Membrane Science Commons^™

Sodium Doping Effects On Properties Of Czts Thin Filmsfabricated By Sol-Gel Convective Deposition Technique, Orawan Sukchoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cu2ZnSnS4 (CZTS) is an interesting candidate for thin-film solar cell applications due to its availability and attractive properties (energy band gap of 1.5 eV and high absorption coefficient). However, CZTS solar cell performance is limited because of the defect formation from small grain size, pinholes, rough surface, and negative defects in CZTS such as CuZn. One of the most possible ways to reduce these negative defects, and to increase solar cell performance is by doping with sodium. In this work, CZTS films were synthesized by sol-gel convective deposition technique and Na was doped in CZTS film using 2 different methods: …

Sulfonated Polyetheretherketone/Polyvinylidene Fluoride Blend Polymeric Cation Exchange Membrane As Separator In Zinc-Iodine Flow Batteries, Pimpen Pusanasuwanasri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Zinc-iodine flow batteries (ZIFBs) are very appealing owing to their abundance of active materials, low cost, high safety and environmental friendliness. The cation exchange membrane (CEM) separator contributes a significant part to the cost and determines battery performance. Sulfonated poly (ether ether ketone) (SPEEK) is a promising candidate as a CEM separator. The ionic conductivity of SPEEK CEM can be tuned by adjusting a degree of sulfonation (DS), but the mechanical property of CEM could be deteriorated. Blending poly (vinylidene fluoride) (PVDF) with SPEEK can improve the mechanical strength of SPEEK membrane. Therefore, this study examined the effect of PVDF …

Bimetallic Nanoparticles Integrated Membranes For Groundwater Remediation: Synthesis, Characterization And Applications, Hongyi Wan

Theses and Dissertations--Chemical and Materials Engineering

The detoxification of chlorinated organics from groundwater, such as trichloroethylene (TCE), tetrachloroethylene (PCE), polychlorinated biphenyl (PCB) and carbon tetrachloride (CTC), is a challenging area. Reductive dechlorination has been investigated using iron and iron-based nanoparticles, such as bare Fe, sulfidized Fe (S-Fe) and palladized Fe (Pd-Fe). However, issues including particle agglomeration, difficulties in recycling and particle leaching have been reported to hinder the application and wide usage of these techniques. The integration of nanoparticles and membranes can address these issues because of the large surface area, stability, and the potential for versatile functionalities. In this study, commercial polyvinylidene difluoride (PVDF) microfiltration …

Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch

Theses and Dissertations--Chemical and Materials Engineering

Novel metallic thin film composite membranes are synthesized and evaluated in this work for improved separations and catalysis capabilities. Advances in technology that allow for improved membrane performance in solvent separations are desirable for low molecular weight organic separation applications such as those in pharmaceutical industries. Additionally, the introduction of catalytic materials into membrane systems allow for optimization of complex processes in a single step. By adding a nanostructured metallic thin film to its surface, a polymer membrane may be modified to exhibit these improved properties. Using magnetron sputtering, thin metal films may be deposited on commercially available membranes to …

Microfiltration Membrane Pore Functionalization Approaches For Chloro-Organic Remediation To Heavy Metal Sorption, Mohammad Saiful Islam

Theses and Dissertations--Chemical and Materials Engineering

Microfiltration polyvinylidene fluoride (PVDF) membranes have distinct advantage for open structure in terms of high internal surface area and ease of access in the pore domain. Functionalization of PVDF membranes with different functional groups (-COOH, -OH, -SH) enables responsive (pH, temperature) properties to membrane, tuning of effective pore size, controlling permeate flux. PVDF microfiltration membrane functionalization with suitable responsive polymer such as poly acrylic acid (PAA) to incorporate carboxyl (-COOH) group enables further modification of functionalized PAA-PVDF membranes for different application ranging from catalysis, bio reactor to heavy metal sorption platform. As a catalytic reactor bed, this PAA-PVDF membranes are …

The Development Of Temperature And Ph Responsive Hydrogels And Membranes For Selective Sorption Of Perfluoroorganics And Nanoparticle Integrated Catalytic Degradation Of Pcb, Anthony Saad

Theses and Dissertations--Chemical and Materials Engineering

The functionalization and use of responsive and catalytic polymeric membranes and materials were explored for contaminant capture and degradation. While membranes have a wide variety of uses across multiple industries, the inclusion of materials that are temperature and pH responsive in the membrane pore domain yields a wide range of applications and possibilities for water treatment. Temperature and pH responsive polymers, as well as controlled nanostructured materials, were synthesized in membrane pores for advanced adsorption-desorption and catalytic treatment of emerging organic contaminants in water. In this study, supported by the NIEHS, poly-N-isopropylacrylamide (PNIPAm) was used as a model thermo-responsive polymer, …

