Chemical Engineering Commons^™

Alkaline Potassium Polyacrylate Electrolytes For Rechargeable Zinc-Manganese Dioxide Batteries, Jungsang Cho

Dissertations and Theses

Zinc (Zn)–manganese dioxide (MnO₂) rechargeable batteries have high specific theoretical capacity as well as being environmentally friendly, intrinsically safe and low-cost. Liquid electrolytes, such as potassium hydroxide (KOH), are historically used in these batteries; however, many failure mechanisms of the Zn–MnO₂ battery chemistry result from the use of liquid electrolytes, including the formation of electrochemically inactive compounds and shape change of Zn electrodes during charge and discharge cycling. This led to incorporation of an alkaline polymer electrolyte as an alternative to the liquid KOH electrolyte in Zn-MnO₂ rechargeable batteries, with the aim of making them non-spillable …

Surface Activity At The Air-Water Interface And Self-Stratification Of Silica Nanoparticles Functionalized With Tri-Methoxy Poly(Ethylene Glycol) Silane, Hyeongoo Jung

Dissertations and Theses

Aggregated silica nanoparticles (SNPs) have been functionalized with tri-methoxy poly(ethylene glycol) silane (mPEG silane), end-capped with a methyl group. This functionalization imparts surface activity at the air-water interface due to the hydrophobic nature of the end-capped methyl group. To determine the surface coverage of silane on the particle surface, solution-state ¹H-NMR spectroscopy was utilized for characterization, and surface tension measurements were conducted to assess their tension-lowering ability. Solutions containing 10 wt% of the functionalized SNPs reduced the quasi-static surface tension to approximately 53 mN/m, regardless of the amount of reacted mPEG silane. However, the quantification of mPEG silane influenced …

Hydrodynamics Of Drops And Particles Driven By Marangoni And Diffusiophoretic Forces, Subramaniam Chembai Ganesh

Dissertations and Theses

This study investigates the hydrodynamics of particles and drops driven by forces generated by an asymmetrical physical and chemical surrounding environment. In the first part, a novel colloidal motor design driven by surface tension forces is proposed, utilizing an active Janus particle encapsulated in an immiscible liquid drop to form a compound drop/particle. Marangoni forces induced by asymmetric solute adsorption at the liquid-liquid interface of the drop propels the compound system. The propulsion speeds of the motor are analyzed for various relative sizes and configurations of the Janus particle and the encapsulating drop and the effects of varying the transport …

Molecular Origins Of Phase Stability In Phase-Change Nano-Emulsions For Thermal Energy Storage By Nmr Spectroscopy, Jungeun Park

Dissertations and Theses

Phase change materials (PCMs) are latent heat storage materials that can store or release thermal energy during phase transitions. Organic PCM nano-emulsions are formed by emulsifying oil in water in the presence of surfactants, enhancing thermal conductivity and pumpability. However, PCMs nano-emulsions can become unstable due to repeated thermal cycling and shear in heat transfer systems.

To better understand the molecular origins of phase instability in PCMs nano-emulsions, liquid-state nuclear magnetic resonance (NMR) measurements were applied to a model PCM nano-emulsion. Quantitative ¹H single-pulse NMR measurements established the liquid fraction of oil within nano-emulsions as a function of temperature, …

Understand The Structure-Water-Responsive Relationship By Engineering Silk Materials, Yeojin Jung

Dissertations and Theses

Water-responsive (WR) materials mechanically swell and shrink in response to changes in relative humidity, and they have demonstrated the capability to exert higher actuation energy than conventional actuators and artificial muscles. As a result, WR materials have recently gained attention as potential high-energy actuating components for engineering applications. Despite the growing interest in this emerging category of WR materials, the fundamental WR mechanism of their significant performance is still not fully understood, limiting the ability to rationally design engineered systems. This dissertation presents three approaches for understanding the water-responsiveness of materials by engineering Bombyx (B.) mori silkworm silk protein. First, …

The Effect Of Nanoconfined Liquid Properties On The Water-Responsive Behavior Of Bacterial Cell Walls, Seungri Kim

