Engineering Commons^™

Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik

Theses and Dissertations

Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …

Gold-Semiconductor Photocatalysts For Water Treatment Under Visible And Ultraviolet Light, Daniel Willis

LSU Doctoral Dissertations

Water scarcity threatens the lives of millions of people worldwide. It is imperative to improve the energy efficiency and affordability of water treatment methods to avoid a looming water-energy crisis. To meet this challenge, I have pursued research on the use of sunlight—our most reliable and abundant source of energy—to drive water treatment through photocatalysis. I explored the literature and found gold-semiconductor materials to hold promise for harvesting sunlight and catalyzing the breakdown of waterborne contaminants. Initially, I designed a novel optical cavity with gold (Au) nanoparticles on a zinc oxide / titania (TiO₂) / aluminum film stack …

Hydrogen Generation From Eosin Y-Sensitized Pt/Zno Under Solar Light Irradiation, Tianfang Tian

Electronic Thesis and Dissertation Repository

Hydrogen is a promising alternative energy carrier. Generating hydrogen via photocatalysts is clean and energy saving comparing to the current technology for hydrogen generation. ZnO has been proved to have photocatalytic activities for wastewater treatment by multiple studies. However, there are not enough studies to investigate its potential to generate hydrogen as the photocatalyst under light irradiation. Therefore, we will investigate the photocatalytic ability of Pt/ZnO to generate hydrogen. Triethanolamine (TEOA) was used as sacrificial reagent while Eosin Y was used as sensitizer. Pt/ZnO was characterized and tested for its activity for hydrogen generation in different conditions, which are platinum …

Design Of 3d Macroporous Inverse Opal Tio2 Binary And Ternary Composites Sensitized With Gold Nanoparticles And Cds Quantum Dots For Photocatalysis, Daniel A. Corella

Master of Science in Chemical Sciences Theses

Materials composed of titanium (IV) oxide (TiO₂) have received enormous scientific interest due to titania’s abundance, non-toxicity, and photocatalytic proficiency, however its large band gap limits its applicability under ambient conditions. Various attempts have been made to incorporate titania into composite systems to sensitize it for activity under a broader range of wavelengths. One such method includes utilizing narrow band gap semiconductors to form an electron transfer process analogous to photosynthesis referred to as a Z-scheme. Z-scheme systems can catalyze the decomposition of aqueous pollutants via generation of reactive oxygen species after input of sunlight. This work reports …

Synthesis And Energy Applications Of Mesoporous Titania Thin Films, Syed Z. Islam

Theses and Dissertations--Chemical and Materials Engineering

The optical and electronic properties of TiO₂ thin films provide tremendous opportunities in several applications including photocatalysis, photovoltaics and photoconductors for energy production. Despite many attractive features of TiO₂, critical challenges include the innate inability of TiO₂ to absorb visible light and the fast recombination of photoexcited charge carriers. In this study, mesoporous TiO₂ thin films are modified by doping using hydrogen and nitrogen, and sensitization using graphene quantum dot sensitization.

For all of these modifiers, well-ordered mesoporous titania films were synthesized by surfactant templated sol-gel process. Two methods: hydrazine and plasma treatments have been …

Photocatalytic Decomposition Of Phenol Under Visible And Uv Light Utilizing Titanium Dioxide Based Catalysts, Marjorie G. Steiner

Honors Theses and Capstones

Pollution in wastewater effluvia from phenol and phenolic compounds is a common occurrence in many industrial manufacturing plants. Phenol is toxic to human beings as well as a contaminant to the environment, meanwhile, it is difficult to remove from wastewater due to its non-biodegradable nature. To boost the rate of decomposition, various catalytic approaches have been developed. With the interest of decreasing operation cost, titanium dioxide (TiO₂) based catalysts have emerged as good candidates for the photocatalytic process.

In this honors project, a series of TiO₂ based catalysts, including TiO₂, N-TiO₂, Cu-TiO_{2 …}

Evaluation Of Voc Degradation In Photo-Catalytic Air Reactors: Tio2 Immobilization, Energy Efficiency And Kinetic Modeling, Cristina S. Lugo Vega

Electronic Thesis and Dissertation Repository

The high VOC emissions from anthropogenic sources are detrimental to both the environment and humans, contributing with ground-level ozone and particle matter formation. Heterogeneous photocatalysis provides significant potential for VOC degradation. However, the approaches to be used for photocatalyst immobilization in scaled and highly efficient photoreactors are still not well established. Furthermore, there is a lack of reported photonic efficiencies and a shortage of required methods to establish these efficiencies.

