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Full-Text Articles in Chemistry
Thermodynamics, Kinetics, And Activation Energy Studies Of The Sorption Of Chromium(Iii) And Chromium(Vi) To A Mn 3 O 4 Nanomaterial, Yvette Cantu, Abril Remes, Alejandra Reyna, Denise Martinez, Jahaziel Villarreal, Hilda Ramos, Samantha Trevino, C Tamez, A Martinez, Thomas Eubanks, Jason Parsons
Thermodynamics, Kinetics, And Activation Energy Studies Of The Sorption Of Chromium(Iii) And Chromium(Vi) To A Mn 3 O 4 Nanomaterial, Yvette Cantu, Abril Remes, Alejandra Reyna, Denise Martinez, Jahaziel Villarreal, Hilda Ramos, Samantha Trevino, C Tamez, A Martinez, Thomas Eubanks, Jason Parsons
Chemistry Faculty Publications and Presentations
In this study, a manganese oxide, Mn3O4 was used to remove chromium(III) and chromium(VI) from aqueous solutions. The Mn3O4 nanomaterial was synthesized through a precipitation method, and was characterized using XRD, which confirmed the material had a crystal structure similar to hausmannite. In addition, using Scherrer's equation it was determined that the nanomaterial had an average grain size of 19.5 ± 1.10 nm. A study of the effects of pH on the binding of chromium(III) and chromium(VI) showed that the optimum binding pH was 4 and 3 respectively. Batch isotherm studies were performed to determine the binding capacity of chromium(III), …
Supramolecular Biopolymeric Composite Materials: Green Synthesis, Characterization And Applications, Tamutsiwa Moven Mututuvari
Supramolecular Biopolymeric Composite Materials: Green Synthesis, Characterization And Applications, Tamutsiwa Moven Mututuvari
Dissertations (1934 -)
Macrocycles, such as crown ethers (CRs) and resorcinarenes (RESs), exhibit selective complexation of heavy metal ions and organic pollutants respectively. Consequently, they have been investigated for their suitability in adsorbing these aqueous pollutants. However, they are difficult to handle and recycle for reuse because, by themselves, they can only be fabricated in powder form. To alleviate this challenge, we developed a method to encapsulate these macrocycles into film-forming polysaccharides--cellulose (CEL) and chitosan (CS). This was achieved by using a green and recyclable solvent, an ionic liquid, to dissolve both macrocycles and polysaccharides and regenerate corresponding composites in water. Resultant composites …
The Critical Role Of Water At The Gold-Titania Interface In Catalytic Co Oxidation, Johnny Saavedra, H. Doan, Christopher J. Pursell, L. C. Grabow, Bert D. Chandler
The Critical Role Of Water At The Gold-Titania Interface In Catalytic Co Oxidation, Johnny Saavedra, H. Doan, Christopher J. Pursell, L. C. Grabow, Bert D. Chandler
Chemistry Faculty Research
We provide direct evidence of a water-mediated reaction mechanism for room-temperature CO oxidation over Au/TiO2 catalysts. A hydrogen/deuterium kinetic isotope effect of nearly 2 implicates O-H(D) bond breaking in the rate-determining step. Kinetics and in situ infrared spectroscopy experiments showed that the coverage of weakly adsorbed water on TiO2 largely determines catalyst activity by changing the number of active sites. Density functional theory calculations indicated that proton transfer at the metal-support interface facilitates O2 binding and activation; the resulting Au-OOH species readily reacts with adsorbed Au-CO, yielding Au-COOH. Au-COOH decomposition involves proton transfer to water and was suggested to be …
Synergistic Adsorption Of Heavy Metal Ions And Organic Pollutants By Supramolecular Polysaccharide Composite Materials From Cellulose, Chitosan And Crown Ether, Tamutsiwa M. Mututuvari, Chieu D. Tran
Synergistic Adsorption Of Heavy Metal Ions And Organic Pollutants By Supramolecular Polysaccharide Composite Materials From Cellulose, Chitosan And Crown Ether, Tamutsiwa M. Mututuvari, Chieu D. Tran
Chemistry Faculty Research and Publications
We have developed a simple one-step method to synthesize novel supramolecular polysaccharide composites from cellulose (CEL), chitosan (CS) and benzo-15-crown 5 (B15C5). Butylmethylimidazolium chloride [BMIm+Cl−], an ionic liquid (IL), was used as a sole solvent for dissolution and preparation of the composites. Since majority of [BMIm+Cl−] used was recovered for reuse, the method is recyclable. The [CEL/CS + B15C5] composites obtained retain properties of their components, namely superior mechanical strength (from CEL), excellent adsorption capability for heavy metal ions and organic pollutants (from B15C5 and CS). More importantly, the [CEL/CS + B15C5] …
First-Principles Study Of The Electric Field Effect On The Water-Adsorbed Rutile Titanium Dioxide Surface, Abraham L. Hmiel
