The goal of drinking water treatment is to produce and deliver safe water to the consumers. To achieve these objectives water treatment plants are designed based on the concept of the multibarrier approach which combines several drinking water treatment processes in order to increase the reliability of the system. The presence of pharmaceutically active compounds (PhACs), personal care products (PCPs) and endocrine disrupting compounds (EDCs) in drinking water sources is becoming a concern, because of chronic and indirect human exposure to contaminant mixtures at sub-therapeutic levels via drinking water consumption. Membrane filtration can be an efficient treatment process to remove microorganisms and/or trace organic contaminants from drinking water sources. However, membranes are confronted by a major limitation: membrane fouling. Fouled membranes suffer from a loss in performance either leading to a reduction in flux or a higher pressure requirement. Generally, membrane fouling increases the need for membrane maintenance measures such as backwashing and chemical cleaning which has a negative impact on the operating costs and membrane life time. Severe membrane fouling may even impact permeate quality and/or compromise membrane integrity. The aim of this study was to establish if biofiltration pretreatment without prior coagulation would be able to control membrane fouling in natural waters. The second objective investigated the removal of trace organic contaminants by individual treatment processes (i.e. biofiltration and membrane filtration). Parallel to this work, the presence and concentration of selected trace organic contaminants in Grand River (Ontario, Canada) were determined. The trace organic contaminants investigated included atrazine, carbamazepine, DEET, ibuprofen, naproxen, and nonylphenol. Direct biofiltration pretreatment (no coagulation) significantly reduced both reversible and irreversible fouling of ultrafiltration membranes. Results showed that the different degree of reduction of hydraulically reversible fouling was primarily attributed to the absolute concentration of a specific fraction of the dissolved organic matter (i.e. biopolymers) in the biofilter effluent (i.e. membrane feed). The study also suggests that the composition of biopolymers rather than their absolute concentration is important for the control of irreversible fouling. High pressure membranes such as nanofiltration membranes are also subjected to fouling. Results showed that biofiltration pretreatment was able to achieve fouling control but membrane characteristics (i.e. molecular weight cut off) influence the efficiency of the pretreatment. This study also showed that not only biopolymers but also humic substances and low molecular weight acids are being rejected by nanofiltration membranes. Selected trace organic contaminants were detected in Grand River water in the low ng/L range with detection frequencies between 48 to 100%. Seasonal occurrence patterns could be explained by compound use and possible degradation mechanisms. These results confirm the impact of human activities on the Grand River. This study showed that under the right conditions rapid biofiltration is capable of completely removing biodegradable emerging contaminants at ng/L concentrations. DEET, ibuprofen, and naproxen were biodegradable and therefore amenable to removal while carbamazepine and atrazine were recalcitrant. Factors such as empty bed contact time, influent concentration, and temperature influenced the biodegradation kinetics. Finally, both membrane and contaminant properties influenced the degree of rejection achieved by nanofiltration membranes. Results showed that steric hindrance and electrostatic repulsion were the major rejection mechanisms. Several benefits are associated with the use of direct biofiltration for drinking water treatment. These benefits include: the removal of easily biodegradable organic matter leading to biologically stable effluents; the removal of biodegradable trace organic contaminants contributing to the multibarrier approach; the absence of chemicals coagulation which is of advantage for operations in isolated areas; the simple operation and maintenance which is an advantage for locations with limited trained operators; and finally if used prior to membrane filtration biofiltration pretreatment can control membrane fouling.

