Engineering Commons^™

Integrated Experimental And Dft Study Of Palladium And Nickel Metals Supported On Reducible Metallic Oxides For Selective Hydrogenation Of Alkynes And Dienes Bonds, Toyin Daniel Shittu

Dissertations

This dissertation investigates the capacity of ceria (CeO₂) to serve as a stand-alone reactive catalyst, and to act as catalyst support for different catalyst configurations. Experimental and density functional theory (DFT) approach were used to critically predict and to design ceria-containing catalysts. Ceria owes the catalytic propensity to the ability to undergo switch in the oxidation state from the +4 to +3 states. Motivated by experimental studies involving CeO₂ catalysts, defects CeO₂ surface with an oxygen vacancy (CeO2(111)_Vo) was used to explore the decomposition chemistry of methanethiol based on DFT. The potential formation pathways revealed that …

Membrane Bioreactor For Enhanced Enzymatic Hydrolysis Of Cellulose, Saleha Abdullah Al-Mardeai

Dissertations

With the rising environmental concerns related to fossil fuels utilization and the depletion of these resources, interest in bioethanol from lignocellulosic waste as an alternative, sustainable energy source has been increasing. Date palm waste is considered a good feedstock for bioethanol production, especially in countries of large date palm plantations, such as the United Arab Emirates.

In the lignocellulose to bioethanol process, the enzymatic hydrolysis of celluloses to produce simple sugars that can be converted to bioethanol by fermentation is the most challenging step, and enhancing it is essential for efficient and feasible operation. Enzyme inhibition by the products is …

Koh-Based Modified Solvay Process: Optimization And Kinetics Studies, Aya Abdel-Hamid Mourad

Dissertations

While desalination of seawater is important for meeting the water demand, the technology produces large volumes of reject brine and CO₂, causing environmental pollution. Solvay process (based on ammonia, NH₃) and modified Solvay process (based on calcium oxide, CaO) try to manage these wastes. However, more attention is needed to overcome different limitations of these processes such as, alkaline solubility, operating temperature, maintaining high pH value, and low sodium (Na⁺) removal efficiency, which does not exceed 35%. The aim of this work is to introduce an alternative alkaline, namely potassium hydroxide (KOH) and investigate …

Multi Stage Modified Solvay Process For Co2 Capture And Reject Brine Desalination, Ameera Fares Mohammad

Dissertations

Brine management is an environmental concern, as many desalination plants need to find suitable approaches for the treatment or disposal of the large amounts of concentrated brine that are produced. Many conventional methods are used such as disposal through deep well injection, but these methods still suffer from many drawbacks. An alternative approach is to further process the brine by extracting the salts through reactions with carbon dioxide. The chemical reactions of reject brine with high alkalinity products and carbon dioxide are postulated to constitute a new, effective, economic and environmentally friendly approach. On the other hand, a major challenge …

Conversion Of Lignocellulose Biomass From Date Palm Waste To High Value Chemicals, Emmanuel Galiwango

Dissertations

Lignocellulose biomass has gained growing popularity because of its low cost of production compared to food crops, it solves problems of food and energy security, can grow in various climates and land, and it is CO₂ neutral. Date palm trees produce large amounts of fibrous wastes that are good sources of lignocellulose. There are over 40 million date palm trees in UAE and most of their lignocellulosic wastes (i.e., leaves, surface fibers, bunches, etc.) are currently used for low value applications such as compost or electric generation. However, the lignocellulosic components of this waste stream have the potential to …