To address these issues, this PhD Dissertation reports the study of photonic efficiencies, TiO₂ immobilization on a stainless steel mesh and kinetic models in a scaled-up Photo-CREC-Air Reactor. Acetone …

Solar Photocatalytic Reduction Of Zn2+ Using Graphene-Based Tio2 Composite Catalyst For Application To Cso Treatment, Gloria Kumordzi

Electronic Thesis and Dissertation Repository

The improvement of photocatalyst efficiency in utilizing the majority of wavelengths in the solar spectrum, an abundant natural resource, presents the next step in the large scale application of photocatalysis for the treatment of dissolved organic and inorganic pollutants in wastewater. In this study, a composite catalyst of TiO₂ and Graphene synthesized by a hydrothermal treatment method is used to photo-reduce Zn²⁺, the most abundant heavy metal found in combined sewer overflows (CSOs). The performance of this composite catalyst was assessed under various process conditions such as pH, light intensity, catalyst loading and light source. The TiO …

A Comprehensive Study Of Cd(Ii) Removal From Aqueous Solution Via Adsorption And Solar Photocatalysis, Samindika Athapaththu

Electronic Thesis and Dissertation Repository

As the increase in industrial technology continue to progress, it results in the increase in heavy metal pollution, creating harmful effects on humans, plants, and animals. Since toxic metals do not degrade easily, they accumulate over time, posing greater danger to living organisms. Removal of these heavy metals is therefore, of great importance. Though many research studies successfully utilized UV photocatalysis with TiO₂ catalyst for the removal of Cd²⁺, none have performed the photoreduction of Cd²⁺ under visible light using eosin-y dye-sensitized TiO₂. The objective of the present research is to study the photocatalytic …

Photocalytic Degradation Of Malic Acid Under Thin Coated Tio2, Vanessa Silveira Rodgher

Electronic Thesis and Dissertation Repository

Opaque fluids have a limited irradiation transmission. Thus, their decontamination employing near UV irradiation poses significant technical challenges. In the present study, a thin UV-transparent/waterproof glue layer coated with a 1.5 wt% of TiO₂ and a new PhotoReactor Cell were implemented. TiO₂ irradiation in the PhotoReactor Cell was effected on the TiO₂ particle side, not directly in contact with the fluid, allowing the postulation of an “h⁺” site mobility mechanism on photocatalysis.

Photocatalytic degradation experiments with malic and malonic acid in water at 10, 20, 30 and 40 ppm showed the complete degradation of malic …

Nano Tio2/Graphene Composites For Photovoltaic And Photocatalytic Materials, Nasrin Farhangi

Electronic Thesis and Dissertation Repository

Graphene has been recognized as one of the most exciting carbon based materials of the present decade due to its unique electronic, mechanical and thermal properties. High surface area exfoliated graphene sheets with controllable surface functionality is an attractive two-dimensional surface for attaching different metals and semiconductors for improving the performance of catalysts, sensors, photoelectronic and energy conversion devices. Graphene is an ideal material which can be used for improving various metal oxide properties such as those of titania (TiO₂). TiO₂/graphene composites have shown excellent properties compared to bare TiO₂ in various applications. In high …

Water Treatment Using Advanced Oxidation Processes: Application Perspectives, Charles R. Gilmour

Electronic Thesis and Dissertation Repository

Advanced oxidation processes (AOPs) using hydroxyl radicals and other oxidative radical species are being studied extensively for removal of organic compounds from various waste streams. However, large scale applications of these highly effective technologies in water and wastewater treatment are still very limited due to cost and inadequate information about the resultant water quality. This study focuses on the evaluation of the upstream processing and downstream post treatment analysis of selective AOPs. In the first stage of research, the performance of a proprietary catalyst (VN-TiO₂) was compared with the industry standard P25 TiO₂, for the use …

Photocatalytic Reactor Using Tio2 Thin Film On Quartz Tubes, Ram Mahipal Kouda

Graduate Theses and Dissertations

Photocatalysis process, as an environmental application is an advanced oxidation process with tremendous potential in the near future. Previously many researchers, have conducted photocatalysis in different reactor configuration using TiO2 slurry and thin film, using a UV light source, the constraints for these reactors are the need for the removal of TiO2 particles at the outlet stream in a slurry reactor and poor environment for the efficient use of TiO2 film using UV light, as the UV light penetration depth in water is about an inch.

Taking all this into consideration, we propose a design for reactor with efficient contact …

Photocatalytic Degradation Of Phenolic Compounds In Water: Irradiation And Kinetic Modeling, Jesus Moreira Del Rio

Electronic Thesis and Dissertation Repository

Scaling up a photoreactor requires both knowledge of optical properties of the slurry medium and an established kinetic model. Measuring the scattering and absorption coefficients of particles suspended in water involves the use of specialized optical equipment, as well as the partial solution of the radiative transfer equation (RTE). In addition, modeling of the radiation field in photoreactors with complicated geometries offers special challenges.

On the other hand, most of the kinetic models (KM) for phenol photodegradation reported in the literature were obtained for a single organic chemical species only. In fact, neglecting all the intermediate species generated during the …