The goal of drinking water treatment is to produce and deliver safe water to the consumers. To achieve these objectives water treatment plants are designed based on the concept of the multibarrier approach which combines several drinking water treatment processes in order to increase the reliability of the system. The presence of pharmaceutically active compounds (PhACs), personal care products (PCPs) and endocrine disrupting compounds (EDCs) in drinking water sources is becoming a concern, because of chronic and indirect human exposure to contaminant mixtures at sub-therapeutic levels via drinking water consumption. Membrane filtration can be an efficient treatment process to remove microorganisms and/or trace organic contaminants from drinking water sources. However, membranes are confronted by a major limitation: membrane fouling. Fouled membranes suffer from a loss in performance either leading to a reduction in flux or a higher pressure requirement. Generally, membrane fouling increases the need for membrane maintenance measures such as backwashing and chemical cleaning which has a negative impact on the operating costs and membrane life time. Severe membrane fouling may even impact permeate quality and/or compromise membrane integrity. The aim of this study was to establish if biofiltration pretreatment without prior coagulation would be able to control membrane fouling in natural waters. The second objective investigated the removal of trace organic contaminants by individual treatment processes (i.e. biofiltration and membrane filtration). Parallel to this work, the presence and concentration of selected trace organic contaminants in Grand River (Ontario, Canada) were determined. The trace organic contaminants investigated included atrazine, carbamazepine, DEET, ibuprofen, naproxen, and nonylphenol. Direct biofiltration pretreatment (no coagulation) significantly reduced both reversible and irreversible fouling of ultrafiltration membranes. Results showed that the different degree of reduction of hydraulically reversible fouling was primarily attributed to the absolute concentration of a specific fraction of the dissolved organic matter (i.e. biopolymers) in the biofilter effluent (i.e. membrane feed). The study also suggests that the composition of biopolymers rather than their absolute concentration is important for the control of irreversible fouling. High pressure membranes such as nanofiltration membranes are also subjected to fouling. Results showed that biofiltration pretreatment was able to achieve fouling control but membrane characteristics (i.e. molecular weight cut off) influence the efficiency of the pretreatment. This study also showed that not only biopolymers but also humic substances and low molecular weight acids are being rejected by nanofiltration membranes. Selected trace organic contaminants were detected in Grand River water in the low ng/L range with detection frequencies between 48 to 100%. Seasonal occurrence patterns could be explained by compound use and possible degradation mechanisms. These results confirm the impact of human activities on the Grand River. This study showed that under the right conditions rapid biofiltration is capable of completely removing biodegradable emerging contaminants at ng/L concentrations. DEET, ibuprofen, and naproxen were biodegradable and therefore amenable to removal while carbamazepine and atrazine were recalcitrant. Factors such as empty bed contact time, influent concentration, and temperature influenced the biodegradation kinetics. Finally, both membrane and contaminant properties influenced the degree of rejection achieved by nanofiltration membranes. Results showed that steric hindrance and electrostatic repulsion were the major rejection mechanisms. Several benefits are associated with the use of direct biofiltration for drinking water treatment. These benefits include: the removal of easily biodegradable organic matter leading to biologically stable effluents; the removal of biodegradable trace organic contaminants contributing to the multibarrier approach; the absence of chemicals coagulation which is of advantage for operations in isolated areas; the simple operation and maintenance which is an advantage for locations with limited trained operators; and finally if used prior to membrane filtration biofiltration pretreatment can control membrane fouling.

Poly(beta-amino esters) are photopolymerizable and biodegradable polymers prepared by the combination of amines with diacrylates. This study aims to fundamentally understand the polymer network formed by poly(ethylene)glycol diacrylate (PEGDA) MW 700 and 3-methoxypropylamine (3MOPA) as well as to characterize the degradation response of this material with and without cyclic loading. The networks were formed by a two-step process; (1) the synthesis of amine-co-peg diacrylate macromers through a step growth reaction, followed by (2) UV initiated chain growth network formation of the diacrylated macromers. Macromer reaction chemistry was confirmed by 1H NMR measurements. UV calorimetric analysis revealed that network formation was dependent on molecular weight of the PEGDA monomer and light intensity, but not temperature in the range of 20 °C to 40 °C. The glass transition temperature of all networks was measured to be in the range of -40 °C to -30°C with a rubbery moduli ranging from 4 to 10 MPa, depending on the molecular weight of the PEGDA monomer. Partial crystallization was discovered to occur in the networks containing higher molecular weight PEGDA only in the presence of humidity and high frequency cyclic loading. Degradation studies were performed with and without applied cyclical stress, and in both cases elastic modulus decrease and mass loss occurred steadily over a 24-hour period. Increasing frequency of applied compressive stress during degradation served to slightly lower degradation rates, especially in samples cycled at high frequency, which crystallized. In all materials, applied cyclic load resulted in catastrophic fracture of the material prior to an appreciable decrease in modulus. The experiments reveal that degradation rate and failure mode can be influenced by the addition of cyclic loading and this should be considered when screening biodegradable polymers for applications that include mechanical loading.

