosystem. Complete mineralization of the organic contaminants is expensive, while partial mineralization may not produce desirable water quality. The remaining presence and activity of intermediates is hard to assess due to their low concentrations and difficult chemical analyses. Therefore, bioassays which are powerful tools can be used to screen the estrogencity and the toxicity of a complex chemical mixture. In this study two compounds of increasing concern, sulfamethoxazole which is a pharmaceutical, and personal care product (PPCP), and 17-β estradiol, which is an endocrine disrupting compound (EDC), have been used as model compounds. The estrogenic activity is determined by using the yeast estrogencity screen (YES) assay, and the genotoxicity is monitored by using the Ames test, before and after different AOPs. The effects of different concentrations and mixtures of the model compounds, oxidant type, and background water quality have been studied.




October 28th, 2014

3:30-4:30pm SEB 1059

Victor Pupkevich

“Experimental study and scale-up of the BioGenerator”

Nowadays a lion share of all energy generated in the world is relying on fossil fuels and according to forecasts, energy consumption is not going to go down, but will constantly grow. It is becoming more clear to researchers that this situation could be changed only by serious reconsideration of current lifestyles and technological schemes employed in industry. In particular, much more attention has been paid to finding alternative sources of energy as well as development of new technologies (devices) allowing for generating required energy without harmful impact on the environment.

One of the enticing pathways to take is believed to be hydrogen economy. However, a process of bringing this idea to life is very slow and significantly hindered by insufficient development of the fuel cell technology, which is considered to be the main tool for conversion of hydrogen to electricity. The origin of the major problems in current conventional fuel cells (high cost, low stability, and low efficiency) is the slowness of the cathodic oxygen reduction reaction. The uniqueness of the system developed in our lab – the BioGenerator - is in utilizing autolithotrophic iron oxidizing bacteria, which can actually "catalyze" the reaction, and make the whole process of electricity generation very efficient.

The main goal of this project was to scale-up the BioGenerator (0.1 W → 1 W → 300 W → 10 kW) and study its performance over a prolonged period of time. The operating parameters of the BioGenerator in different regimes, as well as oxygen mass transfer and microbial kinetics data in the bioreactor were used to improve the design. Polarization characteristics of the fuel cell stacks obtained were used to identify a root cause of the performance deterioration and help tailor Nafion- and PVA-based proton exchange membranes for the BioGenerator system. The biomass accumulated in the bioreactor during operation underwent toxicological testing and was proved to be non-toxic to Zebrafish and can potentially be used as feed in the fish farming industry.

Tierney Deluzio

“Tissue engineering scaffolds for on-demand oxygen delivery using a cyclodextrin inclusion complex”

Introduction

Fabricating engineered tissue of a clinically relevant size will remain a challenge until oxygen delivery to cells seeded on scaffolds is improved. In the body, oxygen delivery is achieved through convection to the capillaries which ultimately decreases the distance required for diffusion, as well as by hemoglobin, a natural oxygen carrier protein. The lack of convection combined with the low solubility of oxygen in culture media results in insufficient oxygen delivery to tissue engineered constructs by diffusion alone, particularly in the center of constructs where cells become hypoxic and necrotic. 1, 2

It is hypothesized that cyclodextrin/perfluorocarbon inclusion complexes incorporated into tissue engineering scaffolds will enhance oxygen delivery to cells. The objectives of this study are to prepare and characterize cyclodextrin inclusion compounds with perfluorocarbons, incorporate these inclusion compounds into electrospun scaffolds, and analyze their effect in vitro.

Perfluorocarbons (PFCs) have a high dissolving power for oxygen but are hydrophobic, lipophobic, and stable which makes them biologically inert. Unlike oxygen chemically bound to hemoglobin, solubilized oxygen can be rapidly and extensively extracted from perfluorinated molecules when needed.3 Perfluorocarbon emulsions have been investigated as oxygen carriers, simulating the role of hemoglobin; however, the high density of these emulsions results in settling of the droplets.

Cyclodextrins are cyclic ogliosaccharides made up of 6, 7, or 8 glucose units known as α, β, and γ cyclodextrin, respectively. They are biocompatible and non-toxic to cells, and have been used in a number of biological applications, including as drug delivery molecules.4 Their unique shape creates a hydrophobic inner cavity with a hydrophilic exterior surface which allows them to form inclusion complexes with numerous guest species. These complexes are non-covalent, stabilized by van der Waals and hydrophobic forces.

Materials & Methods

In this study, multiple complexation techniques were used to prepare a cyclodextrin inclusion compound with a perfluorocarbon: co-precipitation in solution and physical mixing, both dry and as a paste. In the experiments, the following parameters were varied such that all permutations were carried out: alpha- and beta-cyclodextrin; perfluorodecalin and perfluoroperhydrophenanthrene; 1:1 and 2:1 molar ratio of cyclodextrin to perfluorocarbon. Characterization of the product was done with attenuated total resonance Fourier transform infrared (FTIR) spectroscopy.

The resulting cyclodextrin/perfluorocarbon inclusion complex was incorporated into tissue engineering scaffolds via electrospinning. The polymer system used was polycarbonate urethane with dimethylformamide as a solvent. Concentrations of the cyclodextrin inclusion complex, polymer, and solvent were all varied while keeping the remaining electrospinning parameters consistent. The scaffolds were characterized using scanning electron microscopy (SEM).