First-Principles Study Of The Electric Field Effect On The Water-Adsorbed Rutile Titanium Dioxide Surface, Abraham L. Hmiel
Legacy Theses & Dissertations (2009 - 2024)
TiO2 is a semiconducting material that has been used extensively in many industrial applications, and recently has become a candidate for photocatalytic water splitting, fuel cell anode support materials, sensors, and other novel nanodevices. The interface of TiO2 with water, historically well-studied but still poorly understood, presents a ubiquitous environmental challenge towards the ultimate practical usefulness of these technologies. Ground-state density functional theory (DFT) calculations studying the characteristics of molecular adsorption on model surfaces have been studied for decades, showing constant improvement in the description of the energetics and electronic structure at interfaces. These simulations are invaluable in the …
Zn(Ii) And Cu(Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Zn(Ii) And Cu(Ii) Adsorption And Retention Onto Iron Oxyhydroxide Nanoparticles: Effects Of Particle Aggregation And Salinity, Rebecca B. Chesne, Christopher S. Kim
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Background: Iron oxyhydroxides are commonly found in natural aqueous systems as nanoscale particles, where they can act as effective sorbents for dissolved metals due to their natural surface reactivity, small size and high surface area. These properties make nanoscale iron oxyhydroxides a relevant option for the remediation of water supplies contaminated with dissolved metals. However, natural geochemical processes, such as changes in ionic strength, pH, and temperature, can cause these particles to aggregate, thus affecting their sorption capabilities and remediation potential. Other environmental parameters such as increasing salinity may also impact metal retention, e. g. when particles are transported …
Immobilized Metal Ion Affinity Nanospheres For \Alpha-Amylase Immobilization, Tülden Kalburcu, Müni̇re Nalan Tüzmen, Si̇nan Akgöl, Adi̇l Deni̇zli̇
Immobilized Metal Ion Affinity Nanospheres For \Alpha-Amylase Immobilization, Tülden Kalburcu, Müni̇re Nalan Tüzmen, Si̇nan Akgöl, Adi̇l Deni̇zli̇
Turkish Journal of Chemistry
Immobilized metal chelate affinity chromatography (IMAC) support was practiced for \alpha-amylase immobilization. Poly(hydroxyethylmethacrylate-methacryloylamidotryptophan)-Ni^{2+} [p(HEMA-MAT)-Ni^{2+}] nanospheres, average diameter 100 nm, were produced by surfactant free emulsion polymerization. Characterizations of p(HEMA-MAT)-Ni^{2+} nanospheres were carried out by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). In addition, average particle size, size distribution, and surface charge were specified. The amount of N-methacryloylamidotryptophan (MAT) incorporated to polymer was determined as 1.95 mmol/g polymers by using nitrogen stoichiometry. The specific surface areas of poly(hydroxyethylmethacrylate) [p(HEMA)] and p(HEMA-MAT) nanospheres were calculated as 1856 m^2/g and 1914 m^2/g, respectively. Protein adsorption increased with increasing initial protein …
Adsorption Of The Urea Molecule On The B_{12}N_{12} Nanocage, Mohammad Taghi Baei
Adsorption Of The Urea Molecule On The B_{12}N_{12} Nanocage, Mohammad Taghi Baei
Turkish Journal of Chemistry
The adsorption of the urea molecule on the external surface of the B_{12}N_{12} nanocage was investigated using density functional theory (DFT) calculations. Adsorption of urea on the nanocage releases energies of about --23.70 to --29.50 kcal/mol with a significant NBO charge transfer from the urea to the nanocage. It was also found that the urea molecule can be strongly chemisorbed on the surface of the nanocage with Gibbs free energies of -7.91 to -14.81 kcal/mol. The HOMO--LUMO gap of the nanocage does not change significantly upon urea adsorption, while the Fermi level is dramatically changed from -4.27 eV in the …
Fluctuations In Transient Response Of Adsorption-Based Plasmonic Sensors, Zeljko D. Cupic
Fluctuations In Transient Response Of Adsorption-Based Plasmonic Sensors, Zeljko D. Cupic
Zeljko D Cupic
The basic parameters of a sensor element defining its ultimate performance are sensitivity and intrinsic noise. In plasmonic gas sensors both are determined by refractive index changes due to adsorption and desorption (a–d) of target analyte particles to the sensor active area. In this paper we present a general model that can be simultaneously used to determine sensitivity and intrinsic noise of a plasmonic sensor both during transients and in steady-state and is valid for multi-analyte environments. The model utilizes the conventional probabilistic approach. It is derived without any assumptions about the stochastic nature of the fundamental (a–d) process. It …