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Full-Text Articles in Engineering
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Doctoral Dissertations
In this work, a systematic computational study directed toward developing a molecular-level understanding of gas adsorption and diffusion characteristics in nano-porous materials is presented. Two different types of porous adsorbents were studied, one crystalline and the other amorphous. Physisorption and diffusion of hydrogen in ten iso-reticular metal-organic frameworks (IRMOFs) were investigated. A set of nine adsorbents taken from a class of novel, amorphous nano-porous materials composed of spherosilicate building blocks and isolated metal sites was also studied, with attention paid to the adsorptive and diffusive behavior of hydrogen, methane, carbon dioxide and their binary mixtures. Both classes of materials were …
Carbon-Nzvi Nanocomposites For Dechlorination Of Halogenated Hydrocarbons, Jing Cheng
Carbon-Nzvi Nanocomposites For Dechlorination Of Halogenated Hydrocarbons, Jing Cheng
Electronic Thesis and Dissertation Repository
A family of hybrid nanocarbon/nanoiron composites has been developed with the aim to carry out simultaneous adsorption and dechlorination of chlorinated hydrocarbons from aqueous solutions. Several methodologies for the synthesis of these materials are evaluated in terms of their adsorption capacities and dechlorination activities. Detailed spectroscopic and microscopy studies indicate that the adsorption ability of the carbonaceous support is greatly improved after acid oxidization, attributed to the formation of oxygenated functional groups on their surfaces. When iron nanoparticles are incorporated on the composites, the materials show a much higher trichloroethylene (TCE) removal efficiency compared to bare metallic nanoiron particles or …
Removal Of N-Nitrosodimethylamine And Trihalomethane Precursors With Powdered Activated Carbon, Wilson Beita Sandi
Removal Of N-Nitrosodimethylamine And Trihalomethane Precursors With Powdered Activated Carbon, Wilson Beita Sandi
All Theses
N-nitrosodimethylamine (NDMA) has been used commercially in several applications, including the production of liquid rocket fuel, and a variety of foods, but gained more relevance when it was discovered as a drinking water disinfection by-product (DBP) in 1989. NDMA is a probable human carcinogen with 10-6 lifetime cancer risk associated with a drinking water concentration of 0.7 ng/L, and is listed as a priority pollutant in the Code of Federal Regulations; no federal maximum contaminant level has been established for drinking water yet. However, the United States Environmental Protection Agency is planning to make a preliminary regulatory determination in 2013 …
Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson
Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson
Theses and Dissertations
Graphene-based materials are becoming an astoundingly promising choice for many relevant technological and environmental applications. Deriving graphene from the reduction of graphene oxide (GO) is becoming a popular and inexpensive route toward the synthesis of these materials. While the desired product from GO reduction is pristine graphene, defects and residual oxygen functional groups inherited from the parent GO render reduced graphene oxide (RGO) distinct from graphene. In this work, the structure and bonding for GO and RGO is investigated to the end of a working understanding of the composition and properties of these materials. In situ selected area electron diffraction …
The Production And Characterization Of A Multi-Functional Fiber-Based Composite For Use In Protective Clothing, Jessica Green
The Production And Characterization Of A Multi-Functional Fiber-Based Composite For Use In Protective Clothing, Jessica Green
All Dissertations
A fiber-based composite comprised of two functional components which work concurrently to adsorb toxic organic compounds was developed and characterized for use in chemical threat protective clothing. The first functional component, the sorptive layer, consists of a carded nonwoven loaded with adsorptive particles. In this layer, Capillary-Channeled PolymerTM (C-CPTM) fibers were used instead of traditional round fibers since the grooved nature of the C-CPTM fibers enables increased adsorptive particle loading. The species of adsorptive particles investigated, zeolite and modified PS, are considered as a replacement for more commonly used activated carbon spheres. The second functional component, the flow restrictive layer, …
Application Of Mixed Iron Oxides In Subsurface Remediation Technologies, Saidur Rahman Chowdhury
Application Of Mixed Iron Oxides In Subsurface Remediation Technologies, Saidur Rahman Chowdhury
Electronic Thesis and Dissertation Repository
Heavy metal contamination of soil and groundwater has been a concern in water supply and public health in many countries where the water supply system draws primarily from groundwater. In the present study, mixed maghemite-magnetite nanoparticles have been used as adsorbents for Cr(VI), As and Cd(II) removal. From the study, it is apparent that the removal of Cr(VI ), Cd(II) and As(V) by mixed iron oxide nanoparticles depends on pH, temperature, contact time, solid/liquid ratio and initial concentration of heavy metals. The results showed that Cr(VI) adsorption on mixed maghemite-magnetite was dependent on solution pH between 3 and 6. Theoretical …
First Principle Studies Of Cu-Carbon Nanotube Hybrid Structures With Emphasis On The Electronic Structures And The Transport Properties, Chengyu Yang
Electronic Theses and Dissertations
Carbon nanotubes have been regarded as ideal building blocks for nanoelectronics and multifunctional nanocomposites due to their exceptional strength, stiffness, flexibility, as well as their excellent electrical properties. However, carbon nanotube itself has limitations to fulfill the practical application needs: 1) an individual carbon nanotube has a low density of states at the Fermi level, and thus its conductivity is only comparable to moderate metals but lower than that of copper. 2) Metallic and semiconducting nanotubes are inherently mixed together from the synthesis, and the selection/separation is very difficult with very low efficiency. 3) Carbon nanotubes alone cannot be used …
Pure Component Adsorption Of Methane, Ethylene, Propylene And Carbon Dioxide In Silicalite, Qianqian Zhou
Pure Component Adsorption Of Methane, Ethylene, Propylene And Carbon Dioxide In Silicalite, Qianqian Zhou
ETD Archive
Adsorption isotherms are measured for pure methane, ethylene, propylene and carbon dioxide in silicalite. Isotherm data are collected using a volumetric method at three different temperatures of 10C, 35C and 65C at pressure up to 100psi. The Virial equation and Langmuir equation have been applied to represent excess amount adsorbed in each pure component system. The binary adsorption equilibrium for various mixtures are predicted from the pure component adsorption data, using the Ideal Adsorption Solution Theory (IAST)
Computational Modeling Of Nanosensors Based On Graphene Nanoribbons Including Electron-Phonon Effects, Kirti Kant K. Paulla
Computational Modeling Of Nanosensors Based On Graphene Nanoribbons Including Electron-Phonon Effects, Kirti Kant K. Paulla
Browse all Theses and Dissertations
We investigate detection mechanisms of real time sensors, based on ultra-thin (single and bi-atomic layer thick) and ultra-narrow (~1nm) graphene nanoribbons (GNRs), using first principle based theoretical methods. In the first part of this study we study the electronic and magnetic structures of bilayer graphene nanoribbons (BGNRs) beyond the conventional AA and AB stackings, by using density functional theory within both local density and generalized gradient approximations (LDA and GGA). Our results show that, irrespective of the method chosen, stacking arrangements other than the conventional ones are most stable, and result in significant modification of BGNRs characeristics. The most stable …