Results & Discussion

In the FTIR spectrum of each product, peaks characteristic of the perfluorocarbon were evident. Changes in the fingerprint region confirmed that the products are different from each parent molecule as they possess new spectroscopic signals. However, this data does not confirm that an inclusion complex was formed; the products could be physical mixtures of the two parent molecules. To compare the products to the physical mixture, the absorbances at characteristic peaks in the product were divided by the absorbances at the same wavenumber in the physical mixture. These values were normalized to both the physical mixture and the concentration. A resulting large standard deviation confirms that the product is not a physical mixture. The best permutation of variables was thus determined to be: alpha-cyclodextrin, perfluorperhydrophenanthrene, 2:1 molar ratio, and physical mixing in a paste.

In order to electrospin successfully, the polymer concentration must be decreased upon incorporation of cyclodextrin due to the higher solids loading. Furthermore, the increased conductivity of the solution resulting from the addition of cyclodextrin allows for spinning at lower polymer concentrations.5 Since the SEM images showed beading of the fibers, the electrospinning conditions, specifically polymer, cyclodextrin inclusion complex, and solvent concentrations, must be optimized in order to obtain bead-free, uniform nanofibers.

The design of novel oxygen delivery strategies is critical for developing viable solutions to repair damaged tissues. Cyclodextrin/perfluorocarbon inclusion complexes have been successfully prepared for their potential application as novel oxygen vectors. The inclusion complexes have been incorporated into scaffolds via electrospinning. In future, the effect of the embedded cyclodextrin/perfluorocarbon inclusion complexes will be studied in vitro with respect to oxygen delivery and cytotoxicity.

References

1. Seifu, DG; Isimjan, TT; Mequanint, K; Acta Biomater 2011, 7, 3670-3678. 2. Sutherland, RM; Sordat, B; Bamat, J; Gabbert, H; Bourrat, B; Mueller-Klieser ,W; Cancer Res. 1986, 46, 5320-5329. 3. Reiss, JG; J. Colloids Surf., A 1994, 84 (1), 33-48. 4. Martin Del Valle, EM; Process Biochem 2004, 39, 1033-1046. 5. Uyar, T; Balan, A; Toppare, L; Besenbacher, F; Polymer 2009, 50, 475-480.




November 4th, 2014

3:30-4:30pm SEB 1059

Shahram Amirnia

“Heavy metal adsorption by living and non-living yeast cells: application in environmental biotechnology”

The damaging effects of heavy metals on human being and other habitants are

well known. Water quality and biological community in Lakes are being affected by thousands of tons of toxic metals every year released by polluting industries such as Mining and Ore processing, smelters, electroplating and metal-finishing operations, tanneries, and other metal processing industries. Removal of heavy metals from industrial effluents is usually achieved by physical or chemical processes such as chemical precipitation, oxidation or reduction, evaporation, filtration, reverse osmosis, ion exchange and membrane technologies. Although very effective, these metal removal methods appear to be costly and inadequate. Therefore, search for economically appealing alternatives to conventional metal treatment methods is required.

In this presentation, Biosorption technology is introduced as a promising substitute to physico-chemical methods for removal of heavy metals from waters. Biosorption is defined as an eco-friendly and effective method that uses abundant biomass generated from industrial fermentations, such as brewer’s yeast waste biomass, to adsorb heavy metals from metal-bearing effluents.

Biosorbents with different degrees of metal adsorption capacities, availability, and selectivity showed to be promising for metal removal from aqueous solutions in batch laboratory scale, but it is their applicability in continuous mode that makes this treatment method attractive to industry. So far, an industrially relevant method for removal of toxic metals has not been achieved yet. The main aim of this phase of my project was to examine the ability of yeast biomass to be utilized in a continuous system for removing metal ions from aqueous solutions. We used Baker’s yeast as adsorbent, and copper and lead ions as metals of interest for biosorption.

Shanhua Huang

“Lignin de-polymerization for bio-chemicals and bio-fuels with formic acid”

This paper reports a production process for fuels and chemicals from lignin de-polymerization with presence of formic acid. Under the optimal reaction conditions, i.e., 300°C, the Kraft lignin was effectively decomposed in 50/50 (v/v) water-ethanol co-solvent at 300°C with 3 ml formic acid and led to an 88% yield of degraded lignin (DL), producing < 1% solid residue. The molecular weights of the lignin were remarkably reduced from its original Mw and Mn of 10,000 and 5,000 g/mol to Mw and Mn of 1270 and 410 g/mol, respectively. A higher temperature and a longer reaction time favored lower molecular weight products, but at temperature higher than 300°C the formation of solid residue significantly increased due to the condensation reaction of degradation intermediates. The degraded lignin can be dissolved in organic solvents (such as THF), and were characterized by FT-IR, GPC and elemental analysis. The gas samples were also analyzed by the Micro-GC (TCD).




