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Full-Text Articles in Engineering

Assessing The Feasibility And Mechanism Of Destructive Removal Of Per- And Polyfluoroalkyl Substances (Pfas) From Water, Kaushik Vinaykumar Londhe Dec 2023

Assessing The Feasibility And Mechanism Of Destructive Removal Of Per- And Polyfluoroalkyl Substances (Pfas) From Water, Kaushik Vinaykumar Londhe

Dissertations

One of the most pertinent challenges faced by the drinking water community is the widespread contamination of per- and polyfluoroalkyl substances (PFAS). These anthropogenic chemicals have been ubiquitously used in everyday products such as carpets, stain repellents, dyes, shampoos, non-stick cookware as well as in aqueous firefighting foams. PFAS are linked with adverse health effects in humans such as thyroid disease, obesity, immunological and reproductive disorders and linked to cancer in adults and low birth weight and developmental defects in infants.

Conventional water treatment technologies have proven to be largely ineffective in PFAS remediation, due to their extreme stability and …


Colloidal Behavior Of Nanobubbles And Their Application In Enhancing Plant Growth: Mechanisms Of Nanobubble Interactions With Microbial And Soil Species, Shan Xue Aug 2023

Colloidal Behavior Of Nanobubbles And Their Application In Enhancing Plant Growth: Mechanisms Of Nanobubble Interactions With Microbial And Soil Species, Shan Xue

Dissertations

Climate change has resulted in increasing uncertainties of water resources and disturbance on agricultural activities. For example, the shortage of water resources, land erosion and pollution from runoff significantly affect agricultural sustainability. This dissertation research focuses on the fundamental studies of nanobubble (NB) water and explores the benefits for irrigation to enhance plant germination and growth. Unlike bulk bubbles, NBs exhibit prolonged stability in water and possess large surface areas that facilitate efficient mass transfer and potential tailored reactions (e.g., disinfection). However, the enhancement mechanisms for NBs on seed germination and plant growth remain elusive.

This research first evaluated the …


Faceted Nanomaterial Synthesis, Characterizations And Applications In Reactive Electrochemical Membrane Filtration, Qingquan Ma Dec 2022

Faceted Nanomaterial Synthesis, Characterizations And Applications In Reactive Electrochemical Membrane Filtration, Qingquan Ma

Dissertations

Facet engineering of nanomaterials, especially metals and metal oxides has become an important strategy for tuning catalytic properties and functions from heterogeneous catalysis to electrochemical catalysis, photocatalysis, biomedicine, fuel cells, and gas sensors. The catalytic properties are highly related to the surface electronic structures, surface electron transport characteristics, and active center structures of catalysts, which can be tailored by surface facet control. The aim of this doctoral dissertation research is to study the facet-dependent properties of metal or metal oxide nanoparticles using multiple advanced characterization techniques. Specifically, the novel atomic force microscope-scanning electrochemical microscope (AFM-SECM) and density functional theory (DFT) …


Bioremediation Of Petroleum Hydrocarbons In Coastal Sediments, Charbel Abou Khalil Dec 2022

Bioremediation Of Petroleum Hydrocarbons In Coastal Sediments, Charbel Abou Khalil

Dissertations

The biodegradation of dispersed crude oil in the ocean is relatively rapid (a half-life of a few weeks). However, it is often much slower on shorelines, usually attributed to low moisture content, nutrient limitation, and higher oil concentrations in beaches than in dispersed plumes. Another factor may be the increased salinity of the upper intertidal and supratidal zones since these parts of the beach are potentially subject to prolonged evaporation and only intermittent inundation. Therefore, two laboratory experiments are conducted to investigate whether such an increase in porewater salinity results in additional inhibitory effects on oil biodegradation in seashores.

In …


Understanding The Interfacial Processes Of Reactive Nanobubbles Toward Agricultural Applications, Xiaonan Shi May 2022

Understanding The Interfacial Processes Of Reactive Nanobubbles Toward Agricultural Applications, Xiaonan Shi

Dissertations

There is a growing interest in nanobubble (NB) technology because of its diverse applications (e.g., detergent-free cleaning, water aeration, ultra-sound imaging and intracellular drug delivery, and mineral processing). NBs have a higher efficiency of mass transfer compared to bulk scale bubbles due to the high specific surface areas. The high specific surface also facilitates physical adsorption and chemical reactions in the gas liquid interface. Furthermore, the collapse of NBs creates shock waves and the formation of hydroxyl radicals (OH).

