Physical Sciences and Mathematics Commons^™

Adsorption Of Microcystins To Sediment Affects Their Bioavailability And Remediation, Ashley Womer

Theses and Dissertations

The freshwater harmful algae Microcystis spp produces a family of toxins called microcystins1. These species of algae are known to release microcystins from their cells directly into the surrounding water2. This creates an array of human health risks depending on the fate and transport of the toxins in the water column3,4. Risk modelling and previous literature has shown that sediment is a sink for free microcystin, microcystin can be stably adsorbed to sediment for hundreds of years, and its adsorption to sediment is determined by the sediment adsorption partitioning coefficient (Kd)5,6,7. In this work it is hypothesized that the sediment …

Nonwovens Of Ceramic Decorated Cellulose Based Fine Fibers For Leaded Water Purification, Alejandro J. Castillo

Theses and Dissertations

Fine fibers of cellulose acetate were Forcespun and used to make nonwoven mats of cellulose. Nonwovens were activated using a solution combustion synthesis which deposited iron nitride onto fibers. Cellulose and cellulose composite mats were tested as adsorbents for lead ion in water. Cellulose showed slightly higher adsorption capacities (mg/g) up to 1300 mg/g lead loading. Adsorption data were further analyzed using several isotherms, of which the Dubinin-Raduskevich gave the best fits.

Graphene-Based Materials Coated On Zeolite For The Removal Of Persistent Organic Pollutants From Water, Yan Zhang

Theses and Dissertations

Adsorption is a fast, low-cost and the most commonly implemented water treatment technology for the removal of multiple contaminations from ground water, drinking water or wastewater. Difficulties in removing persistent organic pollutants (POPs) to improve quality and safety of treated water sources require the exploration of novel and multifunctional materials. Graphene-based materials having unique structures, high specific surface areas and tailorable functional groups are promising candidates as adsorbents.

The main goal of this work is to fabricate a novel adsorbent made of GO/rGO attached on natural zeolite substrates for the removal of variably charged organic model compounds and POPs in …

Removal Of Chromium(Vi) And Chromium(Iii) Ions From Aqueous Solution Using Bio-Char Generated From Agricultural Waste Products, Diego Fernando Gonzalez

Theses and Dissertations

Heavy metals are one of the most persistent and prevalent contaminants in the aquatic environment. The removal of chromium from aqueous solution, especially in the hexavalent form is difficult. New technologies, techniques and/or new materials have been designed in order to effectively and efficiently remove chromium from the aqueous environment. The project focuses on the comparison of the effects of pH, time, temperature, binding capacity on bio-char’ generated from agricultural waste produces vs an amino modified derivative of the bio-char. Pineapple skins were dried, ground, sieved, and pyrolyzed to produce a bio-char material. The bio-char was analyzed using FTIR to …

Experimental Evaluation Of Uranyl Transport Into Mesoporous Silica Gel Using Fluorescence, Brandon M. Dodd

Theses and Dissertations

This research investigated parameters that can affect the use of nanoporous silica gel as a media for accumulating a detectable amount of uranium. The unique fluorescence of the Uranyl (UO₂²⁺) ion was used to evaluate the transport kinetics and accumulation within silica gel in a static fluid and under pressure driven flow. The addition of fluid flow decreased the time constant from on the order of an hour to approximately 2s with a very low fluid velocity of 0.36cm/s. The 0.36cm/s fluid velocity was found to be the critical velocity above which there was no gain in …

Understanding The Adsorption And Nucleation Of Transition Metals On A Model Carbon Support, Grant S. Seuser

Theses and Dissertations

Heterogeneous catalysis plays a vital role in the commercial production of chemicals. However, much is still unknown about the fundamental surface chemistry involved in catalyst preparation and the surface chemistry of the catalysts themselves. In the first part of this work, a surface science approach was employed to develop a fundamental understanding of the surface chemistry of strong electrostatic adsorption (SEA) of metal precursors on a model carbon support, highly oriented pyrolytic graphite (HOPG). SEA is a wet impregnation method in which anionic/cationic metal precursors are adsorbed onto positively/negatively charged functional groups by adjusting the pH of the solution above …

Remediation Of Lead And Copper Ions From Water Solutions Using Transition Metal Sulfides, Jesus M. Cantu Jr.