November 11th, 2014

3:30-4:30pm SEB 1059

Raziye Samimihaghgozar

“Supercritical Fluid Chromatography of North American Ginseng Extracts”

Supercritical fluid chromatography (SFC) using scCO2 is considered as a “green” separation method, particularly suitable for the isolation of thermally unstable bioactive components. However, co-solvent and additives are often required in the mobile phase due to the poor solubility of polar components in scCO2. In the present study, the effect of temperature and pressure on the separation of ginsenosides was studied with methanol being added to the CO2 mobile phase. Acidic, basic, and ionic additives were introduced to the mobile phase, respectively, to study their effect on the separation of ginsenosides. The best separation condition was achieved by adding trifluoroacetic acid in methanol. A high-concentration component in the extracts from the supercritical fluid extraction of North American ginseng was isolated by SFC and identified as sucrose with NMR, HPLC, and ESI-MS. These results show that SFC is a promising technique for separation, isolation, and identification of ginseng extracts.

Koosha Azhie

“Antibacterial studies on titania polyurethane nanocomposite coatings”

While temporarily disinfection of a surface is possible with the help of strong cleaners, tremendous interest exists for the control of microorganisms on surfaces by effective, durable antimicrobial coatings to prevent multidrug resistant pathogens. There is a wide spectrum of potential applications for antibacterial coatings, spanning from industrial surface coatings to biomedical applications, where sterile conditions are crucial. This work examined the synthesis of nanotitanium dioxide/polyurethane (nTiO2/PU) composite coatings prepared by using various bifunctional monomers. The antibacterial behavior of virgin PU, nTiO2/PU and silver doped nTiO2/PU composites were investigated qualitatively and quantitatively against both gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. The effect of exposure time was investigated using a UV lamp and solar simulator by monitoring the growth of bacterial populations in the presence and absence of the above-mentioned nanocomposites. The distribution of nTiO2 in the polymer matrix was enhanced by monomer functionalization in which nTiO2 was chemically attached to the backbone of the polyurethane polymer matrix with a bifunctional monomer. Silver is one of the most effective antibacterial agents with low toxicity used for its high degree of biocompatibility and its long-term antibacterial effectiveness against many different bacterial strains, and it was also examined as a TiO2 dopant. The quantitative examination of bacterial activity was determined by the survival ratio as calculated from the number of viable cells, which form colonies on the Petri dishes with nutrient agar. Good inhibition results were observed and demonstrated visually with close to 97% of bacteria killed after 2 hours. In summary the functionalized nTiO2/PU, and silver doped nTiO2/PU composite coatings displayed considerable antibacterial activity against both gram-positive and gram-negative bacteria under UV irradiation while silver doped nTiO2/PU coatings displayed considerable antibacterial activity even under irradiation of visible light.




November 18th, 2014

3:30-4:30pm SEB 1059

Darcy Small

“Enhancement of microalgal biomass production for biofuels and high value products using static magnetic fields”

Microalgae and cyanobacteria have received tremendous attention as the next

generation feedstock for biofuel (biodiesel and fuel alcohol) production because they have many advantages over terrestrial plants: A ten-fold or higher rate of biomass production per unit area compared to higher plants (1); a higher content of fatty acids suitable for conversion to biofuel than higher plants (1); growth is possible on non-arable land eliminating competition with food crops; and many species have a higher tolerance for toxins than higher plants allowing waste streams to be used as sources of carbon dioxide, nitrogen, and phosphate(2). Despite these advantages microalgae-derived fuels are still not competitive with petroleum fuels because the cost of producing microalgae is still too high (2). Our research has focused on increasing the growth rate of microalgae by stimulating cell division by exposing a small portion of the culture to static magnetic fields as has previously been demonstrated (3); using flat-plate bioreactors which can support a high concentration of microalgae because of their high light-exposed surface area (4); and by co-producing novel high-value products to increase the value of the microalgae per unit weight (4).

In the first set of experiments Chlorella kessleri and Haematococcus pluvialis were grown in standard flasks at a low light level and circulated through a static magnetic field at 5, 10 and 15 mT or mock-exposed for a control by pumping through an off electromagnet. Maximum biomass production rate was increased approximately four-fold for both species with a magnetic field strength of 10 mT which was found to increase growth more than the other field strengths tested. Changes in cell size as measured by light microscope, cell ultrastructure as observed by TEM, and biochemical composition were also induced by magnetic field treatment. In both species magnetic field treatment increased oxidative stress as measured spectrophotometrically using the radical scavenging stable free-radical probe 2,2-diphenyl-1-picrylhydrazyl. The content of astaxanthin, a valuable red antioxidant pigment, was also 60 % higher in H. pluvialis exposed to 10 mT static magnetic field compared to the control.

Next a scalable raceway pond was designed to study the effect of magnetic fields on C. kessleri and H. pluvialis under the conditions of large-scale cultivation. While C. kessleri grew to similar biomass density in the pond compared to flask experiments and had a similar increase in productivity with magnetic field exposure, H. pluvialis could not be grown to even 1 g/l in the open pond. To overcome the limitations of open-pond technology we developed a flat-plate photobioreactor (3 L) in which biomass production and final biomass concentration for H. pluvialis exceeded that for flask-growth, and 10 mT static magnetic field treatment provided similar enhancement in growth and astaxanthin content compared to flask cultures. To test the maximum biomass density the bioreactor could support the bioreactor was tried with the fast-growing cyanobacteria Spirulina platensis with high light and 3 % v/v CO2 aeration, and final biomass concentration was increased almost 10-fold compared to growth in flasks, although major settling was apparent. To overcome this issue and to optimize mixing to reduce energy consumption the two phase flow of the reactor was simulated with Fluent using the Grace drag model. The sparger design and reactor corners were optimized so that uniform flow could be achieved, even at relative viscosity=5, with a 50 % reduction in aeration rate.

