Engineering Commons^™

Influence Of Photoreactor Design Parameters On The Performance Of Ultraviolet Light-Induced Degradation Of Per-And Polyfluoroalkyl Substances By Bismuth Oxy Hydroxy Phosphate And Hexagonal Boron Nitride Photocatalystsinfluence Of Photoreactor Design Parameters On The Performance Of Ultraviolet Light-Induced Degradation Of Per-And Polyfluoroalkyl Substances By Bismuth Oxy Hydroxy Phosphate And Hexagonal Boron Nitride Photocatalysts, Mojtaba Qanbarzadeh

All Dissertations

The main objective of this study is to evaluate the practical applicability of heterogeneous photocatalysis technology powered by ultraviolet (UV) photons for the degradation of per and -polyfluoroalkyl substances (PFAS) in contaminated groundwater samples. For this purpose, bismuth oxyhydroxy phosphate (BOHP) and hexagonal boron nitride (hBN) were utilized as the main photocatalysts in slurry photodegradation systems. BOHP (Bi₃O(OH)(PO₄)₂) is a wide bandgap semiconductor with high activity for degrading long-chain perfluorocarboxylic acids (PFCAs) in mild operational conditions. Boron nitride (BN) is another wide bandgap semiconductor material that was used in this study due to its …

Influence Of Salts On The Photocatalytic Degradation Of Formic Acid In Wastewater, Azzah Nazihah Che Abdul Rahim, Shotaro Yamada, Haruki Bonkohara, Tsuyoshi Imai, Yung-Tse Hung, Izumi Kumakiri

Civil and Environmental Engineering Faculty Publications

Conventional wastewater treatment technologies have difficulties in feasibly removing persistent organics. The photocatalytic oxidation of these contaminants offers an economical and environmentally friendly solution. In this study, TiO2 membranes and Ag/TiO2 membranes were prepared and used for the decomposition of dissolved formic acid in wastewater. The photochemical deposition of silver on a TiO2 membrane improved the decomposition rate. The rate doubled by depositing ca. 2.5 mg of Ag per 1 g of TiO2. The influence of salinity on formic acid decomposition was studied. The presence of inorganic salts reduced the treatment performance of the TiO2 membranes to half. Ag/TiO2 membranes …

Visible-Light-Active Disinfection Of Surface Water Coliform Using Silver/Titanium Dioxide/Silver Bromide(Ag/Tio2/Agbr) As Photocatalyst, Ashraya Upadhyaya

University of New Orleans Theses and Dissertations

As human population becomes diverse, the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies to supplement or replace conventional treatment methods are important, especially to satisfy the need of small, rural communities for safe drinking water. These challenges can be somewhat met with the use of semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light-active (VLA) photocatalysis can be effectively applied in disinfection of drinking water. In comparison to traditional, energy-intensive, physical and chemical disinfection methods, VLA photocatalysis is capable of providing high disinfection efficiency with the use of cheaper energy, no harmful by-products, …

Construction Of Bismuth Oxyhallide-Based Heterojunction-Structured Composite And Its Environmental Application For Water Treatment, Li Wang

Theses and Dissertations

With the rapid development of the global economy, environmental protection and sustainable development have become the main trends of current society. In particular, water pollution and energy shortage are outstanding issues that need to be solved in a clean and sustainable way. Recently, semiconductor-based photocatalytic technology, an environmentally friendly technique, has attracted enormous attention and become an emerging research hotspot in the application of water/wastewater treatment and generation of renewable energy as it can convert infinite solar energy into chemical energy. Conventional semiconductor materials usually have a relatively large band gap that only responds to the ultraviolet light, which largely …

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 …

Crumpled Graphene Oxide: Aerosol Synthesis And Environmental Applications, Yi Jiang

McKelvey School of Engineering Theses & Dissertations

Environmental technologies, such as for water treatment, have advanced significantly due to the rapid expansion and application of nanoscale material science and engineering. In particular, two-dimensional graphene oxide (GO), has demonstrated considerable potential for advancing and even revolutionizing some of these technologies, such as engineered photocatalysts and membranes. To realize such potential, an industrially scalable process is needed to produce monomeric and aggregation-resistant GO nanostructures/composites, in addition to new knowledge of material properties, behavior, and performance within an environmental context.