Dissertations and Theses

Water-responsive (WR) materials have the ability to mechanically swell and shrink in response to changes in relative humidity (RH). These WR materials are used by many biological systems to perform essential tasks; for example, pinecones use WR materials to release their seeds in dry environments, and wheat awns open and close to propel seeds into the soil, driven by daily RH changes. The WR actuation of some biomaterials is extremely powerful, for example Bacillus subtilis cell walls display record-high actuation energy and power densities of 72 MJ m^-3 and 9.1 MW m^-3, surpassing those of all existing …

Advancing Natural Hydrogen Exploration: Headspace Gas Analysis In Water-Logged Environments, Krista Davies, Lionel Esteban, Alireza Keshavarz, Stefan Iglauer

Research outputs 2022 to 2026

Natural hydrogen has gained prominence as a potential contributor to the low-carbon energy landscape; however, exploration techniques are still evolving. Current methods primarily rely on dry soil gas studies or gas vent measurements. Because gas vents are scarce and groundwater inhibits hydrogen gas flux from the soil, other field detection techniques are necessary. This research paper presents a novel approach for advancing natural hydrogen exploration through the analysis of headspace gas of agitated groundwater extracted from dedicated shallow boreholes to better estimate the hydrogen gas flux and its variations with time. Several shallow boreholes were drilled in Western Australia on …

Gradient Microstructures And Mechanical Properties Of Ti–6al–4v Alloy Induced By Laser Surface Quenching, Enqing Wang, Jinpeng Tuo, Fengqi Hou, Dongjie Li, Yuanhang Li, Lvhao Zheng, Kai Zhang, Longlong Dong, Yi Yang, Hao Wang, Aijun Huang, Lai Chang Zhang

Research outputs 2022 to 2026

Laser surface quenching (LSQ) was employed to fabricate gradient microstructures in a Ti–6Al–4V alloy. The influence of the LSQ parameters on the surface morphology, the depth of the LSQ layer, gradient microstructure, and microhardness were investigated. The results showed that as the laser energy density increases, the surface roughness and thickness of the heat-affected zone (HAZ) increase. From the internal matrix to the surface, the microstructure in the HAZ changes from the equiaxed structure to the mixt structure, martensitic structure, Widmanstätten structure, and then the oxide layer. The size of the β grains gradually decreases as the distance from the …

The Phase Behaviour And Stability Of An Environmentally Friendly Oil-In-Water Emulsion Produced Using Balanites Aegyptiaca Oil And Green Emulsifiers, Sami A.M. Yagoub, Swee P. Yeap, Nurudeen P. Yekeen, Mohammed A. Ayoub

Research outputs 2022 to 2026

Due to environmental concerns about extensively using chemical emulsifiers and hydrocarbon oil in emulsion systems formation, recent research has shifted to using natural emulsifiers and oil. This study produced green emulsion using Balanites aegyptiaca oil and various bio-emulsifiers (such as sodium alginate, carboxymethylcellulose, guar gum, and Saponin). Phase behavior and stability of the emulsion were tested at different NaCl concentrations over one month of ageing. The emulsion was also produced using Balanites aegyptiaca oil and synthetic emulsifiers (Tween 80 and Triton X-100). The critical micelle concentrations of emulsifiers were determined and used as the fixed concentration for the green emulsion …

Grain Boundary Engineering: An Emerging Pathway Toward Efficient Electrocatalysis, Xiaomin Xu, Yijun Zhong, Magdalena Wajrak, Tejas Bhatelia, San Ping Jiang, Zongping Shao

Research outputs 2022 to 2026

Electrochemical transformation processes involving carbon, hydrogen, oxygen, nitrogen, and small-molecule chemistries represent a promising means to store renewable energy sources in the form of chemical energy. However, their widespread deployment is hindered by a lack of efficient, selective, durable, and affordable electrocatalysts. Recently, grain boundary (GB) engineering as one category of defect engineering, has emerged as a viable and powerful pathway to achieve improved electrocatalytic performances. This review presents a timely and comprehensive overview of recent advances in GB engineering for efficient electrocatalysis. The beneficial effects of introducing GBs into electrocatalysts are discussed, followed by an overview of the synthesis …