Finally, because the market for neutraceutical high value products such as astaxanthin is extremely small compared to the demand for biofuels we have investigated production of natural non-toxic pigments as a further high-value co-product. We envision these will be used in high-quality artist pigments, coatings for consumer items, and food colorings, where there is a growing concern about pigment toxicity and therefore natural products fetch a high premium. To produce a full color spectrum S. platensis is used to produce blue phycocyanin, Porphyridium cruentum is used to produce red phycoerythrin, and Synura Uvella is used to produce yellow fucoxanthin. A method has been developed to extract chlorophyll and other unwanted pigments from S. platensis and P. Cruentum to leave brilliant blue S. platensis or dark red P. Cruentum biomass filled with the water-soluble phycocyanin and phycoerytherin pigments, respectively. A method which uses aqueous base to hydrolyze chlorophyll in S. uvella biomass, solubilizing its chromophore so it can be washed away, has also been developed. The pigments have been informally tested in egg-tempera water-based media and demonstrate color steadfastness over years, compared to weeks for extracted pigments.

The mechanism of biomass enhancement using magnetic field still must be elucidated. This will be done by using radical-sensitive flow-cytometry probes which can pin-point the type of oxidative stress induced by the magnetic field. Photosynthetic and oxidative stress response defective Chlamydomonas sp. mutants from the mutant library will be tested for the effect of magnetic field on growth. ESR spectroscopy will be used to identify any particular radicals which exist at higher concentration with magnetic field treatment. Further experiments will further increase biomass production in the developed flat plate photobioreactor, by optimizing the dependant effects of light, carbon dioxide, and aeration rate. Magnetic field will also be tested on S. uvella, P. cruentum, and S. platensis to increase pigment production and determine how wide-spread the growth enhancement phenomenom is among diverse microalgae and cyanobacteria. Finally the pigments developed will be compared to extracted pigments

using ASTM color steadfastness testing methods, with an effort to identify the components of the algal cells which extend the color steadfastness of enclosed pigments.

1) Chisti Y. 2007. Biotech Adv 25: 294-306

2) Clarens AF, Resurreccion EP, White MA, Colosi LM. 2010. Environ Sci Technol 44: 1813-1819.

3) Wang HY, Zeng XB, Guo SY, Li ZT. 2008. Bioelectromagnetics 29: 39-46.

Samindika Athapaththu

“A comprehensive study of Cd2+ removal from aqueous solution via adsorption and solar photocatalysis”

Heavy metals such as lead, cadmium, zinc, copper and arsenic are emitted by numerous sources including industrial wastes from mining sites, oil refining plants, manufacturing and metal finishing plants. As the increase in industrial technology continue to progress, it results in the increase in heavy metal pollution, creating harmful effects on humans, plants, and animals. Since toxic metals do not degrade easily, they accumulate over time, posing greater danger to living organisms. Therefore, removal of heavy metals from water and wastewater is of great importance. Many have successfully used UV photocatalysis with TiO2 as catalyst, for the removal of Cd2+ from water and wastewater. The present research work aims to study the photocatalytic removal of Cd2+ from aqueous solution, under UV and visible light spectrum, along with the adsorption of Cd2+ onto TiO2. To have a better understanding of the Cd2+ removal, aqueous solutions containing Cd2+ is used in the experiments. In order to use visible light spectrum, dye-sensitized TiO2 is used as the catalyst. Dye-sensitization is obtained by the addition of Eosin-Y dye onto TiO2. The main objective of this research is to study the performance of Cd2+ removal under visible light photocatalysis compared to that of UV photocatalysis. In this presentation, the effect of; pH, initial TiO2 concentration, initial Cd2+ concentration, light intensity, as well as the overall performance of visible light vs. UV photocatalysis on Cd2+ removal will be discussed.

ABSTRACTS WINTER 2013



Department of Chemical and Biochemical Engineering Graduate Seminar Series: January 13rd 2014

3:30-4:30pm SEB 1059 Gureet Chandhok

“Multi-objective optimization approach for enhanced pre-treatment of anaerobic digestate slurry as a feedstock for algal cultivation”

The production of biogas from animal manure is a mature technology however disposal of the resultant digestate especially from large-scale biogas digesters faces both logistical challenges and legislative restrictions. The digestate manure requires a secondary and tertiary treatment which can be effected by further clarifying the effluent and growing microalgae on the anaerobic effluent respectively. Biogas digestate have traditionally been applied in agricultural farms to supplement or replace the use of synthetic fertilizers due to its high nutrient content. Multi-response optimization (MRO) using response surface methodology (RSM) is an efficient method for the pre-treatment of slurry for its nutrients recovery and turbidity removal. Most of the studies in RSM have been focused in single response of interest. RSM was used to optimize the pre-treatment conditions of anaerobic digestate slurry simultaneously for multiple responses in this study. The individual and interactive effects of digestate slurry solid loading, pH and coagulant/flocculant dosage were analysed and optimum values were also determined. A turbidity removal efficiency in the range of 99.9 -100% and nutrient recovery ranging from 15.4 – 97.6% was obtained. The optimized conditions were then used to prepare a feedstock for the cultivation of Chlorella vulgaris. The growth of C. vulgaris on the pre-treated digestate slurry and its ability to remove nutrients from the slurry will be reported.