However, it remains elusive why or how NBs are stabilized in water and particularly, the states of internal pressures of NBs …


Reactive Iron Mineral Coatings In Redox Transition Zones Of A Site With Historical Contamination: Abiotic Attenuation, Xin Yin May 2022

Reactive Iron Mineral Coatings In Redox Transition Zones Of A Site With Historical Contamination: Abiotic Attenuation, Xin Yin

Dissertations

Reactive iron mineral coatings are found throughout reduction-oxidation (redox) transition zones and play a significant role in contaminant transformation processes. In this study, an 18.3-meter core is collected, subsampled, and preserved under anoxic conditions to maintain its original redox state. Screening analyses are conducted at sampling increments of 5.08 cm in depth for the following: elemental concentrations with X-ray fluorescence (XRF), sediment pH, sediment oxidation-reduction potential (ORP), total volatile organic carbon (TVOC) in the sample headspace, and abundant bacteria (16S rRNA sequencing). Using the Fe and S gradients correlated with microbial data, five RTZs are delineated. To characterize iron mineral …


Characterizing Reactive Iron Mineral Coatings And Their Roles In Natural Attenuation At A Site With Historical Contamination, Han Hua Dec 2020

Characterizing Reactive Iron Mineral Coatings And Their Roles In Natural Attenuation At A Site With Historical Contamination, Han Hua

Dissertations

Reactive iron mineral coatings in redox transition zones play an important role in contaminant attenuation. These mineral coatings include poorly crystalline to crystalline iron sulfides, carbonates, and oxyhydroxides, and are a signature of the biogeochemical processes occurring. To better understand these processes, reactive iron mineral coatings are characterized in an 18-m Anaerobic Core collected from a contaminated industrial site. This study targets redox transition zones uncovered in the core. A suite of complementary analyses is applied to distinguish the surface coating mineralogy using X-ray Diffraction, X-ray fluorescence, and field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray analyzer (EDX). In …


The Stability Of Nanobubbles And Its Application In Contaminated Sediment Treatment, Shaini Dilsha Aluthgun Hewage Dec 2020

The Stability Of Nanobubbles And Its Application In Contaminated Sediment Treatment, Shaini Dilsha Aluthgun Hewage

Dissertations

This dissertation consists of two sections. First, nanobubbles' stability and behavior are studied using experimental and theoretical approaches. Second, nanobubbles application combined with ultrasound to remediate contaminated sediments is discussed.

The stability study consists of four sections. (i). Laboratory investigation to determine bubble size distributions and zeta potentials for different gases, pH levels, temperatures, and salt conditions. (ii). A theoretical study based on the diffused double layer theory to explain nanobubbles' behavior in different NaCl concentrations. (iii). Nanobubbles' stability in electrolyte solutions under different ion valencies using deionized water, NaCl, Na2SO4, Na3PO4, …


Compound Flooding In Coastal Areas Emanating From Inland And Offshore Events, Hamed Behzad Koochaksaraii May 2020

Compound Flooding In Coastal Areas Emanating From Inland And Offshore Events, Hamed Behzad Koochaksaraii

Dissertations

The vulnerability of urban populations to natural hazards and climate change is a major theme in many reports on coastal cities with flooding ranking highly among the climate change concerns. Flooding could occur as a result of runoff for inland rainfall that accumulates at the mouth of the estuary to the sea or it could occur due to a storm surge emanating from the ocean. The techniques for modeling the flooding from these events are very different, as they were developed in different scientific fields: hydrology and hydraulic engineering for inland rainfall versus coastal oceanography and coastal engineering for offshore …


Enhanced Removal Of Perfluorooctanoic Acid (Pfoa) Via Microwave-Fenton-Reactive Membrane Filtration, Fangzhou Liu May 2020

Enhanced Removal Of Perfluorooctanoic Acid (Pfoa) Via Microwave-Fenton-Reactive Membrane Filtration, Fangzhou Liu

