Grantee Research Project Results

Final Report: Surfactant Enhanced Photo-oxidation of Wastewaters

EPA Grant Number: R828598C777
Subproject: this is subproject number 777 , established and managed by the Center Director under grant R828598
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico
Center Director: Brouwer, Marius
Title: Surfactant Enhanced Photo-oxidation of Wastewaters
Investigators: Bakker, Martin
Institution: The University of Alabama
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2000 through August 31, 2004
RFA: Gulf Coast Hazardous Substance Research Center (Lamar University) (1996) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

A number of advanced oxidation processes make use of particles of large band gap semiconductors, such as titanium dioxide (TiO₂), to photochemically decompose aqueous phase organic pollutants into carbon dioxide and water.  Because this process occurs at the surface of the TiO₂ particles, it was suggested that concentrating the pollutants at the particle surface using adsolubilization in surfactants aggregates would result in enhanced efficiency.  It was hypothesized that by correctly choosing a surfactant, it would be possible to selectively adsorb one component from a mixture, allowing for selective degradation of pollutants while leaving other solutes to be recycled.

In the course of the research, it became apparent that the colloidal nature of the TiO₂ particles represented a significant problem, both in data analysis and in successful implementation of a process based on the use of such materials.  The objective of this research project was to support the TiO₂ particles in a mesoporous matrix, which would retain the photoactivity of the TiO₂ particles while avoiding the need to separate out the TiO₂ particles after the photodegradation reaction was complete.  Mesoporous matrices were of further interest as the pores were of a scale to exclude other solutes, such as humic acids, that might be present and could adversely affect the photodegradation of the pollutants.

Summary/Accomplishments (Outputs/Outcomes):

Initial research projects using the nonionic surfactant Brij-35 established that this surfactant could successfully adsolublize aromatic organic pollutants such as anthracene, naphthalene, benzoic acid, chlorophenol, and benzene onto the surface of TiO₂ particles.  Adsolublization was shown to enhance the rate of degradation of anthracene; however, the analytical procedure required a series of steps that proved to be very time consuming, including a separation of solution from TiO₂ particles.  The procedure gave reproducibility of data points that did not consistently meet the data quality criteria of the project.  Efforts then were made to improve the particle separation step, particularly by encapsulating the TiO₂ particles being used inside a film of mesoporous silica.

The mesoporous silica preparation method chosen was based on the use of block copolymers of the poly(oxyethylene)-poly(propylene oxide)-poly(oxyethylene) type.  The mesoporous silica synthesized by this method is known as SBA-15 and consists of hexagonal arrays of cylinderical pores of approximately 6 nm diameter.  Addition of ethanol as a cosolvent allows thin films of this material to be cast or coated onto substrates of various forms.  The thickness of the films was determined by variable angle spectroscopic ellipsometry, which also gave an estimate of 46 percent void space in the films, consistent with a formation of a porous silica film.  The incorporation of the TiO₂ particles was monitored by UV-visible optical microscopy, scanning electron microscopy and transmission electron microscopy (TEM).  The mesoporous structure of the silica films was established initially by small angle X-ray diffraction, and recently confirmed by TEM.  TEM also confirmed that pores in the mesoporous silica do not bend around the TiO₂ particles; therefore, the pores in the silica do provide a pathway for the pollutants to diffuse from the surface of the film to the TiO₂ particles and for degradation products to escape into the aqueous phase.

All films were prepared with a film thickness of 380 nm.  Experiments varying the amount of TiO₂ incorporated into the mesoporous silica films showed that films incorporating 12.5 percent by weight  TiO₂ particles achieved the maximum photodegradation efficiency for 2,4-dichlorophenol (2,4-DCP), which was used throughout this phase of the project as the test pollutant.  The TiO₂/mesoporous silica films were coated onto 4 mm outer diameter tubes, which were placed in 10 mL vials containing 5 mL of 150 ppm 2,4-DCP solutions in water.  Irradiations were carried out at 365 nm.  High performance liquid chromatography analyses of the irradiated solutions as a function of time showed that only trace amounts of 2,4-DCP were detectable after 7.5 hours irradiation.  Calculations showed that on a per photon absorbed basis the mesoporous silica/TiO₂ films had approximately two-thirds the efficiency of an equivalent TiO₂ dispersion.