Teresa Turnbull

“The Enhancement of Cellulase Production from Trichoderma viride and Phanerochaete chrysosporium for the Enzyme Degradation of

Anaerobically Digested Fibre”

The controlled production of cellulosic enzymes is of critical importance to the agricultural and biogas industry. In this study, the fungi, Trichoderma viride and Phanerochaete chrysosporium, produce enzymes that can be used to degrade the cellulose within anaerobically digested (AD) fibre. The enzyme activity of the T. viride involves the conversion of cellulose and hemicellulose into glucose and other sugars. The fungus P. chrysosporium produces these same enzymes as well as enzymes that catalyses lignin, a polymer that inhibits the enzymatic hydrolysis of cellulose, allowing further catalysis. The purpose of this study is to determine the conditions for improved enzyme production and the efficacy of utilizing the cellulases from these two fungi to catalyse AD fibre.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: February 3rd 2014

3:30-4:30pm SEB 1059 Abdullah Dughaither

“Conversion of DME into olefins over HZSM-5: Effect of SiO2/Al2O3 ratio on surface chemistry and reactivity properties”

This study investigates HZSM-5 as a potential catalyst for light olefins production from di-methyl ether (DTO). The aim of this study is to provide an in-depth understanding of the unique effect of SiO2/Al2O3 ratio on the physico-chemical and reactivity properties of the HZSM-5 zeolite. N2 adsorption and desorption display isotherms with hysteresis, with this pointing to micropores and intercrystalline mesopores. Zeolite SiO2/Al2O3 ratio shows however, no effect on specific surface area, pore volume and pore size distribution. NLDFT cylindrical model confirmed the characteristic 5.5 Ǻ micropores in HZSM-5 framework. NH3-TPD results exhibit weak and strong acid sites in which both of these acidities being reduced with increasing SiO2/Al2O3 ratio. NH3-desorption kinetics allows prediction of desorption activation energies and the intrinsic rate constants for both strong and weak acid sites. It was shown that the HZSM-5 studied displays higher activation energy for the stronger sites (57-93 kJ/mol) and lower activation energies for the weaker sites (51-68 kJ/mol). Additionally, there is a decrease of the fractions for weak to strong desorption rate constants with increasing SiO2/Al2O3 ratio. These findings demonstrate that the acidity in HZSM-5 zeolites can be correlated with Al2O3 content. Regarding DTO over HZSM5, one can postulate an “in series” reaction where the formed olefins may continue reacting and yielding heavier paraffin and aromatic hydrocarbons. In this respect a lower conversion with less deactivation were observed as SiO2/Al2O3 ratio increased. Conversely, HZSM-5 become more selective towards olefins as Al2O3 content is reduced.

Tennison Yu

“Characterizing a cetyl trimethylammonium bromide (CTAB) and polyvinylpyrrolidone (PVP) system for nanotube dispersion”

The individual use of surfactants and polymers to disperse carbon nanotubes

(CNTs) through non-covalent interactions has been thoroughly investigated. However, there use in combination has only been briefly explored and there is still uncertainty on the exact mechanism in which how either molecule can act together to disperse carbon nanotubes. Using centrimonium bromide (CTAB) and polyvinylpyrolidone (PVP) at different molecular weights, tests including: UV-Vis, viscosity, and surface tension were utilized to characterize the system in its ability to disperse CNTs. It was found that a lower molecular weight of PVP in combination with CTAB was more effective at augmenting the dispersitivity of carbon nanotubes when compared to its absence. Moreover, it was also noticed that different molecular weights of PVP had minimal effect on the critical micelle concentration (CMC) of CTAB therefore PVP is lowering the spontaneity of CNT bundling.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: February 3rd 2014

3:30-4:30pm SEB 1059

Jahirul Mazumder “Catalytic Steam Gasification of Biomass”

La2O3 promoted Ni/γ-Al2O3 fluidizable catalysts are studied for the steam gasification of a cellulose surrogate (glucose) and a lignin surrogate (2-methoxy-4-methylphenol) in a CREC Riser Simulator. Catalysts are prepared by impregnating metal nitrate solution on γ-Al2O3. During the decomposition of La/Ni nitrates under H2 flow, local temperatures can increase above 1000 oC due to highly exothermic reactions involved. Therefore, gas flow play an important role to remove the heat generated. A higher flow minimizes thermal sintering of meta-stable γ-Al2O3 and improves Ni dispersion. It is also found that addition of La2O3 up to 5wt% helps to reduce thermal sintering and Lewis acidity of γ-Al2O3 as well as improves its basicity. Furthermore, a proper amount of La2O3 on γ-Al2O3 reduces Ni crystallite agglomeration and coke formation. A 20% Ni/5% La2O3-γAl2O3 catalyst is developed, in this study, optimizing catalyst formulation and preparation conditions. This catalyst yields a 98% carbon conversion of glucose to permanent gases with no tar formation and negligible coke deposition. In case of 2-methoxy-4-methylphenol gasification, an 86% carbon conversion with tars formation reduced to only 8% is achieved using this catalyst. H2/CO of the gas produced in this process is attained close to 2.0, which makes it suitable for direct alcohol synthesis. Performance of the catalyst ranked favourably while compared with results of the thermodynamic model developed.