Theses

Perfluorooctanoic Acid (PFOA), one of the common per- and poly fluorinated alkylated substances (PFASs), is increasingly detected in the environment due to the diverse industrial applications and high resistance to degradation processes. This study evaluated degradation of PFOA in microwave-assistant catalytic membrane filtration, a process that integrates microwave catalytic reactions into a ceramic membrane filtration. First, water permeation of the pristine and catalyst-coated membranes were examined under the influence of microwave irradiation to analyse the impacts of the coating layer and water temperature increase on permeate flux, which were well interpreted by three models. Then, the PFOA removal was first …


Electrochemically Reactive Membranes For Efficient Biomass Recovery, Pollutant Degradation And Commercialization, Likun Hua May 2019

Electrochemically Reactive Membranes For Efficient Biomass Recovery, Pollutant Degradation And Commercialization, Likun Hua

Dissertations

Micropollution in natural waters such as rivers and groundwater aquifers is a widespread problem that prevents these potentially potable sources from being used as drinking water. In the United States, approximately two-thirds of the over 1,200 most serious hazardous waste sites in the nation are contaminated with trichloroethylene (TCE), a potentially carcinogenic compound. Other emerging and environmentally persistent organic micropollutants include polyromantic hydrocarbons (PAHs), organophosphate flame retardants, endocrine disrupting compounds (EDCs), pesticides, herbicides, pharmaceuticals and personal care products (PPCPs). Membrane filtration is one of the most efficient separation processes widely used for water treatment and pollutant removal. However, traditional membrane …


Fouling And Aging In Membrane Filtration : Hybrid Afm-Based Characterization, Modelling And Reactive Membrane Design, Wanyi Fu May 2019

Fouling And Aging In Membrane Filtration : Hybrid Afm-Based Characterization, Modelling And Reactive Membrane Design, Wanyi Fu

Dissertations

Membrane filtration has been extensively used in water and wastewater treatment, desalination, dairy making, and biomass/water separation. However, membrane fouling, aging and insufficient removal efficiency for dissolved organic matters remain major challenges for wider industrial applications. In order to tackle these challenges, this doctoral dissertation investigates mechanisms of membrane fouling and development of antifouling membrane filtration technologies. Specifically, four major research areas are explored: (i) nanoscale physicochemical characterization of the chemically modified polymeric membranes; (ii) quantitative modelling between membrane properties and membrane fouling and defouling kinetics; (iii) development of quantitative structure-activity relationships for membranes that undergo thermal and chemical aging …


Methods To Improve The Remediation Of Polycyclic Aromatic Hydrocarbons (Pahs) In Aerobic And Anaerobic Environments, Brian Wartell Dec 2018

Methods To Improve The Remediation Of Polycyclic Aromatic Hydrocarbons (Pahs) In Aerobic And Anaerobic Environments, Brian Wartell

Dissertations

Oil spills occur regularly in terrestrial environments and crude oil can contain many compounds that are highly resistant to degradation. Among these compounds are high levels of polycyclic aromatic hydrocarbons (PAHs) which are not only toxic but can also be carcinogenic and/or mutagenic. The first chapter of this dissertation includes an extensive review chapter on the variables affecting the anaerobic degradation of hydrocarbons, with a particular focus on PAHs. Electron acceptors, electron donors, temperature, salinity, pH all play key roles in determining the possibility effective of effective degradation occurring. Thus, by addressing solutions, such as biostimulation, improving environmental variables for …


Experimental And Numerical Characterization Of Multiphase Subsurface Oil Release, Feng Gao Dec 2018

Experimental And Numerical Characterization Of Multiphase Subsurface Oil Release, Feng Gao

Dissertations

Subsurface oil release is commonly encountered in the natural environment and engineering applications and has received the substantial attention of researchers after the disastrous Deepwater Horizon Blowout oil spill in 2009. The main focus on the present research is to systematically study the hydrodynamics of underwater oil jet under a variety of conditions, including the effect of dispersant and different gas to oil ratios (GOR) by using experimental measurement as well as a Computational Fluid Dynamics (CFD) approach, from which the measured turbulent characteristics (e.g., velocity, turbulent kinetic energy, turbulence dissipation rate, etc.) of underwater oil jet are thoroughly examined …


Estimating Vehicles Emissions At Signalized Intersections In The Highway Capacity Manual, Yuanyuan Fan Aug 2017

Estimating Vehicles Emissions At Signalized Intersections In The Highway Capacity Manual, Yuanyuan Fan

Dissertations

Over the past decades, motor vehicle volumes have continued to increase at a high rate. As a result, engineers in the transportation field not only need more robust knowledge of traffic operation control and transportation planning, but more attention is also needed to understand and estimate the influences that this increasing volume of vehicles has on the environment, especially the influence on air quality. The EPA has stated that reducing carbon monoxide (CO) from vehicle emissions is the most significant way to control air pollution from the transportation sector.