Research presented in this thesis addresses both scientific and engineering gaps through the development of a simple, yet robust aerosol-based …

Applications Of Microbial Desalination And Photocatalytic Disinfection For The Removal Of Contaminants In Drinking Water, Kristen Shirlee-Ann Brastad

Theses and Dissertations

Trends in drinking water treatment in recent years have been moving toward the use of membrane separation in order to reduce contaminants in water. There are many forms of membrane separation technology such as ultrafiltration, nanofiltration, microfiltration, reverse osmosis, and extruded ion exchange membranes. These membranes have many different applications and may be used to remove many materials from water such as salts, viruses and bacteria, selectively remove cations or anions, or remove organics.

Microbial desalination cells (MDCs) are an emerging concept which use bioelectric potential produced from organics via microbial metabolism to accomplish desalination. MDCs consist of three compartments, …

The Impact Of Capsid Proteins On Virus Removal And Inactivation During Water Treatment Processes, Brooke K. Mayer, Yu Yang, Daniel Gerrity, Morteza A. Abbaszadegan

Civil and Environmental Engineering Faculty Research and Publications

This study examined the effect of the amino acid composition of protein capsids on virus inactivation using ultraviolet (UV) irradiation and titanium dioxide photocatalysis, and physical removal via enhanced coagulation using ferric chloride. Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. All amino acids demonstrated significant correlations with UV susceptibility. The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. Oxidizing chemicals, including hydroxyl radicals, preferentially degrade amino acids over nucleotides, and the amino …

Novel Nanostructured Materials For Solar Fuel Production And Advanced Rechargeable Batteries, Cunyu Zhao

Theses and Dissertations

Non-renewable fossil fuels are the major sources to meet the energy, electricity and transportation demands of today's world. The over consumption of fossil fuels will lead to the increasing energy crisis and disastrous effects such as air pollution, global warming etc.

The primary greenhouse gas is CO2 mainly emits from the combustion of fossil fuels. Photocatalytic reduction of CO2 using sunlight as the energy input is a promising way to reduce CO2 level in the atmosphere and in the meantime produce alternative fuels such as CO, methane, methanol, etc. Among the various photocatalyst materials reported, nanomaterial TiO2 is the most …

Modeling And Design Of Photocatalytic Reactors For Air Purification, Yangyang Zhang

USF Tampa Graduate Theses and Dissertations

Photocatalysis is a promising technique for the remediation of indoor air pollution. Photocatalysis utilizes semiconductor photocatalysts (such as TiO₂ or ZnO) and appropriate light to produce strong oxidizing agents (OH*) that are able to break down organic compounds and inactivate bacteria and viruses. The overall goal of the research is to develop an efficient photocatalytic reactor based on mass transfer for indoor air purification. This study has focused on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the reactor catalyst surface. The major effect of artificial roughness elements on the catalytic …

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 …

A Comparison Of Pilot-Scale Photocatalysis And Enhanced Coagulation For Disinfection Byproduct Mitigation, Daniel Gerrity, Brooke Mayer, Hodon Ryu, John Crittenden, Morteza Abbaszadegan

Civil and Environmental Engineering Faculty Research and Publications

This study evaluated pilot-scale photocatalysis and enhanced coagulation for their ability to remove or destroy disinfection byproduct (DBP) precursors, trihalomethane (THM) formation potential (FP), and THMs in two Arizona surface waters. Limited photocatalysis (/m³) achieved reductions in most of the DBP precursor parameters (e.g., DOC, UV₂₅₄, and bromide) but led to increased chlorine demand and THMFP. In contrast, enhanced coagulation achieved reductions in the DBP precursors and THMFP. Extended photocatalysis (/m³) decreased THMFP once the energy consumption exceeded 20 kWh/m³. The photocatalytic energy requirements for THM destruction were considerably lower (EEO = …

Simultaneous Treatment Of Organic (Phenol) And Heavy Metal (Cr6+ Or Pt4+) Wastes Over Tio2, Zno-Tio2 And Cds-Tio2 Photocatalysts, Slamet Slamet, R. Arbianti, Daryanto Daryanto

Makara Journal of Technology

Simultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr6+ or Pt4+) Wastes over TiO2, ZnO-TiO2 and CdS-TiO2 Photocatalysts. Treatment of heavy metal (Cr6+ and Pt4+) and organic (phenol) wastes has been studied using the relatively new method, i.e. simultaneous photocatalytic process over TiO2 photocatalysts in the batch photoreactor. Following the photocatalytic reduction of the heavy metal wastes, recovery of Cr and Pt was carried out by precipitation and leaching method, respectively. The experimental results show that in the simultaneous photocatalytic system, there is a synergism effect between the photocatalytic reduction of heavy metal waste (Cr6+ or Pt4+) and the oxidation …