Ha Doan

“Quantification of axial solids mixing and impacts of baffles in counter-current liquid-solids fluidized beds”

Invention of liquid-solids continuous fluidization technology has been much appreciated for its great advantages and potential applications in many fields. The system consists of two main units: a riser and a downer. Typically, reaction or adsorption process involving liquid-phase reactant and solid-phase catalysts or adsorbents takes place in the riser; while regeneration of the deactivated catalysts or desorption of loaded adsorbents is done in the downer. Both processes are equally important in contributing to performance efficiency of the system. However, extensive studies have been done in the riser compared to the downer. One of the parameters that have been investigated for the riser but no data available in literature for the downer is back-mixing of solid-phase. Up to now there is no instrumentation that can trace particles in a dense slow moving bed, which makes the study on axial solids mixing, also called back-mixing, in the downer difficult. Yet this is a critical factor in evaluate performance of the downer, subsequently of the entire system.

The simplest way to measure solids back-mixing is to conduct residence time distribution of traceable particles in a fluidized bed. To ensure the tracers have the same physical properties, e.g. shape, size, and density, as the rest of the particles, ion-exchange resin is employed. The tracers are resins in Calcium form while the rest are the same resins but in Sodium form. By collecting particle samples at different time intervals and utilizing the adsorption and desorption properties of the resins, residence time distributions are obtained, and Peclet numbers, axial diffusion coefficients are calculated at 3 different operating conditions. In the attempt to characterize solids dispersion in the downer, 3 baffle designs are also considered: louver, mesh-grid and vertical plane. Their impacts on particles movement are assessed. The results show that at a low liquid velocity, fluidized beds behave like a packed bed and particle dispersion is minimal. Therefore, the existence of baffles are only disrupting the smooth path of solids. When the liquid flow increases, dispersion becomes significant and all baffles designs have positive impact as suppressing random movement of fluidized particles. Among 3 designs, louver shows the best result as it reduces mixing by a factor of 2.5 compared to a baffle-free bed.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: February 10th 2014

3:30-4:30pm SEB 1059 Ana Maria Aguirre

“Study of the effect of culture conditions and steam explosion on microalgae cell wall disruption for lipids extraction”

Microalgae cultures have emerged as an attractive alternative for biodiesel

production. However, several obstacles such as increasing lipid productivity and lipid extraction from the cell must be overcome before implementing this technology at industrial scale. In order to develop a successful process for lipid extraction, all aspects related with cell wall disruption should be taken into account. This means that not only the method for breaking down the cell plays an important role, but also the intrinsic characteristics of the cell wall.

In this study, the central composite design of the response surface methodology was employed to evaluate the effect of simultaneous manipulation of carbon dioxide and nitrate concentrations on lipid productivity and cellulose content, which is of special interest for further research in microalgae cell wall disruption. Empirical data was fitted to second order equations by multiple regression analysis. The models obtained for each variable allowed finding the optimal points for lipid productivity and cellulose content as a function of carbon dioxide and nitrate concentration and they can constitute operational points leading to systems with high lipid productivity and low cellulose content.

Same statistical approach was used to study the effect of high pressure steaming on lipid extraction in cultures previously optimized. Manipulated variables were target temperature and algae concentration and response variable were bio-crude and glucose yields.

Shan Gao

“Microflow Structures of circulating fluidized beds”

This study focuses on identifying and characterizing the microflow structure of circulating fluidized beds (CFBs) of different design features, which include different phases (gas-solids and liquid-solids) and flow directions (downflow and upflow systems). Low and high-flux CFB operating conditions will be studied in gas-solid circulating fluidized bed. The effects of operating conditions on flow structure will be studied in different units.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: February 24th 2014

3:30-4:30pm SEB 1059 Christine Haas, President, Renix Inc. “Spinning Out - The Experience of Commercializing New Technology”

Universities have historically been a great source of ideas and technologies, but

getting those ideas to market has not been as successful as hoped. Christine Haas, President of Renix Inc., will describe Uninterrupted Ion Exchange, a technology developed originally in the Western’s Faculty of Chemical/Biochemical Engineering, and will speak on the experience of working toward commercialization of a chemical engineering technology developed through academic research, the challenges experienced, and the rewards of such an undertaking.