The Highway Capacity Manual is a national and international resource that …


Biologically Active Filters: An Advanced Treatment Process For Pharmaceuticals And Personal Care Products, Shuangyi Zhang Jan 2017

Biologically Active Filters: An Advanced Treatment Process For Pharmaceuticals And Personal Care Products, Shuangyi Zhang

Dissertations

With the increasing concern of pharmaceuticals and personal care products (PPCPs) in source water, this study examines the hypothesis that existing filters and adsorbents in water treatment plants can be converted to biologically active filters (BAFs) to treat these compounds. Removals through bench-scale BAFs are evaluated as a function of media, granular activated carbon (GAC) and dual-media, empty bed contact time (EBCT), and pre-ozonation. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater DOC removal normalized to adenosine triphosphate (ATP) are observed indicating a different microbial community compared to dual-media BAFs. ATP concentrations in the upper portion of …


Effectiveness Of Water Quality Benefits Provided By Stormwater Management Facilities/Infiltration Basin, Vinicius Rodrigues De Mattos Barreto May 2016

Effectiveness Of Water Quality Benefits Provided By Stormwater Management Facilities/Infiltration Basin, Vinicius Rodrigues De Mattos Barreto

Theses

Stormwater Best Management Practices (BMP) and devices are systems frequently built under assumed design performances, but rarely verified after construction. Their effectiveness in protecting the environment against pollutants carried by stormwater runoff has been extensively questioned and investigated. This research presents a case study of an infiltration basin in Medford, NJ to verify if the 80% expected Total Suspended Solids (TSS) removal as stated in the New Jersey Stormwater BMP Manual is actually achieved. A sampling pit was installed on the site and infiltrated water samples were collected during three rain events and TSS measurements were compared with the inflow. …


Fates Of Spilt Oil And Factors Affecting The Bio-Degradation Of Oil: A Review, Amogh-Ranganath Chakravarthy Jan 2015

Fates Of Spilt Oil And Factors Affecting The Bio-Degradation Of Oil: A Review, Amogh-Ranganath Chakravarthy

Theses

The usage of crude oil and its products is increasing; in turn, the number of spills is also going up. The inland spills are the more recurrent spills in the U.S today. This review article deals with the weathering of oils, which commences just after oil spills into the environment with various processes such as evaporation, dissolution, photo-oxidation, dispersion, emulsification and bio-degradation along with other possible fates. Biodegradation is one of the most significant processes of weathering which depends on oil physical and chemical characteristics, environmental characteristics, pH, salinity and oil concentration. There is a range of oil concentration for …


Physical Controls On Water Flow And Solute Transport In Coastal Aquifers, Xiaolong Geng May 2014

Physical Controls On Water Flow And Solute Transport In Coastal Aquifers, Xiaolong Geng

Dissertations

Groundwater flow and associated subsurface solute fates have a significant impact on the structure and productivity of near-shore coastal ecosystems. For proper assessment and management of these coastal groundwater resources, it is quite essential to investigate the key factors (tides, waves, evaporation, and freshwater recharge etc.) affecting coastal groundwater systems. The main objective of this study is to examine and quantify two important physical control factors, oceanic waves and evaporation, on the groundwater flow and solute transport in near-shore aquifers. For the investigation of wave effects, a Computational Fluid Dynamics (CFD) modeling tool, Fluent, is used to simulate wave- induced …


Field Methods For Rapidly Characterizing Contaminant Mobility In Paint Waste During Bridge Rehabilitation, Zhan Shu May 2014

Field Methods For Rapidly Characterizing Contaminant Mobility In Paint Waste During Bridge Rehabilitation, Zhan Shu

Dissertations

Currently, the New York State Department of Transportation (NYSDOT) uses a conservative approach of classifying all paint waste as hazardous from bridges undergoing rehabilitation which were constructed before 1989. This practice stems from the fact that there is no approved reliable, fast, and efficient method for classifying paint waste in-situ as non-hazardous. The main objective of this study was to develop a model that can predict the leachability of trace metals in paint waste generated during bridge rehabilitation. A statistically significant number of bridge sites were sampled based on hypothesis testing. Samples were then evaluated for total concentration of Resource …


