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2022

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Articles 61 - 65 of 65

Full-Text Articles in Chemistry

Calcite Depression In Bastnaesite-Calcite Flotation System Using Organic Acids, Emmy Muhoza Jan 2022

Calcite Depression In Bastnaesite-Calcite Flotation System Using Organic Acids, Emmy Muhoza

Graduate Theses, Dissertations, and Problem Reports

Bastnaesite is the primary source of light REEs, namely cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), to name a few. Bastnaesite is typically concentrated using the froth flotation beneficiation method. Flotation of bastnaesite suffers from high reagent consumption due to the similar surface characteristics of bastnaesite and associated gangue minerals, including calcite. Additionally, complex stages of high-temperature conditioning are often required to suppress the detrimental impact of dissolved calcium ions on the flotation of bastnaesite. This research seeks to investigate the capabilities of organic acids in the bastnaesite-calcite flotation systems to selectively depress calcite minerals and effectively chelate calcium …


Scale-Up Of Flow-Electrode Capacitive Deionization Method For Hard Water Softening, Noah Henry Jan 2022

Scale-Up Of Flow-Electrode Capacitive Deionization Method For Hard Water Softening, Noah Henry

Williams Honors College, Honors Research Projects

This study’s purpose is to further document a capacitive deionization design that could be capable of purifying H2O at a household scale where clean water is otherwise unobtainable in applicable regions of the world. The hypothesis behind this study was continuously larger scaled electrochemical cell-units would increase their water softening capabilities in sustainable fashion. The trend at which performance will scale is currently unknown. The units studied were constructed using graphite plates, anion exchange membranes, cation exchange membranes, and Teflon channels. Three streams, two being CaCl2 solutions in DI H2O (one being concentrated with CaCl …


Reinforcement Of Elastomers By Reactive Ionic Surfactant, Nicole Vickerman Jan 2022

Reinforcement Of Elastomers By Reactive Ionic Surfactant, Nicole Vickerman

Williams Honors College, Honors Research Projects

Elastomers without cross-linking agents or fillers do not have the necessary properties for practical applications in the rubber industry. Elastomers must be reinforced with fillers and/or cross-linking agents to achieve the needs of physical and mechanical properties for commercial products. Sodium octyl 6-mercaptohexyl phosphate (SOMP) and sodium ethyl (6-mercaptohexyl) phosphate (SEMP) were used to investigate the influence of a reactive ionic surfactant and its influence on the physical properties of peroxide crosslinked styrene butadiene rubber (SBR). SEMP and SOMP were both found to be able to be grafted successfully on to the SBR chains within the rubber using extraction testing …


A Local Mode Study Of Ring Puckering Effects In The Infrared Spectra Of Cyclopentane, Edwin L. Sibert Iii, Peter F. Bernath Jan 2022

A Local Mode Study Of Ring Puckering Effects In The Infrared Spectra Of Cyclopentane, Edwin L. Sibert Iii, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

We report and interpret recently recorded high-resolution infrared spectra for the fundamentals of the CH2 scissors and CH stretches of gas phase cyclopentane at −26.1 and −50 C, respectively. We extend previous theoretical studies of this molecule, which is known to undergo barrierless pseudorotation due to ring puckering, by constructing local mode Hamiltonians of the stretching and scissor vibrations for which the frequencies, couplings, and linear dipoles are calculated as functions of the pseudorotation angle using B3LYP/6-311++(d,p) and MP2/cc-pVTZ levels of theory. Symmetrization (D5h) of the vibrational basis sets leads to simple vibration/pseudorotation Hamiltonians whose solutions …


Efficient Removal Of Lead Ions From Aqueous Media Using Sustainable Sources On Marine Algae, Hannah Namkoong, Erik Biehler, Gon Namkoong, Tarek M. Abdel-Fattah Jan 2022

Efficient Removal Of Lead Ions From Aqueous Media Using Sustainable Sources On Marine Algae, Hannah Namkoong, Erik Biehler, Gon Namkoong, Tarek M. Abdel-Fattah

Electrical & Computer Engineering Faculty Publications

The goal of this project is to explore a new method to efficiently remove Pb(II) ions from water by processing Undaria pinnatifida into immobilized beads using sodium alginate and calcium chloride. The resulting biosorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). Using immobilized U. pinnatifida, we investigated the effect of various factors on Pb(II) ion removal efficiency such as temperature, pH, ionic strength, time, and underlying biosorption mechanisms. For Pb(II) ion biosorption studies, Pb(II) ion biosorption data were obtained and analyzed using Langmuir and Freundlich adsorption models. It …