Assessing The Impact Of Geochemical Mechanism And Interpolation Factor Selection On The Precision Of Low-Salinity Waterflooding Modelling: A Comparative Study, Malek Jalilian, Sedigheh Mahdavi, Peyman Pourafshary, Zheinjiang You, Amir H. Mohammadi

Research outputs 2022 to 2026

The efficacy of low salinity waterflooding (LSWF) as an enhanced oil recovery (EOR) method in carbonate formations has been well established; however, its geochemical modelling in such reservoirs remains insufficiently explored. This study aims to bridge this gap by conducting a comparative analysis of three well-recognised geochemical mechanisms including fines migration, rock dissolution/precipitation, and multi-ion exchange (MIE). Our research encompasses two parts: experimental and modelling. First, we conducted four coreflooding experiments to study the effect of LSWF on oil recovery in core scale as well as on rock wettability by measuring the contact angle of the crude oil-brine-rock system. In …

Green Synthesis Of Nanomaterials For Smart Biopolymer Packaging: Challenges And Outlooks, Shima Jafarzadeh, Majid Nooshkam, Masoumeh Zargar, Farhad Garavand, Sabyasachi Ghosh, Milad Hadidi, Mehrdad Forough

Research outputs 2022 to 2026

There are several physical and chemical methods for synthesizing nanomaterials, while the most appropriate techniques involve using green chemistry and eco-friendly material. Recently, green synthesized materials for different applications have gained attention as a result of their environmental friendliness and cost-effectiveness. Applying green synthesized nanoparticles (NPS) in food packaging has been extensively investigated. Biopolymers require filler to enhance the optical, barrier, thermal, antimicrobial, and mechanical properties of packaging. Biopolymer packaging incorporated with green synthesized NPs is expected to simultaneously enhance performance while reducing environmental damage. The current review article focuses on biopolymer films with bio (green)-synthesized nanomaterials and their effectiveness …

A Bi-Functional Air Electrode Developed From A Dual-Mof Strategy For High-Performance Zinc-Air Batteries, Yasir Arafat, Muhammad Rizwan Azhar, Yijun Zhong, Xiaomin Xu, Moses O. Tadé, Zongping Shao

Research outputs 2022 to 2026

A durable, high-performing and cost-effective bi-functional catalyst toward oxygen reduction/evolution reactions (ORR/OER) is the key towards the practical application of Zn-air batteries (ZABs). Here, we report a new concept of combining pristine and carbonized MOFs for developing a bifunctional electrocatalyst for ZABs, where the pristine MOF acts as a support for the OER catalysts and the carbonized MOF acts as the ORR catalyst and enhances the electronic conductivity. By electroless NiP-plating over the surface of the Fe-containing 3D MOF (MIL-100), the catalyst shows superior activity for the OER, delivering a current density of 10 mA cm⁻² at an overpotential …

Development Of Tio2/Nh2-Mil-125 Nanocomposite For The Removal Of Ciprofloxacin Under Induced Solar Irradiation, Bilkis Mojisola Ajiwokewu

Theses

This research focuses on the development and application of Metal-Organic Frameworks (MOFs)-based nanocomposites for the photocatalytic removal of pharmaceutical contaminants, with a specific emphasis on ciprofloxacin (CIP). The photocatalytic degradation of CIP was investigated using as-synthesized photocatalysts of TiO₂ nanowires (TiO₂NWs), bare MOF of NH₂-MIL-125, TiO₂NW/NH₂-MIL-125 composite, and Lanthanum (La)-doped composite. Intriguingly, the TiO₂NW/NH₂-MIL-125 composite exhibited the highest efficiency, achieving a photodegradation rate of 0.0111 min-1, surpassing the independent performances of bare MOF of NH₂-MIL-125 and TiO₂NW. The observed efficiency was attributed to …

Design And Implementation Of Portable Power And Desalination Units Powered By Renewable Energy, Mo'ath A. Massad

Mechanical Engineering Theses

Freshwater scarcity is a critical global issue, especially in remote areas or areas impacted by natural disasters. Water desalination is one of the most effective methods to provide fresh water where it is needed. However, large-scale desalination plants cannot provide fresh water in the case of a natural disaster far from the plant's location. To address this, portable desalination units powered by renewable energy sources can be developed to supply potable water and power as a by-product for emergency situations. This work explored the application of different desalination methods, including reverse osmosis (RO) and electrodialysis (ED), in conjunction with renewable …