Analyses Of Groundwater Contribution To A Riverine Wetland, Farzad Mahmoodinobar Jan 2014

Analyses Of Groundwater Contribution To A Riverine Wetland, Farzad Mahmoodinobar

Dissertations

Rainfall, runoff, overbank flow and groundwater, all contribute water to wetlands. Each transport element is associated with unique modeling approaches and uncertainties. Transpiration is perhaps the hardest to quantify as it is subject to all the variability of plant growth. Transpiration causes land area to lose moisture and the loss amount depends on precipitation incidence, the temperature and type and extent of vegetation. Plants can intercept virtually all recharge during the growing season and almost none from late fall to early spring in northeastern United States. Thus, an improvement in the transpiration element can contribute considerably to an improved groundwater …


Influence Of Beach Hydrodynamics On Saltwater Transport And Oil Persistence In Beaches, Ali Abdollahi-Nasab Jan 2014

Influence Of Beach Hydrodynamics On Saltwater Transport And Oil Persistence In Beaches, Ali Abdollahi-Nasab

Dissertations

The exchange of water and solutes across the aquifer-ocean interface plays an important ecological role in both aquifer and the open water. Saltwater intrusion could prevent utilization of groundwater for either drinking water or irrigation. In addition, the flux of solutes, such as nutrients, from inland groundwater sources plays an important role in shoreline ecology, especially in embayments. This research relies on a three-pronged approach, involving a laboratory beach experiment, field scale experiments and numerical analyses. The laboratory beach experiment is designed to investigate the fundamental processes occurring in beach aquifers. It explores the effects of buoyancy (or lack thereof) …


Leaching Of Metals And Metalloids From Highway Marking Glass Beads And The Potential Environmental Impact, Nimrat K. Sandhu Jan 2013

Leaching Of Metals And Metalloids From Highway Marking Glass Beads And The Potential Environmental Impact, Nimrat K. Sandhu

Dissertations

Glass beads are embedded in pavement markings to obtain retroreflectivity which plays a crucial role in the lighting-up effect needed for safe driving. Elevated metal and metalloid concentrations of As, Sb, and Pb have recently been observed in imported glass beads. The main objective of this research was to assess the environmental impact associated with applying these imported glass beads in highway markings. To achieve this objective, total metal concentrations were measured using two techniques: hydrofluoric acid digestion followed by inductively coupled plasma mass spectroscopy (HF/ICP-MS), and field portable x-ray fluorescence (FP-XRF) spectroscopy. A number of leaching studies were conducted …


Challenges Of Permitting Ballast Water Discharges From Commercial Vessels In U.S. Waters, Paul Rodriguez Aug 2012

Challenges Of Permitting Ballast Water Discharges From Commercial Vessels In U.S. Waters, Paul Rodriguez

Theses

On February 5, 2009, the US Environmental Protection Agency (US EPA) issued the Vessel General Permit (VGP), under the Clean Water Act (CWA), for discharges incidental to the normal operation of vessels, including ballast water discharges. This set forth permit requirements for most commercial vessel discharges within 3 nautical miles of U.S. shore. Since it will expire in December 2013, the US EPA recently issued a draft 2013 VGP. One of the significant changes is the proposal of numerical ballast water discharge standards requiring most commercial vessels to install ballast water treatment systems onboard.

The objective of this thesis is …


Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar May 2011

Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar

Dissertations

Engineered nanoparticles, such as titanium dioxide (TiO2), are important building blocks for the evolution of nanotechnology in industries and commercial products. Ever so increasing use of the engineered nanoparticles is bound to result in a substantial fraction of these nanoparticles ending up in wastewater; or surface water and groundwater, which are sources of intake for drinking water treatment. Removal of these engineered nanoparticles in wastewater and drinking water treatment processes is a very important step towards the protection of environmental and public health as well as protecting water treatment units from fouling and other issues.