Experiments with alternative types of mesoporous silica showed that the lamellar phase was not stable after removal of the templating polymer.  The cubic phase was stable but showed much lower photoactivity, approximately the same as for TiO₂ incorporated into a nonporous silica film.  Some effects on the distribution of the TiO₂ particles within the films also were examined.  The TiO₂ particles can aggregate within the silica films.  Samples were prepared in which the solutions were sonicated to break any possible aggregates of TiO2.  These films were shown to be only approximately 4 percent more efficient than the films that had not been sonicated.  Experiments were also undertaken to study the long-term photoactivity of the mesoporous silica/TiO₂ films.  Repeated irradiations of 7 hour duration showed that after eight such irradiations the loss of 2,4-DCP decreased from 95 percent to a steady state value of approximately 85 percent.

Subsequent to the completion of the research project, we have been evaluating the photoactivity of the mesoporous silica/TiO₂ films in photovoltaic cells.  We are continuing this aspect of the project by synthesizing and evaluating out mesoporous materials as hosts into which the TiO₂ particles are incorporated.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Publications Views

Other subproject views:	All 7 publications	1 publications in selected types	All 1 journal articles
Other center views:	All 359 publications	104 publications in selected types	All 90 journal articles

Publications

Type	Citation	Sub Project	Document Sources
Journal Article	Adams WA, Bakker MG, Macias T, Jefcoat IA. Synthesis and characterization of mesoporous silica films encapsulating titanium dioxide particles:photodegradation of 2,4-dichlorophenol. Journal of Hazardous Materials 2004;112(3):253-259.	R828598 (Final) R828598C777 (Final)	Full-text: Science Direct-Full Text HTML Exit Abstract: Science Direct-Abstract Exit Other: Science Direct-Full Text PDF Exit

Supplemental Keywords:

pollution prevention, waste treatment, site remediation, advanced treatment technologies, bioremediation, hazardous waste treatment, HSRC,, Scientific Discipline, Water, Waste, Wastewater, Remediation, Physics, Environmental Chemistry, Environmental Engineering, industrial wastewater, advanced oxidation processes, wastewater remediation, catalytic wet oxidation, chemical contaminants, alternative technology, oxygenates, wastewater treatment plants, chlorinated organic compounds, hydrocarbons, aqueous waste stream, chlorinated compounds, organic contaminants

Relevant Websites:

http://dept.lamar.edu/gchsrc/ Exit

Progress and Final Reports:

Original Abstract

2001 Progress Report

2002

2003

Main Center Abstract and Reports:

R828598    EAGLES - Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R822721C529 Environmentally Acceptable Endpoints: Risk Based Remediation Using Bioremediation
R822721C552 Degradative Solidification/Stabilization Technology for Chlorinated Hydrocarbons
R822721C569 Treatment and Product Recovery: Supercritical Water Oxidation of Nylon Monomer Manufacturing Waste
R822721C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R822721C626 Catalytic Hydroprocessing of Chlorinated Organics
R822721C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R822721C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R822721C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R822721C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R822721C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R822721C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R822721C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R822721C651 Adjustable Biopolymer Chelators for Cadmium, Lead and Mercury
R822721C653 New Electrochemically Smart Catalysts for Hazardous Waste Management and Development of Capillary Electrophoresis for Analysis of their Products
R822721C655 Soil Sampling in South Alabama Oil Fields
R822721C659 Subsurface Contamination Site Characterization via a Computer-Aided Visual Tool
R822721C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R822721C663 Soil Remediation with Ultra-High-Efficiency Hydrocyclones
R822721C669 Solid Acid Catalyzed Alkylation in Supercritical Fluids
R822721C679 Regeneration/Reactivation of Carbon Adsorbents by Radio Frequency (RF) Induction Heating
R822721C687 Improved Halogen Resistance of Catalytic Oxidation
R822721C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R822721C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R822721C700 Effects of Natural and Cyclic Variations on Contaminant Fate and Transport
R822721C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R826694C625 Enhanced Treatment of DNAPLs Contaminated Soils and Groundwater Using Biosurfactants: In-Situ Bioremediation
R826694C626 Catalytic Hydroprocessing of Chlorinated Wastes
R826694C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R826694C629 Biofiltration of BTEX in Petroleum-Contaminated Soil Remediation Off-Gas
R826694C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R826694C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R826694C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R826694C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R826694C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R826694C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R826694C651 Adjustable Biopolymer Chelators for Cadmium, Lead, and Mercury Remeidation
R826694C659 Subsurface Contamination Site characterization Via a Computer-Aided Visual Tool
R826694C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R826694C669 Solid Acid Catalyzed Alkylation in Supercritical Reaction Media
R826694C679 Regeneration and Reactivation of Carbon Adsorbents by Radio Frequency Induction Heating
R826694C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R826694C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R826694C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R826694C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R826694C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R826694C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R826694C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R826694C731 Development and Application of a Real-Time Optical Sensor for Atmospheric Formaldehyde
R826694C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C001 Field Study Abstract: A Model of Ambient Air Pollution in Southeast Texas Using Artificial Neural Network Technology
R828598C002 Hollow Fiber Membrane Bioreactors for Treating Water and Air Streams Contaminated with Chlorinated Solvents
R828598C003 Fugitive Emissions of Hazardous Air Pollutants from On-Site Industrial Sewers
R828598C004 Biofiltration Technology Development
R828598C005 A Risk-Based Decision Analysis Approach for Aquifers Contaminated with DNAPLs
R828598C006 In-Situ Remediation for Contaminated Soils Using Prefabricated Vertical Drains
R828598C007 Membrane Technology Selection System for the Metal Finishing Industry
R828598C008 Sequential Environments for Enhanced Bioremediation of Chlorinated Aliphatic Hydrocarbons
R828598C009 Waste Minimization in the Magnetic Tape Industry: Waterborne Coating Formulations for Magnetic Tape Manufacture
R828598C010 Soil Remediation by Agglomeration with Petroleum Coke
R828598C011 Recovery of Dilute Phosphoric Acid in Waste Streams Using Waste Gas Ammonia: The Regenerative MAP/DAP Process
R828598C012 Stochastic Risk Assessment for Bioremediation
R828598C013 Selective Removal of Heavy Metals from Wastewater by Chelation in Supercritical Fluids
R828598C014 Optimization of Treatment Technologies for Detoxification of PCB Contaminated Soils
R828598C015 Wastewater Remediation by Catalytic Wet Oxidation
R828598C016 Permanence of Metals Containment in Solidified and Stabilized Wastes
R828598C017 Combustion Enhancement by Radial Jet Reattachment - Low Generation of Hazardous Gases and High Thermal Efficiency
R828598C018 A Process To Convert Industrial Biosludge and Paper Fines to Mixed Alcohol Fuels