Brief Biography

Ms Haas is founder and President of Renix Inc., provider of Uninterrupted Ion Exchange technology for industrial purification. She is a professional engineer and manufacturing process integration specialist with twenty years’ experience in manufacturing, project management, consulting, & business development in the industrial services sector. She has a BESc, Chemical & Biochemical Engineering from The University of Western Ontario, and completed the Ivey School of Business Executive Development Program. Prior to founding Renix, Ms Haas was a business unit director for a leading process automation firm where her focus was optimizing plant operations for clients in Pharmaceuticals, Food & Beverage, Specialty Chemicals, and Water Treatment.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: March 3rd, 2014

3:30-4:30pm SEB 1059 A.D. Wong

“Development of new cascade degradable polymers”

Cascade degradable polymers (CDPs) are a novel class of stimulus-responsive

materials, designed to remain stable in the presence of an endcap, and degrade from head to tail in response to an external trigger. A variety of CDPs have been designed and synthesized by our group and others, and these materials promise unparalleled control over degradation rates and conditions when compared to traditional degradable materials. Recent work has involved the design and synthesis of novel endcapping agents for triggered degradation with hydrazines.

Selected References: A.D. Wong, M.A. DeWit, E.R. Gillies. Adv. Drug Deliv. Rev. 64, 2012, p.1031-1045

Adam Golin “Electrospun Scaffolds for Use in Tympanic Membrane Regeneration”

With the aim of creating a biodegradable scaffold for tympanic membrane (TM) tissue regeneration, core-shell nanofibers composed of a poly(caprolactone) shell and a poly(ethylene glycol) core were created using a coaxial electrospinning technique. In order to create an optimal core-shell morphology, the effect of relative humidity on the core-shell nanofibers was systematically studied, with a FITC-BSA complex encapsulated in the core to act as a model protein. The core-shell nanofibers were electrospun at relative humidity (RH) values of 20, 25, 30, and 40% RH within a glove box outfitted with a humidity control system. The core-shell morphology of the fibers was studied via the use of scanning electron microscopy, ultramicrotoming, transmission electron microscopy, and laser scanning confocal microscopy. It was found that humidity does alter the core-shell morphology by altering the solvent evaporation rate and that there is an ideal humidity for the coaxial electrospinning of core-shell fibers. In addition, the fibers were fashioned into a biomimetic scaffold for TM regeneration using a rotating mandrel to align the nanofibers and to create a dual layer fibrous mat similar to the structure of native TM collagen fibers.



Department of Chemical and Biochemical Engineering Graduate Seminar Series: March 10th, 2014

3:30-4:30pm SEB 1059 Alejandro Montes

“Study on the critical amount of liquid for Bubbling Fluidized Bed (BFB) boilers Agglomeration”

Biomass conversion for thermal/power generation in fluidized bed processes still

has some technical difficulties. Agglomeration at high temperature is one of the most important and challenging problems. Typically, the conversion of the solid fuel is carried out with silica sand as bed material in the presence of ash. Inorganic alkali components from the fuel, mainly potassium (K) and sodium (Na) can be problematic as they form low-melting alkali compounds and may also react with the bed material forming low-melting alkali silicates. These low-melting alkali compounds, characterized by low melting temperatures, coated the sand particles with a sticky layer. This makes sand particles agglomerate upon collisions and grow larger with time. This eventually leads to partial or complete defluidization of the reactor.

In the present study, the critical amount of liquid (molten ash in real biomass boiler operations) that would result in severe bed agglomeration and defluidization was studied in a small pilot-scale BFB using non-invasive capacitance sensors and differential pressure transducer. The bed was filled out with silica sand as a bed material and different quantities of a glycerol-water (30%v/v) solution were injected to the bed, simulating molten ash in real biomass boiler operations. The effect of gas velocity on the agglomeration phenomena was also evaluated.

It was found that in the present fluidization system the critical liquid amount for bed agglomeration is likely 0.2 wt% (in relation to the weight of bed material loaded) and 0.7wt% would cause severe channeling and very poor fluidization conditions.

Alejandro Montes, Majid Hamidi, Cedric Briens, Franco Berruti, Chunbao (Charles) Xu and Honghi Tran.

Nicholas Prociw

“Evaluation of agglomerate stability in an industrial scale fluidized bed using conductivity method”

Liquid injection in fluidized beds is used for various applications in the petroleum

upgrading and refining industries such as Fluid Catalytic Cracking and Fluid CokingTM. In Fluid CokingTM operations, the injection of liquid sprayed onto a fluidized bed of coke particles results in the formation of wet agglomerates, which limits heat and mass transfer rates. Sprays that produce less stable agglomerates would, thus, increase the process efficiency. Mohagheghi et al. (1) performed local bed capacitance measurements in a small scale fluidized bed with various atomization gas flowrates and various bed fluidization velocities. They developed a new method to infer agglomerate stability from capacitance measurements.

The objective of the present study was to adapt this method to the testing of commercial-scale spray nozzles, with a water flowrate of about 150 kg/min. Since this required a fluidized bed of 8 tonnes of sand, a large steel column had to be used, precluding accurate capacitance measurements. Instead, bed conductance measurements were performed with 24, non-invasive, wall electrodes. Preliminary experiments indicated that the bed conductance is not affected by the liquid trapped within agglomerates, so that the bed conductance can be directly related to the free moisture, i.e. the liquid that is not trapped within agglomerates (2).