Cellulose is a biodegradable, renewable, flexible, inexpensive, biopolymer which is abundantly present in nature. In spite of these inherent advantages, cellulose fibers cannot be used directly in a number of potential industrial applications because of their hydrophilic nature; a surface modification is often required to alter the surface properties of cellulose. This thesis work reports a fabrication method that results in superhydrophobic properties (contact angle (CA) > 150°) on cellulose (paper) surfaces. Superhydrophobicity was obtained by domain-selective etching of amorphous portions of the cellulose fiber in an oxygen plasma, and by subsequently coating the etched surface with a thin fluorocarbon film deposited via plasma enhanced chemical vapor deposition from a pentafluoroethane precursor. Two forms of superhydrophobicity with vastly different degrees of adhesion were obtained by varying the plasma treatment conditions, in particular the duration of oxygen etching: "roll-off" (contact angle (CA): 166.7° ± 0.9° and CA hysteresis: 3.4° ± 0.1°) and "sticky" (CA: 153.4° ± 4.7° and CA hysteresis: 149.8±5.8°) superhydrophobicity. The CA hysteresis could be tuned between the two extremes by adjusting the oxygen etching time to control the formation of nano-scale features on the cellulose fibers. The effects of fiber types (soft vs. hard wood) and paper making parameters on fabricating superhydrophobic paper were also investigated. There were no significant differences in the formation of the nano-scale features created via oxygen etching on paper substrates obtained from different fiber types and paper making parameters. Because "roll-off" superhydrophobicity is primarily determined by the nano-scale roughness, this property is therefore not significantly affected by the fiber types or paper making parameters. While the fiber type does not affect "roll-off" or "sticky" superhydrophobicity, paper making process parameters affect the structure of the paper web on the micro-scale and thus lead to variations in "sticky" superhydrophobicity. Superhydrophobic paper substrates were patterned with high surface energy ink deposited using a commercial desktop printer. The patterns could be used to manipulate the drag and extensional adhesion of water drops on the substrates. Classic 'drag' and 'extensional' adhesion expressions were used to model the behavior of water drops on basic dot and line patterns of variable dimensions. A fundamental understanding of the adhesive forces of water drops as a function of pattern shape and size was thus obtained. Based on this knowledge, patterned paper substrates were then designed and fabricated to perform simple unit operations, such as storage, transfer, mixing and merging of water drops. These basic functionalities were combined in the design of a simple two-dimensional lab-on-paper (LOP) device. Further studies of more complicated pattern shapes led to the generation of patterns that allowed directional mobility and tunable adhesion of water drops. These developments are critical for designing novel components for two-dimensional LOP devices such as flow paths, gates/diodes, junctions and drop size filters.

Thesis (M.S.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed Jan. 26, 2010). Includes bibliographical references (p. 40-43).

The translocation of a biopolymer through a narrow pore exists in universal cellular processes, such as the translocations of nascent proteins through ribosome and the degradation of protein by ATP-dependent proteases. However, the molecular details of these translocation processes remain unclear. Using computer simulations we study the translocations of a ubiquitin-like protein into a pore. It shows that the mechanism of co-translocational unfolding of proteins through pores depends on the pore diameter, the magnitude of pulling force and on whether the force is applied at the N- or the C-terminus. Translocation dynamics depends on whether or not polymer reversal is likely to occur during translocation. Although it is of interest to compare the timescale of polymer translocation and reversal, there are currently no theories available to estimate the timescale of polymer reversal inside a pore. With computer simulations and approximate theories, we show how the polymer reversal depends on the pore size, r, and the chain length, N. We find that one-dimensional transition state theory (TST) using the polymer extension along the pore axis as a reaction coordinate adequately predicts the exponentially strong dependence of the reversal rate on r and N. Additionally, we find that the transmission factor (the ratio of the exact rate and the TST rate) has a much weaker power law dependence on r and N. Finite-size effects are observed even for chains with several hundred monomers. If metastable states are separated by high energy-barriers, transitions between them will be rare events. Instead of calculating the relative energy by studying those transitions, we can calculate absolute free energy separately to compare their relative stability. We proposed a method for calculating absolute free energy from Monte Carlo or molecular dynamics data. Additionally, the diffusion of a knot in a tensioned polymer is studied using simulations and it can be modeled as a one-dimensional free diffusion problem. The diffusion coefficient is determined by the number of monomers involved in a knot and its tension dependence shows a maximum due to two dominating factors: the friction from solvents and “local friction” from interactions among monomers in a compact knot. / text

M. Tech. Pharmaceutical Sciences. / Aims to design, evaluate and optimize an extended release matrix tablet of Nicotinic acid using natural polymers to match the in-vitro dissolution profile of Niaspan.