Theses and Dissertations

Heavy metal contamination in water solutions has been a major concern since many transition metals don’t play a role in any biological function and are actually detrimental to human health. There have been several techniques that have been implemented for the remediation of heavy metal contaminants. For this project, three metal sulfides—Fe7S8, ZnS, TiS 2—were synthesized and studied for their capabilities to remove Pb(II) and Cu(II) from water solutions. Several parameters were investigated to determine the effects of pH, time, temperature, binding capacities, and interfering ions. The room temperature adsorption capacities ranged 6.23–333.3 mg/g for Pb(II) and 1.31–250 mg/g for …

Remediation Of Trivalent And Hexavalent Chromium Ions From Aqueous Solutions Using Titanium Dioxide Polymorphs, Yvette Cantu

Theses and Dissertations

Three titanium dioxide (TiO2) polymorphs were synthesized and used for the removal of chromium (III) and chromium (VI) from aqueous solutions. Various solution parameters were studied to determine the effects of pH, temperature, time, possible interfering ions, and capacities on the binding of Cr(III) and Cr(VI) to all three polymorphs. pH assays determined the optimum pH for the binding of both Cr(III) and Cr(VI) to each polymorph. Adsorption isotherms determined that the adsorption of Cr(III) was non-spontaneous for the three polymorphs with ΔG values ranging from 6.03 to 12.89 kJ/mol. Furthermore, the binding of Cr(VI) to anatase was also non-spontaneous …

Nonlinear Spectroscopic Investigation Of Adsorption To C-18 Model Stationary Phase, Anthony D. Peterson

Theses and Dissertations

Reversed-phase liquid chromatography (RPLC) is a commonly used separation technique in chemistry. Nevertheless, the mechanistic interactions at the molecular level among the eluent, analyte, and the stationary phase are not fully understood. Because of this limited understanding, optimization of the separation must be done experimentally. Learning more about molecular interactions should aid in improving separations. We are currently using second-harmonic generation (SHG) spectroscopy to investigate how analytes adsorb to the surface. SHG is a spectroscopic technique that produces signal only at places of non-isotropic symmetry; this typically occurs at surfaces. SHG can be used to produce surface isotherms of test …

Probing Bonding And Dynamics At Heterogeneous Adsorbate/Graphene Interfaces, Eric Charles Mattson

Theses and Dissertations

Graphene-based materials are becoming an astoundingly promising choice for many relevant technological and environmental applications. Deriving graphene from the reduction of graphene oxide (GO) is becoming a popular and inexpensive route toward the synthesis of these materials. While the desired product from GO reduction is pristine graphene, defects and residual oxygen functional groups inherited from the parent GO render reduced graphene oxide (RGO) distinct from graphene. In this work, the structure and bonding for GO and RGO is investigated to the end of a working understanding of the composition and properties of these materials. In situ selected area electron diffraction …

Evaluations Of Two Proposed Mechanisms Of Cation Adsorption By Silicate Minerals, Norman D. Larsen

Theses and Dissertations

Previous work done at the Brigham Young University by Andelin^1, Roberts^2, and Olsen^3, has established the mechanism by which xanthate collectors are adsorbed on molybdenite ores to produce the hydrophobic surfaces necessary for flotation. This thesis is an attempt to better understand the mechanism by which the silicate minerals, which are found in conjunction with the ores, become hydrophyllic and as a result are not floated when in contact with air bubbles. It has been previously established that silicate minerals do adsorb cations on their surfaces^4. The present study has been undertaken to more fully understand the mechanism by which …

An Investigation Of Phosphate Adsorption By The Clays Montmorillonite And Kaolinite /|Cby Gordon Richard Bradford, G. R. Bradford

Theses and Dissertations

Clay minerals have widespread application in industry and play an important role in plant life (2, 17). It is the adsorptive capacity of clay which determines largely its importance to man (2). The purpose of this investigation is to interpret the mechanism of adsorption of the phosphate anion by the two clay minerals montmorillonite and kaolinite. This particular system was singled out for two reasons: 1. It has agricultural significance. 2. It is believed that if the particular phosphate adsorption mechanism is understood it will aid in an understanding of many other adsorption phenomena associated with clay.

A Study Of Chromatographic Adsorption Analysis And Its Application To Inorganic Qualitative Analysis, Sidney Marion Beck

Theses and Dissertations

This work is a study of the analytical applications of the chromatographic method, particularly as applied to inorganic qualitative analysis. It is divided into four parts as follows: (a) The main part of the work is a search of the common laboratory reagents, likely to be found in any beginning qualitative analysis laboratory, with the purpose of finding the best reagents for developing an invisible chromatogram on an adsoption column of activated alumina. For the most part, only inorganic reagents were used, but in special cases, a few of the more common orgaic reagents were used. (b) An evaluation of …