A Thermodynamic And Feasibility Study Of Green Solvents For The Fabrication Of Water Treatment Membranes, Xiaobo Dong

Theses and Dissertations--Chemical and Materials Engineering

Nonsolvent induced phase separation (NIPS) has been widely used to fabricate polymeric membranes. In NIPS, a polymer is dissolved in a solvent to form a dope solution, which is then cast on a substrate and immersed in a nonsolvent bath, where phase inversion occurs. Petroleum-derived organic solvents, such as N-Methyl-2-Pyrrolidone (NMP) and Dimethylacetamide (DMAc), have been traditionally used to fabricate polymeric membranes via NIPS. However, these solvents may have negative impacts on environmental and human health; therefore, using greener and less toxic solvents, preferably derived from biomass, is of great interest to make membrane fabrication sustainable. In this dissertation, two …

Polymeric Nanocomposite Membranes With Phosphorene Based Pore Fillers For Fouling Control, Joyner Eke

Theses and Dissertations--Chemical and Materials Engineering

Phosphorene is a two-dimensional material exfoliated from bulk phosphorus. Specifically, relevant to the field of membrane science, the band gap of phosphorene provides it with potential photocatalytic properties, which could be explored in making reactive membranes able to control the accumulation of compounds on the surface during filtration, or fouling. Another reason phosphorene is a promising candidate as a membrane material additive is due to its catalytic properties which can potentially destroy foulants on the membrane surface.

The first goal of this study was to develop an innovative and robust membrane able to control and reverse fouling with minimal changes …

Methods For Film Coating Electrospun Fibers, Kristopher Dejean

Williams Honors College, Honors Research Projects

Electrospinning uses high voltages to form polymer nanofiber membranes. These membranes have potential for use in filtration, tissue engineering, drug delivery, and catalysis. The nonwoven fiber mat is malleable but has a low tensile strength compared to a solid film of the same polymer. Joining the fibers with a thin film is desired to balance the strength and flexibility. Three methods of producing a film on fiber membrane were tested. The techniques are spraying then melting, spin coating, and dip coating. Electrospinning setup conditions, solvent ratios, damage to fibers, and spin coating speeds were determined. Research was abruptly stopped and …

Methods For Film Coating Electrospun Fibers, Kristopher Dejean

Williams Honors College, Honors Research Projects

Electrospinning uses high voltages to form polymer nanofiber membranes. These membranes have potential for use in filtration, tissue engineering, drug delivery, and catalysis. The nonwoven fiber mat is malleable but has a low tensile strength compared to a solid film of the same polymer. Joining the fibers with a thin film is desired to balance the strength and flexibility. Three methods of producing a film on fiber membrane were tested. The techniques are spraying then melting, spin coating, and dip coating. Electrospinning setup conditions, solvent ratios, damage to fibers, and spin coating speeds were determined. Research was abruptly stopped and …

Towards Efficient Water Treatment: Mechanism Of Colloidal Fouling Of Ultrafiltration Membranes, Ikenna Henry Ozofor

Dissertations, Master's Theses and Master's Reports

This research study first reviewed challenges of conventional and membrane separation systems for water treatment. Though membrane separation systems appeared superior to the conventional counterparts for water and wastewater treatment, wider applications of membrane systems have been limited by some factors, most notably is membrane fouling. Experimental studies were therefore conducted to achieve the goal of this research, which is to investigate how feed properties affect fouling of ultrafiltration (UF) membranes by colloids.

Feed salinity, pH, and nanoparticle concentration were the variables studied to unravel how different UF membranes are fouled by model silica colloids (with average diameter of 25nm). …

Functional Importance Of Lipin Phosphorylation, Stephanie Elizabeth Hood

Graduate Theses and Dissertations

Highly conserved throughout evolution, lipins are dual functioning proteins found from yeast to humans. Functioning in the cytoplasm as phosphatidate phosphatase enzymes (PAP), lipins produce diacylglycerol that serves as a precursor for neutral fats and membrane phospholipids. Alternatively, nuclear lipins are responsible for the regulation of metabolic genes. Interestingly, both the mammalian lipin 1 paralog and the single Drosophila Lipin ortholog are highly phosphorylated proteins. Target of rapamycin (TOR) has previously been identified as one of the kinases that controls the subcellular localization of both lipin 1 and Drosophila Lipin. However, other serine and threonine kinases are predicted to be …

Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo

Graduate Theses and Dissertations

Noble metal nanoparticles and two-dimensional (2D) transition metal dichalcogenide (TMD) crystals offer unique optical and electronic properties that include strong exciton binding, spin-orbital coupling, and localized surface plasmon resonance. Controlling these properties at high spatiotemporal resolution can support emerging optoelectronic coupling and enhanced optical features. Excitation dynamics of these optical properties on physicochemically bonded mono- and few-layer TMD crystals with metal nanocrystals and two overlapping spherical metal nanocrystals were examined by concurrently (i) DDA simulations and (ii) far-field optical transmission UV-vis spectroscopic measurements. Initially, a novel and scalable method to unsettle van der Waals bonds in bulk TMDs to prepare …

Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose

Graduate Theses and Dissertations

Since aromatic and charged residues are often present in various locations of transmembrane helices of integral membrane proteins, their impacts on the molecular properties of transmembrane proteins and their interactions with lipids are of particular interest in many studies. In this work, I used solid-state deuterium NMR spectroscopy in designed model peptide GWALP23 [GGALW(LA)6LWLAGA] with selective deuterium labels to addresses the pH dependence and influence of single and multiple “guest” histidine residues in the orientation and dynamic behaviors of transmembrane proteins. The mutations include Gly to His (G2/22 to H2/22), Trp to His (W5/19 to H5/19) and Leu to His …

Applications Of Ionic Liquids In Membrane Separation, Mohanad Kamaz

Graduate Theses and Dissertations

Ionic liquids represent an emerging attractive material in membrane technology. The central theme of this doctoral dissertation is to develope novel membranes using ionic liquids. Two different approaches were used to prepare ionic liquid membranes including the immobilization of ionic liquid within the membrane pores or the use of pressure assembly method to deposit a selective ionic liquid layer on the top membrane surface.

In chapter 2, imidazolium ionic liquids with three different alkyl halides were successfully synthesized and used to prepare supported ionic liquid membranes (SILMs). SILMs preraper were tested for aqueous and nonaqueous applications. For nonaqueous applications, the …

Development Of Forward Osmosis Based Separations: A Novel Approach In Membrane Technology, Yu-Hsuan Chiao

Graduate Theses and Dissertations

Tackling the worldwide severe water shortage, the membrane technology is considered to be the most efficient approach and hence, used widely as a cost-effective sustainable solution. “Forward osmosis (FO)” has been the major attention in recent time. FO uses osmotic pressure as the driving force to draw the water passing the membrane and achieve the desired separation performance. In general, it is considered to be a process with tremendous potential to resolve the present-day water shortage with extremely low energy consumption. However, the challenges of membrane and draw solution regeneration associated with FO processes must be conquered prior to their …

Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems.

Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be …

Engineered Carbon-Nanocatalyst Composites And Carbon Mixed ‎Matrix Membranes ‎For Water And Wastewater Treatment ‎, Mojtaba Abolhassani

Graduate Theses and Dissertations

Carbonaceous materials such as graphene oxide, and activated ‎carbon have a wide range of ‎applications in water and wastewater treatment due to the high surface ‎area, unique structure, ‎and chemical and thermal stability. Carbon-based materials can be used as a ‎membrane, an ‎adsorbent, a support for nanomaterials, or ‎as a filler within membranes to remove contaminants ‎from water. In this research, the specific carbon materials and how their properties influence their ‎use and performance in ‎specific engineering applications is explored. ‎

Here, membrane filtration and adsorption/degradation of the water and wastewater using carbon-‎based material are investigated. The research firstly focuses …

Biomethane Production From Distillery Wastewater, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Distillery wastewater treatment is a great ecological problem, for example, India produces 2.7 billion liters of alcohol that results in 40 billion liters of wastewater. However, this material can be seen as a resource since 11 million cubic meters of biogas at 60% methane could be produced in addition to cleaning the water. The distillery has two options of what to do with the biogas. The first is to use the biogas to fuel the distillery making the production plant more energy efficient and removing some of the need to buy natural gas. The other is to upgrade the biogas …

Nano-Enhanced Composite Membranes For Water Desalination, Benjamin Fredrik Victor Sundling Von Fürstenrecht

Materials Engineering

In theory single walled carbon nanotubes (SWCNT) will aid in ion rejection due hydrophobicity and smoothness of the SWCNT. An efficient means of water desalination utilizing SWCNT in a membrane seems plausible. A lyotropic liquid crystal (LLC) solution was made with a synthesized polymerizable surfactant methacryloxy ethyl hexadecyl dimethyl ammonium bromide (C16MA) to help with vertical alignment of SWCNT. Due to SWCNT lack of solubility and tendency to agglomerate in water, a dispersion performed using an inert surfactant centrimonium bromide (CTAB) to make sure that the SWCNT were homogeneously dispersed in the solution without altering the hexagonal packing factor of …