R828598C019 Homogeneous Catalysis in Supercritical Carbon Dioxide
R828598C020 Ultrasonic Enhancement of the Removal of Heavy Metals
R828598C021 The Binding Chemistry and Leaching Mechanisms of Advanced Solidification/Stabilization Systems for Hazardous Waste Management
R828598C022 Development of an Air-Stripping and UV/H2O2 Oxidation Integrated Process To Treat a Chloro-Hydrocarbon-Contaminated Ground Water
R828598C023 A Comparative Study of Siting Opposition in Two Counties
R828598C024 Sonochemical Treatment of Hazardous Organic Compounds II: Process Optimization and Pathway Studies
R828598C025 Laser Diagnostics of the Combustion Process within a Rotary Kiln Incinerator
R828598C026 Use of Inorganic Ion Exchangers for Hazardous Waste Remediation
R828598C027 Kaolinite Sorbent for the Removal of Heavy Metals from Incinerated Lubricating Oils
R828598C028 Destruction of Chlorinated Hydrocarbons in Process Streams Using Catalytic Steam Reforming
R828598C029 Integrated Process Treatment Train (Bioremediation {Aerobic/Anaerobic} and Immobilization) for Texas Soils Contaminated with Combined Hazardous Wastes
R828598C030 Photo-Oxidation by H2O2/VisUV of Off-Gas Atmospheric Emissions from Industrial and Environmental Remediation Sources
R828598C031 Concentrated Halide Extraction and Recovery of Lead from Soil
R828598C032 Biodegradable Surfactant for Underground Chlorinated Solvent Remediation
R828598C033 A Software Guidance System for Choosing Analytical Subsurface Fate and Transport Models Including a Library of Computer Solutions for the Analytical Models
R828598C034 Hydrodynamic Modeling of Leachate Recirculating Landfill
R828598C035 Measurement of Oxygen Transfer Rate in Soil Matrices
R828598C036 Sorbent Technology for Multipollutant Control During Fluidized Bed Incineration
R828598C037 Pollution Prevention by Process Modification Using On-Line Optimization
R828598C038 Pollution Prevention by Process Modification
R828598C039 Water Solubility and Henry's Law Constant
R828598C040 Transferring Technical Information on Hazardous Substance Research by Publishing on the World Wide Web
R828598C041 Stress Protein Responses to Multiple Metal Exposure in Grass Shrimp
R828598C042 Life-Cycle Environmental Costing for Managing Pollution Prevention in the Chemical and Petroleum Refining Industries: A Cross-Border Approach
R828598C687 Improved Halogen Resistance of Catalytic Oxidation Through Efficient Catalyst Testing
R828598C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R828598C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R828598C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R828598C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R828598C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R828598C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R828598C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R828598C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R828598C731 Development and Application of a Real Time Optical Sensor for Atmospheric Formaldehyde
R828598C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C743 Field Demonstration of Ultrasound Enhancement of Permeable Treatment Walls
R828598C744 Optical Fibers Coated With Titania Membrane/UV-Generating Crystal in a Distributed-Light Photoreactor for VOC Oxidation
R828598C749 Characterization and Modeling of Indoor Particulate Contaminants In a Heavily Industrialized Community
R828598C753 Adsolubilization and Photocatalysis in a Semiconducting Monolithic Reactor for Wastewater Treatment
R828598C754 Remote Detection of Gas Emissions in Industrial Processes
R828598C759 Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
R828598C761 Development of a Phytologically-Based Biosorptive Water Treatment Process
R828598C766 Chlorinated Solvent Impact and Remediation Strategies for the Dry Cleaning Industry
R828598C769 Soil/Sediment Remediation by Hot Water Extraction Combined with In-Situ Wet Oxidation
R828598C771 Fluoracrylate Polymer Supported Ligands as Catalysts for Environmentally Benign Synthesis in Supercritical Fluids
R828598C774 The Feasibility of Electrophoretic Repair of Impoundment Leaks
R828598C777 Surfactant Enhanced Photo-oxidation of Wastewaters
R828598C778 Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
R828598C786 Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
R828598C787 Biosurfactant Produced from Used Vegetable Oil for removal of Metals From Wastewaters and Soils
R828598C789 Genetic Engineering of Enzymatic Cyanide Clearance
R828598C791 Characterizing the Intrinsic Remediation of MTBE at Field Sites
R828598C799 Simultaneous Water Conservation/Recycling/Reuse and Waste Reduction in Semiconductor Manufacturing
R828598C801 Building Defined Mixed Cultures To Biodegrade Diverse Mixtures Of Chlorinated Solvents
R828598C802 Engineering of Nanocrystal Based Catalytic Materials for Hydroprocessing of Halogenated Organics
R828598C807 Commercial Demonstration of Hydrogen Peroxide Injection to Control NOx Emissions from Combustion Sources
R828598C809 Evaluating Source Grouting and ORC for Remediating MTBE Sites
R828598C810 Application of Total Cost Assessment To Process Design In the Chemical Industry
R828598C846 Quantitative Demonstration of Source-Zone Bioremediation in A Field-Scale Experimental Controlled Release System