Experimental studies showed …


A Study Of The New York / New Jersey Coastal Water : Bio-Optical Characteristics Of The Harbor Estuary And The Effects Of Heavy Metals On Brown Tide Alga Of The Bight, Bin Wang May 2011

A Study Of The New York / New Jersey Coastal Water : Bio-Optical Characteristics Of The Harbor Estuary And The Effects Of Heavy Metals On Brown Tide Alga Of The Bight, Bin Wang

Dissertations

The New York / New Jersey (NY/NJ) coastal area is one of the most productive regions around the world and a major natural and scenic resource for New York and New Jersey. As a result of excessive nutrient loading in the water, algal blooms have been observed since 1950’s. The NY/NJ coastal area includes the NY/NJ Bight and the NY/NJ Harbor Estuary, and in the former, brown tides (Aureococcus anophagefferens) were first observed in 1985 becoming a more serious water quality problem over the last 25 years. The influence of micronutrients, namely trace metals, on A. anophagefferens that are widespread …


Phosphate And Thermal Stabilization Of Heavy Metals In Dredged Sediments, Peter Kuria Ndiba Jan 2009

Phosphate And Thermal Stabilization Of Heavy Metals In Dredged Sediments, Peter Kuria Ndiba

Dissertations

Treatment and reuse of dredged harbor sediments in construction as an alternative to disposal reduces costs and conserves resources. This research focused on leachability of metal contaminants subsequent to phosphate addition and thermal treatment at 700 °C. X- ray absorption spectroscopy (XAS) in combination with principal component analysis, target transformation, and linear combination revealed that in the untreated sediments Zn precipitated as the relatively soluble smithsonite (ZnCO3) (67%) and adsorbed to hydrous iron oxides (15%) and hydrous manganese oxides (18%). Phosphate addition and calcination resulted in sparingly soluble phases, hopeite (Zn3(PO4)2.4H2 …


Characterization Of Natural Organic Matter And Precursors To Trihalomethanes Using Spectral Flourescence Signatures, Krit Punburananon Jan 2009

Characterization Of Natural Organic Matter And Precursors To Trihalomethanes Using Spectral Flourescence Signatures, Krit Punburananon

Dissertations

Disinfection is an essential process to kill pathogens (i.e., disease causing organisms) in source water during the production of drinking water. Chlorine is most widely used disinfectant because it is effective, affordable, and also provides chlorine residual to ensure that the water is safe through the distribution system. Nonetheless, chlorine reacts with Natural Organic Matter (NOM) and forms potentially carcinogenic Disinfection By-products (DBPs). The major chlorination DBPs are dominantly Trihalomethanes (THMs). However, not all organic compounds are equally reactive to THMs formation.

NOM in water samples collected from the Delaware & Raritan Canal and its tributaries (Central New Jersey) was …


Evaluation Of Environmental Carrying Capacity And Application Of The Sustainability Target Method, Chatpet Yossapol Aug 2006

Evaluation Of Environmental Carrying Capacity And Application Of The Sustainability Target Method, Chatpet Yossapol

Dissertations

The environmental carrying capacity (CC) is defined as the capacity of the earth to absorb or tolerate potentially stressful burdens imparted at various scales and locations, that is, to accommodate the ecological stresses without showing permanent damage. The CC can be used as a reference dataset for Life Cycle Assessment (LCA) purposes and as a baseline for other environmental studies.

In this research, a set of impact-oriented U.S. CC is developed for both input- and output-related impacts. CC for eight common impact categories is evaluated: resource depletion, global warming, ozone depletion, acidification, eutrophication, photochemical ozone formation, human toxicity, and eco-toxicity. …


The Impact Of Abiotic And Biogenic Mn Oxide Coatings On Contaminant Mobility, Bioavailability, And Attenuation, Thipnakarin Boonfueng Aug 2006

The Impact Of Abiotic And Biogenic Mn Oxide Coatings On Contaminant Mobility, Bioavailability, And Attenuation, Thipnakarin Boonfueng

Dissertations

Abiotic and biogenic manganese oxide coatings significantly impact the mobility and bioavailability of metals in soils and sediments. While sorption to discrete Mn oxides has been investigated in a number of studies, coatings have not received as much attention. Abiotic nanocrystalline (hydrous manganese oxide (HMO)) and crystalline Mn oxides (bimessite and pyrolusite) coated on montmorillonite were studied for formation, structure, stability, and surface properties. Coatings dominated the clay surface characteristics where the surface charge behaved similar to that of the discrete oxide and the local structure was consistent with the pure oxide phase. Furthermore, in sorption studies, Zn and Pb …