The bed-averaged free moisture varied with time. Liquid injection took about 10 s and ended at t = 0 s. Free moisture is created as agglomerates break up and free moisture simultaneously disappears through evaporation. At first, agglomerate breakup predominated while, after about 1200 s, evaporation predominated. By accounting for evaporation, the evolution of the cumulative amount of liquid that had been freed from agglomerates could be estimated. At the end of the liquid injection, for t = 0 s, about 30% of the injected liquid had been freed from agglomerates. The rate of agglomerate breakup then decreased with time so that it took about 100 s to free 70% of the liquid and 850 s to free all the liquid. An advantage of this method is that the bed regions where most of the agglomerate breakage occurs may be identified from local bed conductance measurements.

This method was used to show that increasing the flowrate of atomization gas through the spray nozzles resulted in agglomerates that broke up more quickly. Increasing the fluidization velocity was very effective in speeding up agglomerate breakup.

Nicholas Prociw, Tarek J. Jamaleddine, Cedric Briens, Franco Berruti, and Jennifer McMillan.

REFERENCES

1. M. Mohagheghi, M. Hamidi, C. Briens, F. Berruti, J. McMillan. The Effects of Liquid Properties and Bed Hydrodynamics on the Distribution of Liquid on Solid Fluidized Particles in a Cold-Model Fluidized Bed. Submitted to Fluidization XIV.

2. Mohammad Ali Zirgachianzadeh, C. Briens, F. Berruti, J. McMillan. Liquid Distribution from Industrial Scale Spray Jets in Fluidized Beds. Masters Thesis. Western University, London, ON, Canada, 2012




November 4th, 2014

3:30-4:30pm SEB 1059

M.A. Mumin

“Engineered Quantum Dots for Solar-Polymer Films”

Light selective polymer films based on poly (ethylene-co-vinyl acetate) (PEVA) are of significant current interest in emerging solar materials, including PV encapsulants and greenhouse plastic films. Quantum dots (QDs) have been shown to absorb UV light while transmitting light of higher wavelengths which potentially can be advantageous for enhancing PV efficiencies or in the case of greenhouse films, controlling plant growth. However, a simple procedure for integration of the bright and photostable QDs into PEVA films with retention of the light selective properties has been elusive. This work provides a simple procedure for loading encapsulated QDs into PEVA by simple melt-mixing in a twin-screw extruder. Highly luminescent bare and core-shell QDs with 5 nm sizes were synthesized using a facile approach based on pyrolysis of the single molecule precursors. To make both the bare and core-shell structure QDs more resistant against photochemical reactions, they were encapsulated in a carrier through a novel reverse microemulsion technique based on hydrophobic interaction and coupling agent. This encapsulation enhanced the quantum yield and photostability compared to the bare QDs. The encapsulated nanocrystals were then melt-mixed into PEVA in a mini-compounder, with the resulting blends extruded and pressed into thin films of different thickness using a Universal Film Maker and a Carvar hydraulic press. Confocal laser scanning microscopy showed that encapsulation enhanced dispersibility of QDs throughout the PEVA. Both the encapsulated bare and core-shell QDs were studied at various loading levels from 0.1% to 1%, showing decreased UV (up to 75%), and IR transmission, while retaining high visible light transmission (90%).

1Dr. Paul A. Charpentier. Department of Chemical and Biochemical Engineering, Western University, London Ontario, N6A 5B9,Canada;

Medhavi Gupta

"Mesophilic Biohydrogen Production and Microbial Community Analyses from Co-fermentation of Glucose, Starch, and Cellulose"

The aim of this study was to assess the synergistic effects of co-fermentation of

glucose, starch, and cellulose using anaerobic digester sludge (ADS) on the biohydrogen production and the associated microbial communities. Batch studies were conducted with overall substrate concentration of 13.5 gCOD/L and an initial substrate-to-biomass (S/X) ratio of 4 gCODsubstrate/g VSSseed. H2 yields of 1.22, 1.00, and 0.15 mol H2/mol hexose-added was observed in glucose, starch, and cellulose as mono-substrates. The hydrogen yields were greater by 27 ± 4% than expected, which affirmed that co-fermentation of different substrates improved the hydrogen potential. Glucose addition to starch and/or cellulose favored acetate synthesis, while cellulose degradation was associated with the propionate synthesis pathway. Interestingly, hydrogen yield was inversely proportional to the hydrogen production rate. However, hydrogen yields had a linear relationship with the number of observed species. Co-fermentation caused noticeable variation in the microbial community structure. Illumina sequencing technology and bioinformatic analyses revealed operational taxonomic units (OTUs) in the Phyla Bacteroides, Chloroflexi,Firmicutes, Proteobacteria, Spirochaetes, Synergistes, and Thermotogae were common in mono- and co-substrate batches. However, OTUs in the Phyla Acidobacteria, Actinobacteria, and Bacteroidetesee were unique to only the co-substrate conditions.

Medhavi Gupta1, Preethi Velayutham2, David B. Levin2, George Nakhla, Department of Chemical and Biochemical Engineering, Western University, London Ontario, N6A 5B9, Canada; 2 Department of Biosystems Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 3V6, Canada

seminar abstract book 2 - faculty of engineering _2013_2014.pdf · nov 25th, 2013 invited speaker:...

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