Functionalized Microfiltration Membranes For Aerosol Capture To Chloro-Organic Degradation, Rollie George Mills

Theses and Dissertations--Chemical and Materials Engineering

The environmental remediation of water and air sources is a challenging field, due to widespread contamination, pollutant variety, and efficiency of existing treatment options. Remediation of certain pollutants, such as per- and polyfluorinated chemicals (PFAS), polychlorinated biphenyls (PCBs), volatile organic compounds (VOCs), and viral aerosols, has shown promise via adsorptive, degradative, or filtration-based processes, each with their respective advantages and limitations. Membrane technology is one option that has exhibited considerable pollutant removal from environmental sources via reverse osmosis (RO) filtration, but is limited by low permeabilities and lack of pollutant detoxification. With the support of NIEHS and NSF, the functionalization …

Molecular Understanding And Design Of Deep Eutectic Solvents And Proteins Using Computer Simulations And Machine Learning, Usman Lame Abbas

Theses and Dissertations--Chemical and Materials Engineering

Hydrophobic deep eutectic solvents (DESs) have emerged as excellent extractants. A major challenge is the lack of an efficient tool to discover DES candidates. Currently, the search relies heavily on the researchers’ intuition or a trial-and-error process, which leads to a low success rate or bypassing of promising candidates. DES performance depends on the heterogeneous hydrogen bond environment formed by multiple hydrogen bond donors and acceptors. Understanding this heterogeneous hydrogen bond environment can help develop principles for designing high performance DESs for extraction and other separation applications. This work investigates the structure and dynamics of hydrogen bonds in hydrophobic DESs …

Exploring The Effect Of Casting Solution Composition, Additives, And Casting Conditions On The Morphology And Separation Performance Of Pvdf Membranes, Rachel Kaplan

Theses and Dissertations--Chemical and Materials Engineering

Global water scarcity and quality concerns in the past decade have led to a looming global water crisis. Polymeric membranes have emerged as a potential solution due to their modularity, operational reliability, and wide range of contaminant removal. Polyvinylidene fluoride (PVDF) is often selected as a membrane material for its enhanced chemical resistance, thermal stability, and mechanical strength. However, these membranes often require more complex fabrication methods or support materials to achieve optimum performance. Flat-sheet unsupported PVDF membranes were fabricated via nonsolvent induced phase separation. The influence of solvent, polymer composition, pore forming additives, and casting conditions were explored with …

Development Of Glutathione-Responsive Disulfide-Containing Poly(Beta-Amino Esters) With Varied Hydrophilicity And Acrylate Functionality, Anastasiia Aronova

Theses and Dissertations--Chemical and Materials Engineering

Smart biomaterials are becoming promising for therapeutic deliveries due to their ability to respond to changes in the environment. Redox-responsive hydrogels are a promising type of smart polymer that can swell and degrade according to cellular oxidative stress levels. Glutathione, abundant in cells, is crucial in redox-responsive biomaterials, serving as a key reactive molecule. This study explored the degradation kinetics of glutathione-responsive poly(β-amino ester) (PBAE) polymers created through a single-step Michael addition. We examined how disulfide content influences the degradation kinetics of these PBAE networks. Additionally, we investigated how the hydrophilicity and functionality of acrylate affect the degradation of disulfide-containing …

Sustained Release Systems For Endometrial Cancer, Claire E. Rowlands

Theses and Dissertations--Chemical and Materials Engineering

Endometrial cancer (EC) is the sixth most common cancer in women worldwide and is the most common cancer of female reproductive organs. From 2007-2016 there has been a global rise in incidence of EC of 1.3 %. Typically, EC is treated with surgery, but at later stages surgery is less effective requiring chemotherapy and/or radiation therapy. These treatment options are less effective than surgery and there are very few FDA approved chemotherapies for EC. The minuscule number of effective treatment options as well as an increase in incidence shows the need for creating improved treatments for EC. There has been …