The overall objective of the present study was to evaluate the effectiveness of using a variety of hydrophobic biopolymers and hydrophobic biopolymer-coated sands as technically and economically feasible in-situ sediment amendments or alternative capping materials on a laboratory scale. Cutin from tomato peels, cellulolytic enzyme lignin from sitka spruce chips, and keratin azure from commercially dyed sheeps wool were isolated, prepared, tested, and evaluated as feasible hydrophobic biopolymers for the removal of selected Polycyclic Aromatic Hydrocarbons (PAHs). Testing included chemical and physical characterization, as well as the measurement of kinetics and equilibrium sorption parameters for the sorbates naphthalene, phenanthrene, and pyrene as model hydrophobic organic contaminants. Tomato peel cutin exhibited the largest overall affinity for PAHs, however, keratin azure was selected for further evaluation as the most feasible material due to its low preparation cost. Amendment of industrial sand with a stable, uniform, cross-linked keratin azure derivative was achieved to produce hydrophobic biopolymer-coated sand products containing zero, moderate, and high mass fractions of sand. Chemical and physical material parameters, as well as kinetics and equilibrium sorption parameters for the sorbates naphthalene, phenanthrene, and pyrene, were then obtained for the coated sand products. This allowed simple finite difference modeling of PAH fate and transport through a thin cap comprised of the same, insight into the specific sorption mechanisms involved, and information which could prove useful in predicting potential of keratin products to provide a suitable capping material. Conclusions and recommendations for future research focus on the technical and economical feasibility of the prepared hydrophobic biopolymers and hydrophobic biopolymer-coated sand products as capping or in-situ sediment amendments. / text

Oxygen scavengers are used in active packages to protect the food against deteriorative oxidation processes. The aim of this work was to investigate the possibilities to produce oxygen-scavenging packaging materials based on oxygen-reducing enzymes. The enzymes were incorporated into a dispersion coating formulation applied onto a food-packaging board using conventional laboratory coating techniques. Various enzymes were used: a glucose oxidase, an oxalate oxidase and three laccases originating from different organisms. All of the enzymes were successfully incorporated into a coating layer and could be reactivated after drying. For at least two of the enzymes, re-activation was possible not only by using liquid water but also by using water vapour. Re-activation of the glucose oxidase and a laccase required relative humidities of greater than 75% and greater than 92%, respectively. Catalytic reduction of oxygen gas by glucose oxidase was promoted by creating an open structure through addition of clay to the coating at a level above the critical pigment volume concentration. Migration of the enzyme and the substrate was reduced by adding an extrusion-coated liner of polypropylene on top of the coating. For the laccase-catalysed reduction of oxygen it was possible to use lignin derivatives as substrates for the enzymatic reaction. The laccase-catalysed reaction created a polymeric network by cross-linking of lignin-based entities, which resulted in increased stiffness and increased water-resistance of biopolymer films. The laccases were also investigated with regard to their potential to function as oxygen scavengers at low temperatures. At 7°C all three laccases retained more than 20% of the activity they had at room temperature (25°C), which suggests that the system is also useful for packaging of refrigerated food.

Nanopores (1 – 10 nm diameter) constructed in solid-state membranes, have shown promise as next-generation biopolymer analysis devices offering both high resolution and high throughput. One promising application of nanopores is in the analysis of nucleic acids, such as DNA. This involves translocation experiments in which DNA is placed in an ionic solution and is forced through a nanopore with the aid of an applied electric field. The modulation of ionic current through the pore during DNA translocation can then be correlated to various properties of the biopolymer such as the length. To optimally design and operate nanopore devices, it would be advantageous to develop an accurate computer simulation methodology to predict the physics of the translocation process. Hence, I have developed a physically accurate, computationally efficient simulation methodology to predict and analyze the physics of biopolymer translocation through solid-state (silicon nitride) nanopores. The overall theme of this thesis is to use this simulation methodology to thoroughly investigate important issues in the physics underlying translocation experiments and thereby determine the effects of key structural and operation parameters, such as nanopore dimensions, applied voltage, hydrodynamic interactions, solvent viscosity, and the polymer chain length. The results from these simulation studies can assist in not only proper nanopore design, but also help determine the proper experimental environments and parameters for nanopore operation.